Path Analyses for Percent Fiber, and Cane and Sugar Yield in Sugarcane

Abstract

Path coefficient analysis is an excellent technique for measuring the direct and indirect effects of interrelated components of a complex trait. Although percent fiber in sugarcane(Saccharum spp.) is an important factor from the standpoint of milling efficiency, its effect on tons per hectare of cane( THC) has not been investigated. A knowledge of the effects of components of percent fiber and of the contribution of percent fiber to THC would be useful in deciding on selection criteria for improving THC. This study of plant‐cane and first‐ratoon crops from two locations was conducted to: (i) evaluate the direct and indirect effects of rind puncture resistance(measured by a rind penetrometer), percent juice extraction, and percent moisture retained by fiber (bagasse) on percent fiber, and( ii) determine the direct and indirect effects of percent fiber, stalk weight, and stalk number on THC. The direct effect of rind puncture resistance on percent fiber was positive( 0.1925), and those of percent juice extraction and percent moisture retained by bagasse were negative (−0.4729 and −0.7275, respectively). The coefficient of genetic variation (CGV) for rind puncture resistance was higher( 14.4%) than the CGVs for percent juice extraction and percent moisture of bagasse (2.6% and 3.7%, respectively). Reasonably rapid progress in reducing percent fiber would be made by selecting for softer stalks. The direct effect of percent fiber (0.024) on THC was negligible in relation to the direct effects of stalk weight(0.478) and stalk number (0.841). Cane yield would be increased by placing the greatest emphasis on stalk number, and next on stalk weight. Percent fiber was the least important component of THC. THC was the most important component of tons per hectare of sugar (THS), followed by sugar concentration. Percent fiber was the least important component of THS.