Ing. Cubelac Erica Teză de doctorat - USAMV ClujIng. Cubelac Erica Teză de doctorat 2 Introduction...

Ing. Cubelac Erica Teză de doctorat

UNIVERSITY of AGRICULTURAL SCIENCES AND VETERINARY MEDICINE of CLUJ NAPOCA

PhD SCHOOL FACULTY OF AGRICULTURAL SCIENCES

Eng. BULUCZ ERICA (CUBELAC)

PHD THESIS ABSTRACT

IMPROVING THE PRODUCTION TECHNOLOGY OF SEED POTATO IN THE SINTEU CLOSED MICRO AREA – BIHOR COUNTY

SCIENTIFIC COORDINATOR PROFFESOR PhD Eng. MORAR GAVRILĂ,

2011


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Introduction

The production and the multiplication of seed potato in Romania, in recent decades is

passing through a difficult period for cultivated areas and for quality of potato produced in traditional closed areas. The causes are many and well known such as non rotanding four-years, the distance of the containment and control measures of vector virus diseases, which is the main factor in the degeneration of potato. One of the measures required and accepted by all the responsible factors could be production of higher links to biological category Base, Elite class in the former territory of closed areas and their multiplication, Certificates biological categories, Classes A and B outside the traditional closed areas. In this way they could more accurately meet the four-year rotation, isolation distances, framing works in the best period.

Thus, for relieving the traditional closed areas of seed potato production of below biological links (Class A Certified and Class B Certified), would be necessary in counties with mountainous area, where climatic and orographic conditions allow, must be established microzone of multiplication of seed potato.

Such microzone was identified in Bihor County, where the natural conditions of isolation in space, climatic conditions similar to those in closed areas, may become a potential multiplication area of seed potato of lower generation.

This doctoral thesis on the topic “IMPROVEMENT OF PRODUCTION TECHNOLOGY OF SEED POTATO IN SINTEU CLOSED MICROZONE FROM BIHOR COUNTY”, aimed at identifying key of principals technological links of the production of seed potato that determine or influence in determining production and seed quality obtained in this closed microzone.

Research undertaken has been made in Sinteu microzone, located in the Plopis Mountains, where they approached the main determinants of obtaining a quality potato seeds:

- Study of soil conditions, orographic and climate of the area and comparing them with those in traditional closed areas;

- Study the number and species of aphid vectors of viruses identified in Sinteu microzone and comparing them with those from closed area of Brasov;

- Suitability of varieties, the influence of seed size and density planting on seed potato quality;

- Influence of vegetation on the prevention and disruption spread with serious viral infections ( Potato leaf roll virus and virus Y of potato leaf) on potato seed multiplication;

- Influence of storage conditions on potato degeneration (sprouting capacity and output). Since the development of this thesis could not be achieved only through my own

contribution, I wish to thank in this way all those who contributed in one way or another to prepare this thesis.

Author


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CHAPTER I

Potato: Importance, Usage, Evolution of areas and distribution

The chapter includes general information on potato crop, the economic and social

importance, areas development areas and productions achieved on worldwide and in our country during 1990-2007.

Also, there are presented the uses of potato as a food-consumption per capita and as animal feed feed, such as the role and importance of production and multiplication of potato for seed.

CHAPTER II

THE PRESENT LEVEL OF RESEARCHES IN CONTROL AND CULTIVATION TECHNOLOGY FOR PRODUCING AND MULTIPLICATION PLANTING POTATO

MATERIAL

Chapter deals with the theoretical foundations of production and multiplication of seed potato, with reference to the concept of degeneration of potato and the influence factors. There are presented in detail the virus degeneration of potato and physiological degeneration.

It also, deals with different methods and schemes of seed potato production, which are used worldwide and in our country, from classical methods to those used today. Original methods of potato seed production were the Dutch and German, from which have evolved the national system existing currently in major producing countries.

Also in this section is treated in detail the specific cultivation technology of seed culture.

CHAPTER III THE RESEARCH AIMS AND GOALS, MATERIAL

AND RESEARCH METHOD

RESEARCH GOAL

a) Identifying the main technological methods for producing the potato-seed, which determine or decisively influence the production and quality of the seed, obtained in the closes Sinteu closed microzone.

b) Planting density closely related to the size of the material used in the field. There have been studied 3 densities: 60.000, 70.000 and 80.000 tubers per hectare, within three sizes: 45-55mm; 35-45mm; 25-35mm.

c) Establishing the infection degree with viruses and the transmission pattern to the seeds, one of the main targets also included the possibility of suspending the growth at about 70 days since the springing, for the Elite category, for four species of the most important Romanian varieties.

d) Study of the influence of storage conditions on production, a concept in which seed material was kept under optimum conditions in the latter case where the buds were torn twice before planting.


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RESEARCH OBJECTIVES

- Obtaining a seeding material with the less virus infection as possible, suitable for certification for different biological categories which can be grown in the closed microzone of Sinteu (Elite Class Base, Class A and B Certified).

- Testing the most valuable Romanian varieties, created at Brasov, Targu-Secuiesc and Miercurea Ciuc, to cut down the quantity of the imported seeds and better capitalization of the Romanian creations, better adapted to the climatic conditions in our country and under scientifically more rigorously tests for the approval of production in our country.

- Physiological degeneration caused by conditions less favourable for potato storage was another goal which was to our attention; inadequate requirements of storage space may result in impairment of potential production of potato due to this phenomenon.

METHOD OF RESEARCH ORGANIZATION

The research was made between 2004 and 2006 in the Sinteu microzone of Bihor County,

based on three experiments in which they approached the main determinants of obtaining quality of potato seed.

Experiment no 1. Influence of variety, seed size and planting density on seed potato quality. Factors and graduation were as follows: THE A FACTOR- the experimental year with three graduations:

a1 - 2004 a2 - 2005 a3 - 2006

THE B FACTOR- the size of seed potato used for planting, with three graduations: B1 - 45-55 mm B2 - 35-45 mm B3 - 25-35 mm

The C Factor- planting density, with three graduations: c1 - 60.000 tubers per hectare c2 - 70.000 tubers per hectare

c3 - 80.000 tubers per hectare The whole experience was repeated on three potato varieties:

- Rozalia - Redsec

- Amelia Experiment no 2. Influence of vegetation disruption on prevention and spread of serious main viral

infections (potato leaf roll virus and virus Y of potato leaf). The experience was made considering three factors of the type 3x4x2 observing the following factors and graduations:


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THE A FACTOR - the experimental year: a1 - 2004 a2 - 2005 a3 – 2006

THE B FACTOR - potato variety with graduations: b1 - Siculus b2 - Rozalia b3 - Nemere b4 - Dumbrava The C factor - the interruption of vegetation: c1 - Continuous vegetation c2 - Discontinued vegetation about 70 days since springing. Number of repetitions - 4.

Experiment no 3. The influence of the storage conditions upon the germination and production

capabilities for a range of six potato varieties, with the next factors and graduations: THE A FACTOR - the experimental year: a1 - 2004 a2 - 2005 a3 - 2006 THE B FACTOR - the potato variety, with the next graduations: b1 - Amelia b2 - Eterna b3 - Dacia b4 - Redsec b5 - Productiv b6 - Rozalia THE C FACTOR - storage conditions: c1 - Best conditions c2 - Sub-optimal conditions, breaking the thorns twice For every experience were considered parcels with size about 10 sqm., using classical

technology with 70 cm between rows and 24 cm between tubers in turn, resulting in a density of 60,000 nests per hectare, except of course variants with different densities.

Fertilization experience was made using complex fertilizers, type 15:15:15, dose of 800 kg /ha, applied simultaneously with planting.

The planting process was made strictly using the right planting technology, all works being made in optimal conditions and in time, with a very strict control for the Colorado beetle and potato manna.

For every experience were made phonological observations, concerning the main stages of vegetation and at the harvest it was determined the overall tubers production, the overall crop of seed, the number and the mass of tubers divided in fractions of seed: 25 - 35mm, 35 - 45mm, 45 - 55mm and overall 25-55mm.

Calculation and interpretation of results were performed by the method of variance analysis with three factors, for the tri-factorial experiment, completely randomized.


