LEAF PERFORMANCES OF CASSAVA GENOTYPES IN DIFFERENT SEASONS AND ITS RELATIONSHIP WITH BIOMASS

Information on leaf performances in different growing seasons of cassava could help achieve the recommendation regarding suitable cassava genotypes for particular planting date and a new plant type to improve cassava productivity. The objective of this study was to investigate leaf growth habit and biomass of the four cassava genotypes grown under irrigated condition in different growing seasons. The four cassava genotypes, i.e., Kasetsart 50, Rayong 9, Rayong 11 and CMR38-125-77 were grown at 30 June 2015 and 20 May 2016 and 3 November 2016 at Khon Kaen University, Thailand. A Randomised Complete Block Design (RCBD) with four replications was used for each planting date. Data recorded were leaf life, fallen leaf ratio, leaf area index (LAI), leaf area duration (LAD), storage root dry weight, total crop dry weight, harvest index (HI) and daily weather data. The results indicated that greater values of leaf life during 180 days after planting (DAP), LAD during 180-270 DAP, and LAI at 270 DAP appeared to associate with higher temperature. A combination of LAI at 180 DAP, leaf life during 90 and 180 DAP and fallen leaf ratio for 90 and 180 DAP was related to total biomass, while storage root dry weight was associated with a combination of LAI at 180 and 270 DAP and fallen leaf ratio for 90 and 180 DAP. CMR38-125-77 produced high total biomass and storage root dry weight at 270 DAP with possessing high LAI at 180 DAP.