Identifying the Principal Contributing Traits for Commercial Cane Sugar Yield at First Clonal Selection Stage in Sugarcane (Saccharum spp.)

Abstract

Commercial cane sugar (CCS) yield is the main target product in sugarcane, which depends on the sucrose content and cane yield related traits. Understanding the factors influencing CCS yield would help us to enhance the selection efficiency for sugar yield. A population of 1,080 seedlings derived from nine bi-parental crosses involving Indian Co canes and Co allied hybrids were evaluated in seedling stage. A subset comprised of 270 clones selected from the single stool stage were evaluated in the first clonal trial to identify major component traits of CCS yield in the early stages of selection. Investigations were undertaken in the population to explore the feasibility of employing PCA and regression analyses to provide a basis for selection criteria for identification of sugarcane genotypes that are higher in CCS yield. Comparative performance of families at ground nursery indicated that screening of seedling progenies should be towards the crosses with higher mean value of H.R. brix% and single cane weight to enhance the frequency of superior individuals in subsequent clonal generations. The results of correlation analysis at first clonal stage suggested that yield related traits including tillers at 120 days, single cane weight, number of millable stalks and cane yield are the most important characters that significantly influences the CCS yield. Principal component analysis revealed that four factors could explain approximately 80.40% of the total variation for CCS yield in the population studied. The first factor which accounted for 31.19% of the variation was strongly associated with juice brix%, sucrose%, H.R. brix%, purity% and CCS%, whereas the second component had a positive effect from single cane weight, juice weight and cane diameter explaining 21.74% of total variability. The third factor accounted for 18.97% of variability and had contribution from tillers at 120 days, number of millable stalks and cane yield. Stalk height was independent from other traits which accounted for 8.48% of variation in component 4. Stepwise regression analysis demonstrated that CCS%, cane yield and sucrose % had considerable high effects on commercial cane sugar yield which explained 85.53% (expressed as R2) of variability in clones derived from bi-parental crosses between Indian Co canes.