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

Abstract

Expanding 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 (Fv′/Fm′) 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′, 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 Fv′/Fm′ and Fv/Fm as criteria to improve the efficiency for cassava varietal selection.

Cassava Growth Analysis of Production during the Off‐Season of Paddy Rice

“…The high photosynthetic capability of the leaf is of fundamental importance for more growth and storage root yield of cassava (El-Sharkawy et al, 1990;De Tafur, 2010). In addition to LGR during 120 to 180 DAP, quantum efficiency of photochemistry of Photosystem II of leaves may serve as a selection criterion to improve the efficiency of cassava yield trials, as Sawatraksa et al (2018) showed a significant relationship between this trait and storage root yield of cassava grown in upper paddy field during the rice off-season. A study from Phoncharoen et al (2019) with the same four cassava genotypes but under ) using a graphical approach for analyzing the genotype main effect plus genotype ´ environment interaction (G + GE) or GGEbiplot software (PC 1 and PC 2 are the first and second principal components, respectively; SVP is singular value partitioning).…”

“…Pellet and El-Sharkawy (1993) and Pellet and El-Sharkawy (1997) reported that the growth rate of leaves is a fundamental cassava characteristic to enhance the formation of the leaf canopy, leaf area index, light interception, and canopy photosynthetic rate, and consequently high storage root yield and total biomass. In addition to LGR during 120 to 180 DAP, quantum efficiency of photochemistry of Photosystem II of leaves may serve as a selection criterion to improve the efficiency of cassava yield trials, as Sawatraksa et al (2018) showed a significant relationship between this trait and storage root yield of cassava grown in upper paddy field during the rice off-season. There are, therefore, various suggested criteria for cassava varietal selection.…”

“…Therefore, cassava can be a potential crop for upper paddy fields during the off-season of rice with limited and unreliable soil water. This study found that large values of chlorophyll fluorescence were related to high total and storage root dry weights and starch yield, which suggests that cassava leaf photosynthetic capacity was not inhibited by drought conditions (Sawatraksa et al, 2018). Polthanee et al (2014) studied growth, yield, and starch content of different cassava genotypes (Rayong 7, Rayong 11, Rayong 72, Kasetsart 50, and Huay Bong 80) grown under rainfed conditions after rainfed lowland rice harvest in northeast Thailand.…”

“…A study on chlorophyll fluorescence as an indicator trait for efficiency of Photosystem II and leaf photosynthetic capacity and biomass of four cassava genotypes (Kasetsart 50, Rayong 9, Rayong 11, and CMR38-125-77) grown on an upper paddy field in Thailand has been reported. This study found that large values of chlorophyll fluorescence were related to high total and storage root dry weights and starch yield, which suggests that cassava leaf photosynthetic capacity was not inhibited by drought conditions (Sawatraksa et al, 2018). To gain additional knowledge and more understanding about adaptability and physiological determinants of yield for cassava grown after rice under upper paddy field conditions, there is a need to evaluate growth rates and other crop performance of cassava in multiple environments.…”

Physiology, Growth and Yield of Different Cassava Genotypes Planted in Upland with Dry Environment during High Storage Root Accumulation Stage

“…Oyetunji et al [12] reported the performances on chlorophyll fluorescence and biomass of two cassava genotypes (TMS 4(2) 1425 and TME1) grown under water stress for 3-6 months at the International Institute of Tropical Agriculture (IITA), Ibadan, Nigeria. The data in terms of relative water content (RWC), chlorophyll fluorescence, and biomass for cassava genotypes were documented for growing in a greenhouse with water stress during the early growth stage [13] and for planting under rainfed conditions (water shortages between 2 to 6 months after planting) in upper paddy fields during the off-season of rice [14]. However, there is no evidence of physiological characteristics with respect to Pn, crop water status, chlorophyll fluorescence (Fv/Fm and Fv /Fm ), stomatal conductance, and water use efficiency (WUE) coupled with biomass and yield of other commercial cassava genotypes grown under rainfed upland conditions with limited water during a growth period, of high partitioning to storage root (9-12 months after planting) [15] in Thailand.…”