Performance Evaluation of New Table Grape Varieties under High Light Intensity Conditions Based on the Photosynthetic and Chlorophyll Fluorescence Characteristics

Abstract

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.