Inheritance pattern of okra enation leaf curl disease among cultivated species and its relationship with biochemical parameters

ABSTRACT

Okra production in eastern India at present is severely threatened by whitefly-mediated okra enation leaf curl disease(OELCuD). Identification of resistant genotype and understanding the genetic control and biochemical relationship of OELCuD resistanceare prerequisite for developing an effective breeding strategy. This study was conducted employing six populations (P1, P2, F1, F2, BC1 andBC2) of two selected (resistant 9 susceptible (R9S)) crosses. Associationship between severity of OELCuD and biochemical parametersof parents and hybrids at preflowering and flowering stages was studied. Segregation pattern of the genotypes in F2 generation showingOELCuD reaction of two crosses suggested that two duplicate recessive genes was operative for resistance to OELCuD. Generation meananalysis revealed involvement of both additive and nonadditive effects in the inheritance of disease resistance. Hence, postponement ofselection in later generations or intermating among the selected segregates followed by one or two generations of selfing to break theundesirable linkage and allow the accumulation of favourable alleles could be suggested for the development of stable resistant genotypeagainst this disease. Higher peroxidase activity and total phenol content in leaf emerged as reliable biochemical markers for early selectionof genotype resistant to OELCuD.