Critical evaluation of the possibilities for modifying crops for high production per unit of precipitation [a review]
1988
Ludlow, M.M. | Muchow, R.C.
The potential for putative traits to increase grain yield per unit of precipitation assessed via their contribution to three components of yield (water transpired, water-use efficiency, and harvest index), and to three determinants of survival (drought escape, dehydration avoidance, and dehydration tolerance). Based on this assessment, benefits to yield potential and yield stability, and the scope for genetic improvement, traits are recommended in order of priority for grain sorghum and cowpea grown in intermittent and terminal stress environments in both modern and subsistence agriculture. Matching the phenology of the crop to the expected water supply is the most important trait in all four situations. In all but terminal stress in subsistence agriculture, the next most important traits are osmotic adjustment and larger root systems to maximize transpired water. Traits that enhance leaf survival are more important in intermittent than in terminal stress, and more important in subsistence than in modern agriculture. Traits for sorghum and cowpea were similar except that developmental plasticity was an additional important trait in cowpea for intermittent stress environments. Other traits specific to one or more of the four situations are also given. Finally, the need to develop techniques for demonstrating the value of putative traits and to apply them before traits are proposed as selection criteria is stressed.
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