Genetics and introgression of resistance to root-knot nematodes (Meloidogyne spp.) in common bean (Phaseolus vulgaris L.)
AbstractGenetics studies on the resistance to Meloidogyne spp. in common bean (Phaseolus vulgaris L.) were carried out in a glasshouse. F1 hybrids and F2-F4 progenies, derived from crosses of the Mesoamerican resistant accessions A#445 and PI#165426 with CRA-ISCI lines 212/28 and 15/7-70, were evaluated for resistance to Italian populations of Meloidogyne incognita race 1 and M. javanica. All F1 hybrids were resistant to both nematode species. Ninety-eight, 17 and 136 F2 lines were resistant, susceptible and segregant to the nematodes, respectively, and 1909 and 655 plants were resistant and susceptible, respectively. The results suggest a monogenic dominant control of the resistance, with a ratio 3:1 of resistant to susceptible plants. Of the 52 selected F4 lines tested for their reaction to race 1 of M. incognita, 22 were resistant, 24 segregant and six susceptible. Of the 52 F4 lines tested against M. javanica, 31, 11 and 10 were resistant, segregant and susceptible, respectively.