Tassels and the Productivity of Maize¹

Abstract

Shading of underlying leaves by maize tassels probably reduces photosynthetic rates in the community and hence the grain yields. The shading effect is small at low plant populations but increases with plant density. Tassel size varies with plant population and variety. The area of shade cast by a single tassel varies with sun angle. Possible effects of tassel shading on grain yield are estimated by computer simulation.

Morphological and physiological traits associated with barrenness and grain yield in the maize breeding population, Iowa Upright Leaf Synthetic #1

“…Loomis et al (1968) reported that light penetration into maize canopies is largely determined by the orientation of the upper leaves, and Loomis et al, (1968) and Pendleton et al (1968) hypothesized that maize varieties with erectophile upper canopies and planophile lower canopies should produce high grain yields at high plant: densities. Results obtained by several researchers working with theoretical models (Duncan et al, 1967;Anderson and Denmead, 1969;Monteith, 1969;Duncan, 1971) have corroborated this hypothesis.…”

“…Grogan (1956), suggested this phenomenon primarily was due to decreased competition for nutrients between the tassel primordia and ear primordia. Additionally, Duncan et al (1967) and Hunter et al (1969) hypothesized that positive yield responses associated with detasselling resulted from reduction of shading of upper canopy layers of maize plants grown at high densities» Duvick (1958) and Chinwuba et al (1961) demonstrated significant decreases in barrenness and concomitant signif icant increases in grain yield at high plant densities when male-sterile hybrids were compared with their male-fertile counterparts. Chinwuba et al (1961) harvested 41% more grain from male-sterile than from malefertile hybrids at 68,000 plants/ha and concluded this was a consequence of reduced competition between the tassel and the ear.…”

Analysis of Vegetation Indices to Determine Nitrogen Application and Yield Prediction in Maize (Zea mays L.) from a Standard UAV Service

“…These height measurements were repeated until tassel insertion, in order to avoid the possibility of differences in height caused by the length of the tassel. According to Duncan et al [34], tassel size varies with both plant population and variety. Linear regression analysis was performed between the image and in-field height, yielding an R 2 coefficient of 0.82 (RMSE = 0.15 m and p-value < 0.001).…”

Performance of maize genotypes of Rio Grande do Sul using mixed models

“…For the tassel length character, this had great reduction in modern maize hybrids compared to hybrids released in the 1930s, 1940s and 1950s (Duvick, 2005). Tassel may affect grain yield, reducing the light interception in the canopy of plants, as well as through the use of photo-assimilated resources produced by plant (Duncan et al, 1967). For the EI character it was observed that the CD 308, AS 3466, Caiano Branco, AS 1551 and BRS Planalto genotypes, had in this order, the best performances, with genotypic values below the overall average 125.17 cm, showing to be promising as a gene/alleles source for reducing character.…”