Comparative Analysis of Photosynthetic Traits, Yield, and Fruit Quality Among Different Chestnut Cultivars

This study aimed to compare the photosynthetic physiological traits, fruiting characteristics, and fruit quality of four different chestnut cultivars. The cultivars studied were ‘Yanshanzaofeng’ (YS), ‘Guangdedahongpao’ (GD), ‘Chang’anhuijianli’ (CA), and ‘Guizhouyouli’ (GZ). Leaf functional traits, photosynthetic activity, fruit setting characteristics, and both external and internal fruit quality indicators were measured. The results indicated significant differences in leaf traits among cultivars. Cultivar GD exhibited the largest leaf area and dry matter content, while cultivar GZ had the smallest. The photosynthetic rate (Pn) followed a bimodal curve, with an obvious ‘lunch break’ caused by stomatal limitations. Cultivar GD had the highest Pn, followed by CA, YS, and GZ. The water use efficiency (WUE) and CO2 utilization of cultivar CA were notably superior, indicating its suitability for arid conditions. In terms of yield, cultivar GD had the highest bur, nut weight, and plant yield, followed by CA, YS, and GZ. The phenotypic quality of the fruit was also superior in cultivar GD. However, cultivar YS had the highest amylopectin and soluble sugar content, and cultivar GD had the greatest amylose, total starch, and fat content. Cultivars CA and YS exhibited better overall fruit quality than GZ. Correlation analysis revealed that single bur weight, single nut weight, and single plant yield all exhibited highly significant or significant positive correlations with Pn, stomatal conductance (Gs), intercellular CO2 concentration (Ci), and the transpiration rate (Tr). The longitudinal diameter of burs showed a significant positive correlation with vitamin C (Vc), Pn, and Gs, with a correlation coefficient of 0.99. Additionally, both the transverse and longitudinal diameters of nuts were significantly positively associated with Pn and Ci. Furthermore, the total starch content and water content of nuts demonstrated a significant positive correlation with Pn. In conclusion, cultivar GD was found to be ideal for high-yield starch production, while cultivar YS offers superior sweet and waxy nut qualities. Cultivar CA presents a balance of photosynthetic capacity, yield, and quality, making it the second-best candidate. Cultivar GZ is unsuitable for large-scale cultivation.