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The significance of differences was assessed by Student test (difference threshold) and after multiple comparison test (Duncan).

BIOLOGICAL MATERIAL USED Varieties tested in the range 2004-2006 are part of the national range of potato varieties

entered in the official List of varieties (hybrids), plants grown in Romania, between 2001 and 2005.

The initial biological material, used in the experiments, was brought from closed seed-potato production areas: Miercurea-Ciuc, Targu Secuiesc and Brasov, respectively SCDC Miercurea Ciuc, SCDC Targu-Secuiesc and INCDCSZ Brasov.

CHAPTER IV RESULTS REGARDING

THE STUDY OF GEOGRAPHICAL AND PEDOCLIMATIC CONDITIONS AND THE LEVEL OF ACCOMPLISHMENT FOR POTATO REQUESTS TOWARDS CLIME AND SOIL IN MICRO ZONE ŞINTEU , BIHOR COUNTY

In Bihor county, a micro area in the perimeter of Sinteu village, which through his

geographical position, space isolation, pedological and climatic conditions could become a micro area breading seed potato. Extends over an area of 40 km, Sinteu village is situated in the northern part of Western Carpathian Mountains at an altitude of 615 m. Sinteu village is situated on 47° 08'

Image from Sinteu

north latitude and 22° 30' east latitude. Space isolation from sources of infection with aphids, it’s made by large surfaces of

natural pastures and forests with a width of 5-10 km. Isolation is made by forests and large surfaces of natural pastures.

In Plopisului Mountains, where Sinteu is situated, the annual average temperatures is low, reaching 7-8 C degree, summers are chilly and there is lot of snow in winter time.

Precipitations reach values of 700-800 mm, air humidity is high. In Sinteu area the wind is always blowing.If the wind is blowing with over 2 m/s aphids can’t fly.

In general the soil profile is thin ( 0-30 cm ) with a lot of humus which makes it more acid. The predominant soil is podsol argillaceous-iluvial (luvosol) with an easy texture and acid


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reaction pH (4-5). The map of Sinteu area – original All factors as, humidity, temperature and soil are meet here. One of the most important

element that makes an area good for potato are the average temperatures of warmest month, July, in this area. July don’t pass 20 C degree in this area, only in two out of 10 years.

Value of the annual average temperatures is 8.2 C degree, it’s a chilly climate good for potato. Comparing annual average temperatures, daily average temperatures from the growing sinteu micro area has suitable temperatures for potato culture.

Table 4.3

The temperatures registered in the micro zone Şinteu, Bihor County, compared to the traditional closed areas for the production of seed potatoes

Weather Station Zece Hotare

*after MAN and colab. 1969

** Source – DirecŃia Apelor Criş – Oradea jud. Bihor

*** Source INMH Bucureşti, CMR Banat – Crişana

In Sinteu area, temperatures of over 25 C degree happen rarely and with the wind blowing, infections chances with viroses are low.Potatoes have big demands towards water, they need a constant supply of water, differentiated on growing stage.

Water consumption differentiated on growing stages compared to rain level in Sinteu, is almost enough for potato growing. ( Table 4.10 )

Traditionally closed areas Climatic elements Râşnov Hărman Suceava Ciuc

M.z ** Huedin

M.z.*** Şinteu

Annual average temperature (°C)

7,8 7,5 7,8 5,6 7,2 8,2

Daily average temperatures for months

VI,VII,VIII (°C)

17,0 17,2 18,0 16,0 17,1 17,5

Average temperature In the warmest mounth

July (°C)

17,8 18,0 19,0 16,7 23,3 18,3


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Figure 4.4 Number of days with temperatures higher than 25 °C

Table 4.10

The consumption of water mm/day, differentiated on vegetation phases Source G.MORAR 1999

Nr, Crt.

Vegetation phase Number of days/vegetation

phases

Required water consumption

mm/day

Precipitation amount in Şinteu

mm/day

1 Planting - sprouting 33 1,6 – 1,8 2,1 2 Sprouting – budding 35 1,8 – 3,5 2,7 3 Budding – blossom 28 3,0 – 3,5 2,4 4 Blossom - maturation 91 5,0 – 7,0 6,7

Yearly average of multi annual precipitation sum from June, July, August and the number

of days with precipitation over 0.1 mm, realized in Sinteu micro area makes this area suitable to grow potatoes.( Table 4.13)

Table 4.13

The analysis of the precipitation in the micro area of Şinteu, Bihor County compared to the traditionally closed areas for producing seed potato tubers

Source – G.MORAR - 1999

Traditionally closed areas

Climatic elements

Râşnov Hărman Suceava Ciuc

M.z.** Huedin

M.z.*** Şinteu

Rainfalls multi annual average (mm)

726,5 610,0 625,0 540,0 604,4 724,6

Rainfalls average in june,july,august

327,0 277,1 268,0 236,5 245,7 223,4

Average number of days with rainfalls over 0,1 mm in june-july

28,7 29,2 20,5 25,9 19,0 20,6

* after MAN şi colab. 1969 ** Source – DirecŃia Apelor Criş – Oradea jud.Bihor *** Source INMH Bucureşti, CMR Banat Crişana


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CHAPTER V THE STUDY OF INFECTIONS SOURCES WITH VIRUSES

AND VIRAL VECTOR In comparison that it is wanted to be done between the experimental fields from INCDSZ

Braşov in the Râşnov closed area and Şinteu micro yone from Bihor county regarding the captured aphids situation, the data are as following:

Table 5.1

The number of aphides captured on the experimental fields Braşov and Şinteu within 2004 – 2006

From the total of captred aphids in the year 2004 in Braşov experimental field, 75% (715

aphids) have been virus vectors, comparing with the experimental field from the locality of Şinteu where just 56% (381 aphids) were virus carriers.In the year 2005, the aphids percentage that carry potato viruses is dropping significantly to 35% ( 89 aphids) in Braşov experimental field and to 33% (71 aphids) in Şinteu experimental field.

The percentage of virus vector aphids is increasing in the year 2006 to 65% (568 aphids) in Brasov experimental field and to 54% ( 55 aphids) in Şinteu experimental field. The number of identified species is modifying insignificantly along the three study years (2004-2006), being between 38-46 in Brasov experimental field and between 22-41 in Şinteu experimental field. From the total amount of identified aphids species in the potato culture, only nine species are potato virus vectors ( Aphis fabae, Aphis frangulae, Aphis nasturtii, Aulacorthum solani,

Brachyardus helichrysi, Macrosiphum euphorbia, Myzus persicae, Phorodon humuli,

Rhopalosiphum padi ). Analyzing the virus vector species along the three study years in Şinteu experimental

field, it has been noticed tht in the year 2004 is the greatest individual abundance, in the year 2005, the individuals number from the species Aphis fabae, Aphis frangulae and Rhopalosiphum

padi are decreasing. A comparative analysis of virus vector species for the three years taken in the study (table

5.5) in the Sinteu experimental field, shows that in 2004 is the greatest abundance of individuals, in 2005 the number of individuals of the species Aphis faba, Aphis and Rhopalosiphum frangulae

padi fall sharply, and in 2006 the number of individuals of the listed species slightly decreases.

2004 2005 2006 Specifications Braşov Şinteu Braşov Şinteu Braşov Şinteu

Total aphids captured 941 681 252 216 877 101 Aphids viruses vectors 715 381 89 71 568 55


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Table 5.5 The main viruses vector species on the experimental fields Şinteu and Braşov,

during 2004 - 2006

2004 2005 2006 Species

Brasov Sinteu Brasov Sinteu Brasov Sinteu

Aphis fabae 569 233 61 44 33 32

Aphis frangulae 91 85 10 19 129 18

Aphis nasturtii 5 4 7 3 12 1

Aulacorthum solani 0 0 0 0 0 0

Brachycaudus helichrysi 9 12 1 1 4 1

Macrosiphum euphorbiae 2 5 1 1 0 0

Mysus persicae 3 3 0 0 2 0

Phorodon humuli 28 4 5 1 80 3

Rhopalosiphum padi 8 35 4 2 4 0

The comparison between the nine species of potato vector virus, reveals that during 2004

to 2006, species of aphids Myzuz persicae, as the main vector for viruses, is found in very low numbers in the studied group of potato (three individuals captured), both in Sinteu as well as in INCDCSZ Brasov in 2004; are missing from the experimental field Sinteu and Brasov in 2005, and in 2006 appears only in the experimental field of Brasov in number of two copies.

