Clonal improvement of sugarcane based on selection for moisture content: Fact or fiction

Sugarcane quality components traditionally have been measured on a fresh weight basis for industry payment purposes ,ad for clonal evaluation. This paper reports a test of a hypothesis that there is no genetic variation for sucrose per cent dry matter and that selection for sucrose per cent fresh weight merely exploits variation in moisture content. Data for CCS, dry matter pol, fibre, moisture, and pol in cane from three Stage 4 selection trials were examined for genetic variability and direct and correlated selection responses in CCS. The basic constituents of solubles, insolubles, and moisture were determined independently. Dry matter pol differed little from CCS for heritability and genetic variability. Genetic variability for moisture was restricted. CCS and moisture were negatively and weakly to !I1oderately correlated, while CCS and dry matter pol varied from being intermediately to moderately highly correlated across trials. Moisture and dry matter pol were moderately correlated in two trials. Direct selection for moisture and dry matter pol resulted in average correlated responses in CCS of 39.3% and 73.3%, respectively, of the 10.0 g kg-1 estimated gain from direct selection. The results from the analyses conducted provided no support for the hypothesis, and further consideration of this for plant improvement appears unwarranted.