Influence of Tissue Culture and Leaf-bud Propagation on the Growth Habit of ‘Northblue’ Blueberry

Abstract

Abstract ‘Northblue’ blueberry (Vaccinium corymbosum L.) plants propagated by tissue culture (TC) have a branching pattern and growth rate different from plants propagated by leaf-bud cuttings. Two to 3 times more basal branches were formed on tissue culture-derived plants by the time they were 27 to 34 weeks old. These basal branches were maintained on older plants in the field, where lateral branching was also twice as high. The growth rate of the young TC-derived plants was 3 times the rate of young leaf-bud, cutting-propagated (ST) plants. However, lateral branch length of older plants in the field was similar for both groups of plants, indicating a reduction in the growth rate of TC-derived plants from 34 to 82 weeks after propagation. Pruning and chilling methods reduced basal branch length and the number of lateral branches produced in the field, while enhancing the length of lateral branches and total buds per lateral branch. Although TC-derived blueberry plants had numbers of total flower buds and total buds per lateral branch similar to ST-derived plants, they produced more flower buds per plant. The enhanced branching framework of TC-derived plants, composed of rapidly forming basal and lateral branches, may increase photosynthesis at an early age and hasten fruit production.