Response of wheat germplasm to infestation of English grain aphid (Hemiptera: Aphididae).

The English grain aphid, Sitobion avenae (F.), is a destructive insect pest of wheat. In this study, wheat germplasm was evaluated for resistance and tolerance to English grain aphid infestation. Except for spikelet number/spike, the 1,000-kernel weight, spike weight, grain weight/ spike, and sterile spikelet number/spike of infested plants were all significantly impacted by English grain aphid infestation. Of 292 wheat accessions, only one genotype showed English grain aphid high resistance, and most genotypes showed intermediate resistance. Tolerance index values ranged widely among all accessions, but 11 genotypes had high tolerance to English grain aphid. Different resistance and tolerance parameters were positively correlated. Five green bug-resistant genotypes had a better English grain aphid tolerance index than other genotypes. Eleven genotypes exhibited a high or moderate level of tolerance and moderate level of resistance to English grain aphid. The broad-sense heritability of 1,000-kernel weight loss rate and peak aphid density were also estimated. English grain aphid resistant and tolerant lines identified in our study will be helpful in future breeding programs.