|Raese, John - RETIRED,USDA,ARS,TFRL|
Submitted to: Tree Fruit Production
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 19, 1995
Publication Date: N/A
Interpretive Summary: Increasing yield of 'Anjou' pear trees has not been reported as a major effect of calcium chloride sprays. Three long-term (9 to 13 years) calcium spray experiments in northcentral Washington state were evaluated for yield and fruit quality. The results show that fruit (yield) and fruit calcium concentrations increased and the fruit disorders, alfalfa greening and cork spot incidences were reduced with four annual sprays of calcium chloride. Fruit quality indicies were not affected by the calcium sprays. It is speculated that yield may have been enhanced by an adequate supply of available calcium present in the tree throughout the year. Other researches have linked calcium with pollen germination and pollen tube growth and cold hardiness of plant cells. The above may at least partially explain why yield is increased in pear trees receiving repeated annual sprays of calcium in May to August. In addition to controlling fruit disorders, enhanced yield is an additional incentive to the orchardist for using calcium sprays on "Anjou' pears.
Technical Abstract: Yield of 'Anjou' pears, Pyrus communis L., was increased with repeated annual (9-13 years)calcium chloride (CaC12) sprays. The incidence of fruit disorders (alfalfa greening cork spot) was decreased by CaC12 sprays with or without Regulaid but some minor calcium spray phytotoxicity occurred on fruit and leaves. Fruit calcium concentrations in peel and cortex were increased with calcium chloride sprays. However, these sprays had little or no effect on leaf weight, fruit size, leaf Ca concentrations, tree vigor, shoot growth, fruit firmness, soluble solids, titratable acids, fruit color, fruit rots or storage scald. This study suggested that, long-term calcium chloride sprays of 60.5 g Ca per 100 liters of water or 33 to 44 kg CaC12 per ha should provide the pear grower with a means of not only controlling fruit disorders but also for increasing 'Anjou' pear yield.