Chapter 16 - Water availability and potato crop performance

Abstract

Agricultural research can help mankind in several ways to cope judiciously with global problems of producing sufficient food from limiting supplies of water. This chapter: (i) summarizes basic concepts on how the system works, (ii) addresses methods of monitoring the water status, (iii) presents the crop responses to drought, and (iv) addresses the environmental and genetic differences in water-use efficiency and product quality. The importance of ensuring sufficient availability of water is illustrated comparing potential and water-limited potato yields in Africa. Ignoring the very small proportion of water taken up by the plant that is stored, the general equation describing this relation can be repeated to describe the fluxes in the several parts of the SPAC. Several lines of evidence support the idea that abscisic acid (ABA) plays a central role in stress signaling, inducing stomatal reactions. There are two general designs —equilibrium and dynamic—that differ in their control philosophy. This technique is now reaching beyond development and is approaching the stage where it can be used in commercial applications. The relative rate of cell expansion, R, has been described as a linear function of turgor pressure above a threshold value pressure, below which there is no cell growth. Water use, leaf dynamics and potato productivity are also elaborated. Varieties may vary in their tolerance of drought, expressed as the relative yield of crops subjected to drought compared with crops optimally supplied with water.