Study on Vertical Distribution of Leaf Area, Yield and Assimilate Remobilization in Grain Corn Hybrids (Zea Mays L.)

In order to determine the vertical distribution of leaf area index and remobilization of assimilates to grain in mid- and late maturing hybrids of grain corn, an experiment was carried out in Randomize complete block design (RCBD) with four replications in Lorestan Agriculture Research Center in 2014. Average numbers of green leaves in investigated hybrids at flowering stage were 11. Vertical distribution of leaf area index curve was third-order polynomial as bell-shaped with highest leaf area density in the middle of canopy. A third-order polynomial accurately as S-shaped curve described the relationship between cumulative leaf area index (LAI) and plant height at tassel emergence stage. Maximum and minimum of total LAI were achieved from hybrids 4 and 9 respectively, but highest and lowest grain yield achieved from hybrids 11 and 3 (8675.5 and 6237.3 kg/ha, respectively). No remobilization was found between hybrids. Significant and negative correlation between remobilization and LAI (-0.54*), non significant correlation between grain yield and LAI and lack of remobilization indicates a high level of current photosynthesis in the grain filling stage with a severe physiological sink restriction in advanced grain corn hybrids.