Julia L. Kornegay1, César Cardona1, Carmen E. Posso1
1Bean Program Centre Internacional de Agriculture Tropical CIAT A.A. 6713 Cali Colombia
Tóm tắt
Arcelin, a seed protein discovered in wild Phaseolus vulgaris L. accessions, gives high levels of resistance to the Mexican Bean Weevil [MBW; Zabrotes subfasciatus (Boheman)]. Five arcelin variants have been described. To better understand the genetic control of arcelin and MBW resistance, an inheritance study was conducted. Bioassay tests for insect response, and biochemical lasts to detect the presence‐absence of arcelin, were performed on the same individual seed. Accessions G12952 (arc‐4) and G02771 (arc‐5) had the highest level of resistance to MBW with no adults emerging from infested seed. Resistance was also found in G12882 (arc‐1) and G12866 (arc‐2), while G12922 (arc‐3) and the commercial cultivar, Pijao, were susceptible to the insect. The genetic study confirmed that all arcelin variants were inherited as a single dominant gene based on biochemical evaluations for presence‐absence of arcelin. Nevertheless, in bioassay tests with MBW, only crosses with arc‐1 and arc‐5 showed a single, completely dominant gene mode of inheritance, with the presence of arcelin being highly associated with resistance to the insect. For arc‐1 and arc‐5, biochemical tests can be reliably used to select for MBW resistance. For arc‐2, a combination of biochemical and bioassay tests is needed. As arc‐4 segregated few resistant individuals, and arc‐3 gave only intermediate to susceptible offspring, the use of these two arcelin variants is not recommended in a routine resistance breeding program. Electrophoretic patterns and bioassay tests of F1 and F2 generations showed that arc‐5 and arc‐1 variants are inherited as a single unit and are codominant.
