Inheritance of genes imparting resistance to pod fly (Melanagromyza obtusa) in pigeonpea (Cajanus cajan)

Abstract

A study was conducted during 2002–05 to examine the mode of inheritance of field resistance in 8 crosses involving 4 resistant parents, viz. ‘PDA 88-2E’, ‘PDA 89-2E’, ‘PDA 92-2E’ and ‘PDA 93-2E’ and 4 susceptible parents, viz. ‘DA11’, ‘NDA1’, ‘ICP 5174’ and ‘ICP12386’ and their allelic relationship among genes imparting resistance to pod fly (Melanagromyza obtusa L. Malloch.) in resistant parents. The parental lines, their F1s, F2s and back crosses were evaluated for the pest reaction. In the F1 of all crosses between resistant and susceptible parents, a susceptible reaction was observed that indicates dominance of susceptibility over the resistance. The segregation pattern in F2 of these crosses revealed that resistance was controlled by 2 genes (mor1mor1Mor2Mor2) with interaction between recessive and dominant alleles in resistant donors, ‘PDA 88-2E’ and ‘PDA 89-2E’ and 2 homozygous recessive genes (mor1 mor1 mor2 mor2) were responsible for resistance in the parents, ‘PDA 92-2E’ and ‘PDA 93-2E’. From the reaction of individuals in F2 and backcross generations of crosses between resistant parents, the same genes were present in resistant lines, ‘PDA 88-2E’ and ‘PDA 89-2E’ which were allelic but differed for a single gene with the genes present in ‘PDA 92-2E’ and ‘PDA 93-2E’.