Effects of the brachytic-2 dwarfing gene on maize (Zea mays) root systems and grain yield under moisture stress

摘要

Drought resistance is a complex of many morphological, physiological, and biochemical characteristics. Maize cultivars adapted to marginal rainfall areas of Zimbabwe should have deep and dense rooting systems in order to reduce the effects of frequentand intermittent droughts during the growing season. Deep and dense rooting systems were associated with drought resistance in wheat (Cholick et al., 1977; Hurd and Spratt, 1975) and rice (Chang et al., 1982; O'Toole, 1982; Yoshida and Hasegawa, 1982).Dwarf plants were found to have a more extensive and deeper rooting system than normal height wheat cultivars (Hurd, 1974; Lupton et al., 1974; Cholick et al., 1977). On the other hand, Mackay (1973) reported that root growth occurred in a mirror image manner of the aerial plant in spring wheat. The recessive brachytic-2 (br-2) gene reduces plant height without a corresponding decrease in the size of the major plant parts of maize (Anderson and Chow, 1963; Scott and Campbell, 1969). This study was conducted to investigate the effects of the br-2 gene on maize root systems and grain yield under moisture stress, in order to determine whether it can be exploited for improving drought tolerance in maize.