ABSTRACT
A two-year study was carried out in Giza Agricultural Experiments and Research Station, Agricultural Research Center (ARC), Giza, Egypt in the 2020 and 2021 summer seasons to evaluate the relative tolerance of ten soybean genotypes for cotton leafworm infestation under field conditions. Soybean genotypes H11L145, H155, H113, H4L4, H15L17, H129, H30, H19L96, Giza 111, and Crawford were distributed in randomized complete blocks design with three replications. Soybean genotypes differed significantly for cotton leafworm at the 6th, 7th, and 8th week from sowing. Low values of cotton leafworm assemblages were recorded for H113, H4L4, H15L17, Giza 111, and H129. Low percentages of the larval survival number and weight, as well as the number of the survival of pupa were recorded by feeding on leaves of genotypes H4F4, H15L17, and Giza 111 under laboratory conditions. There were significant differences among the studied genotypes in most yield attributes in both seasons. Soybean genotypes H15L17, Giza 111, H113, H129, H19L96, and H4L4 gave higher seed yield per ha, meanwhile soybean genotypes H155, H19L96, H30, Giza 111, and H15L17 had higher seed oil content than the other genotypes in both seasons. The number and weight of larvae surviving, as well as the number of pupa survival, were negatively correlated with leaf total phenols and seed oil content. It can be concluded that soybean genotypes H15L17, H4L4, and Giza 111 are promising genotypes with desirable seed oil content for tolerating cotton leafworm infestation in breeding programs.