Screening pigeon pea accessions for resistance to root knot nematode (Meloidogyne incognita) under field conditions

Abstract

Field experiments were conducted for two consecutive years (2006 and 2007) to access the reaction of 10 accessions of pigeon pea for resistance to natural infestation of Meloidogyne incognita. Fifteen weeks after planting, 10 randomly selected plants per treatment were examined for root-galls. Data on plant height, stem girth, days to flowering, days to 50% flowering, number of main branches, number of sub-branches, height to main branch, pod length, seed/pod and yield were also collected. Root galling varied significantly among the pigeon pea accessions. Root galling correlated negatively with number of pods and leaves; however, there was positive correlation between root gall and stem girth when all the 10 accessions were considered. Of the 10 pigeon pea accessions, none out of the 10 accessions evaluated was resistant to M. incognita and none was also immune to M. incognita under field conditions. Two of the accessions were tolerant to M. incognita under field conditions (Cc 10B and Cc 12), with grain yield ranging between 1356 and 1300 kg/ha in 2006 and 1300 and 1200 kg/ha in 2007, a gall index rating of <2 and a reproduction factor of >1, while the rest eight accessions were susceptible to M. incognita under field conditions with grain yield ranging between 1035 and 896 kg/ha in 2006 and 1025 and 865 kg/ha in 2007, with a gall index rating of >2 and a reproduction factor of >1. Based on reproduction factor, all the susceptible pigeon pea accessions supported greater nematode reproduction while the tolerant pigeon pea accessions were poor host of M. incognita.