Drought resistance evaluation of the new Yunnan dryland wheat variety Yunmai 112

【Objective】To investigate and identify the drought tolerance of the new Yunnan dryland wheat variety Yunmai 112, which could provide reference for selecting wheat varieties adapted to the arid regions of Yunnan and enhancing wheat yield. 【Method】Using Yunmai 112, Yunmai 56, and Yangmai 33 as experimental materials, they were subjected to polyethylene glycol-6000（PEG-6000） simulated drought treatment to evaluate drought tolerance during the germination stage, with deionized water treatment serving as the control. Germination status and the root length on the 8^th day after PEG-6000 treatment was recorded. Under the field conditions of greenhouses, different irrigation times were applied throughout the entire growth period. Effects of different irrigation times on root length, leaf net photosynthetic rate at jointing stage, the activities of superoxide dismutase（SOD）, catalase（CAT）, and peroxidase（POD）, 3 yield components（spike number, 1000-grain weight, grains per spike） and plot yield at maturity, relationship between traits and drought resistance of varieties, the breeding indicators of drought-resistant varieties in Yunnan, and the drought resistance capacity of the tested varieties were analyzed and investigated. 【Result】In the PEG-6000 treatment, Yunmai 112 exhibited a relative germination rate of 91.40%, classified as extremely strong drought tolerance. Yunmai 56 and Yangmai 33 showed relative germination rates of 70%-89%, classified as strong drought tolerance. In the PEG-6000 treatment and control, the root length of Yunmai 112 at germination stage were 6.58 cm and 8.93 cm respectively, and were significantly longer than that of Yunmai 56（4.48 cm and 7.25 cm） and Yangmai 33（4.25 cm and 7.58 cm）（P＜0.05, the same below）. Under both once and twice irrigation treatments, the root length of Yunmai 112 were 17.01 cm and 18.20 cm respectively,which were significantly longer than that of Yunmai 56（12.94 cm and 14.10 cm） and Yangmai 33（12.52 cm and 14.69 cm）. Across all irrigation times treatments, the net photosynthetic rates of Yunmai 112 were 6.27, 8.46 and 12.09 μmol/（m²·s）, which were significantly or extremely significantly（P＜0.01, the same below） lower than that of Yunmai 56 and Yangmai 33. Under once irrigation treatment, the activities of SOD, CAT, and POD in Yunmai 112 leaves were 178.28 U/g, 308.74 μmoL/（min·g） and 194.33 U/g respectively,which were significantly or extremely higher than those of Yunmai 56 and Yangmai 33. Under all irrigation times, the spike number, grain number per spike and plot yield of Yunmai 112 were significantly higher than that of other 2 varieties. Moreover, with irrigation times increasing, the spike number, grain number per spike and plot yield among the 3 yield components increased. Correlation analysis revealed that yield was extremely significantly and positively correlated with the spike number and grains per spike, the coefficients of correlation were 0.90 and 0.74, but yield was negatively correlated with 1000-grain weight, coefficient of correlation was-0.41. Root length showed significantly nor extremely significantly positive correlations with the plot yield, spike number and grains number per spike, the coefficients of correlation were 0.46, 0.45 and 0.62. 【Conclusion】Yunmai 112 responds to drought stress through deep root growth, reduced transpiration and rapid activation of the antioxidant enzyme system regulation. It has an extremely strong drought resistance level and high yield potential, making it suitable for promotion and cultivation in drought-stricken areas of Yunnan.