Genetic diversity analysis of some exotic, Indian and mutant Brassica sp. through RAPD markers

Genetic make-up of Brassica crops has been playing a major contributory role towards its enhanced production. The exploitation of genetic variation among races and gene pools in oilseed Brassica is essential as considerable diversity exists in the set of plants. In the present investigation, the isolatedDNA from 20 Brassica genotypes including exotic, Indian and few mutant varieties were subjected to 40 RAPD primers among which 31 detected polymorphism. A total of 240 DNA fragments were generated by the 31 primers. Cluster analysis of 1 - 0 bivariate data using UPGMA method delineated the genotypes into 4 groups and the data was further used for constructing a dendrogram

Segregation distortion and genome-wide digenic interactions affect transmission of introgressed chromatin from wild cotton species

This study reports transmission genetics of chromosomal segments intoGossypium hirsutumfrom its most distant euploid relative,Gossypium mustelinum. Mutilocus interactions and structural rearrangements affect introgression and segregation of donor chromatin. Abstract: Wild allotetraploid relatives of cotton are a rich source of genetic diversity that can be used in genetic improvement, but linkage drag and non-Mendelian transmission genetics are prevalent in interspecific crosses. These problems necessitate knowledge of transmission patterns of chromatin from wild donor species in cultivated recipient species. From an interspecific cross, Gossypium hirsutum × Gossypium mustelinum, we studied G. mustelinum (the most distant tetraploid relative of Upland cotton) allele retention in 35 BC3F1 plants and segregation patterns in BC3F2 populations totaling 3202 individuals, using 216 DNA marker loci. The average retention of donor alleles across BC3F1 plants was higher than expected and the average frequency of G. mustelinum alleles in BC3F2 segregating families was less than expected. Despite surprisingly high retention of G. mustelinum alleles in BC3F1, 46 genomic regions showed no introgression. Regions on chromosomes 3 and 15 lacking introgression were closely associated with possible small inversions previously reported. Nonlinear two-locus interactions are abundant among loci with single-locus segregation distortion, and among loci originating from one of the two subgenomes. Comparison of the present results with those of prior studies indicates different permeability of Upland cotton for donor chromatin from different allotetraploid relatives. Different contributions of subgenomes to two-locus interactions suggest different fates of subgenomes in the evolution of allotetraploid cottons. Transmission genetics of G. hirsutum × G. mustelinum crosses reveals allelic interactions, constraints on fixation and selection of donor alleles, and challenges with retention of introgressed chromatin for crop improvement