Analysis of Genetic Differentiation and Phylogenetic Relationships among Sugarcane Genotypes Differing in Response to Red Rot

摘要

The selection of parents is the most crucial step in any breeding programme. A better understanding of genetic diversity among the available genotypes would help the breeder to make better crosses. Advancements of DNA marker techniques in many crops have supplemented the morphological traits with molecular markers to identify the diverse genotypes. The genetic diversity of 30 sugarcane genotypes differing in response to red rot resistance was carried out using simple sequence repeat (SSR) markers. The polymorphism information content (PIC) ranged from 0.216 to 0.813 with an average of 0.525. The highest values (0.86) of proportion of polymorphic loci (P) and expected heterozygosity (He) were obtained in the susceptible population (S) and moderately resistant population (MR), respectively. Fst values between populations ranged from -0.043 to 0.041. However, AMOVA did not show much variation among the groups. Cluster analysis clearly distinguished all the genotypes from each other. The resistant genotypes namely ISH150 and SES594 emerged out to be most distinct genotypes, whereas the rest of the genotypes could be grouped in two broad clusters separating the moderately resistant and susceptible sugarcane genotypes. The clustering pattern was fairly supported by Mantel's test (r = 0.894) and high bootstrap value (75.0%). Thus, information given in the present study can be used in genetic resource management as well as in broadening the genetic base of cultivated sugarcane for red rot and selection of suitable parent for generating the mapping population for tagging the red rot resistance gene(s) in sugarcane.