Effects of Elevated Temperature on Agronomic, Morphological, Physiological and Biochemical Characteristics of Potato Genotypes: 1. Agronomic and Morphological traits

Abstract

AbstractGlobal elevated temperatures create uncertainties in crop yield production and sustainability, threatening potatoes’ food security and sustainability roles. This has been among the primary research concerns necessitating the need to evaluate potato genotypes’ response to elevated temperature under field conditions. This study assessed potato genotypes’ agronomic and morphological responses to elevated temperatures. The experiments were conducted under field conditions in the 2022 and 2023 cropping seasons in a split-plot design. Two heat treatments were applied; a control treatment in which the plants received the field temperature of the experimental station, and a heat treatment in which the plants received a temperature of + 6.0–10.0 °C depending on the date and time of day. The agronomic and morphological traits evaluated included tuber yield, mean tuber weight, days to emergence, plant height, number of stems per plant, days to physiological maturity, and tuber size distribution. The results showed significant (P < 0.01) variations in the potato genotypes in response to elevated temperature in all traits except days to emergence. Elevated temperature promoted plant height by 36.94%, and days to physiological maturity by 2.55%, while reducing the number of stems per plant by 11.77% and days to emergence by 2.31%. Furthermore, elevated temperature increased total tuber yield by 25.38%, the number of tubers per plant by 18.75%, mean tuber weight by 8.89%, third-class tuber size distribution by 25.95% and malformed tuber ratio by 1.98%, while decreasing first-class tuber size distribution by 10.11%, second-class size distribution by 1.70% and marketable tuber yield by 4.22%. The results of this study demonstrated the impact of heat stress on potato tuber yield and size distribution. The study showed that temperatures around 27.0 °C to 33.0 °C effectively promoted total tuber yield, number of tubers per plant and mean tuber weight; thus, an increase in temperature within the effective range of potato plants promoted yield and yield-related components. This study demonstrates that open-sided field chambers can be a screening tool for heat tolerance of potato genotypes under field conditions. Potato genotypes with less variation in the traits between the heat and control treatment demonstrate heat tolerance and could be used as selection markers for heat-tolerant genotypes.