Abstract

Sixteen field pea (Pisum sativum L.) genotypes were evaluated using Randomized Complete Block Design (RCBD) with four replications for evaluating genotype x environment interaction (GEI) and yield stability across 12 environments during 2004 to 2006 at south eastern Ethiopia. The objectives were to compare various statistical methods of analyzing yield stability and to determine the most suitable parametric procedure to evaluate and describe yield stability of field pea (Pisum sativum L.) genotypes performance under south eastern Ethiopian conditions. Several statistical analyses were conducted: coefficient of variation (CV_i); mean (); Shukla’s stability variance (); Wricke’s ecovalence (W_i); regression coefficient (b_i); deviation from regression (S_di²); cultivar superiority measure (Pi); deviation from the linear response (λ_i) coefficient of determination (r²_i) and additive main effect and multiplicative interaction. IFPI-1523 and IFPI -2711 were the most stable genotypes according to 8 out 10 stability statistics used in the study. Spearman’s rank correlation coefficient between the stability parameters indicated that Shukla’s stability variance (σ_i²), Wricke’s ecovalence (W_i), Eberhart and Russell’s deviation from regression (S²_di), and additive main effect and multiplicative interaction stability value (ASV) had a highly significant correspondence over the three years of study. No significant rank correlation between Lin and Binns’s superiority measure (Pi) and Finlay and Wilkinson’s procedure (b_i) with the other procedures were found. Thus, these two procedures are not recommended for use on their own as a measurement of yield stability. Conclusively, it is suggested that the use of appropriate biometrics techniques is necessary for identifying the most adapted, responsive and stable genotypes in the final phases of the plant breeding program, where the high cost and the time spent in assays are powerful justifications to search for improved methods.

Key words: Field pea, Pisum sativum L., Genotype x Environment interactions, yield stability.