Crop yield response to water - Cra

Figure 1 Production trends for plums in the principal countries (FAO, 2011).6 000China Serbia Turkey USA RomaniaChile4 0002 000Production (1 000 tonnes)1 0008006004002000198519901995200020052010the environmental conditions and the cultivar. Bud formation starts with the appearance of thefirst basal leaves and continues through June on mature trees (Westwood, 1993). Reproductivebuds are in a lateral position on terminal shoots or on short shoots called spurs. Flower budsare initiated in the growing season prior to anthesis, and development continues throughthe dormant season until the following spring just before bud break. The proportion of spurand terminal shoots varies largely with variety and species and so does the proportion of fruitborne on spurs and shoots, which also varies with tree age. Most commercial plum cultivarsare not self-pollinating and therefore the use of pollinators is required. Plum trees bloom veryprofusely and thinning is required, either performed manually, chemically or mechanicallyto obtain commercial fruit sizes. For example, Black-Gold in Mediterranean conditions mayset around 10-40 percent of the flowers produced, but good commercial yields are obtainedwith only about 5-10 percent of fruit set (Intrigliolo and Castel, 2005). Normally, floweringis completed by late April (Northern Hemisphere) and is followed by rapid fruit expansivegrowth with concomitant rapid shoot growth.PLUM 349