Evolutionary Dynamics of Chromosomal Diversity in Saccharum spontaneum Population from Punjab and Haryana, India

Abstract

Saccharum spontaneum, the wild species of sugarcane, is an important germplasm resource with exceptional properties of pest and disease resistance and stress tolerance. Chromosomal diversity and its evolutionary dynamics in this species have been revealed through the study of 88 clones collected from the states of Punjab and Haryana, India. Twelve cytotypes were identified with five euploids [2n=40 (5x), 48 (6x), 56 (7x), 64 (8x), 72 (9x)] and seven aneuploids (2n=50, 52, 54, 60, 70, 74, 76). The random meiotic analysis showed predominant bivalent formation. The clone IND 16-1847 (2n=72) showed meiotic abnormalities like univalents, laggards, bridges, and multipolar chromosome segregation. Analysis of the evolutionary origin of different cytotypes revealed the independent, as well as multiple origins and the ploidy evolution, might be a network type rather than in a single direction. This leads to the increased allelic and genetic variation and gene flow among different ploidy levels of S. spontaneum.