Genetic diversity for yield traits in prebreeding material of Saccharum spp

Abstract

Principal Component Analysis (PCA) was used in evaluating genetic divergence among the sugarcane interspecific hybrids generated based on 16 traits. The variation among the F1 hybrids of improved S.officinarum x improved S. robustum was attributed by cane height. Cane height was the only trait which contributed maximum towards variability followed by NMC. In backcross generation, it was observed that diversity among the genotypes with high positive factor loads was from cane height; NMC and cane diameter, SCW, brix%, sucrose% and CCS% also had positive loads for PC1 in relation to cane height. SCW, brix%, sucrose% CCS% were positively associated with cane height and NMC but cane diameter was negatively contributed to the variation. Cane height followed by NMC (which has positive factor loads in PC1) contributed maximum towards variation among hybrids. In BC1 and BC2 hybrids, PC1 is beneficial in selecting high yielding clones in terms of cane height and PC2 is important in selecting high quality clones in terms of brix% and sucrose %. Through the present study, a representative sample of 200 clones from various introgressed groups were identified based on the evaluation of yield and quality traits from the prebred gene pool (680 clones). The frequency distribution analysis for different traits indicated that the genetic variability available in the gene pool has been observed in the representative sample also. This group due to its reduced size, will aid in proper extensive exploitation of available genetic variability for biotic and abiotic stresses to identify clones with desirable characteristics for utilization in crop improvement programmes to combat with future challenges and in genomic studies.