Chlorophyll fluorescence and biomass of four cassava genotypes grown under rain‐fed upper paddy field conditions in the tropics

Abstract

AbstractExpanding the area under cultivation and increasing the productivity are two solutions to fulfil the high cassava demand. The objective was to determine the quantum efficiency of photochemistry, relative water content (RWC), growth and biomass of four cassava genotypes grown under rain‐fed upper paddy field conditions. The four cassava genotypes (Kasetsart 50, Rayong 9, Rayong 11 and CMR38–125–77) were evaluated under three environments in rain‐fed upper paddy field conditions in the Khon Kaen province, Thailand, between 2015 and 2017. The experiment used a randomized complete block design (RCBD) with four replications. Data recorded were soil characteristics prior to planting, soil moisture, leaf RWC, chlorophyll fluorescence under natural light () and artificial dark (Fv/Fm) conditions, total dry weight (TDW), storage root dry weight (SRDW), starch yield and weather data during crop duration. The results from combined analysis indicated that the growing environment had a greater effect than genotypes for RWC (except for RWC at 90 days after planting (DAP), , Fv/Fm, TDW (except for TDW at 150 DAP), SRDW (except for SRDW at 150 DAP) and starch yield. There were significant interactions between genotypes and environments for TDW, SRDW and starch yield. CMR38–125–77 was the superior genotype for growing under rain‐fed upper paddy field conditions when compared to the other three cassava genotypes. This study also showed the possibility of using and Fv/Fm as criteria to improve the efficiency for cassava varietal selection.