Effects Of Planting Patterns Research Articles

EFFECTS OF GENOTYPE, PLANTING PATTERN, AND PLANT DENSITY ON PLANT-TO-PLANT VARIABILITY AND GRAIN YIELD OF CORN

Three experiments were conducted near Guelph in 1971 and 1972 with the objectives of studying (1) the effect of planting pattern, plant density, and genotype on plant-to-plant variability in corn (Zea mays L.), and (2) the effect of this variability on grain yield. All three studies entailed detailed measurements of the height of individual plants at various times during vegetative development, and of per plant grain yields. Frequency distributions of individual plant height and grain yield were normal; a coefficient of variability was used to characterize the variation within each treatment. In the first experiment, plant density was found to have a significant effect on plant-to-plant variability in grain yield; row spacing did not affect variation among individuals in either plant height or yield. The second experiment involved study of five double-cross hybrids, five single-cross hybrids, and the 10 possible 50:50 mixtures of the single-cross hybrids. Single-cross hybrids were more uniform and higher yielding than their double-cross counterparts. Mixtures did not vary in yield or variability from the mean of their pure-stand components. In the third experiment, corn was over-planted and differentially thinned in early July (when plants were approximately 60 cm tall) to produce two treatments: uniformly and non-uniformly thinned. Uniformly thinned plots were higher yielding, particularly at a high plant density (103,000 plants/ha). The results lend support to the hypothesis that variability per se can have a significant effect on the grain yield of corn. Reduced variability may represent a partial explanation of the generally higher yield of elite single-cross hybrids over their double-cross counterparts.

Canopy structure, light interception, and photosynthetic characteristics under different narrow-wide planting patterns in maize at silking stage

Planting pattern affects canopy structure of crops and influences other physiological characteristics such as light interception and radiation use efficiency. In the current paper, the effects of planting patterns on the canopy structure, light interception, and photosynthetic characteristics at silking stage of two maize (Zea mays L.) cultivars (Beiyu288 and Xianyu 335) were examined in three planting patterns narrow–wide rows of (1) 30 cm + 170 cm (P1, 6.4 plants m–2), and (2) 40 cm+90 cm (P2, 6.4 plants m–2), and uniform row of 65 cm (control, i.e. CK, 6.4 plants m–2). The ratio of leaves perpendicular to rows was highest in P1 and the leaf orientation value in P1 was constant and slightly lower in P2 compared with that in CK. Although a decrease in the total intercepted photosynthetically active radiation (IPAR) of P1 was found in the two cultivars, more incoming PAR was detected at the middle-low canopy strata of P1. The apparent quantum yield and the net photosynthesis rate (PN) in P1 and P2 were significantly higher than those in CK. The PN and stomatal conductance (gs) values in P1 were significantly higher than those in CK, and the intercellular CO2 concentration decreased with an increase in PN. These results indicated that narrow-wide row planting patterns improved the canopy structure, allowed more IPAR to reach the middle–low strata of the canopy, and enhanced the leaf photosynthetic characteristics of maize crops at silking stage compared with CK.