Morphological characterization and genetic diversity analysis of interspecific hybrids of sugarcane

Interspecific hybrid derivatives involving Saccharum spontaneum, S. robustum and S. barberi were morphologically characterized with twenty two qualitative and six agronomic traits. Principal component analysis (PCA) of qualitative traits revealed that first nine principal components with eigen value > 1 accounted for a cumulative variance of 62.40 %. The traits viz, ligule shape, auricle type, internode shape and its alignment, cane thickness, dewlap color, leaf blade width and curvature, leaf sheath hairiness, bud cushion and bud groove were identified as principal discriminatory characters which will be useful in preliminary screening and identification of interspecific hybrids. Cluster analysis of qualitative traits grouped hybrids into seven clusters. Maximum inter cluster distance was between cluster IV and VI followed by cluster I and III, III and VII and between VI and VII. Metroglyph analysis of agronomic traits categorized hybrids into ten groups. Groups III, IV, V, VIII and X with highest mean index scores were identified as genetically most distant. Thirty eight superior interspecific hybrids with high index score for agronomic traits (from metroglyph analysis) and wider inter cluster distance were identified as prebreeding stocks and utilized in further backcross programmes. BC1 progenies of SBH 12-45 x Co 0303 and SRH 12-275 x Co 0240 were significantly superior for single cane weight and brix %. Elite recombinants from back crosses SSH 12-158 x Co 0209, SSH 12-409 x Co 09014 and SRH 12-119 x Co 94008 surpassed commercial check for cane yield and were on par for quality.