Tomato Crossing Block

Myakka City, FlFall 2012

Greenhouse Layout• Two, 90ft x 40ft gutter connected greenhouses

• Micro-Grow Procom controller and Weathermaster weatherstation

o Active and Passive Heating/Cooling

• 546 plants

o Assorted tomato parent lines

o Evenly spaced throughout 13 rows

o 5 gallon disposable pots

o Fafard 51L Mix: Canadian Sphagnum Peat Moss (30%), processed pine bark, perlite, starter nutrients, wetting agent & Dolomitic limestone (some perlite is mixed in by hand)

Greenhouse Layout• Drip irrigation with two zones

o Hunter Irrigation Controller

o Solenoid Valves

o "A" and "B" stock with Dosamatic SuperDos30 injectors

o Netafim piping, emitters, manifolds, angle arrow drippers, flow meter

Pollen Collection

A. Picking Flowers

B. Scraping Procedure

C. Storage/ Organization

Pollen Collection: Picking Flowers

• Plants designated "male" are used as a pollen donor

• This pollen must be collected by hand

• Flowers are picked, placed in a container, labeled and brought to a location free from the elements; in this case, the office

Pollen Collection: Picking Flowers• Since the collection of seed is important from these "male" plants, only select flowers are picked

• The first hand of flowers is not picked to help promote more flowering

• Flowers that appear to have pollinated themselves, or are shriveled and old are left on the plant with the intentions that they develop into tomatoes

• Flowers that appear healthy are picked and placed a plastic container lined with a paper towel

• The paper towel is labeled to correctly identify containers and flowers

Pollen Collection: Picking Flowers

Pick These Flowers

Pollen Collection: Picking Flowers

Pick

Pollen Collection: Picking Flowers

Do Not Pick

OK to Pick

Pollen Collection: Scraping Procedure

• Once flowers are gathered, pollen must be scraped from them

• Required Tools:

o Scalpel

o Petri dish,

o Microscope slide

o Micro-centrifuge tube

o Alcohol

o Sharpie

• A microscope slide and petri dish are labeled with a pollen code that matches the flowers’ code

o Slides and dishes are reused throughout the season

Pollen Collection: Scraping Procedure

• The microscope slide is placed inside one half of the petri dish

• Flowers are held above the microscope slide and anthers are scraped with a scalpel

o This scraping agitates the flower and pollen falls directly onto the slide

o Flowers are sometimes sliced vertically and then scraped, creating more room for pollen to escape

Pollen Collection: Storage/Organization

• After one group of flowers has been scraped, the pollen can be stored

• If there is just a small amount of pollen, the top is placed on the petri dish, and the whole unit is placed into storage

o Pollen usually is used within a day or two

o Not transfering pollen to a container creates minimal pollen loss

Pollen Collection: Storage/Organization

• If a good amount of pollen is collected, the pollen is transferred from a microscope slide to a micro-centrifuge tube and then labeled

o Pollen can be stored for longer periods in these tubes than in a petri dish

o Better protection for the pollen

o Some pollen sticks to the sides of the tube, so this method is not used for storing small amounts of pollen

• Thrips are sometimes found inside flowers and can fall into the pollen being collected

o If thrips are found, two extra steps are taken to eliminate them from living in gathered pollen

1. Leave the centrifuge tube open for a little while and the thrips will crawl out of the top

2. Place pollen in a freezer overnight to kill remaining thrips

NEW TUBE

POLLEN STUCK INSIDE TUBE

Pollen Collection: Storage/Organization• Pollen is stored in the seed storage room after collection

o Temp : 65 F, Humidity: 35%

*Different storage methods would be used for achieving maximum storage time and minimal degradation of pollen quality*

Emasculation

• Equipment

• Anatomy of Tomato Flower

• Ideal Flower

• Procedure

Emasculation: Equipment

• Supplies:o Forcepo Scissorso Yarno Tagso Sharpie

Emasculation: Equipment

• Keep your tools clean with alcohol!

Acceptable

Too Dirty

Emasculation: Flower Anatomy

Sepal

Petals

Stigma

Style

Pistil

Anthers

Stamen

Ovary

Filament

Emasculation: Flower Anatomy

• Pistil (Female)o Stigma- Site pollen will

be placedo Style- Pollen tube

grows through to reach ovule

o Ovary- Becomes the fruit after fertilization. Flesh becomes pericarp walls

• Stamen (Male)o Filament-Supports the

antherso Anther cone-

Surrounds the pistil and is the source of pollen

Emasculation: Selecting Flowers• Do not make crosses on flowers that may have had an opportunity to self pollinate!

o Try to steer clear of flowers that do not have fused anthers

Acceptable Stages for Crossing

Emasculation: Procedure• Tomatoes are traditionally perfect flowers, so before applying pollen, male parts must be removed to prevent

self pollination

• Removal of the anther cone is accomplished by teasing with forceps

• After the anther cone is removed, the sepals are clipped to help distinguish hybrids from selfed fruit

