THE EFFECT OF SUMMER PRUNING DATE IN 'STAR', 'O'NEAL' AND 'ELLIOTT'

The effect of the summer pruning date was studied on blueberry cultivars 'O’Neal', 'Star' and 'Elliott'. Shoots were cut back from mid-December to mid-March (Southern hemisphere) at two different locations in Chile. Lateral number and length, flower bud number, fruit size and harvest date were measured in the year after pruning. Pruning in mid-December resulted in more and longer laterals than pruning later in the season. Shoots produced no laterals when pruning was done at the end of the summer growing season in mid-February. Differences in the dormancy stage of buds determined the degree of response to pruning, and pruning effects varied by cultivar. No laterals were formed when pruning was done after the end of January in 'Elliott' or after mid-February in 'O’Neal' or 'Star'. For all cultivars, summer pruning delayed the harvest season the following year. Fruit size and number were also affected by the treatments, as well as the number of flower bud induced on each lateral.