The number of captured individuals of the species Aphis Frangulae changes significantly from year to year; the less individuals (10) were captured in 2005 in the experimental field Brasov, and the most(129) in 2006 again in the experimental field Brasov.

In both localities in the three years studied, the species of aphids Aphis nasturtii were caught between 1-12 individuals.

The species of Aulacortum solana was not identified in any of the localities studied in all years of research.

Of all the vector species of potato virus, the Aphis fabae specie has the greatest number of individuals captured in all years of study, between 32 in 2006 in the experimental field of Sinteu and 569 individuals in the experimental field Brasov in 2004.

Other species of aphids that transmit viruses within potato plants, captured in Sinteu and in Brasov, but occur accidentally in potato crop are: Brachycadus helichrysi specie with a number between 1-12 individuals, Phorodon humuli specie with a number between 1-80 individuals and Padi Rhorodon with a number between 2-35 individuals.


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CHAPTER VI EXPERIMENTAL RESULTS ON THE PRODUCTION

AND THE MULTIPLICATION OF POTATO SEED IN THE MICROZONE SINTEU OF BIHOR COUNTY

6.1. INFLUENCE OF VARIETY, SEED SIZE AND PLANTING DENSITY ON THE PRODUCTION AND QUALITY OF POTATO SEED PRODUCED IN MICRORZONE SINTEU OF BIHOR COUNTY

6.1.1.2. Influence of seed size on total seed production Total seed production of the three varieties oscillates between 17-18 t / ha, a reasonable level of total seed production (Table 6.2).

By planting the tubers of various sizes we find no significant difference between the large size (45-55 mm) and the seed medium size (35-45 mm). This means that the medium size seed breeding is much more economical, having regard to the rule used in breeding, when the same production is obtained. If the Redsec variety production from large and medium seed fraction is virtually equal, for Rozal and Amelia varieties the total seed amount is even lower at higher fraction than middle fraction, a result highlighted by Duncan test (see Table 6.2).

Small fraction of seed used for breeding carried out between 81 and 90 % of the seed medium fraction, which is considered worthy of a wider economic calculation. Results express the total seed production levels for an average density of 60.000 plants/ha. But differentiated in terms of size interaction x, the production density, they reflect details worthy of consideration.

Table 6.2 The influence of seed size on total seed production

Variety Planted

seed size Yield t/ha

Percentage

Difference t/ha

Significance Duncan classification

LSD

45-55 17,97 98,9 -0,20 - B 35-45 18,17 100 0 Mt. A

Rozal

25-35 16,25 89,9 -1,91 000 C

LSD( p 5%) 0,19 LSD (p 1%) 0,26 LSD (p 0,1%) 0,36

45-55 18,54 100 0,03 - B 35-45 18,51 100 0 Mt. B

Redsec

25-35 15,35 82,9 -3,16 000 A

LSD( p 5%) 0,25 LSD (p 1%) 0,35 LSD (p 0,1%) 0,47

45-55 17,48 98,1 -0,34 0 B 35-45 17,81 100 0 Mt. A

Amelia

25-35 14,59 81,9 -3,22 000 C

LSD( p 5%) 0,25 LSD (p 1%) 0,35 LSD (p 0,1%) 0,47


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6.1.1.3. The influence of planting density on total seed production

The average planted fractions of calibration, the analyzed densities confirm clearly the role of this technological measure in achieving a high yield of seed potato. In all the three studied species we find very significant germs of the total seed production by increasing the density from 60.000 to 80.000 plants per hectare (see Table 6.3). Moreover, there could be (by extrapolation) a reserve for increasing the total production of seed and over 80.000 plants / ha density, but we can not make this statement as we have not experienced it. The fact is that most of the total seed production to achieve has a density of 80.000 plants per hectare, well statistically assured, both by Student test and the Duncan test, all varieties averaged over three experimental years (see Table 6.3).

Table 6.3 The influence of planting density on total seed production

6.1.1.5. The total production of seed 25-55 mm obtained in the variety interaction x

density x size of seed planting

Following the average seed production obtained from the three size fractions, namely

large, medium and low; in the three densities we notice a very significant increase in production with a growth of planting density in the three varieties (Table 6.5).

From this point of view, the constant increase in variety is seen in Amelia, where production increases by approx. 5% for 70.000 plants density for all three size fractions, namely 116-117% at a density of 80.000 plants compared with the evidence.

Rozal variety shows the greatest growth, as Duncan test also expresses for the fraction 45-55 mm at a density of 80.000 plants / ha, increasing by 3.43 tons, compared with 20.9% from the evidence. Both at the middle fraction and the small fraction, the increase of seed production for a density of 80.000 plants/ ha exceeded 2 tonnes / ha production gain.

Compared to previous varieties, the Redsec variety distinguishes through increasing production at 25-35 mm fraction, increased production of seed density of 80.000 plants / ha more than 3 tons, and 23% (Table 6.5). Production increases in the other two fractions have

Variety Density/ha Yields t/ha

% Percentage

Difference t/ha

Significance

Duncan classification

LSD

60.000 16,13 100 0 Mt. A 70.000 17,44 108,1 1,30 *** B

Rozal

80.000 18,82 116,6 2,68 *** C

LSD( p 5%) 0,22 LSD (p 1%) 0,29 LSD (p 0,1%) 0,38

60.000 16,31 100 0 Mt. A 70.000 17,20 105,5 0,89 *** B

Redsec

80.000 18,89 115,8 2,57 *** C

LSD P 5%) 0,22 LSD (p 1%) 0,29 LSD (p 0,1%) 0,38

60.000 15,50 100 0 Mt. A 70.000 16,32 105,3 0,82 *** B

Amelia

80.000 18,06 116,5 2,56 *** C

LSD( p 5%) 0,20 SDL (p 1%) 0,27 LSD (p 0,1%) 0,35


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approximately equal growth of over 4% to 70.000 plants, respectively, 112.9% at a density of 80.000 to 60.000 plants from density taken as evidence.

In conclusion, there is a close relationship between the average yield of seed and planting density seen in the gradual increase of the seed tubers production with an increasing density, up to 80.000 plants per hectare. It should be noted that seed fraction of 25-35 mm, considered small fraction is not negligible and can be used for planting with the same success as the larger fractions, provided that they are a biological category with production potential.

Table 6.5.

Total seed production between 25 – 55 mm obtained depending by planting density and seed size

Variety Planted seed size

Density/ha Yields t/ha

% Percentage

Difference t/ha


60.000 16,35 100 0 Mt. B 70.000 17,78 108,7 1,42 *** D

45 - 55

80.000 19,78 120,9 3,43 *** E 60.000 17,06 100 0 Mt. C 70.000 17,87 104,8 0,82 *** D

35 – 45

80.000 19,57 114,8 2,52 *** E 60.000 15,00 100 0 Mt. A 70.000 16,67 111,1 1,67 *** B

Rozal

25 – 35

80.000 17,10 114,0 2,10 *** C 60.000 17,53 100 0 Mt. D 70.000 18,30 104,4 0,77 *** E

45 – 55

80.000 19,79 112,9 2,26 *** F 60.000 17,51 100 0 Mt. D 70.000 18,26 104,3 0,75 *** E

35 – 45

80.000 19,76 112,9 2,25 *** F 60.000 13,90 100 0 Mt. A 70.000 15,05 108,3 1,16 *** B

Redsec

25 – 35 80.000 17,10 123,1 3,21 *** C 60.000 16,28 100 0 Mt. D 70.000 17,18 105,6 0,91 *** F

45 – 55

80.000 18,98 116,6 2,70 *** G 60.000 16,66 100 0 Mt. E 70.000 17,46 104,8 0,81 *** F

35 – 45

80.000 19,32 116,0 2,66 *** G 60.000 13,57 100 0 Mt. A 70.000 14,32 105,5 0,75 *** B

Amelia

25 - 34

80.000 15,89 117,2 2,33 *** C LSD(p5%) 0,38 LSD (p 1%) 0,51 LSD (p 0,1%) 0,66

6.1.2.4. Production ratio of 45-55 mm seed obtained in the interaction variety x biological

category x planting density x during 2004-2006.


