Plant Population Density Effects on Maize Inbred Lines Grown in Short-Season Environments
1998
Modarres, A. M. | Hamilton, R. I. | Dijak, M. | Dwyer, L. M. | Stewart, D. W. | Mather, D. E. | Smith, D. L.
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.
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