Genomic Constitution and Genetic Relationship among the Tropical and Subtropical Indian Sugarcane Cultivars Revealed by AFLP

Abstract

Sugarcane (Saccharum spp.) is a tropical plant. In India, systematic breeding initiated early in the twentieth century led to the development of cultivars suitable for subtropical conditions. In spite of a long breeding history, no systematic effort has been made to understand the genetic constitution of these cultivars. The present study was performed to characterize 28 commercial sugarcane cultivars grown in the tropical and subtropical regions of India by means of amplified fragment length polymorphism (AFLP). Eleven of the 12 selective primer combinations used in the study could individually discriminate all the cultivars from each other, which suggested their usefulness in identification of sugarcane cultivars. Comparison of the AFLP profiles of the cultivars with that of their progenitor species revealed the presence of 78.8% of the 250 S. officinarum L. specific DNA fragments, whereas 28.85% of the 260 S. spontaneum L. specific fragments could be traced in the cultivars. Saccharum officinarum specific DNA fragments were found equally shared by the tropical and subtropical cultivars. The subtropical cultivars, however, retained significantly higher number of S. spontaneum specific DNA fragments than did the tropical cultivars, reflecting the breeding strategy followed in the development of these cultivars. The level of genetic diversity between the tropical and subtropical cultivars was much higher than most of the pair‐wise diversity measures within each of these two adaptive groups. The AFLP‐based clustering of the cultivars also corresponded well with their pedigree relationships.