Repeatability of the Stability‐variance Parameter in Oats1

Abstract
Mean yields and stability variances were calculated for grain and straw yields of 80 F9‐derived lines of oats (Avena sativa L.) grown in 24 field environments. The repeatability of these parameters was investigated by correlating arrays of average phenotypic values obtained from subsets of the 24 environments arranged by random, stratified, and extreme methods. Correlations between arrays of mean yields from different subsets ranged from 0.78 to 0.85 for grain yield and 0.81 to 0.86 for straw yield, which shows good repeatability for means of these traits. Arrays of stability variances from different subsets showed correlations that ranged from 0.06 to 0.12 for grain yield and from −0.01 to 0.30 for straw yield. Obviously, the stability‐variance parameter was only repeatable to a limited extent for the materials and environments studied. These repeatabilities were discussed with reference to breeding for improved stability.