Crop yield response to water - Cra

Figure 3(a): Relationship between average fruit weight and number of fruit per tree of four peach cultivars(b): Relationship between yield per tree and number of fruit per tree of four peach cultivars(Johnson and Handley, 1989).300abx xxx300Average fruit weight (g)250200150100xxx O’HENRYxxxx xxxx ELEGANT LADY++++ + + + +++++ + ++++ + + JUNE LADYMAY CREST +Yield kg / tree (kg/tree)24018012060xxx+++O’HENRYx xxxxx x+++ +++ + ++ +xxxx+ + ++xELEGANT LADYJUNE LADY+MAY CREST0 400 800 1 200 1 600 2 0000 400 800 1 200 1 600 2 000Fruit number / treeFruit number / treeand midseason cultivars. Both final fruit size (Figure 3a) and total yield per tree (Figure 3b)are fruit load dependent. Fruit size increases as fruit load decreases (Figure 3a), while finalyield increases with increases in fruit load (Figure 3b) For each cultivar, and depending onmarket prices, the total number of fruit per tree that are left after thinning should be chosento optimize profits by obtaining a maximum yield with a minimum fruit load. Final fruit sizedepends also on the timing of hand thinning. Early hand thinning reduces fruit competitionand allows larger fruit.Bud developmentThe terminal peach bud at the end of a shoot is always vegetative and produces a leafy shoot.Auxiliary buds develop during the summer at the base of leaves on the current season'sshoots and can be either leaf or flower buds. A flower bud produces a single flower thatcan set one fruit. Each node on a vegetative shoot may have from zero to three buds. Thebuds that generate vegetative growth are small and pointed while flower buds are larger,rounder, and more hairy. Many of the nodes on the lower two-thirds of a shoot have twoor three buds arranged side by side. Most often a leaf bud is flanked by flower buds. Thenumber and distribution of flower buds on a shoot varies with tree vigour, cultivar, and theradiation environment that the shoot experiences. Short shoots generally have the most fruitbuds per unit length. Moderately vigorous shoots have a high proportion of nodes with twoflower buds. The leaf buds at most nodes develop into lateral shoots that may be fruitful insubsequent years. In the very vigorous current season's shoots, a number of auxiliary budsproduce secondary shoots that are not desirable because fruit buds do not develop at manyof their nodes. Ideal shoots (between 30 and 50 cm long) have enough growth to producesufficient fruit buds for the following season but do not have secondary shoots.396crop yield response to water