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Seed production in the fraction of 45-55 mm obtained during the three years 2004, 2005 and 2006 corresponding to the transition from biological category Base SuperElit to Class A Certified is closely correlated with planting density, thus high biological category seed production corresponding to 2004 depends not so much on planting density. In all tested varieties when Base SuperElit seed potatoes is used, seed production ratio of 45-55 mm is almost equal between densities 60.000 and 80.000 plants/ ha (Table 6.9). In other words, the potential for a greater production of a superior biological category is also shown in the production of seed (45-55 mm) and is virtually equal between 60 and 80 thousand plants per hectare, but at a lower-class biological variety the solution for a greater seed production remains a large density increase at least 80.000 plants per hectare. At this density, significant differences for all varieties are obtained. The role of planting density increases as the biological category decreases.

Table 6.9

Seed production from size 45 – 55 mm obtained in variety interaction x biological category x planting density in years 2004 – 2006.

Variety Years Density/ ha

Yields t/ha

Percentage Difference t/ha

Significance


LSD

60.000 7,77 100 0 Mt. BC 70.000 7,68 98,9 -0,09 - B

2004

80.000 8,11 104,3 0,34 - C 60.000 7,84 100 0 Mt. BC 70.000 8,03 102,3 0,18 - BC

2005

80.000 9,64 122,9 1,80 *** D 60.000 7,13 100 0 Mt. A 70.000 7,70 108,1 0,58 ** BC

Rozal

2006

80.000 7,66 107,5 0,54 ** B

LSD( p 5%) 0,37 LSD (p 1%) 0,49 LSD (p 0,1%) 0,64

60.000 7,03 100,0 0 Mt. BC 70.000 7,26 103,3 0,23 - CD

2004

80.000 7,11 101,2 0,09 - BCD 60.000 7,25 100 0 Mt. CD 70.000 7,48 103,2 0,23 - D

2005

80.000 7,28 100,4 0,03 - CD 60.000 6,15 100 0 Mt. A 70.000 6,89 112,0 0,73 *** BC

Redsec

2006

80.000 6,80 110,6 0,65 *** B

LSD( p 5%) 0,36 LSD (p 1%) 0,47 LSD (p 0,1%) 0,62

60.000 7,38 100 0 Mt. AB 70.000 7,22 97,8 -0,16 - A

2004

80.000 7,35 99,6 -0,3 - AB 60.000 7,49 100 0 Mt. AB 70.000 7,32 97,8 -0,17 - AB

2005

80.000 7,27 97,1 -0,22 - A 60.000 7,29 100 0 Mt. AB 70.000 7,50 102,8 0,20 - AB

Amelia

2006

80.000 7,60 104,2 0,31 * B

LSD( p 5%) 0,27 LSD (p 1%) 0,36 LSD (p 0,1%) 0,47


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6.1.3.4. Production of seed of 35-45 mm fraction obtained according to the planting

density , biological category and studied potato variety.

Results on seed production from the ratio of 35-45 mm obtained depending on the planting density, the biological category and the studied potato variety confirm the results of fraction 45-55 mm and show the important role of high density of 80.000 plants / ha in obtaining high seed production and the fact that as the biological category decreases, density contribution increases in achieving the production of all tested varieties (see Table 6.14)

Table 6.14 The seed production from size 35-45 mm obtained depending by planting density, biological

category and potato variety studied.

Variety

Year Density/ ha

Yields t/ha

% Percentage

Difference t/ha

Significance


LSD

60.000 7,77 100 0 Mt. BC 70.000 7,68 98,9 -0,09 - B

2004

80.000 8,11 104,3 0,34 - C 60.000 7,84 100 0 Mt. BC 70.000 8,03 102,3 0,18 - BC

2005

80.000 9,64 122,9 1,80 *** D 60.000 7,13 100 0 Mt. A 70.000 7,70 108,1 0,58 ** BC

Rozal

2006

80.000 7,66 107,5 0,54 ** B

LSD( P 5%) 0,37 LSD (p 1%) 0,49 LSD (p 0,1%) 0,67

60.000 8,82 100 0 Mt. E 70.000 9,11 103,4 0,30 * F

2004

80.000 9,64 109,3 0,82 *** G 60.000 7,17 100 0 Mt. C 70.000 7,31 102,0 0,14 - C

2005

80.000 7,79 108,6 0,62 *** D 60.000 4,82 100 0 Mt. A 70.000 4,82 100,1 0,01 - A

Redsec

2006

80.000 5,79 120,2 0,97 *** B

LSD P 5%) 0,30 LSD (p 1%) 0,40 LSD (p 0,1%) 0,51

60.000 7,54 100 0 Mt. C 70.000 7,67 101,8 0,13 - C

2004

80.000 9,06 120,2 1,52 *** D 60.000 5,48 100 0 Mt. A 70.000 6,17 112,6 0,69 *** B

2005

80.000 7,57 138,3 2,10 *** C 60.000 5,97 100 0 Mt. B 70.000 5,27 88,3 -0,70 000 A

Amelia

2006

80.000 6,24 104,5 0,27 - B

LSD P 5%) 0,29 LSD (p 1%) 0,38 LSD (p 0,1%) 0,50


16

6.1.4.3. Production of seed size of 25-35 mm obtained according to the density of

planting, biological category and studied potato variety.

Planting density plays a very important role in obtaining 25-35 mm seed category. High seed yields of this fraction are obtained for all varieties, by planting densities of 70.000 and 80.000 plants/ ha (see Table 6.19).

Table 6.19 The seed production from size 25-35 mm depending by planting density

in years 2004-2006 at the three varieties

Variety

Years

Density/ ha

Yields t/ha

% Percentage

Difference t/ha

Significance


LSD

60.000 3,47 100 0 Mt. D 70.000 3,70 106,5 0,23 * E

2004

80.000 4,13 119,0 0,66 *** F 60.000 2,72 100 0 Mt. C 70.000 3,46 127,3 0,74 *** D

2005

80.000 3,35 123,2 0,63 *** D 60.000 1,81 100 0 Mt. A 70.000 1,90 105,3 0,09 - A

Rozal

2006

80.000 2,31 127,6 0,50 *** B

LSD P 5%) 0,17 LSD (p 1%) 0,23 LSD (p 0,1%) 0,30

60.000 3,37 100 0 Mt. E 70.000 3,93 116,5 0,55 *** F

2004

80.000 4,43 131,3 1,06 *** H 60.000 2,70 100 0 Mt. C 70.000 3,04 112,7 0,34 *** D

2005

80.000 4,16 154,5 1,47 *** G 60.000 1,58 100 0 Mt. A 70.000 1,60 101,3 0,02 - A

Redsec

2006

80.000 2,27 143,3 0,68 *** B

LSD P 5%) 0,20 LSD (p 1%) 0,26 LSD (p 0,1%) 0,34

60.000 3,07 100 0 Mt. E 70.000 3,58 116,6 0,51 *** G

2004

80.000 3,91 127,3 0,84 *** H 60.000 2,10 100 0 Mt. C 70.000 2,82 134,6 0,73 *** D

2005

80.000 3,44 164,2 1,35 *** F 60.000 1,34 100 0 Mt. A 70.000 1,42 106,0 0,08 - A

Amelia

2006

80.000 1,79 133,7 0,45 *** B

LSD( P 5%) 0,13 LSD (p 1%) 0,18 LSD (p 0,1%) 0,23


17

6.1.5.The analyzed factors influence on the number of tubers per plant

The total number of tubers per plant is an important indicator of the potato crop multiplication coefficient for seed. Multiplication factor is determined by the genetic structure of the variety, but is strongly influenced by the interactions within the applied technological factors (in our case the size of resource used in planting and planting density). In x variety interaction, x biological category, planting density (Table 6.23), confirms the great influence of planting density on the number of tubers per plant for all varieties and in all experimental years, for all biological categories (Table 6.23) and in interaction with seed size (Table 6.24).

