Crop yield response to water - Cra

Lead AuthorSJoan Girona(IRTA, Lleida, Spain),Elias Fereres(University of Cordoba andIAS-CSIC, Cordoba, Spain)Contributing AuthorsJordi Marsal(IRTA, Lleida, Spain),David A. Goldhamer(formerly University of California,Davis, USA; currentlyCooperative Extension Emeritus),Amos Naor(GRI, University of Haifa, andMigal - Galilee TechnologyCenter, Israel),M. Auxiliadora Soriano(University of Cordoba,Cordoba, Spain)PeachIntroduction and BackgroundPeach (Prunus Persica L.), was originally from China, but in ancient Greeceand Rome it was thought to have originated in Persia, is a stone fruittree that exhibits ample diversity in terms of fruit types: freestone orcling; round or flat shape; hairy or smooth skins; flesh that is either firm orsoft and white or yellow. There is also a wide-range of maturity dates for thepeach cultivars; from very early where the fruit matures at the end of spring,to very late that reach maturity at the end of summer, as much as four monthsafter the earliest varieties arrive at the market. The tree is vigourous and canreach more than 5 m in height, but peach production is limited worldwide byits relatively narrow range of climatic adaptation. On the one hand, it flowersearly and is quite sensitive to frost–particularly at flowering- but on the other,it has chilling requirements that are not met in some of the frost-free areas ofthe temperate zones and the subtropics.The evolution of peach production in selected countries in the last tenyears is shown in Figure 1. In 2009 there were over 1.5 million ha of peachand nectarine globally with an average yield of 13.0 tonne/ha (FAO, 2011).The main producing country is China, which represents 50 percent of theworld peach production. Production in China rose spectacularly over the lastdecades from 380 000 tonne in 1970 and an average yield of 3.6 tonne/ hato over 10 million tonne in 2009 with an average yield of 14.4 tonne/ ha,followed by Italy (FAO, 2011). Other major commercial production areasare located in southern Europe (Spain, Greece, and France), United States(California, Georgia), Chile, and Australia. Highest yields are obtained inUnited States with almost 20 tonne/ha.The fruit is usually consumed fresh and, because consumers in many worldareas prefer large-size fruit, peach is grown mostly under irrigation evenin many subhumid areas. There, the most important role of irrigation is tostabilize production in years of below-normal rainfall, and to guaranteeadequate soil moisture during the critical fruit enlarging period, just prior toharvest. In more arid areas where rainfall is only a fraction of ET c , irrigation isessential for commercial production, as the period of fruit growth can spanall summer in the late maturing varieties. Most peach production systemsare quite intensive, with orchards planted at high densities (from 400 upto 1 000 tree/ha); the highest densities are normally for peach productionused in industry (canning and food processing). A wide-variety of trainingsystems are used, designed to maximize the distribution of solar radiation toall tree parts in order to achieve good fruit colour, and to promote fruiting392crop yield response to water