Molecular screening of Heterorhabditis bacteriophora inbred lines for polymorphism and genetic crosses for the development of recombinant inbred lines

Males and females of two entomopathogenic nematode (EPN) inbred lines, H. bact -1 and H. bact - 2, whose infective juveniles expressed contrasting performance for stress factors, were used as candidates in genetic crosses. The crosses produced an initial pool of 108 F2 progenies and these were advanced by self-fertilization for 6 generations, each starting from a single hermaphrodite. After 6 generations and about 96% of homozygosity, 60 separate recombinant inbred lines (RILs) were recovered. The parental lines were previously subjected to molecular screening for polymorphism. The polymorphic markers detected in the parental inbred lines were screened across the genomic DNA of all the RILs for segregating allelic loci. Presence or absence of gel bands were scored as alleles due to the homogeneity attained by the inbred lines after 6 generations of self-fertilization. From the polymorphic markers detected, 19 were scored throughout the RIL population. This indicates the existence of a genetic heritable component for traits observed in the parental line of H. bacteriophora and therefore can be used to screen new population for desirable traits through marker assisted selection and could be useful for developing a genomic linkage map. Keywords: Genetic-crosses, RILs, Polymorphisms, Genetic-Markers, EPN