Table 6.23 The total tubers per plant, obtained depending by

Planting density and seed size

Variety Years Density/

ha

Total tubers

per plant Percentage Differecne

t/ha Significance


LSD

60.000 10,25 100 0 Mt. I 70.000 9,74 95,0 -0,51 000 H

2004

80.000 9,06 88,4 -1,19 000 G 60.000 8,64 100 0 Mt. F 70.000 8,26 95,6 -0,38 000 E

2005

80.000 7,82 90,4 -0,83 000 D 60.000 7,56 100 0 Mt. C 70.000 7,19 95,1 -0,37 000 B

Rozal

2006 80.000 6,73 88,9 -0,84 000 A

LSD(p 5%) 0,17 LSD (p 1%) 0,23 LSD (p 0,1%) 0,30

60.000 11,74 100 0 Mt. G 70.000 11,28 96,1 -0,46 000 F

2004

80.000 10,60 90,3 -1,14 000 E 60.000 9,60 100 0 Mt. D 70.000 9,32 97,1 -0,28 0 C

2005

80.000 9,02 93,9 -0,58 000 B 60.000 6,88 100 0 Mt. A 70.000 6,78 98,5 -0,10 - A

Redsec

2006 80.000 6,72 97,8 -0,15 - A

LSD( p 5%) 0,27 LSD (p 1%) 0,35 LSD (p 0,1%) 0,46

60.000 10,82 100 0 Mt. H 70.000 10,36 95,8 -0,45 000 G

2004

80.000 9,70 89,7 -1,11 000 F 60.000 8,47 100 0 Mt. E 70.000 8,34 98,5 -0,13 - E

2005

80.000 8,09 95,4 -0,39 000 D 60.000 6,76 100 0 Mt. C 70.000 6,61 97,8 -0,15 0 B

Amelia

2006 80.000 6,46 95,6 -0,30 000 A

LSD( P 5%) 0,14 LSD (p 1%) 0,19 LSD (p 0,1%) 0,25


18

Table 6.24

The total tubers per plant, obtained depending by

Planting density and seed size

Variety

Seed size mm

Density/ ha

Total tubers per

plant

% Percentag

e

Difference t/ha


LSD

60.000 9,29 100 0 Mt. F 70.000 8,54 91,9 -0,75 000 CD

45-55

80.000 7,94 85,4 -1,36 000 B 60.000 9,10 100 0 Mt. E 70.000 8,62 94,8 -0,47 000 D

35-45

80.000 8,40 92,4 -0,69 000 C 60.000 8,07 100 0 Mt. B 70.000 8,04 99,6 -0,03 - B

Rozal

25-35

80.000 7,26 90,0 -0,81 000 A

LSD(p 5%) 0,17 LSD (p 1%) 0,23 LSD (p 0,1%) 0,30

60.000 9,98 100 0 Mt. E 70.000 9,73 97,4 -0,26 - E

45-55

80.000 9,41 94,2 -0,58 000 D 60.000 9,91 100 0 Mt. E 70.000 9,70 97,9 -0,21 - E

35-45

80.000 9,26 93,4 -0,65 000 D 60.000 8,33 100 0 Mt. C 70.000 7,95 95,5 -0,38 00 B

Redsec

25-35

80.000 7,67 92,1 -0,65 000 A

LSD(p 5%) 0,27 LSD (p 1%) 0,35 LSD (p 0,1%) 0,46

60.000 9,11 100 0 Mt. F 70.000 8,91 97,7 -0,21 00 E

45-55

80.000 8,78 96,4 -0,33 000 E 60.000 9,11 100 0 Mt. F 70.000 8,83 97,0 -0,27 000 E

35-45

80.000 8,43 92,6 -0,68 000 D 60.000 7,83 100 0 Mt. C 70.000 7,57 96,8 -0,25 000 B

Amelia

25-35

80.000 7,04 90,0 -0,79 000 A

LSD( p 5%) 0,27 LSD (p 1%) 0,35 LSD (p 0,1%) 0,46


19

6.1.6. Influence of experimental factors on the percentage of the total seed tubers.

Seed tubers percentage out of total production has values between 70-76%, which shows a

high coefficient of the tested varieties multiplication (Tables 6.25 - 6.27). Besides, the soil has a particular coefficient of seed propagating; some experimental

factors had a major influence on the seed production potential as follows: planting density of 80.000 plants per hectare resulted in some very significant percentage gains of seed tubers out of the total production (Table 6.25).

Table 6.25

The seed tubers percentage from total depending by planting density in years 2004-2006

Variety Years Density/ha Seed tubers

percentage

% Percentage

Difference %

Significance


LSD

60.000 69,84 100 0, Mt. A 70.000 70,42 100,8 0,57 - AB

2004

80.000 70,94 101,6 1,10 - AB 60.000 72,32 100 0 Mt. CD 70.000 74,39 102,9 2,07 ** DE

2005

80.000 76,15 105,3 3,83 *** F 60.000 71,38 100 0 Mt. BC 70.000 71,37 100,0 -0,01 - BC

Rozal

2006

80.000 73,39 102,8 2,02 ** DE

LSD( p5%) 1,23 LSD (p 1%) 1,64 LSD (p 0,1%) 2,14

60.000 69,44 100 0 Mt. A 70.000 70,42 101,4 0,99 - AB

2004

80.000 70,59 101,6 1,14 - AB 60.000 74,59 100 0 Mt. CD 70.000 73,61 98,7 -0,97 - C

2005

80.000 75,77 101,6 1,18 - DE 60.000 70,85 100 0 Mt. AB 70.000 71,49 100,9 0,64 - B

Redsec

2006

80.000 76,62 108,1 5,77 *** E

LSD( p 5%) 1,38 LSD (p 1%) 1,83 LSD (p 0,1%) 2,39

60.000 71,45 100 0 Mt. A 70.000 72,84 101,9 1,39 ** BC

2004

80.000 75,48 105,6 4,02 *** D 60.000 72,51 100 0 Mt. B 70.000 73,36 101,2 0,86 - BC

2005

80.000 76,09 104,9 3,58 *** D 60.000 73,62 1 0 Mt. C 70.000 72,87 99,0 -0,76 - BC

Amelia

2006

80.000 73,73 100,2 0,11 - C

LSD( p 5%) 0,94 LSD (p 1%) 1,25 LSD (p 0,1%) 1,62


20

In the interaction with the category of biological variety and planting density, the percentage of the total production of seed tubers seems to increase starting from 70.000 plants per hectare (Table 6.26).

Table 6.26

The influence of experimental factors on seed tubers percentage beside total

6.2. THE INFLUENCE OF VIROTIC DEGENERATIONS ON YIELD AND

QUALITY OF SEED POTATO.

6.2.1. The evolution of critical virotic infection (PLRV and YPV) during the multiplication in Şinteu, Bihor County

In the experiment during 2004 - 2006 the number of plants infested with serious virus was determined in the field: the virus of potato leaf rolling (VRFC) and potato virus Y (VYC), the period when plants were 30-40 cm tall, before flowering. In case of Siculus variety, a number of plant viruses, which corresponds to the virus allowed by current regulations, were identified every year (Table 6.28).

Table 6.28 The evolution of critical virotic infection (PLRV and YPV) during the

multiplication in Şinteu, Bihor County – Siculus variety

Variety

Density/ha Seed Tubers

percentage

% Percentage

Difference Signific ance


LSD

60.000 71,18 100 0 Mt. A 70.000 72,06 101,2 0,88 * B

Rozal

80.000 73,49 103,3 2,32 *** C

LSD( p 5%) 0,71 LSD (p 1%) 0,95 LSD (p 0,1%) 1,23

60.000 71,62 100 0 Mt. A 70.000 71,84 100,3 0,22 - A

Redsec

80.000 74,32 103,8 2,70 *** B

LSD P 5%) 0,79 LSD (p 1%) 1,06 LSD (p 0,1%) 1,38

60.000 72,53 100 0 Mt. A 70.000 73,02 100,7 0,50 - A

Amelia

80.000 75,10 103,5 2,57 *** B

LSD P 5%) 0,54 LSD (p 1%) 0,72 LSD (p 0,1%) 0,94

Years

Biological categories

% of virotics in field

% of virotics admitted

2004 Base.Elit class 0,83 1

2005 Class A Certified 1,66 3


21

Regarding Rozal variety, as a result of a material received from closed areas (Miercurea

Ciuc), infected with the virus, the results recorded on the number of plant viruses at Sinteu were above our expectations.

