GENETIC-ANALYSIS OF SOYBEAN RESISTANCE TO STINKBUG

Genetic mechanisms controlling the characters yield, healthy seed weig ht (HSW), percentage of healthy seeds (PHS) and leaf retention (LR) we re studied in crosses involving the commercial cultivars Davis, BR-13 and Lancer and the breeding lines IAC 74-2832 and IAC 78-2318, that ar e reported to carry insect resistance genes. These materials and their segregating F-2 and F-4 generations were evaluated in the field, unde r insect (Nezara viridula, Piezodorus guildinii and Euchistus heros - Pentatomidae) pressure. Line IAC 74-2832 was the most resistant. The g enetic models fitted to the means of the generations indicated the pre sence of additive, dominance and epistatic effects. The variance analy ses indicated a predominance of additive effects, but also revealed th e presence of linkage and genotype x microenvironmental interaction. T he breeding potential analyses indicated that it is possible to obtain high yielding resistant lines from Lancer x IAC 74-2832 and Davis x I AC 74-2832 crosses.