Effect of water stress and soil texture on growth, yield and quality attributes of potatoes (Solanum tuberosum L.)

Abstract

Potato (Solanum tuberosum L.) is an annual dicotyledonous tuber herbaceous crop. The crop is relatively susceptible to water stress when compared to other major field crops. Soil texture plays a pivotal role in the correlative relationship between climate, soil, and vegetation, which are dependent on soil moisture dynamics and in correlation to vegetation water stress. This study investigated the effects of water stress and soil texture on potato growth, yield, and quality attributes. The pot experiment was conducted during the 2021(spring)/2022(winter) cropping seasons in a plastic tunnel at the University of Venda (UNIVEN) Experimental Farm situated at Thohoyandou. The experiment was laid out in a Completely Randomized Design (CRD) with two potato cultivars (Mondial and Bp1), three soil textural classes (clay, sandy clay loam, sandy loam), and three water stress levels (30%FC (field capacity), 60%FC,100%FC) with three replicates making a total of 54 experimental units (polyethylene pots). Data collected was subjected to ANOVA using Minitab 21. Water stress × soil texture interaction had a significant (p<0.05) effect on plant height at 51 DAP (days after planting) to 72 DAP, and from 44 DAP to 86 DAP during the 2021/2022 cropping seasons, respectively. The interaction of water stress and soil texture had a non-significant (p>0.05) effect on leaf area. Water stress × soil texture interaction had a significant (p<0.05) effect on stem diameter at 93 DAP, and 65 DAP during the 2021/2022 cropping seasons, respectively. There was no significant (p>0.05) interaction effect between water stress and soil texture on marketable potato yield during the 2021 cropping season, but the interaction had a significant (p<0.05) effect during the 2022 cropping season. This study suggested that severe water stress (30%FC) could be adopted for potato cultivation in winter season. The tuber sizes and shapes produced during the 2021 cropping season were observed to be smaller (<55mm) and short-oval (1.10 to 1.29) to oval (between 1.30 and 1.49). However, during the 2022 cropping season tuber sizes and shapes obtained larger tuber sizes (≥75mm) and long oval (between 1.50 and 1.69) to long (≥1.70). The specific gravity (1.05 -1.07) was suitable for the potato tubers to be used for processing. The skin colour of the Bp1 and Mondial cultivars were yellowish, while flesh colours were light yellow making them suitable for consumers and the market. Therefore, the results suggest vi that 30%FC irrigation water level can be economical for production during the winter season in semi-arid region regardless of the soil texture type (clay, sandy loam, and sandy clay loam).