Potential of soybean genotypes as insect resistance sources

Partial diallel crosses between insect-attack susceptible and resistant soybean genotypes were realized in order to check the possibility of joining favorable alleles of insect resistance and high grain yield in the same genotype. F2 progeny was evaluated in three distinct locations, each one with a different priority: grain yield and responses to sucking and chewing insects. The experimental design was of randomized blocks with six replicates to evaluate F2 generation from 16 crosses and eight parent lines, amounting to 24 treatments. The experimental plot was represented by 12 individual plants with a row/plant spacing of 0.5 x 0.6 m. The best general combining ability was detected in parent IAC-100 for insect resistance and grain yield. Cross Davis x IAC-100 showed a higher potential for specific combining ability to grain yield and resistance to sucking and chewing insects.