GENETIC VARIABILITYAND SMUT RESISTANCE OF SUGARCANE (SACCHARUM OFFICINARUM L.) GENOTYPES FOR BREEDING IMPROVEMENT

Abstract

This study evaluated the agronomic performance, genetic variability and smut resistance of sugarcane (Saccharum officinarum L.) genotypes under field conditions. Thirty-five genotypes were evaluated using a Randomized Complete Block Design (RCBD) with three replications. Phenotypic and genotypic variances were estimated from analysis of variance, while cluster analysis, principal component analysis and correlation analysis were employed to assess genetic diversity and trait relationships. Seven selected genotypes, comprising five resistant and two susceptible parents were crossed using the North Carolina II mating design to estimate additive and dominance genetic variances, dominance ratio and heritability. Significant (P < 0.05) differences were observed among the genotypes for several agronomic and quality traits. The highest cane yields in the plant crop were recorded for NCS-009 (112.80 t ha⁻¹), NCS-003 (111.10 t ha⁻¹) and NCS-002 (104.43 t ha⁻¹), whereas NCS-002 produced the highest ratoon yield (74.43 t ha⁻¹). CP72-2086-1 recorded the highest plant crop brix (23.00%), while BR971007 (23.87%) and CP72-2086-1 (23.70%) maintained superior brix values in the ratoon crop. Genotypes NCS-002, NCS-007, KNB9218, NCS-003, DB75159, BR971007 and B245/B0197 exhibited high resistance to smut. High genotypic and phenotypic coefficients of variation for millable stalk and cane yield indicated a substantial genetic variability. The evaluated genotypes and progenies displayed variable responses to smut infestation across environments and crop cycles. Notably, the cross N27 × NCS-008 produced progenies with complete resistance to smut, highlighting its potential for developing resistant sugarcane cultivars.