Emasculation: Procedure• After a flower is emasculated, bright red yarn is placed over the inflorescense

• Instead of placing pollen on each stigma immediately after emasculation, groups of flowers are emasculated, tagged with yarn, and then pollinated

• Some people wait a day or two to place pollen on the stigma; here it is done in the same hour as emasculation

o Waiting to pollinate allows time for the flower to develop and be the most receptive to pollen

o It also creates an opportunity for an unwanted type of pollen to land on the stigma in that time period

Pollination

• Process

• Marking Hybrids

Pollination: Process• After a group of flowers has been emasculated and tagged with yarn, it is time to go back and pollinate

• The label on the pollen is checked against the label on the pots, to make sure the correct pollen being placed on the stigma

• The stigma is tapped against either the microscope slide or the top of the centrifuge tube; whatever the pollen was stored in/on

• When using a centrifuge tube to pollinate with, be careful not to have the cap of the tube hit anything while moving from flower to flower

o There have been multiple times when a tube of pollen is spilled due to carelessness

• Do not “wipe” the stigma through the pollen; tap the stigma in the pollen

o Although important to apply enough pollen, pollen is time consuming to collect, so wasting pollen should be avoided at all costs

Pollination: Identifying Fruit

• After pollinating, it is important to be able to identify hybrids when they fruits form, especially when there are more than one type of pollen applied to each per plant

• There are a variety of checks and balances to make sure that fruit are identifiable before picking

o Each plant must be labeled

Male plants are labeled with a pollen “code” (ex. PA,PB,PC etc.) and female plants are labeled with both parents’ codes (ex. 1 x PA, 2 x PA, 3 x PB)

• Male plants

o Pot is labeled, Stake in pot is labeled

• Female plants are intensely labeled

o Each pot is labeled, stakes in pots are labeled, a tag is made for above the plants, and each inflorescence gets a tag when applying more than one type of pollen per plant

o The tags above the plants receiving only one pollen type have the dates of crossing written on them each time a round of crossing has been completed

o The tags above the female plants that have more than one type of pollen on them have each type of pollen to be transferred written on them. Each time a flower is cleaned and pollinated, a tally mark is written next to the corresponding pollen code

o After marker results have been received, if there are any pollen plants that have segregated, they are removed and new pollen is collected from the acceptable plants remaining. New rounds of crossing is done with this new pollen. A “*” is placed after the pollen code to signify a different hybrid. These newly pollinated flowers are each tagged with a label.

Pollination: Identifying Fruit

Inventory

• Tagging

• Data Sheets

Inventory: Data Sheets• I make data sheets that include all the potential crosses that are scheduled to be made in the greenhouse

• Taking an inventory midway through the crossing season allows us to prioritize plants to make crosses on for the second part of the season

• For a general inventory, I inspect tags

o # of crossing rounds/ # of flowers cleaned and pollinated is noted

o This inventory is a quick way to prioritize crossing needs, but is no where near as accurate as counting each hybrid that has set on each plant (detailed inventory)

o Just beacuse a plant has had 6 rounds of crossing completed on it does not mean it will have more hybrid fruits than a plant that has received 2 rounds of crossing

• To do a detailed inventory, I walk down the rows and inspect each plant

o If fruit has set on the plant, I will count and record the number of successful crosses on the data sheet

o If no fruit has set, I will make a note of that on the data sheet

o This is the most accurate way to prioritize needs

• It is important to balance pollen collection with the needs of your crossing block through inventorying

o Collecting pollen without consulting an inventory sheet will result in having pollen on hand that will never be used

Inventory: Tagging

• Tagging plants does not only aid in identify hybrids, it allows us to keep track of crosses that were made and inventory success rates

• After a good amount of crosses have been made, I walk through the crossing block and inventory our crosses

Inventory: Data Sheets

• Basic Inventory Sheets

Inventory: Data Sheets

• Basic Inventory Sheetso R1 : Parentso R2 : # rounds crossingo R3 : Statuso R4 : # rounds since

inventory was made (row left blank while taking inventory) are tallied

o R5 : * and parents listed means more crossing is needed

More stars (*)= more important

R1 R2 R3 R4 R5

Inventory: Data Sheets

• Detailed Inventory Sheets

Inventory: Data Sheets

• Detailed Inventory Sheets

o # of set crosses listed (see P1 x PA)

o If no crosses have been set, but crosses have been made, the cell is left blank (see P1 x PB)

o If no crosses have been made, the cell is circled and highlighted (see P12 x PB)

• After a detailed sheet has been made, crossings are prioritized

o Plants with no crosses made on them are given top priority, followed by plants with no set fruit, followed by those with set fruit (if time remains)

• After crosses have been made, a checkmark is placed in the corresponding cell (see P1xPD)

2/3 set0/1 set