CULTIVAR AND GROWING REGION INFLUENCE RETURN BLOOM IN CRANBERRY UPRIGHTS

This research was undertaken to document the extent of biennial bearing in flowering uprights by American cranberry (Vaccinium macrocarpon Ait) cultivar and growing region. Seven cultivars were studied: three found in all states considered (Massachusetts, New Jersey, Wisconsin, Oregon), two common to Massachusetts and New Jersey, and two other commercially grown cultivars, one each from Wisconsin and Oregon. There were significant cultivar, region, and cultivar x region interaction effects for both percent return bloom (%RB) and percent return fruit (%RF). Percent RB ranged from 74% for 'Ben Lear' in Wisconsin to 14% for 'Howes' in New Jersey. 'Ben Lear' differed the most in %RB among regions, from 74% in Wisconsin to 14% in Massachusetts. However, in some regions, especially in Wisconsin, many blossoms did not set viable fruit. There was no significant difference in %RB among cultivars grown in Massachusetts or Oregon; however, cultivars grown in these regions did differ in %RF.