Plant Population Density Effects on Maize Inbred Lines Grown in Short‐Season Environments

Abstract

Development of maize (Zea mays L.) types that produce leaf area quickly and tolerate high plant densities could enhance yields in midto short-season environments. The leafy and reduced-stature traits each make contributions to this end, but have not previously been combined. Our objective was to evaluate the effect of plant densities on leafy normal-stature (LNS), non-leafy normal-stature (NLNS), leafy reduced-stature (LRS), and non-leafy reduced-stature (NLRS) inbreds. Twenty-one inbreds were field-grown over 2 yr at low (65 000 plant ha-1) and high (90 000 plant ha-1) densities. Above-ear leaf number, above-ear leaf area, and single plant grain yield were lower for LNS and NLNS at the high, as compared with the low, plant density, but were not affected for LRS or NLRS. The corn heat unit (CHU) requirements from planting to tasseling, and from planting to silking, as well as days between tasseling and silking, were greater under high plant density for LNS and NLNS, but were not affected for LRS or NLRS. Grain yield increased to a greater extent under high density compared with low density for LRS and NLRS than for LNS or NLNS. The LRS inbreds had a shorter vegetative period, longer grain-filling period, highest yields, and were more tolerant of high plant density than the normal-stature genotypes. These characteristics indicate potential both for increased yields and production in areas with lower CHU availability. These advantages are expected to be conferred to LRS hybrids.

Mapping Density Response in Maize: A Direct Approach for Testing Genotype and Treatment Interactions

“…In addition, the few plants without this peculiar manifestation produced few kernels. Density treatments were consistent with works published previously (Modarres et al 1998;Maddonni et al 2001;Borras et al 2003).…”

Influence of population density, row spacing and hybrid on forage corn yield and nutritive value in a cool-season environment

“…However, there is no all-encompassing recommendation for plant population density for all regions and environments within regions, because it is dependent on environmental factors such as soil moisture, and management factors such as soil fertility, hybrid selection and time of planting and harvest (Duncan 1984;Modarres et al 1998) including row spacing (Duncan 1984) and use as grain or silage (Daynard 1978;Daynard and Muldoon 1981).…”

“…This practice is thought to be more of an advantage in northern compared with southern areas of North America (Cox et al 1998). In areas where corn is adapted, there are concerns about costs of equipment conversion when moving to narrower (e.g., 30-or 50-cm rows) from standard row spacing, when yield improvement is small and uncertain (Stewart 2003). However, on the northern fringes of the corn-growing region of the Canadian Prairies, small grain seeding equipment has row spacing ranging from 15 to 30 cm.…”

Co-regulation Of ear growth and internode elongation in corn

“…This response results in morphological changes characterized by elongated internodes, small but more erect leaves and reduced ear development (Wilson and Allison 1978;Modarres et al 1998;Maddonni et al 2001). Internode elongation is necessary to make the plant taller so that it can be in a better position for more solar radiation.…”