Production performance and photosynthetic characteristics of different green-feed corn varieties in rain-fed and irrigated areas

To screen out high-yield and high-quality forage corn varieties suitable for planting in rain-fed and irrigation areas, 20 green-fed corn varieties were planted in both areas, and their production performance and photosynthetic characteristics were analyzed and compared in their mid-milk stage. The results showed that ‘Yuqingzhu 23’ planted in rain-fed areas had the highest fresh dry weight, followed by ‘Longdan No.10’; ‘Guiqingzhu No.1’ planted in the irrigation area had the highest fresh weight. The heights of ‘Jinsui 715’ and ‘Tunyu 168’ grown in rain-fed areas were significantly higher than ‘Shuyu 201’ (P < 0.05). The heights of ‘Yuqingzhu 23’, ‘Jinsui 715’, and ‘Beinongqingzhu 208’ in the irrigation area were significantly higher than those of other varieties (P < 0.05). The stem-leaf ratio of ‘Tunyu 168’ in the rain-fed area was significantly higher than that of other corn varieties (P < 0.05). In contrast, the stem-leaf ratio of ‘Jinsui 715’ showed a higher stem-leaf ratio in the irrigation area. In contrast, ‘Hejiayuantieyan 53’ showed the highest leaf area per plant in the two areas, especially in the irrigation area. ‘Yanke 288’ had the highest number of dead leaves in the two areas, while ‘Guiqingzhu No.1’ had the least number of dead leaves, especially in rain-fed areas, and thus had the best green retention; ‘Jindan 73’ in the irrigation area had the lowest number of dead leaves, followed by ‘Shuyu 201’. In terms of photosynthetic physiological characteristics, the contents of chlorophyll, P_n and G_s of ‘Beinongqingzhu 208’, T_r and C_i of ‘TW268’ in rain-fed areas were significantly higher than those of the other varieties (P < 0.05). The chlorophyll content of ‘Ningdan No.34’, T_r of ‘Guiqingzhu No.1’, P_n of ‘Longdan No.10’, and G_s of ‘Yuyu 22’ in the irrigation area were significantly higher than those of the other varieties (P < 0.05). Comprehensive analysis of grey correlation degree showed that ‘Guiqingzhu No.1’, ‘Beinongqingzhu 208’ and ‘Yuqingzhu 23’ in the rain-fed area had better comprehensive performance and are suitable for planting in rain-fed area, ‘Shuyu 201’ and ‘Longdan No.10’ in the irrigation area had a better comprehensive performance.