Response of primocane-fruiting 'Polana' red raspberry to boron fertilization

The objective of this study was to examine the response of red raspberry to boron (B) fertilization. The experiment was carried out during 2002-2003 in a commercial plantation in central Poland on primocane-fruiting 'Polana' raspberries planted on a sandy loam soil with low status of organic matter and hot water-extractable B. Raspberries were fertilized with B via foliar or soil application. Foliar B sprays were made four times per season: two weeks before flowering, at the beginning of blooming, and three and six weeks later. In each spray treatment, B was used at a rate of 0.1 kg ha(-1) . Soil B was applied at the stage of bud break at a rate of 1 kg ha(-1) . Plants untreated with B served as a control. The results showed that B fertilization, regardless of application mode, increased flower and leaf B concentrations, fruit set, and berry yield. Fruit of B-fertilized plants were firmer, and had higher soluble solids concentrations and numbers of drupelets than those of the control plants. Boron fertilization had no effect on plant vigor, mean berry weight, and titratable acidity of fruit. The obtained results indicated that on coarse-textured soils with low B status, soil or foliar B application should be recommended in red raspberry cultivation to increase yield and improve berry quality.