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

Settawoot Wongnoi,Nimitr Vorasoot,Piyada Theerakulpisut,Poramate Banterng,Sanun Jogloy

doi:10.3390/agronomy10040576

Abstract

Additional information on the physiological performances for different cassava genotypes would support better decision-making about desirable genetic resources for water-limited conditions. The objective of this study was to evaluate the physiological expression and yield of eight different cassava genotypes grown under a dry environment during high storage root accumulation. The eight cassava genotypes, i.e., Kasetsart 50, Huay Bong 80, Rayong 5, Rayong 7, Rayong 9, Rayong 11, Rayong 90, and CMR38-125-77 were evaluated under rain-fed upland conditions at Khon Kaen University, Thailand, during 2018 to 2020. A randomized complete block design (RCBD) with three replications was used. Soil moisture contents, chlorophyll fluorescence (Fv/Fm and Fv′/Fm′), net photosynthesis (Pn), stomatal conductance, water use efficiency (WUE), relative water content (RWC) for leaf, leaf area index (LAI), specific leaf area (SLA), starch content, crop dry weight, and starch yield were observed at 180, 270, and 360 days after planting (DAP), and weather data during the experimental period were also recorded. The results from both 2018/2019 and 2019/2020 indicated that Pn was positively and significantly correlated with stomatal conductance and Fv/Fm during the high storage root accumulation stage (270 and 360 DAP) with soil moisture content lower than field capacity. CMR38-125-77 had satisfactory performances in Pn, RWC, Fv/Fm, Fv′/Fm′, stomatal conductance, LAI, SLA, WUE, biomass, starch content, and starch yield at a last growth stage with soil moisture content lower than permanent wilting point. Significant association between crop dry weight and WUE at 360 DAP was recorded, and CMR38-125-77 and Kasetsart 50 were classified as favorable genotypes with high WUE and biomass.

Highlights

Cassava is an important economic crop in the world, and it is widely cultivated in tropical and subtropical regions [1,2]
The recorded values of soil moisture contents at 270 and 360 days after planting (DAP) were lower than the field capacity (FC) and closer to the permanent wilting point (PWP), respectively
This study reviewed the physiology, biomass and starch yield of eight different cassava genotypes planted under limited rainfall conditions during high storage root accumulation

Summary

Introduction

Cassava is an important economic crop in the world, and it is widely cultivated in tropical and subtropical regions [1,2]. Due to the world population increasing, the global demand for cassava is scaling up. Thailand is recognized as a major cassava producer, yielding approximately 31.2 million tons in. The average productivity in a country is approximately 23 ton ha−1 , which is a lower than. Agronomy 2020, 10, 576 expected yield (80 ton ha−1 ) [2]. Most of the farmers in Thailand have cultivated the cassava under rainfed conditions in upland areas with the occurrence of water shortages during the growing period, leading to water stress and low productivity [8,9]. Breeding and selection for high yield potential and for smaller yield reduction when a crop is affected by the limited water is an alternative strategy to overcome such a problem in a sustainable manner

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Results

Conclusion