Host Plant Resistance and Analysis of Chemical Compounds Responsible for Bruchid Resistance in Greengram Vigna radiata (L.) Wilczek

Background: Greengram Vigna radiata (L.) Wilczek, is an important legume crop that serves as a low-cost source of protein. The bruchid (Callosobruchus spp.) is a serious storage pest affecting greengram and other pulse crops. Thus, a study was designed to investigate bruchid resistance (Callosobruchus chinensis) in inter sub-specific derived lines of greengram and to identify chemical compounds responsible for resistance. Methods: The experimental material comprised of 200 inter sub-specific derived lines of F-9 generation of VBN (Gg) 2 (susceptible to bruchid). Vigna radiata var. sublobata/2 (resistant to bruchid) and a susceptible check variety. The bruchid screening experiment was carried out in completely randomized design and replicated twice with 50 seeds in each replication by adopting no choice test. Out of 200 lines evaluated for bruchid screening, seed damage due to bruchid was less than 20 per cent in 11 lines, identified as resistant. However, three resistant lines viz., GGISC 124, GGISC 140 and GGISC 150 were taken for further confirmation for bruchid resistance and GC-MS analysis to discover the chemical compounds conferring resistance (Clarus SQ 8C, Perkin Elmer). Result: In confirmation screening, seed damage due to bruchid (Callosobruchus chinensis) on 30(th) day was less than 20 per cent in three inter sub-specific lines viz., GGISC 124, GGISC 150 (17.00%) and GGISC 140 (18.00%), whereas the susceptible check [VBN (Gg) 2] reached 100 per cent adult emergence. The three inter sub-specific lines recorded susceptibility index of 0.046 (GGISC 124), 0.047 (GGISC 140) and 0.048 (GGISC 150) and classified as resistant. The susceptible check [VBN (Gg) 2] recorded the susceptibility index of 0.085. GC-MS study was carried out in resistant lines GGISC 124, GGISC 140, GGISC 150 and susceptible check VBN (Gg) 2. The results revealed that the existence of three compounds viz., 9, 12-octadecadienoic acid, methyl ester; Hexadecanoic acid, 1-(hydroxymethyl)-1, 2-ethanediyl ester and Hexadecanoic acid, 2-oxiranyl methyl ester in resistant lines conferred resistance against C. chinensis in greengram.