Leafy Reduced-Stature Maize Hybrids for Short-Season Environments

Development of maize (Zea mays L.) types that produce leaf area quickly and mature rapidly may increase maize yields in mid- to shortseason areas. The leafy (Lfy1) and reduced-stature (rd1) traits each contribute to this objective; however, these two traits have not previously been combined. Our objective was to determine the effect of these traits, alone or in combination, on morphology, reproductive development, and yield of maize hybrids. A field experiment including 14 hybrids [two non-leafy reduced-stature (NLRS), four leafy reduced- stature (LRS), eight leafy normal-stature (LNS)], and three commercial hybrid checks [non-leafy normal-stature (NLNS)] was conducted in 1992 and 1993. The following variables were recorded for each hybrid: plant height, internode length, ear height, above-ear leaf number, above-ear leaf area, corn heat units from planting to tasseling, corn heat units from planting to silking, days from tasseling to silking, grain yield (Mg ha⁻¹), grain moisture content, husk dry weight, husk moisture content, cob dry weight, cob moisture content, kernel number per row, maximum ear circumference, and ear length. The normal stature hybrids were the tallest plants, with higher ear placement than reduced stature hybrids. The leafy trait was associated with shorter internodes, increased leaf number, and greater above-ear leaf area. The reduced stature hybrids required fewer corn heat units to reach anthesis than the normal stature hybrids. The reduced stature hybrids had the lowest grain moisture (210-270 g kg⁻¹), husk moisture, and cob moisture contents at the time of harvesting. The LNS hybrids matured late and had grain moisture contents of 350 to 400 g kg⁻¹ at harvest. In general grain yield, husk dry weight, cob dry weight, kernel number per row, ear length, and maximum ear circumference were higher for the normal stature hybrids than for the reduced stature hybrids. The earlier anthesis and lower grain, husk, and cob moisture contents indicated potential for successful grain production and harvest of leafy reduced-stature hybrids in shorter growing season areas.