GENETICS OF 6 COMPONENTS OF AUTOFERTILITY IN VICIA-FABA

The inheritance of six components of autofertility was studied in faba beans in two consecutive years (1989 and 1990) by analysing parents, Fl and segregating generations of 14 crosses between preselected pure lines. Genetic analysis was performed by a joint scaling test proposed by CAVALLI (1952). Additive gene effects were more important than dom inance effects in flowers/node, pods/flower and ovules/ovary. In contr ast, characters directly related with the seed such as pods/node, seed s/pod and, to a lesser extent, seeds/ovule showed high positive values of dominance. The three latter traits in general exhibited strong het erosis, probably due to genetic interactions. In order to produce sele ction gain, any breeding programme has to consider that dominance and heterosis vary according to the character involved. The present study reveals different degrees of dominance expression depending on cross s pecificity as well as on environmental conditions. The advantages of s tudying segregating generations instead of diallel crosses and the nee d for a simultaneous study of many crosses are emphasized in this pape r.