Pleiotropic Effects of the tr Trichomeless Gene in Pearl Millet on Transpiration, Forage Quality, and Pest Resistance
1977
Burton, G. W. | Hanna, W. W. | Johnson, Johnny C. | Leuck, D. B. | Monson, W. G. | Powell, J. B. | Wells, H. D. | Widstrom, N. W.
The single recessive tr gene when homozygous suppresses all trichomes in pearl millet, Pennisetum americanum (L.) Leeke. By comparing the near-isogenic Tilt 23S (tr tr) and the pubescent Tilt 23H (Tr Tr) the following pleiotropic effects were discovered. The tr gene reduced transpiration from 8.9 to 35.0% in eight genotypes without altering stomate length or frequency. The tr gene imparted a smooth wax-like surface to the cuticle of the leaves that caused the leaves (blades) to accumulate more dew, kept the leaves wet longer, and increased the rate at which rust developed on them. This modified tr cuticle apparently reduced in vitro dry matter digestibility (IVDMD) rates in intact leaf sections and slowed the drying rate of excised green leaves. The tr gene increased the palatability of pearl millet forage for cattle and tended to increase intake for the first few days of a green feeding test. However, it failed to increase overall livestock gains, probably because the slower digestion rate of tr forage slowed its passage through the gastrointestinal tract, reduced intake, and offset its greater palatability. The tr gene significantly reduced oviposition of the fall army worm, Spodoptera frugiperda J. E. Smith and corn earworm, Heliothis zea Boddie and reduced the foliar feeding of first and second instar fall army worms fourfold.
显示更多 [+] 显示较少 [-]