breeding techniques for vegetables

#6 breeding

“lemato”

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“All our major food crops wereoriginally developed byamateurs. Until recently, allgardeners and farmers savedtheir own seed; all gardenersand farmers were automaticallyamateur plant breeders -- andamateur plant breeding was theonly kind of plant breeding therewas.” Carol Deppe

basic plant breeding

• selection/evaluation

• inbreeding (fixing genes)

• making F1 hybrids

• using F2 hybrids

• outcrossing

• backcrossing

• recurrent backcrossing

• new mutations

• wide crosses

1Breed Your Own Vegetable Varieties, Carol Deppe, Little, Brown and Company, 1993

selection

inbreeding, fixing genes

Y y

YY Yy yy

YY YY Yy yy yy“To develop an inbred line, just self-pollinate a few plants fortwo to four generations. Then maintain the lines normally.”

Breed Your Own Vegetable Varieties, Carol Deppe, Little, Brown and Company, 1993

Making F1 hybrids

Introduction to Genetic Analysis. 4th Ed. 1989. Suzuki, Griffiths, Miller, and Lewontin. W.H. Feeman and Co. Chapt. 2.

Genotype = 4 - Y y

Phenotype = 4 - yellow

Y Y

y

y

Y y

Y y Y y

Y y

Genotype = 1 YY : 2 Y y : 1 y y

Phenotype = 3 yellow : 1 green

Use F2’s

Y y

Y

y

Y y

Y y y y

YY

outcrossing

Principles of Plant Breeding, Allard, 1st Edition, 1960.

The majority of lines selected are likely to be retained.

Mass selection can effect improvement in land varieties.

The basis of improvement in less developed agricultural areas.

Residue remaining after discarding the obviously unproductive ordefective lines retains the best features of the original variety.

backcrossing

1Breed Your Own Vegetable Varieties, Carol Deppe, Little, Brown and Company, 1993

Cross your selected F2 with the parent. If you do this over andover with the “recurrent” parent, this is called recurrentbackcrossing.

Recurrent backcrossing is useful only with dominant genes.

This is useful especially when you want one trait from a givenvariety and want the rest of the traits to be identical to yourestablished variety.

Once you find what you want in an F2, backcrossing allowsyou to eliminate nearly all of the genes of the other varietyexcept the ones you are specifically selecting for in eachgeneration.

using mutations

Everbearing Strawberries

wide crosses

Matt’s Wild Cherry Tomato

basic breeding example

1Breed Your Own Vegetable Varieties, Carol Deppe, Little, Brown and Company, 1993

do the cross

raise a few F1’s

raise 20 or more F2’s

if you find what you want, self-pollinate. select. repeat.

evaluate F4’s, F5’s, F6’s

rogue where necessary

if you don’t find what you want, use what you have learned.

try a different cross

raise more F2’s

evaluate F3’s, F4’s, etc.

tim peters trick

1Breed Your Own Vegetable Varieties, Carol Deppe, Little, Brown and Company, 1993

Field Guides

http://www.seedalliance.org/Publications/

Field Guides

http://www.seedalliance.org/Publications/

Field Guides

http://www.seedalliance.org/Publications/

Seed Production Guides

http://campus.extension.org/course/view.php?id=377

SeedSchool

BreedingTechniquesTim Peters TrickResources

#6 Outcome