Thus, for all tested biological categories during the three years, the percentage of plant viruses has exceeded the percentage allowed by the rules in force, being 1.66 serious viral Elite biological category, 3.33 at Class A certified, and a rate of 6,65 at Class B certified (Table 6.29).

Table 6.29

The evolution of critical virotic infection (PLRV and YPV) during the multiplication in Şinteu, Bihor County – Rozal variety

Years Biological categories





2006 Class B Certified 6,60 5

Rozal variety proved to be less appropriate for seed potato propagation in Sinteu

microarea, Bihor County. Nemere variety brought from St. Gheorghe of SCDC Targu Secuiesc closed area was a

fair variety multiplied by Elite biological category. The degree of viral infection led us to the three biological categories falling within the permissible percentage of virus (Table 6.30).

Table 6.30

The evolution of critical virotic infection (PLRV and YPV) during the

multiplication in Şinteu, Bihor County – Nemere variety

Years




2004 Base.Elit class 0 1





22

Dumbrava variety originating in Rasnov (Brasov) closed area had a low degree of viral

infection for which the corresponding biological category has been propagated and answers the propagation in Sinteu microzone. (Table 6.31).

Table 6.31 The evolution of critical virotic infection (PLRV and YPV) during the multiplication in Şinteu, Bihor County – Dumbrava variety

It is worthy of note the susceptibility of Siculus, Rozal and Dumbrava PLRV varieties prevailing in these varieties and VYC which is more sensitive with Nemere variety.

6.2.2. Results production obtained on the varieties tested in the three categories of biological micro propagated in Sinteu 6.2.2.1. Results on the total production of tubers during three years of successive

multiplications

Table 6.32 Total tubers production

LSD (p 5%) 0,38

Years






2006 Class B Certified 5 5

Years

Variety

Yields t/ha

% Percentage

Difference

t/ha

Significance

2004 30,95 100,0 0 Mt. 2005 28,84 93,2 -2,12 000 2006

Siculus

22,67 73,3 -8,28 000 2004 27,61 100,0 0 Mt. 2005 25,44 92,1 -2,17 000 2006

Rozal

22,08 80,0 -5,53 000 2004 38,38 100,0 0 Mt. 2005 28,08 73,2 -10,30 000 2006

Nemere

23,68 61,7 -14,70 000 2004 31,24 100,0 0 Mt. 2005 29,13 93,2 -2,12 000

2006

Dumbrava

23,71 75,9 -7,53 000


23

LSD (p 1%) 0,53 LSD (p 0,1%) 0,76 Tubers production bears the four tested varieties clear imprint of the viral infections grade, the production potential of this biological category (Table 6.32) Every variety is found to have a decrease in the production from a biological category to another, differences being very significant when compared with Elite biological category taken as evidence. In general the difference in biological production from one category to another is gradually, coming after three years of propagation from 20-25 to 40% depending on variety. Nemere is the most sensitive variety in degeneration, thus the production decreases to 61.7% within two years of propagation followed by Siculus and Dumbrava biological differences among categories are significant negative. Vegetation adjournment for Elita biological category differentiates varieties by the accumulation until the date when vegetation is interrupted. From this point of view, the variety order on production level is: Nemere, Dumbrava, Siculus and Rozal. Compared with Siculus variety, Nemere variety accumulates very significant production and Rozal variety negative differences (Table 6.48).

62.2.5. Results on seed production of size 25-55 mm

For the entire quantity of seed produced - fraction of 25-55 mm (Table 6.45) in the first year of experimentation with Elite biological category when vegetation stopped in the 70th day, the best quality can be associated with Nemere and Siculus varieties with yields over 23 t / ha seed. Near the overall potential of the seed varieties grown in Romania (about 20 t / ha), there is Dumbrava variety and Rozal variety which is inferior to the former this year. The last two varieties show significant negative differences, compared with the Siculus controlled variety. In comparisons that we can make, according to Duncan test (Table 6.45) we have the same classification order, Nemere and Siculus varieties being practically equal, followed by Dumbrava and Rozal.

Table 6.45

Seed production at size 25 – 55 mm in year 2004 ( Base Elit class )

Variety Yields t/ha

% Percentage

Difference t/ha

Significance


Siculus 23,12 100,0 0,00 Mt C

Rozal 16,35 70,7 -6,77 000 A

Nemere 23,06 99,7 -0,06 - C

Dumbrava 19,10 82,6 -4,02 000 B

LSD ( p 5% ) 0,91 LSD ( p 1% ) 1,31 LSD ( p 0,1% ) 1,92


24

In 2005 referring to the biological Class A Certified category, the culture that has not stopped vegetation, total seed production reflects the high ecological plasticity and a lesser degree of degeneration of the Siculus variety, thus the total seed production exceeding 22 t / ha.

An increased degeneration and seeds negative significant differences can be noticed in Nemere variety along with the other two varieties, Rozal and Dumbrava, when compared to Siculus variety Table 6.46).

Table 6.46.

Seed production at size 25 – 55 mm in year 2005

(Class A Certified)

Variety Yields t/ha

% Percentage

Difference t/ha

Significance


Siculus 22,21 100,0 0,00 Mt. C

Rozal 16,75 75,4 -5,46 000 A

Nemere 18,13 81,6 -4,08 000 B

Dumrava 16,18 72,9 -6,03 000 A

LSD ( p 5% ) 0,99 LSD ( p 1% ) 1,42 LSD ( p 0,1% ) 2,09

In assessing the significance of differences according to Duncan test, the order of total seed value remains the same as that determined by the Student test.

Certified organic seed in Class B category obtained in 2006 from Class A Certified seed of the last year, has much lower potential, placing itself between the yields 12-17 t / ha (Table 6.47), compared to over 20 t / ha in some species they used to belong to Elite biological category.

Table 6.47 Seed production at size 25 – 55 mm in year 2006

(Class B Certified)

Variety Yields t/ha

% Percentage

Difference t/ha

Significance


Siculus 17,24 100,0 0,00 Mt. C

Rozal 16,48 95,6 -0,76 - BC

Nemere 15,78 91,5 -1,46 00 B

Dumbrava 11,99 69,6 -5,25 000 A

LSD ( p 5% ) 0,98 LSD ( p 1% ) 1,41 LSD ( p 0,1%) 2,08


25

Resistance to degeneration succeeds as follows: Siculus, Rozal, Nemere and Dumbrava. Most affected by degeneration after three years of being propagated are Nemere and Dumbrava varieties , which total production decreased from 23.06 t / ha to 15.78 t / ha in Nemere variety, and from 19.10 t / ha to 11.99 t / ha in Dumbrava variety. We note Siculus variety that produces large amounts of seed, this character reduction is relatively small over three years of propagation, from 23 t / ha to 17 t / ha

6.3 INFLUENCE OF SEED STORING ON YIELD AND QUALITY OF SEED

POTATO. Storage conditions affect the physical quality of potato seed and potato seed production. Starting from this consideration there have been sought the influences that may occur in normal temperature (2-4°C) potato storage and under conditions when preservation at higher temperature is less appropriate and buds emerge from buds, during the 6-7 months of storage tusks break twice, which is applicable as the third generation of tusks to give rise to seed-producing plants. Seed yields obtained this way are a consequence of potato physiological degeneration.

6.3.1. Influence of storage conditions on total tuber production.

The average for the three experimental years, keeping a degraded potato seed and twice removed the tusks has led to lower production potential of varieties with significant negative differences (see Table 6.48).

Table 6.48. The total tubers production depending by storing conditions in years 2004 – 2006.

