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High temperatures significantly affect the growth and development of grapevines, cause irreversible damage to plants, and severely impact grape production and quality. Biostimulants can promote the growth of plants and enhance their resistance to adverse stress. However, the effects of biostimulants on grapevines under high temperatures have not been studied in detail. To analyze the effects of various biostimulants on the growth and development of grape seedlings under high temperatures, we measured chlorophyll fluorescence parameters with observed seedling phenotypes under high temperatures in open field conditions in Turpan. We conducted a comprehensive analysis of the effects of different biostimulants on the growth, development, and photosynthesis of grapevine seedlings. Our study aimed to provide scientific evidence to improve cultivation methods for grapevines under high-temperature stress. The results revealed that biostimulants have a positive effect on promoting the growth of grapevine seedlings under high-temperature stress conditions. They also positively affect the accumulation of chlorophyll components in grapevine leaves, inhibiting chlorophyll degradation and maintaining photosynthesis. However, the effects of different biostimulants were inconsistent. A comprehensive analysis revealed the following effectiveness order: T2 > T1 > T3 > Control. These findings suggest that T2 is the most effective in alleviating high-temperature stress and promoting grapevine growth. We recommend the use of T2 to improve the cultivation of grapevine seedlings during high-temperature periods. This has implications for grape production in hot and arid climatic areas.

The evaluation of photosynthetic characteristics of plants is important for the success rate of germplasm introduction. To select grape varieties with higher adaptability and trait performance, this experiment is aimed at evaluating and comparing the photosynthetic indices, chlorophyll fluorescence parameters, photosynthetic pigment content, and leaf characteristics of five Chinese hybrid varieties. The results showed that under high light intensity stress, the leaf growth of ‘Ruidu Cuixia’ was most affected and its specific leaf weight was the lowest, while ‘Jing Hongbao’ had the highest chlorophyll content. The maximum net photosynthetic rate (Pnmax), maximum light quantum yield (Fv/Fm), and apparent quantum efficiency (AQE) were different among varieties. It was reported that the ‘Ruidu Zaohong’ variety had the highest Pnmax. ‘Ruidu Wuheyi’ was found to have the highest Fv/Fm, while the highest AQE was recorded for ‘Ruidu Cuixia’, with intercellular CO2 concentration (Ci) and stomatal conductance (gs) at 292.56 μmol·mol−1, 766.56 mmol·m−2·s−1, and 66.8 μmol·m−2·s−1, respectively. The indices of ABS/CSm, TRo/CSm, and DIo/CSm were significantly different among varieties, and these indices of ‘Ruidu Zaohong’ were the highest. Pn was positively correlated with Ci and Tr, gs were positively correlated with Fv and TRo/CSm. The specific leaf area was negatively correlated with Fv/Fm and ΦDIo. The results of the principal component analysis and TOPSIS comprehensive evaluation showed that ‘Jing Hongbao’ and ‘Ruidu Cuixia’ performed best. Overall, the measurement of the photosynthetic characteristics of the plants during the growing period provided valuable data for the varietal introduction strategies. The better photosynthetic performance of ‘Jing Hongbao’ and ‘Ruidu Cuixia’ indicates more adaptability to the long day, high light intensity, and the high-temperature climate of Xinjiang.

The Munake grape is a local variety of grape that is widely distributed in Xinjiang, China. This study aims to clarify the genetic structure of the Munake grape population, characterize genetic differentiation and gene flow among populations, gather germplasm, and establish the core germplasm collection. In total, 144 samples were collected from eight geographic populations. Twenty-two SSR markers were used to characterize the genetic diversity as well as the genetic structure of Munake grape germplasm and to establish the core germplasm collection. At each site, the average number of effective alleles (Ne) was 5.019. Overall, genetic diversity was high in the various geographic populations of Munake grapes. Polymorphic information content (PIC) ranged from 0.501 to 0.908, with an average of 0.728. Estimates of genetic differentiation and gene flow indicated that the Artux population had significant genetic differences from the other populations. Screening results indicated that a sampling proportion of 95% of the sample was required to achieve 100% allelic coverage, or a sampling proportion of 65% for 95% allelic coverage. This analysis was based on conventional genetic diversity indicators, with a core germplasm diversity index of 95% coverage. Characterization of the genetic diversity of germplasm from 144 Munake grapes not only provides valuable resources for future genetic mapping and functional genome research, but also facilitates the utilization of core germplasm and molecular breeding of Munake grapes.

Global warming will significantly affect grapevine growth and development. To analyze the effects of high temperature on the leaf tissue structure of grapevines in the field, 19 representative cultivars were selected from the grapevine germplasm resources garden in Turpan Research Institute of Agricultural Sciences, XAAS. Twelve tissue structure indexes of grapevine leaves, including the thickness of the upper epidermis (TUE), the thickness of palisade tissue (TPT), leaf vein (LV), the thickness of spongy tissue (TST), the thickness of the lower epidermis (TLE), stoma (St), guard cell (GC), cuticle (Cu), leaf tissue compactness (CTR) and leaf tissue porosity (SR), were measured during the natural high-temperature period in Turpan. The results showed significant differences in the leaf tissue structure of the 19 grapevine cultivars under natural high temperature. Based on the comprehensive comparative analysis of the leaf phenotype in the field, we identified that the leaves of some cultivars, including ‘Zaoxia Wuhe’, ‘Centennial Seedless’ and ‘Kyoho’ showed strong heat tolerance, whereas grapevine cultivars ‘Golden Finger’, ‘Shine Muscat’, ‘Flame Seedless’, ‘Bixiang Wuhe’ and ‘Thompson Seedless’ showed sensitivity to high temperature. We further evaluated the heat tolerance of different grapevine cultivars by principal component analysis and the optimal segmentation clustering of ordered samples. These findings provide a theoretical basis for adopting appropriate cultivation management measures to reduce the effect of high temperatures and offer fundamental knowledge for future breeding strategies for heat-tolerant grapevine varieties.