Crop yield response to water - Cra

Figure 1 Production trends for kiwifruit in the principal countries (FAO, 2011).New ZelandChileGreeceItalyFrance500450Production (1 000 tonne)400350300250200150100500198519901995200020052009Quality considerationsParticular attention should be paid to kiwifruit calcium (Ca) nutrition because of itsinvolvement in determining tissue mechanical strength and tolerance to biotic andabiotic stresses. Cessation of Ca import into fruit has been linked to a number ofmorpho-anatomical changes of fruit properties related to reductions in fruit waterloss, as transpiration from the fruit is the only mechanism responsible for Ca import.Therefore, it is desirable that canopy and irrigation management ensure adequatelight distribution and windspeed within the canopy to enhance fruit transpiration andCa accumulation. (Montanaro et al., 2006; Xiloyannis et al., 2008).Stages of development in relation to yield determinationBud development starts in spring and is largely completed by midsummer. Some buds arevegetative in that they give rise to vegetative shoots, while others are mixed, generatingboth leaves and flowers that develop from the same bud. The induction of the reproductivedevelopment of the bud occurs during late-summer to autumn followed by inflorescencedifferentiation, which will be completed by the next spring.The chilling requirement to break dormancy is about 700-800 Richardson units for the Haywardcultivar (Linsley-Noakes, 1989), while for the yellow-fleshed cultivars chilling requirements arelower (500-600 units). The growing-degree-hours for bud break range from about 9 000 to16 000 (Wall et al., 2008). The buds break in spring which takes 10-15 days, thereafter shootselongate quickly reaching 20-30 cm after 3 weeks. Leaves expand very rapidly during the early30 days of growth, and the full leaf area is reached within three months (Figure 2). Values of LAIKIWIFRUIT 489