Variety Storing conditions

Yields t/ha

% Percentage

Difference t/ha

Significance


Unsprouted 22,60 100 0 Mt. B Amelia

remove tusks twice 20,76 91,9 -1,83 000 A Unsprouted 27,54 100 0 Mt. H Eterna

remove tusks twice 25,52 92,7 -2,02 000 E Unsprouted 25,77 100 0 Mt. E Dacia

remove tusks twice 22,90 88,9 -2,87 000 F Unsprouted 25,44 100 0 Mt. C Redsec

remove tusks twice 23,54 92,5 -1,91 000 E Unsprouted 25,49 100 0 Mt. D Productiv

remove tusks twice 22,40 87,9 -3,09 000 B Unsprouted 28,97 100 0 Mt. I Rozal

remove tusks twice 26,79 92,5 -2,18 000 G LSD ( p 5%) 0,21 LSD ( p 1% ) 0,28 LSD ( p 0,1% ) 0,30


26

On average, according to varieties, the effect of removing the tusks twice during storage is shown by significant differences on production potential for all three biological categories (Table 6.49).

Among varieties there is a greater influence on some, such as Productiv, Dacia, Eterna and Rozal varieties and less on Redsec and Amelia.

Table 6.49 Total tubers production obtained depending by storing condition


Storing conditions

Yields (t/ha)

% Percentage

Difference t/ha

Significance


Unsprouted 29,35 100 0 Mt. F Base SuperElit remove tusks twice 28,26 96,3 -1,09 000 E

Unsprouted 26,21 100 0 Mt. D Base class Elit remove tusks twice 23,40 89,3 -2,82 000 C

Unsprouted 22,34 100 0 Mt. B Class A Certified remove tusks twice 19,30 86,4 -3,05 000 A

LSD ( p 5%) 0,15 LSD ( p 1% ) 0,20 LSD ( p 0,1% ) 0,26

The effect on production potential is progressively higher with the transition to a lower biological category. If the tusks are removed for the Base SuperElit class biological category, the production potential is reduced only by one tone per hectare, but for the Base Elite Class biological category, production potential reduction reached 2.81 t / ha and the Class A Certified category goes lower production with 3 t / ha, the difference being highly statistically assured by both the Student test and Duncan test (Table 6.50).

Production potential of each variety was influenced by significant differences by breaking negative tusks during storage (Table 6.50), for all biological categories, which expresses the importance of storage conditions on maintaining the production potential of varieties, one exception was found in the Rozal variety in 2004 for the Biological Basis SuperElit class category, which will be also examined having in view this variety resistance against degeneration.


27

Table 6.50

Total tubers production obtained depending by storing condition

LSD ( p 1% ) 0,48 LSD (p 0,1 ) 0,36 LSD ( p 5%) 0,63

Variety Biological categories

Storing conditions

Yields (t/ha)

% Percent

age

Difference t/ha

Significance


Unsprouted 25,29 100 0 Mt. J Base

SuperElit remove tusks twice 23,71 93,7 -1,59 000 H Unsprouted 22,74 100 0 Mt. G Base

class Elit remove tusks twice 20,74 91,2 -2,00 000 E Unsprouted 19,76 100 0 Mt. C

Amelia

Class A Certified remove tusks twice 17,84 90,3 -1,92 000 A

Unsprouted 30,69 100 0 Mt. Q Base SuperElit remove tusks twice 29,85 97,3 -0,84 000 P

Unsprouted 27,77 100 0 Mt. M Base class Elit remove tusks twice 24,16 87,0 -3,61 000 I

Unsprouted 24,17 100 0 Mt. I

Eterna

Class A Certified remove tusks twice 22,55 93,3 -1,61 000 G

Unsprouted 28,42 100 0 Mt. N Base SuperElit remove tusks twice 26,27 92,5 -2,14 000 K

Unsprouted 26,16 100 0 Mt. K Base class Elit remove tusks twice 23,73 90,7 -2,42 000 H

Unsprouted 22,75 100 0 Mt. G

Dacia

Class A Certified remove tusks twice 18,70 82,2 -4,05 000 B

Unsprouted 29,25 100 0 Mt. O Base SuperElit remove tusks twice 28,62 97,8 -0,63 000 N

Unsprouted 26,32 100 0 Mt. K Base class Elit remove tusks twice 23,40 88,9 -2,92 000 H

Unsprouted 20,76 100 0 Mt. E

Redsec

Class A Certified remove tusks twice 18,58 89,5 -2,18 000 B

Unsprouted 29,65 100 0 Mt. P Base SuperElit remove tusks twice 28,32 95,5 -1,33 000 N

Unsprouted 25,18 100 0 Mt. J Base class Elit remove tusks twice 21,07 83,7 -4,11 000 E

Unsprouted 21,63 100 0 Mt. F

Productiv

Class A Certified remove tusks twice 17,80 82,3 -3,83 000 A

Unsprouted 32,78 100 0 Mt. R Base SuperElit remove tusks twice 32,78 100 0 Mt. R

Unsprouted 29,12 100 0 Mt. O Base class Elit remove tusks twice 27,27 93,6 -1,85 000 L

Unsprouted 25,01 100 0 Mt. J

Rozal

Class A Certified remove tusks

twice 20,33 81,3 -4,68 000 D


28

6.3.2. Influence of storage conditions on total seed production

Analyzing the influence of storage conditions on the total production of tested seed varieties, we observe a similar evolution of the tested varieties.

Thus, seed production lowers very significantly (Table 6.52) for all variants that have broken tusks twice before planting in comparison with the seed to be kept in good condition.

The difference in seed production is dependent on variety with values between 1.13 t / ha (Rozal variety) and the largest difference of 1.89 t / ha (Productiv variety).

Table 6.52.

The total seed production obtained from planted material stored in different conditions, at studied varieties.

Variety Storing

conditions Total seed production

(t/ha)

% Percentage

Difference t/ha

Significance


Unsprouted 14,86 100 0 Mt. C Amelia

remove tusks twice 13,21 88,9 -1,65 000 A Unsprouted 20,42 100 0 Mt. H Eterna

remove tusks twice 18,66 91,4 -1,77 000 G Unsprouted 16,27 100 0 Mt. E Dacia

remove tusks twice 14,88 91,5 -1,39 000 C Unsprouted 17,66 100 0 Mt. F Redsec

remove tusks twice 16,41 92,9 -1,25 000 E Unsprouted 18,28 100 0 Mt. G Productiv

remove tusks twice 16,39 89,7 -1,89 000 E Unsprouted 15,36 100 0 Mt. D Rozal

remove tusks twice 14,23 92,6 -1,13 000 B DL ( p 5%) 0,45 DL ( p 1% ) 0,60 DL ( p 0,1% ) 0,78

In conclusion, referring to potential seed production, Eterna variety stands well above, followed by Productiv and Redsec for both varieties of planting resource storage. (Table 6.52)

6.3.3. Influence of storage conditions on seed production in the size 45-55 mm.

Planting the properly stored tubers and tusks broken twice, the seed production obtained

from the size 45-55 presented in Table 6.55., highlights a very significant effect of broken tusks on the seed production fraction of 45-55 mm, on the variety of biological category derived seed and direct effect of cutting the tusks during three averaged experimental years.

Physiological degeneration influence on seed potential in the size 45-55 mm is clearly expressed by the significant and very significant differences.


29

Table 6.55.

The total seed production from size 45 – 55 mm obtained from planted material stored

in different conditions at studied varieties. Variety Storing

conditions Total seed production

(t/ha) 45 – 55 mm

% Percentage

Difference t/ha

Significance


Unsprouted 6,69 100 0 Mt. B Amelia remove tusks twice 5,95 88,9 -0,74 000 A

Unsprouted 7,39 100 0 Mt. EF Eterna Remove tusks twice 7,02 95,0 -0,37 0 CD

Unsprouted 7,42 100 0 Mt. EF Dacia Remove tusks twice 7,21 97,1 -0,22 - DE

Unsprouted 7,47 100 0 Mt. EF Redsec Remove tusks twice 7,16 95,9 -0,31 0 DE

Unsprouted 7,35 100 0 Mt. EF Productiv Remove tusks twice 6,67 90,7 -0,68 000 B

Unsprouted 7,60 100 0 Mt. F Rozal Remove tusks twice 6,78 89,2 -0,82 000 BC

LSD ( p 5%) 0,30 LSD ( p 1% ) 0,40 LSD ( p 0,1% ) 0,52 6.3.4. Influence of storage conditions on seed production in the size 35-45 mm.

