Direct and indirect selection for grain yield in oats (avena sativa L.)

Abstract

Direct and indirect selection for increased grain yield were carried out on a population of 678 F2-derived lines of oats. A selection intensity of 10% was used with direct selection (selection for grain yield itself) and with indirect selection using three criteria, harvest index, vegetative growth rate, and the index of harvest index + vegetative growth rate. Expected gains from 1978 evaluations were compared to actual gains measured in 1980. Actual grain yield increases were 4, 8, 7, and 6% from selection via harvest index, vegetative growth rate, grain yield, and harvest index + vegetative growth rate, respectively. Thus, indirect selection via vegetative growth rate gave a greater increase in grain yield than did direct selection. Heritability values computed via components of variance ranged from 0.50 to0.57 for the three traits, harvest index, vegetative growth rate, and grain yield, whereas regression heritabilities ranged from 0.41 to 0.55. Realized heritabilities were 0.33, 1.00 and 0.89 for the three traits, respectively. Selection via all criteria caused significant changes in nearly all agronomic traits except weight per volume. Vegetative growth rate, which gave the greatest gain in grain yield, caused less drastic changes in days to anthesis, plant height, biological yield, and vegetative yield than did direct selection for grain yield.