QUANTITATIVE GENETIC ANALYSIS OF IN VITRO CALLUS PROLIFERATION IN ALFALFA

Genetic variability exists for in vitro callus growth within plant species, including alfalfa (Medicago sativa L.). The objective of this study was to investigate, using diallel crosses, the genetic variance components of in vitro callus production in tetraploid alfalfa. Nine genotypes were randomly chosen from among 60 plants from the cultivar Saranac and the experimental population OAC81-120R, which were previously characterized as being able to initiate callus. The group of nine plants was divided and crossed to generate two, six-plant diallel sets (A and B) with reciprocals; and the progeny were evaluated for callus production. Significant (P < 0.01) differences were found among crosses and for general combining ability (GCA) effects in both diallels. Specific combining ability (SCA) and reciprocal effects were found to be nonsignificant (P < 0.05). Estimates of heritability (h2) for callus production on a plot mean basis were 73% and 61% for diallel A and B, respectively. Since the heritabilities wer...