RESPONSE TO INDIRECT SELECTION IN RATOON OF SUGARCANE SEEDLINGS

Effectiveness of indirect selection criteria for brix yield based on 4 primary characters (number of millable canes per stool, NMC), cane di ameter, 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 b est, followed by selection based on selection index and cane height in ratoon crop. The differences in mean performance in ratoon crop disap peared at the evaluation stage in the clonal nursery under normal and restricted irrigated conditions. In general, all selection criteria, e xcept selection based on HR Brix, gave similar responses for brix yiel d. Low repeatability of traits, insignificant regression coefficients, and low proportion of clones outyielding the best standard variety Co H 35 at selection and evaluation stages indicated the ineffectiveness of selection at the single-stool ratoon seedlings stage. The reasons f or ineffectiveness of selection based on the selection index are discu ssed.