Evaluation of ratooning ability in several sweet sorghum (Sorghum bicolor [L.] Moench) mutant lines

Abstract

Sweet sorghum (Sorghum bicolor [L.] Moench) is a multipurpose plant which can be grown for grain, forage, silage, syrup and/or sugar, and bioethanol production. Ratooning plant is an additional double ratooning scheme whereby the plant is harvested two or more times from a single planting during the growing season. The character of the main plant in the sorghum plant will determine the yield of the ratoon plant, however, information on the ratooning ability is lacking. The research objective was to determine the ratooning ability in the mutant lines of Numbu sorghum. The plant material consisted of 20 genotypes of the M6 mutant line which developed from gamma ray irradiation of Numbu variety. This research was arranged using completely randomized design which consisted of three replications with a cutting height of 10 cm. Each mutant line as a treatment was planted in a plot size of 3 m×2.5 m, with 70 cm spacing between rows and a 25 cm spacing in row. The observation was conducted on plant height, stalk diameter, panicle weight, and length, and sugar content (brix) of the stalk sap. The results indicated that mutant lines were having more or similar values when compared to the main plant in plant height, stalk diameter, and sugar content of stalk sap. The mutant lines N17-2, N17-3, and N17-5 that have high ratooning ability which is a desirable trait, as it reduces overall inputs in terms of seed and labor for field preparation, will be further used in research concerning their utilization for feeds and the fermentation industry.