Observed and Predicted Response to Selection for Protein and Yield in Peas1

Abstract

Few reports of selection for seed yield and seed protein concentration, two important traits in peas, are available in the literature. This study involved the effect of selection for protein in the F2, F3 and F4 and for seed yield in the F3 and F4 generations of four pea (Pisum sativum L.) crosses grown in the field nursery. Mean protein of all progeny in each population was generally lower than the higher parent and tended toward the lower parent. Seed yield/plant values were generally higher than the midparent and tended toward the higher parent. Narrow sense hecitability values estimated through the parentprogeny regression method varied with crosses and generations, and were generally greater for protein (17 to 56%) than for seed yield (0 to 41%).The observed change from selecting for higher % protein ranged from ‒0.84 to 5.85% of the population mean and was generally less than that predicted (2.07 to 5.54%). The observed decrease (‒0.75 to ‒7.05%) in the same trait for negative selection was generally greater than that predicted (‒2.18 to ‒4.62%). The relationship between observed increase in yield from selection (3.22 to 12.53%) and that predicted (0.00 to 19.25%) was variable, but the observed decrease (‒1.93 to ‒17.25%) was generally greater than that predicted 0.00 to ‒17.65%).Correlations between protein and seed yield were small and inconsistent, suggesting that selection for either trait would not necessarily influence the level of the other. Selection for the two traits appears to be effective even in early generations. The amount and rate of progress would be influenced by choice of parents and selection intensity.