ISHS Acta Horticulturae 715: VIII International Symposium on Vaccinium Culture
THE IMPACT OF EARLY CROPPING ON SUBSEQUENT YIELD OF HIGHBUSH BLUEBERRY |
| Authors: | B. Strik, G. Buller |
| Keywords: | Vaccinium corymbosum, pruning, growth, flower buds, fruit bud set, in-row spacing, berry size, planting |
| Abstract:
The effect of early cropping (no blossom removal the first two years) and in-row spacing at 0.45 m and 1.2 m were studied in ‘Duke’, ‘Bluecrop’, and ‘Elliott’ blueberries (Vaccinium corymbosum L.) grown on raised beds for 4 years. In a separate study, the effect of early cropping on yield of ‘Bluecrop’ on “flat ground” was studied for 8 years. No yield was produced on the control plants in the planting year (year 1) and the year after planting (year 2). In ‘Bluecrop’ grown on flat ground, cumulative yield at 0.45m was 106% higher than at 1.2 m over the 8 years of the study. Early cropping increased cumulative yield by 17% from years 3 through 8 compared to control plants. In a separate study of ‘Bluecrop’, ‘Duke’, and ‘Elliott’, however, plant growth at the start of year 3 was adversely impacted by early cropping. Early cropping reduced the dry weight of the root system, crown, and one- to three-year-old wood in all cultivars. ‘Bluecrop’ plants had less total dry weight than those of ‘Duke’ or ‘Elliott’. Roots accounted for 30 to 45% of the total plant dry weight depending on cultivar. Early-cropping reduced root system weight 42% compared to control plants. Early-cropped plants had a lower percentage of fruit buds in ‘Bluecrop’ and ‘Duke’ than control plants. Early cropping reduced yield in year 3 by 18% in ‘Bluecrop’, 26% in ‘Duke’, and 54% in ‘Elliott’. Yield of ‘Elliott’ in year 4 was still affected by early cropping. Cumulative yield (years 1 through 4) was not affected by early cropping in ‘Bluecrop’ or ‘Duke’, whereas in ‘Elliott’, cumulative yield was lower in early-cropped plants. Plants spaced at 0.45m produced 62% to 140% more yield than those spaced at 1.2m. ‘Elliott’ plants seemed less suited to high density planting due to their large total dry weight and large root system. | |
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