Evaluation of Late Vegetative and Reproductive Stage Soybeans for Resistance to Soybean Aphid (Hemiptera: Aphididae)

The soybean aphid,Aphisglycines Matsumura, has become the most signiÞcant soybean (Glycine max (L.) Merrill) insect pest in the north central soybean production region of North America. The objectives of this research were to measure selected genotypes for resistance to the soybean aphid in the later vegetative and reproductive stages under Þeld conditions, and conÞrm the presence of tolerance in KS4202. The results from 2007 to 2011 indicate that KS4202 can support aphid populations with minimal yield loss at levels where signiÞcant yield loss would be expected in most other genotypes. The common Nebraska cultivar, OAsgrow 2703, appears to show signs of tolerance as well. None of the yield parameters were signiÞcantly different between the aphid infested and noninfested treatments. Based on our results, genotypes may compensate for aphid feeding in different ways. Asgrow 2703 appears to produce a similar number of seeds as its noninfested counterpart, although the seeds produced are slightly smaller. Field evaluation of tolerance in KS4202 indicated a yield loss of only 13% at 34,585Ð53,508 cumulative aphid-days, when 24 Ð36% yield loss would have been expected.