Breaking tusks effect on the potential seeds of varieties is clearly expressed by recorded differences on seed production in the fraction 35-45 mm, both for varieties and experienced biological categories, the differences being significantly negative in case of broken tusks for all studied interactions (Tables 6.58.)


30

Table 6.58 The seed production from size 35 – 45 mm obtained from stored planted material

in different conditions on 6 varieties.

Variety Storing

conditions Seed

production 35 – 45 mm

(t/ha)

%

Percentage

Difference

t/ha

Significance

Duncan

classification

Unsprouted 5,60 100 0 Mt. D Amelia Remove tusks twice 5,11 91,3 -0,49 000 B

Unsprouted 8,38 100 0 Mt. J Eterna Remove tusks twice 7,37 87,9 -1,01 000 H

Unsprouted 6,30 100 0 Mt. F Dacia Remove tusks twice 5,34 84,8 -0,95 000 C

Unsprouted 7,64 100 0 Mt. I Redsec Remove tusks twice 7,37 96,4 -0,28 00 H

Unsprouted 6,83 100 0 Mt. G Productiv Remove tusks twice 5,79 84,8 -1,04 000 E

Unsprouted 5,24 100 0 Mt. BC Rozal Remove tusks twice 4,87 92,8 -0,38 000 A

LSD ( p 5%) 0,17 LSD ( p 1% ) 0,22 LSD ( p 0,1% ) 0,29

6.3.5. Influence of storage conditions on seed production in the fraction 25-35 mm. Seed production ratio of 25-35 mm is strongly influenced by the breakdown of tusks in all

varieties (Table 6.61), with significant and very significant differences for the studied varieties. Table 6.61.

The seed production from size 25 – 35 mm obtained from stored planted material in

different condition at studied varieties. Variety Storing

conditions Seed

production 25 – 35 mm

(t/ha)

% Percentage

Difference

t/ha

Significance

Duncan

classification

Unsprouted 2,61 100 0 Mt. C Amelia Remove tusks twice 2,19 83,9 -0,42 000 A

Unsprouted 4,65 100 0 Mt. G Eterna Remove tusks twice 4,26 91,6 -0,39 000 F

Unsprouted 2,55 100 0 Mt. C Dacia Remove tusks twice 2,33 91,3 -0,22 00 B

Unsprouted 2,55 100 0 Mt. C Redsec Remove tusks twice 2,27 88,9 -0,28 000 AB

Unsprouted 4,10 100 0 Mt. E Productiv Remove tusks twice 3,94 96,0 -0,16 0 D

Unsprouted 2,62 100 0 Mt. C Rozal Remove tusks twice 2,58 98,5 -0,04 - C


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LSD ( p 5%) 0,13 LSD ( p 1% ) 0,17 LSD ( p 0,1% ) 0,22

GENERAL CONCLUSIONS

Following research carried out and its outcomes, on favourability of Sinteu area of Bihor County to become a potential microzone for potato seeding, the following conclusions have been drawn:

1. The geographical location, space clustering through natural areas protection, its altitude, and the cold and damp weather conditions which are very similar to those in the closed areas of potato seed production, the Sinteu microzone is a very favourable area for potato seed breeding.

2. The continental climate with cool springs and summers, with average annual temperature of 8.2°C, and the warmest month temperature of 18.3°C, can provide similar conditions to those in closed areas for seed potato breeding.

3. In Sinteu microzone, the annual average temperatures, the average daily temperatures during the potato growing season (April to September) and the average maximum temperature in July are falling in the range of temperatures existing in the enclosed areas of potato seed production.

4. The maximum temperatures of the warmest months (June-July) do not generally overcome the thermal threshold of 23°C, which is the favourable temperature for the activity of aphids as viruses’ vectors, more than once in June and four times in July, which generally causes a lower appetence for flying of virus vector aphids. 5. The high rate of negative temperatures during January to March, the late, cold, rainy and windy springs, all lead to a prolonged wintering of aphids, and thus delaying their appearance in the potato crops.

6. The average of yearly rainfall of 724.6 mm and the amount of yearly rainfall during the potato growing season of 448.9 mm in Sinteu microzone, Bihor County, fully meet the potato breeding related requirements in this regard.

7. During potato vegetation period, the number of days with precipitation above 0.1 mm when the aphids do not fly, is between 60-78 days, another factor which is added to the Sinteu microzone favourability notes in seed potato production and replication.

8. The Sinteu microzone resembles in terms of rainfall with the closed area neighbouring Râsnov in Brasov County, and in terms of rainfall distribution in the summer months with the Ciuc closed area.

9. Sinteu soil through its physical and chemical characteristics shows a high degree of suitability for seed potato crop.

10. The main aphids species acting as viruses vectors, monitored by their occurrence rate and frequency during three years, by means of daily capturing in Moerike type yellow wessels, were annually and progressively compared with those collected by the National Research Institute for Potato and Beet Sugar BraSov. The results were similar and sometimes superior in the Sinteu microzone, as regards the most dangerous species, namely Myzus persicae or Aphis fabae and as a result of a very good insulation of Sinteu microregion and with a limited number of host species.

11. Research made in Sinteu microzone in order to verify the relation between potato varieties and planting density, fully validated the working assumption the study of three varieties has began with, namely Rozal, Redsec, and Amelia. If the Rozal variety forms a fewer number of


32

tubers per nest, the best results are achieved at the highest nesting density of 80.000 per hectare. In the case of Redsec variety with a large number of medium sized tubers, the optimal density can be lowered to 70.000 plants per hectare where one achieve the highest production and even larger in the case of Amelia variety, up to 60.000 nests per hectare due to the breeding of a large number small-sized tubers.

12. The seed production from the 45-55 mm fraction resulting in the three years 2004, 2005 and 2006 corresponding to the transition from Base biological category, SuperElit class, Base Elite Class to A class Certified Base class is closely correlated with planting density, i.e. the superior biological category (Base SuperElit class) corresponding to 2004, the seed production depends not so much on planting density. For all varieties experienced when breeding with Base category SuperElit class, the seed production of 45-55 mm fraction is almost equal between the densities of 60.000 and 80.000 plants per hectare. As biological category falls, the role of planting density increases so that for the A class certified biological category in order to obtain high yields in 2006, one needed to increase planting density to 80.000 plants per hectare. At this density one obtain significant differences for all varieties. The role of planting density increases as biological category decreases.

13. It is certain that in case of all varieties and all sizes used in planting, density of 80.000 plants per hectare leads to the higher seed production in the 35-45 mm fraction.

14. Besides the variety capacity to have a particular coefficient of seed dissemination, some of new experimental factors we studied had a major influence on the potential for seed production as follows: planting density of 80.000 plants per hectare resulted in some very significant increases in total seed tubers out of total production while in interaction with the biological category and density, it seems that starting with 70,000 plants per hectare, the percentage of the total production of seed tubers increases.

15. The potato seeds storage affects the physical quality and seed production in the case of all six varieties studied for three years. The production potential of each variety was influenced by negative significant differences by tusks broken during storage at all biological categories, which expresses the importance of storage conditions on preserving production potential.

16. Breaking tusks from the seed derived from biological categories experienced has different impacts from one variety to another. Some varieties are affected in the case of a superior biological category with a very significant difference, as in case of Amelia variety, while in case of others such as Dacia or Productiv, the effect of tusk breaking is more pronounced in the case of lower biological categories.

17. The most suitable varieties for multiplication in Sinteu area – Bihor county are Siculus and Nemere varieties with a great seeding potential and slower degeneration than in the case of Rozal and Dumbrava varieties during successive dissemination.

18. By breeding for three years those Basis Elite class varieties brought from the closed areas, namely the percentage of viral infection was within the limits allowed by the provisions in force for the varieties Siculus, Nemere and Dumbrava. The Rozal variety has shown a high degree of viral infection which was brought from the closed area and remained at a high percentage at biological categories and dimeninated for two years.

19. Within the Sinteu micronzone of Bihor county one can replicate potato seed with very good results, this microzone having the potential to become a supply centre with seed potato for A and B class biological categories for the North-West Romania area.


33

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