breeding techniques for vegetables
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#6 breeding
“lemato”
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#6 Outcome
“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