Genetic modulation of yield and phenotypic plasticity of yield in winter wheat
For winter wheat grown in the United States Central Great Plains, phenotypic plasticity of yield is agronomically adaptive. Phenotypic plasticity and phenotypic connectance converge to predict yield plasticity and heritability of yield are negatively correlated. Theory and empirical evidence in other species suggest genetic modulation of yield plasticity and yield per se are partially independent. Using data from variety trials conducted between 2000 and 2022 and cultivars released between 1967 and 2022, we explored time trends in yield plasticity and heritability of yield. We hypothesize that i) if yield plasticity is agronomically adaptive , newer cultivars will have higher yield plasticity; ii) genomic regions associated with yield depend on the environment and do not fully overlap to those associated with yield plasticity . Breeding for yield and agronomic adaptation increased yield plasticity at a rate of 0.5% year -1 and decreased heritability of yield from 0.23 in 1993 to 0.15 in 2017 . Genome-wide-association analysis suggests genomic regions associated with yield varied with yield environment and were partially independent of those associated with yield plasticity. Time trend analysis shows newer germplasm pools have greater frequency of favorable alleles associated with yield and yield plasticity. We discuss implications for research, breeding and agronomy.KeywordsHeritability, genotype, environment, phenotypeAbbreviationsCredible interval (c.i.), genotype x environment (G x E), Centro Internacional de Mejoramiento de Maiz y Trigo (CIMMYT).