Selection for grain yield of oats via vegetative growth rates measured at anthesis and maturity

Abstract

Grain yield of oats can be improved by increasing either vegetative growth rate or harvest index, but these two traits are negatively associated. Currently, harvest index of oats is near an optimum at 45%, so further improvement in grain yield must come from increased vegetative growth rate. In this study, vegetative growth rate was measured at anthesis and at maturity by dividing vegetative dry weight at anthesis and straw yield, respectively, by days to heading. Genotypic correlations between the two estimates of vegetative growth rate ranged from 0.53 to 0.66. When the highest 10% of the lines were selected for the two growth rate measurements, the actual genetic gain in grain yield was 3.5% when vegetative growth at anthesis was used, and a slight decrease occurred when vegetative growth rate at maturity was used. Selection for either growth rate measurement caused associated increases in biological and straw yields and dry weight at anthesis.