Corn Morphology, Mass, and Grain Yield as Affected by Early-Season Red: Far-Red Light Environments.

The spatial arrangement among plants affects both vegetative and reproductive meristem development. More axillary meristems develop at lower plant densities, which are associated with relatively high red:far-red light ratios (R:FRs; 645:735 nm). However, little is known about the effect of R:FR on corn (Zea mays L.) productivity. We conducted field research to determine the effect of early-season (VE-V7 corn) R:FR environments on corn morphology and productivity. Low, control, and high R:FR treatments were established by varying corn plant density (107,600, 53,800, and 3000 plants ha-1, respectively). At canopy closure (V7 corn), R:FR in the low, control, and high R:FR treatments was 0.23, 0.49, and 0.99, respectively. Each treatment was subsequently thinned to 3000 plants ha1 to avoid confounding effects of R:FR treatments and shading among plants. Grain yield per plant in the high R:FR treatment was 1.5 and 2.0 times greater than in control and low R:FR treatments, respectively, across years. Greater yield in the high R:FR treatment was attributed to greater tiller grain yield. Soil moisture and nutrient availability were similar among R:FR treatments. These results indicate that early-season R:FR was an important factor affecting corn productivity. Greater understanding of the R:FR-dependent pathway that controls axillary meristem development may provide direction for increasing productivity of elite nonprolific corn genotypes. [ABSTRACT FROM AUTHOR]