Analyse de croisements diallèles pour les caractères agronomiques de plantes saines et virosées chez le haricot (Phaseolus vulgaris L.)
The study of agronomic characters of healthy and virus diseased plants in a diallel cross program concerning five different varieties of bean, shows that in both cases the general combining ability for yield and its components usually has positive or negative significant values; the maximum value of the general combining ability for each yield component is characteristic of each variety; and the number of specific combining ability cases are less numerous than those of general combining ability. Usually positive specific combining ability is obtained from two negative and positive cases of general combining ability because of nonadditive genes interaction. Values for general and specific combining abilities are, in some cases, significantly modified by the bean common mosaic virus. This shows that quantitative genetic studies concerning agronomical and physiological characters are always influenced by external factors including culture conditions as well as parasites. The results obtained are valuable only for the studied varieties and conditions in which the experiment is achieved.Key words: bean, diallel crosses, virus No. 1, combining ability.