Generation mean analysis for yield components in common bean.

In order to choose an efficient breeding procedure, it is necessary to have knowledge of the genetic system controlling agronomically important traits. Common bean is one of the major legumes containing large amount of proteins and other valuable nutrients. The aim of this study was to determine genetic parameters for yield and yield components, using six generations (P1, P2, F1, F2, BC1, and BC2) derived from DERAKHSHAN × AND1007 and GOLI × D81083 crosses of common bean. A field experiment for these six generations was carried out in a randomized complete block design with three replications. The measurements included seed yield, pod weight, pod number per plant, seed number per pod, seed number per plant, and 100 seed weight. Generation mean analysis with three-parameter genetic model showed inadequacy of additive-dominance simple model to illustrate the genetic mechanism of the evaluated traits. Significant differences for two or more individual scaling tests (A, B, C, and D) in both crosses were recorded. Hayman six parameters genetic model suggested that both dominance and epistasis effects were important for most of the evaluated traits. Furthermore, expression of some traits in both crosses was affected by additive gene effects. Broad sense heritability was high for all traits except 100 SW in DER × A1007 cross. Estimation of narrow sense heritability range was moderate for most traits. For SY and traits where portion of non-additive gene effect was higher, it is possible to exploit heterosis using the plant materials in this study.