Inheritance of resistance to Aphis glycines in soybean P746 from China.

The soybean aphid (Aphis glycines Matsumura) is one of the most serious pests of soybean (Glycine max [L.] Merrill) worldwide. Aphid resistance genes have been identified. However, little is known about genes for resistance to Chinese soybean aphid strains. The objective of this study was to identify the type of aphid resistance in the soybean cultivar P746 and to determine the inheritance of the resistance. In choice and no-choice tests, significant differences in the average number of aphids and the damage index were observed between P746 and the susceptible cultivar Dongnong 47 11 d and 21 d after aphid infestation. F2 plants and their F2:3 families were tested to identify the mode of inheritance of resistance. The 240 F2 plants segregated into 178 resistant and 62 susceptible plants, which matched an expected 3:1 ratio for inheritance of a single dominant trait. Segregation among F2:3 families also matched a 1:2:1 ratio. These results indicated that a single, dominant gene mediated aphid resistance in P746. This information will be useful to soybean breeders developing antibiosis-resistant soybean cultivars.