STABILITY OF SOME COMMON BEAN CULTIVARS UNDER DIFFERENT PLANT DENSITIES

Abstract

A field experiment was carried out during two successive summer season at years 2016 and 2017 at privet farm, in Al-Rahmania district, El-Behira governorate, Egypt, to examine the magnitude of genotype-environment interactions over six different environments. The five commercial cultivars of common bean (Paulista, Valentino, Bronko, Nebraska, and Giza-6) were evaluated under six environments, i.e., combinations of one and two planting sides with densities (25, 20 and 15 cm). Pooled analysis of variance over all densities (environments) displayed significant to highly significant differences between genotypes and environment relative to studied traits, while significant genotypes × environment (G×E) were shown for each of plant height (cm), number of leaves/plant, number of pods/plant, pod yield/m2 and pod yield/feddan in both seasons as well as leaf area and each of number of branches, total chlorophyll and pod diameter in 1st and 2nd season, respectively indicating that genotypes responded differently to various environments which indicated a wide range of variability among the genotypes performance. The value of Regression coefficient “bi” approached nearly unity in some genotypes for some traits, indicating average response to the fluctuating environmental conditions prevailed the different densities across both seasons. On the other hand, “bi” value was more than one (bi>1) for some genotypes and on contrary, regression coefficient was less than 1 (bi<1) for 4 genotypes at least two to six studied traits in both seasons. Conclusively, high potential response for Nebrasca genotype in favorable environments with adequate water and other input and reverse trend for Paulista cv which exhibited low yield, regression coefficient “b value” was less than 1 for yield and some traits, showing it is more productive under unfavorable environments. The studied cultivars under studied densities might be of prime importance fortraditional agricultural procedures for high yield and/or some of its important components.