Abstract:

To address the constraints of drought stress on potato production and the scarcity of high-quality drought-tolerant varieties in the arid and semi-arid regions of Longzhong, this study aimed to screen drought-tolerant and high-yielding potato varieties suitable for cultivation in the cool and cold areas of Longzhong. Using 12 potato varieties (or lines) as materials, including ‘L14140-5’, ‘Ganyin 9’, and ‘Ly1742-2’, a split-plot experimental design was implemented. The main plots consisted of two water treatments: drought stress (non-irrigation) and normal irrigation, while the subplots comprised the varieties. Agronomic traits such as plant height, leaf area index (LAI), SPAD values, and yield were measured. A comprehensive evaluation of drought tolerance was conducted using the drought resistance coefficient, principal component analysis, membership function method, and cluster analysis. The results revealed that: (1) drought stress significantly inhibited potato growth and yield. Under irrigation treatment, increases of 0.77%-67.74% in plant height, 2.94%-32.25% in LAI, 0.82%-83.01% in SPAD values, 4.73%-21.07% in dry matter accumulation per plant, and 1.53%-75.89% in yield were observed compared to drought stress conditions. (2) Significant differences in drought tolerance were observed among varieties. ‘Longshu 10’ exhibited the best performance, with only a 1.53% yield reduction under drought stress, a drought resistance coefficient of 0.98, and a drought resistance index of 1.402. (3) Cluster analysis categorized the varieties into three groups: four highly drought-tolerant varieties (‘Longshu 10’, ‘L14140-5’, ‘Ly1742-2’, ‘Ly1725-1’), six moderately drought-tolerant varieties, and two weakly drought-tolerant varieties (‘Fuda 1’, ‘Wotu 5’). In conclusion, ‘Longshu 10’ and ‘L14140-5’ demonstrated excellent comprehensive traits, strong drought tolerance, and stable yields, making them suitable for promotion and cultivation in the semi-arid regions of Longzhong. Future research should involve multi-year and multi-location trials, combined with physiological, biochemical indicators, and molecular markers, to further elucidate the drought tolerance mechanisms and provide more comprehensive support for drought-resistant breeding.

Key words: Longzhong region, potato varieties, drought stress, drought resistance, agronomic traits, yield, subordinate function, cluster analysis