Growth and Development of Oat (Avena sativa L.) Cultivars in Response to Water Stress

Water stress occurs frequently in the North Central Plains and causes significant reductions in plant growth, development and grain yield. These effects of water stress apparently are dependent on the ability of plants to adapt to less than optimal environments. Plant water potential is dynamic, changing not only with the soil water content and atmospheric conditions, but also with the stage of growth. When plant water potentials become limiting, various physiological processes associated with plant growth, development and final yield are affected. The reduction in productivity in semi- arid environments is directly related to the inability of crop plants to withstand water stress. Water stress is ubiquitous in arid and semi-arid parts of the world. Therefore understanding the physiological basis of drought resistance is useful for improving oat productivity. In South Dakota, water deficits are one of the primary factors affecting oat growth, development and yield. About 1. 7 million acres were planted in South Dakota in 1984 with average production of about 87 million bushels (Reeves, 1986). Unfortunately, very little research exists on drought resistance in oats, and the associated genetic variability. The overall goal of these experiments was to provide a foundation for incorporating improved resistance to water stress into the oat breeding program. The main objectives of this study were: (1) To examine germination, radicle length under control conditions and its relationships to field conditions. (2) To examine the growth, development and yield of oat cultivars in response to water stress. (3) Determine the ability of oat cultivars to osmotically adjust in response to water stress. (4) Examine the relationship between root characteristics and yield capacity under water stress