GENETIC STUDIES ON GROWTH, EARLINESS YIELD AND ITS COMPONENTS, AND SEED QUALITY IN BROAD BEAN (Vicia faba L.)

Abstract

A 4 x 4 diallel cross with reciprocals was performed among four cultivars of broad bean (Vicia faba, L.), i.e., two Spanish cultivars named Luz de otono and Reina mora, one local cultivar called Giza planka, and a selected line, cv. (Sabaaty). The four parents and their 12 F1 hybrids and reciprocal crosses were evaluated in a field experiment designed in a randomized complete block with 3 replicates. This investigation was carried out during the winter seasons of 2005/2006, 2006/2007 and 2007/2008 under field conditions at Sabaheya Horticultural Research Station, Alexandria Governorate, Egypt. The main objectives were to evaluate the average degree of heterosis in the crosses in addition to the estimation of combining ability and its components. The obtained results reflected generally that all of the first hybrid generations, including the reciprocal crosses, tended to show values either higher than those of their respective lower parental values or deviated towards their higher parental values for the vegetative growth characters. The results indicated also that all of the F1 hybrid populations were either more than their mid-or high- parental values for total yield and all its components characters. Positive heterosis estimates, relative to mid-parents, were detected in most of the F1 hybrids for vegetative growth characters. Concerning total yield and its components, positive heterotic effects were noticed on most of the first hybrid generations, including reciprocals. The results indicated also that both general combining ability G.C.A. (additive effects) and specific combining ability S.C.A. (non-additive effects) appeared to be important in controlling the expression of all studied characters; but with relatively more important roles for S.C.A. effects. The results indicated also that the parental cultivar Reina mora (P1) could be considered as a good general combiner for breeding to earliness, vegetative characters and yield and its components. The combinations of P1 X P2, P1 X P3, and P2 X P3 exhibited significant positive values for the most characters of vegetative growth, yield and its components. Correlation values among pairs of characters exhibited that number of pods/plant and pod weight should to be the first concern for improving yield of faba bean.