Quantitative Traits
Objectives:
After completing this section, you should:
1.
2.
3.
4.
5.
6.
7.
Define quantitative traits
Define additive gene action
Contrast quantitative and qualitative traits
Define and calculate broad sense heritability given variance information
Define QTL (quantitative trait locus)
Apply the principles of segregation and independent assortment to explain the
distribution of phenotypes among individuals for a quantitative trait.
Predict the work a breeder would need to do to improve a quantitative trait given
a heritability value for this trait.
Some key terms:
Epistasis
Metabolic pathway
qualitative trait
quantitative trait
heritability
phenotypic variation
genotypic variation
environmental variation
On line lessons:
Quantitative Traits
http://plantandsoil.unl/croptechnology2005/pages/index.jsp?what=topicsD&topicOrd
er=1&informationModuleId=979259458
Corn Breeding: Introduction to concepts in quantitative genetics
http://plantandsoil.unl/croptechnology2005/pages/index.jsp?what=topicsD&topicOrd
er=1&informationModuleId=1099518689
AABBccddeeff x aabbCCDDEEff
F1
F2: # of Genotypes?
# of Phenotypes?
minimum seed protein = 10%
upper case alleles add 5%
lower case alleles add 0%