On-Farm Plant Breeding - I Michael Mazourek Cornell University
Addressing Grower Needs“Breeding, Research, and Education Needs Assessment for Organic Vegetable Growers in the Northeast”Hultengren, Glos and Mazourek 2016 https://ecommons.cornell.edu/handle/1813/44636
210 growers responded to a survey sent to over 1,000 growers in the Northeast.
Working group of researchers, students, growers, extension, and seed companies reviewed responses.
Crops Prioritized by Growers for Cultivar DevelopmentA
rugu
laA
sian
Gre
ens
Bas
ilB
eet
Bro
ccol
iB
russ
els
Spro
uts
Cab
bage
Car
rot
Cila
ntro
Cuc
umbe
rC
ucur
bits
Eggp
lant
Fava
Bea
nG
arlic
Gre
en B
ean
Kal
eLe
ekLe
ttuce
Mel
onM
usta
rdO
kra
Oni
onPa
rsni
pPe
aPe
pper
Pota
toR
adis
hSh
allo
tSp
inac
hSu
mm
er S
quas
hSw
eet C
orn
Swis
s C
hard
Tom
ato
Wat
erm
elon
Win
ter S
quas
h
Cau
liflo
wer
Cel
ery
Certified Organic Grower Responses
Responses from growers
Define Seed Resources• Learn what others are growing in your area
• Ask at conferences like this!
• Call seed suppliers for recommendations• Organic variety trial database www.eorganic.info• www.pickacarrot.com – like google for seeds• Seed Savers Exchange• Regional seed groups
Requesting PI Accessions from NPGS (GRIN)
• Cultivar – distinct plant germplasm grown in agriculture
• Line – true breeding plant germplasm that may be appropriate for use as a cultivar
• Accession – a sample of seed that was collected, can include mixture
Requesting PI Accessions from NPGS (GRIN)
• Accession – a sample of seed that was collected, can include mixture
• Potential for disease• Not all individuals will have trait you seek• Balance benefit of request with erosion of
genetic diversity collected from nature
Flowers Can Hint toward Best Pollination and Breeding Approaches
• Plant that tend to self-pollinate tend to have perfect flowers (pollen and pistil on each flower)
• These can often be self-pollinated with little to no inbreeding depression
• There are exceptions• Plants that tend to outcross tend to have separate
male and female flowers tend to outcross• These can often show inbreeding depression• There are exceptions
Peppers• Perfect flowers• Self-pollinate readily• In the field outcross at about 20%
depending on pollinators present• Emasculated bud serves as female• Pollinated by open flower shedding pollen
Broccoli- an exception• Perfect flowers but
• Will not self-pollinate• Exhibits inbreeding depression
• Self-incompatibility common in brassica• Reject pollen similar to themselves• Promotes outcrossing• Circumvent by pollinating like a pepper (bud pollination)
• Cytoplasmic male sterility introduced• Controversial• Facilitates hybrid seed production
Cucumbers• Monoecious, Gynoecious and more• No real inbreeding depression• Although separate male and female flowers
require vector• Hybrids easily generated by planting
gynoecious alongside monoecious plants • Seed increase of gynoecious plants by use
of silver or hormones
Mendel• Alleles – different forms for a gene that control a trait
• Dominant allele – written in CAPITAL LETTERS• Recesive allele – written in smalls
• True Breeding = Homozygous
• Cross dominant plant x recessive plant • Heterozygous offspring• AA x aa => Aa F1
Breeding with HybridsDominant traits• only needs to be inherited from one parent to appear in
progeny – see it in the F1• visible if presentRecessive traits • needs to be inherited from both parents to appear in progeny• plant can be an invisible carrier Hybrid with dominant trait• may or may not be true breeding• Common for disease resistanceHybrid with recessive trait • progeny will be true breeding• Common for domestication traits