Photosyntheticcharacterization and yield of summer corn (Zea mays L.) during grain filling stage under different planting pattern and population densities
不同群体结构夏玉米灌浆期光合特征和产量变化

Population structure is one of the important factors affecting photosynthetic efficiency and yield formation of crop plants. A 3 x 4 factorial field experiment with maize (Zea mays L.) was arranged in a split plot design with 4 replications. Three population densities (75000, 90000, 105000 plants/hm2) were assigned in the main plots, each of which was divided into four subplots to host the planting patterns: 1) even plant spacing in a conventional 60 cm row, 2) double plants in a triangle arrangement in the same 60cm row spacing, 3) even plant spacing in a twin-row arrangement with 50 cm within each twin-row and 70 cm row spacing between two twin-rows, and 4) similar to 3), but with double plants in a triangle arrangement within each row in the twin-row arrangement. During the grain filling period, photosynthesis and chlorophyll fluorescence parameters were measured. The results showed that under the high plant density, canopy apparent photosynthesis of double-plant planting pattern in the twin-row treatment was higher (P < 0.05) than that of the even plant spacing in the conventional 60 cm row spacing. With increasing plant densities, the values of Fv/Fm, and qP were all reduced slightly to significantly, there were larger reductions in the chlorophyll florescence parameters in twin-row than in single row planting patterns, and in double-plant planting pattern than in the equal-distance single row plant spacing. The 90000 plants/hm2 density in double-plant planting pattern and twin-row spacing arrangement had the greatest canopy photosynthetic productivity and greater yield.