A THESIS SUBMITTED TO THE DEPARTMENT OF PLANT SCIENCES COLLEGE OF AGRICULTURAL SCIENCES, SCHOOL OF GRADUATE STUDIES ARBA MINCH UNIVERSITY IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN AGRONOMY

Abstract

Sugarcane chemical ripening is aimed at accelerating the sucrose accumulation in the stalks of sugarcane for harvesting when climatic conditions of crop year are hardly optimal for natural ripening at Omo Kuraz sugar project. Ripening in sugarcane is a problem due to high temperature and frequent rains resulting in continuous growth of crop influencing the effect of cropping off period. The study was conducted with the major objective of inducing ripening in sugarcane by application of Glyphosate at eight month age of the crop and six weeks before harvesting at Omo Kuraz sugar project during 2018 – 2019 cropping season. The study consisted of three sugarcane varieties, B52298, NCo334 and C86/12 and five rates of Glyphosate ripener treatment. viz., 240 g ai. ha-1, 300 g ai. ha-1, 360 g ai. ha-1,420 g ai. ha-1and control. Field experiment was laid out in split plot design with varieties as main plot and ripener treatments as sub plot. The varieties were differed significantly for cane yield, quality parameters and sugar yield. Brix (%) trend of three sugarcane varieties were showed conspicuous difference among varieties in the juice quality improvement. All the ripener treatments significantly improved quality characteristics such as Juice Brix, pol, purity and recoverable sugar percent cane. Ripener treatment at the rate of 360 g ai. ha-1 was found appropriate for varieties, B52298 and C86/12, whereas420 g ai. ha-1 was optimum for variety, NCo334. Marginal rate of return was maximum at ripener rate of 360 g ai. ha-1 that was 26.59.It was concluded that Glyphosate at 360g ai. ha-1 used for varieties B52298 and C86/12, and Glyphosate at 420 g ai. ha-1 for variety NCO334 may be used to induce ripening in sugarcane-and obtaining maximum sugar yield and income at Omo Kuraz sugar project.