GENOTYPE BY ENVIRONMENT INTERACTIONS FOR SUCROSE CONTENT IN SUGARCANE (Saccharum spp. hybrid) CLONES GROWN UNDER RAINFED CONDITIONS IN WESTERN KENYA

Abstract

Sugarcane (Saccharum spp hybrid) refers to sucrose storing members of the family (poaceae) and is cultivated primarily for the extraction of sucrose (sugar) from the plant stalks. Recent uses of this tropical crop include the utilization of its plant biomass for cogeneration and production of ethanol. Genotype × Environment interaction is the relative difference in response of genotypes in different environments. Limited research has been conducted to determine the magnitude of G×E on sucrose content in Kenya. The objectives of this study were: (i) to avail and enhance information on the magnitude of genotype × environment interaction for sugarcane sucrose content, (ii) to evaluate 22 sugarcane clones and 3 cultivars for sucrose content and agronomic traits in Western Kenya, (iii) to identify promising clones of sugarcane for further testing. The study was conducted in three sites namely KALRO Sugar research Institute at Kibos, Mumias Sugar Company nucleus estate and South Nyanza Sugar Company Awendo in Western Kenya. Lattice square design with three replications was used in the study. Significant differences among the genotypes were observed in most traits tested; Genotype × location interactions were significant (p<0.01) for milleable stalks, stalk girth, and brix. The effect of environment was significant for all the quantitative and qualitative traits studied. Milleable stalks and stalk height were significantly associated with cane yield. Significant correlations were observed among cane yield components with the exception of girth. Sucrose content was positively correlated with juice purity. Performance of clones in cane and sugar yield related traits varied across locations. Overall, the genotypes performed better in South Nyanza than in Kibos and Mumias in quantitative traits. However, performance was better in Kibos for qualitative traits. The most outstanding genotypes in both cane quality and yield were KEN 04 -1809, KEN 04 -1603, KEN 04-1079, KEN 04-419, KEN 04-2010 and KEN 04-2192. Genotype KEN 82-493 was outstanding in sucrose production across the three locations. This study has demonstrated the importance of multi-location testing of genotypes to enhance selection traits of interest.