Response to indirect selection in ratoon of sugarcane seedlings

Abstract

Effectiveness of indirect selection criteria for brix yield based on 4 primary characters (number of millable canes per stool, NMC), cane diameter, cane height, and hand refractometer brix (HR Brix) was studied. A general index involving these traits was studied in 3 populations of ratoon seedlings. Selection based on number of millable canes was best, followed by selection based on selection index and cane height in ratoon crop. The differences in mean performance in ratoon crop disappeared at the evaluation stage in the clonal nursery under normal and restricted irrigated conditions. In general, all selection criteria, except selection based on HR Brix, gave similar responses for brix yield. Low repeatability of traits, insignificant regression coecients, and low proportion of clones outyielding the best standard variety CoH 35 at selection and evaluation stages indicated the ineffectiveness of selection at the single-stool ratoon seedlings stage. The reasons for ineffectiveness of selection based on the selection index are discussed.