320 Does Water Availability Influence Photosynthesis and Yield Components of the Lowbush Blueberry (Vaccinium angustifolium Ait.)?

Abstract

Drought is the most limiting factor of crops worldwide. Sound management of any crop is based on a knowledge of its physiology as well as response to drought. Therefore, water use management has become an agricultural priority, with increased research focusing on plant growth and yield under limited water conditions. The lowbush blueberry (Vaccinium angustifolium Ait.) is the most important horticultural crop in Nova Scotia in acreage, export sales, and value to the economy. A study initiated at the Nova Scotia Wild Blueberry Inst., Debert (45°26′N, 63°27′W), N.S., during the 1998 growing season investigated the effects of water availability on the growth and development of the lowbush blueberry. Treatments consisting of supplemental irrigation (i), drought stress (d), and a control (c) were applied to plants in their cropping phase of production. Net photosynthetic rates (Pn) were highest during bloom (i: 11.9, d: 9.7, c: 9.8 μmol·m-2·s-1) and then declined throughout the season. No significant (P = 0.05) treatment effect on Pn was observed. Stem sample analysis before harvest showed no significant differences (P = 0.05) between stem length, node number, flowering node number, flowering zone length, or number of fruit per stem. Samples from 1-m2 quadrats indicated the drought-stressed plots produced the lowest yield (378 g·m-2) compared with the supplemental irrigation (449 g·m-2) or control (512 g·m-2) plots. Results from this study suggest drought stress on the lowbush blueberry does not produce significant differences in the number of fruit set; it does result in smaller fruit.