Morpho-Physiological Evaluation of Potato Genotypes Reveals Differential Responses to Drought Stress under Field Conditions

Potato yield and quality productivity are often constrained by drought stress, which affects food security and sustainability. However, under natural growth conditions, few studies have investigated the response of potato genotypes under field conditions. This study was conducted to assess the response of 29 potato genotypes to drought stress under field conditions. The experiment was set up in a randomized complete block with four replications for two potato-growing seasons using drip irrigation. Drought treatment was initiated 35 days after sowing. The stress treatment was irrigated at 3-day intervals, while the control treatment was irrigated at 6-day intervals until 15 days before harvesting. All potato genotypes showed differential responses to drought stress, with plant height, leaf temperature, leaf area index, total tuber yield, marketable tuber yield and dry matter content being significantly (p ≤ 0.05) affected. Based on the drought tolerance, drought susceptibility and yield stability indices, genotypes MEÇ04, MEÇ07, MEÇ12, MEÇ13, MEÇ16, MEÇ17, MEÇ19, MEÇ20, MEÇ22, and MEÇ24 showed tolerance to drought stress conditions, while the rest of the potato genotypes were susceptible to drought. An analysis of Pearson correlation and principal component analysis indicated that the first four PCs accounted for 70.77% of the total variation in stand establishment, number of stems per plant, plant height, leaf area index, leaf chlorophyll content, leaf temperature, specific gravity, total tuber yield, and marketable tuber yield. Potato breeding material for drought stress tolerance could be derived from these resilient potato breeding lines for potato breeders for future breeding programs to cope with drought stress problems and ensure food security. This study also provides potato farmers and breeders with the characteristic features of potato genotypes ideal for water stress and water-abundant environments. Research is recommended to examine the correlation between morphophysiological and biochemical traits of potato genotypes under water stress conditions by combining morphophysiological and biochemical traits.