Growth Response of Cassava to Deficit Irrigation and Potassium Fertigation during the Early Growth Phase

Abstract

Cassava (Manihot esculenta Crantz) experiences intermittent water deficit and suffers from potassium (K) deficiency that seriously constrains its yield in the tropics. Currently, the interaction effect between deficit irrigation and K fertigation on growth and yield of cassava is unknown, especially during the early growth phase. Therefore, pot experiments were conducted under controlled greenhouse conditions using cassava cuttings. Treatments initiated at 30 days after planting included three irrigation doses (30%, 60%, 100% pot capacity) and five K (0.01, 1, 4, 16, and 32 mM) concentrations. The plants were harvested 90 days after planting. Decreasing irrigation dose to 30% together with 16 mM K lowered the leaf water potential by 69%, leaf osmotic potential by 41%, photosynthesis by 35%, stomatal conductance by 41%, water usage by 50%, leaf area by 17%, and whole-plant dry mass by 41%, compared with full-irrigated plants. Lowering the K concentration below 16 mM reduced the values further. Notably, growth and yield were decreased the least compared with optimal, when irrigation dose was decreased to 60% together with 16 mM K. The results demonstrate that deficit irrigation strategies could be utilized to develop management practices to improve cassava productivity by means of K fertigation under low moisture conditions.

Red-Green-Blue and Multispectral Imaging as Potential Tools for Estimating Growth and Nutritional Performance of Cassava under Deficit Irrigation and Potassium Fertigation

“…Four pot experiments were conducted with single-stem cuttings (25 cm) of yellow cassava "Mutura" cultivar (Kenya Agricultural and Livestock Research Organization (KALRO), Nairobi, Kenya) under controlled conditions in a greenhouse at the University of Helsinki, Finland, from 2017-2019, as described previously by Wasonga et al [48]. The experimental design was a split-plot arranged in a completely randomized design with four (EXP.…”

“…During the experiment, the plants were grown at day/night temperatures of 28/20 • C, relative humidity of 55% ± 5%, and photoperiod of 12 h light/dark with a photosynthetic photon flux density of 600 µmol m −2 s −1 of photosynthetically active radiation (PAR) at the top of the canopy. Further details of the treatments, experimental design, growth media, and plant management are described in [48]. Otherwise, imaging of the cassava plants was performed under greenhouse conditions for methodological reasons to determine applicability under field conditions.…”

Unlocking the inherent potential of plant genetic resources: food security and climate adaptation strategy in Fiji and the Pacific

“… Yam (English), uvi (Fiji), u'i (Cook Islands), ufi (Samoa), mami (PNG) Highly susceptible to cyclone damage (Taylor et al 2016 ) Anthracnose incidence increases (Wright and Peters 2002 ; O’Sullivan 2010 ) Anthracnose incidence increases (Wright and Peters 2002 ; O’Sullivan 2010 ) Rotting and death of plant (Onwueme et al 1994 ) Tuberization is delayed and yield reduced. (Onwueme et al 1994 ; Daryanto et al 2016 ) Salt intolerant, necrosis and poor root development (O’Sullivan 2010 ) Reduced tuberization (Bell and Taylor 2015 ; Onwueme et al 1994 ) Wild relatives could be utilized for enhancing pest and disease resistance and increasing tuber yield Ex-situ and In-situ conservation of traditional farmer varieties for mining desirable genes Manihot esculenta Cassava (English), tavioka (Fiji), manioka (Samoa), manioc (Vanuatu), maniota (Cook Islands) Strong winds can cause lodging of plants resulting in severe root damage (McGregor and Sheehy 2019 ) Root rot (Akrofi et al 2018 ; Lebot 2009 ) Higher incidences of Cassava Bacterial Blight (CBB), anthracnose and superelongation disease of cassava (Frison and Feliu 1991 ) Tolerant to droughts (FAO 2010 ) Reduced biomass, growth and yield, and increase in the concentration of cyanogens (Vandegeer et al 2012 ; Burns et al 2010 , Wasonga et al 2020 ) Reduced biomass, leaf area and rate of photosynthesis, and low concentration of macro and micronutrients in tubers (Gleadow et al 2016 ) Increased infestation of whitefly, vector of cassava mosaic and cassava brown streak diseases (Macfadyen et al 2018 ) Genomics, transcriptomics and metabolomics approach for cyanogen accumulation in varied temperatures Improving the existing genetic material present in PICs through recombinant DNA techniques and next-generation sequenc...…”

“…Reduced biomass, growth and yield, and increase in the concentration of cyanogens (Vandegeer et al 2012 ; Burns et al 2010 , Wasonga et al 2020 )…”

“…Prolonged exposure to dry spells during tuberization can lower yields by 32–60% (Boansi 2017 ). Decline in yield is attributed to reduced stomatal conductance, photosynthesis, number of leaves and leaf area, and is more pronounced during the first 5 months of planting (Burns et al 2010 ; Wasonga et al 2020 ). Cyanide concentration is around three times higher during drought years than in years with normal rainfall (Burns et al 2010 ).…”