Summary of the recently released European Pear, ‘Gem’

Todd Einhorn, Ph.D. Michigan State University

USDA Pear Breeding Objectives

• High fruit quality cultivars (Flavor, texture, appearance, size, and no physiological disorders are major traits).

• High productivity and early bearing • Wide range of maturities • Resistance to fire blight (Primarily Pyrus communis sources of resistance) • Resistance to pear psylla (Pyrus ussuriensis and East European Pyrus communis

sources of resistance) • Resistance to Fabraea leaf spot and pear scab

Background

* Slide compliments of Dr. Richard Bell, USDA-ARS Pear Breeder

USDA Pear Cultivars Notable Features 1960 Releases: ‘Magness’ High fire blight resistance and quality

‘Moonglow’ High fire blight resistance and productivity ‘Dawn’ High quality, moderate fire blight resistance

1980 – 2016 Releases: ‘Potomac’ ‘Moonglow’ X ‘Anjou’- Anjou type flavor, fire blight resistance ‘Shenandoah’ Late maturity, large size, fire blight resistance

‘Blake’s Pride’ Excellent aromatic flavor, fire blight resistance (-) size, russet ‘Sunrise’ Early August maturity, fire blight resistance,

excellent flavor/ (-) relatively no storage life/size ‘Gem’ Cultivar Release Publication

Releases

* Slide compliments of Dr. Richard Bell, USDA-ARS Pear Breeder

Potomac

Photo: Adams County Nursery

Shenandoah Sunrise

Precocious and productive Crisp/juicy texture at harvest Can be ripened to melting quality Non-russeting, smooth finish Flesh non-browning Fire blight tolerance

‘Gem’ Summary

‘Gem’ 16-April 1-Sept ‘Bartlett’ 17-April 15-Aug ‘d’Anjou’ 13-April 5-Sept

‘Gem’- Bloom and Harvest Timing

05

101520253035404550

0 2 4 6 8 10

Freq

uenc

y (%

)

Seeds/fruit

'd'Anjou'

'Bartlett'

'GR Bosc'

'Comice'

'Gem'

'Starkrimson'

• Compatible with all cultivars evaluated; bloom timing near ‘Bartlett’

• Fruits from 20 % of self-pollinated flowers were parthenocarpic

‘Gem’- Pollination

Gem: Planted 2005Leaf Yield 8x15x 6x15 6x12 5x12 4x12 Avg. fruit wt. Avg. fruit size

Year (year) (lbs/tree) 363 484 605 726 908 (g) (box sz)2007z 3 11 3.6 4.8 6.1 7.3 9.1 175 110/1202008z 4 22 7.3 9.7 12.1 14.5 18.2 175 110/1202009z 5 77 25.4 33.9 42.4 50.8 63.6 150 1352010z 6 115 38 50.6 63.3 75.9 94.9 155 1352010y 6 56 18.5 24.6 30.8 37 46.2 205 1002011z 7 120 39.6 52.8 66 79.2 99.1 150 1352011y 7 66 21.8 29 36.3 43.6 54.5 215 902012 8 n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d.

2013w 9 90 29.7 39.6 49.5 59.4 74.3 211 100/90z Unthinnedy Thinned to 4 fruits/cm2 trunk cross-sectional areaxActual spacing of orchardwThinned commerically to Bartlett levelsOptimal spacing

Bins/acre for a range of spacings and tree densities

‘Gem’- Production Central leader system- 890 trees/ha on OH X F 97

‘Gem’- Yield and Fruit Size

‘Gem’ will require thinning if size 90s and larger are desired

0

10

20

30

40

50

70 80 90 100 110 120 135 <135

Perc

ent

Fruit size (no. fruit per 44 lb box)

HeavyModerateLightCommercial

8.5 fruits/cm2

6 fruits/cm2

3 fruits/cm2

4 fruits/cm2

‘Gem’- Cropload vs. Fruit Size 890 trees/ha

‘Gem’- Harvest Timing

Delaying harvest to optimize harvest eating quality resulted in a linear improvement in fruit size

13-15% 0.3 -

0.5% 10.5 lb

(47.5 N) ~50% of

fruits 90 to 100

240 to 194 g Smooth

no russet

‘Gem’- Fruit Quality ‘Gem’ is a crisp/crunchy pear that can be consumed directly ‘off the tree’

‘Gem’ can also be ripened to a melting flesh dessert quality pear

At 10 lb harvest pressure, ~30 d of chill were required to ripen

PH (RA) storage life is 5 months

‘Gem’- Postharvest Quality

‘Gem’- Postharvest Quality

• Gem pears were processed on Duckwall’s commercial ‘Comice’ line (brushes covered by belts)

‘Gem’ -Fire Blight

• Original source of fire blight resistance was ‘Seckel’

• Inoculation of actively growing shoots showed high level of resistance

• Blossom susceptibility (observed on nursery trees in 2016)

‘Gem’ – Distribution Issues

• Infected with PVY virus- presumably due to grafting to infected rootstocks • Clean Plant Network (Prosser, WA) successfully treated PVY infected material via heat therapy • A limited supply of vf buds were available Fall 2016

• 35-40 fruits per tree after thinning

• 166 is precocious and productive

• Bartlett harvested 3-Aug

• -166 harvested 19-Aug

Other New Germplasm

84907-166 91 a 1.43 a 249.2 16.4 12.6 ‘Bartlett’ 122 a 0.83 b 222.4 18.9 11.7 ‘d’Anjou’ 5 b 0.1 c - - -

US84907-166 Parentage: Bartlett x US65062-040 Bartlett-type flavor, sweet Harvest: Aug 20 Storage: 3 months RA Fire blight resistant

- Tested positive for PVY

Other New Germplasm