Comparative Temperature Response of Corn Belt Dent and Corn Belt Dent ✕ Pool 5 Maize Hybrids1
- A. K. Hardacre and
- H. A. Eagles2
Low temperatures occurring during the growth of maize (Zea mays L.) have been shown to reduce growth and yield in cooler maize growing areas of New Zealand, Europe, and North America. As part of a program to breed cool tolerant maize cultivars, the vegetative growth and development of four hybrids of maize were compared in five temperature environments in controlled environment rooms. The hybrids were A665 ✕ W153R, A665 ✕ H99, A665 ✕ NZlA, and H99 ✕ 5-514. The inbred lines A665, W153R and H99 are of Corn Belt Dent origin, while NZlA and 5-514 are derived from CIMMYT (International Maize and Wheat Improvement Center) Pool 5. The temperature environments were 16/6°C day/night, or constant day/night temperatures of 16, 20, 24, and 28°C. Harvests were made of entire plants at comparable stages of development defined by the number of mature leaves. Above 16°C, differences among the hybrids were small. In the 16/6°C environment, plant dry weights, leaf areas, net assimilation rates, shoot:root ratios, and chlorophyll concentrations were markedly greater for A665 ✕ NZlA and H99 ✕ 5-514 than for A665 ✕ W153R and A665 ✕ H99, but the number of mature leaves were almost identical. It is concluded that hybrids containing NZlA and 5-514 can tolerate temperatures below 16°C substantially better than Corn Belt Dent hybrids. Furthermore, their vegetative growth is at least equal to pure Corn Belt Dent hybrids in warmer environments up to 28°C.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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