Application of calcium and boron does not reduce incidence of brown fleck in potato tubers

The potato tuber (Solanum tuberosum) is susceptible to a wide variety of physiological disorders including those that result in tuber internal browning reducing the market quality and economic viability of production. These insidious disorders produce no external symptoms on the tubers. The causes have been ascribed to unfavourable environmental factors including temperature, moisture and crop nutrition. In subtropical Australian potato production, Brown Fleck (BF) is one such disorder that affects spring-harvested potato crops. The role of nutrition, particularly that of calcium (Ca), has been demonstrated to influence the expression of internal browning disorders and there is evidence that boron (B) deficiency may also be involved. However, objective research on the role of Ca and B on the incidence of BF is lacking. A series of field and glasshouse experiments was conducted to evaluate the effects of Ca (at 0-127 kg ha-1) and B (at 0-5 kg ha-1) on BF incidence. The results showed that application of Ca and B (alone or in combination) had no consistent effects on the incidence of BF. Furthermore, where significant effects were observed, these related to interactions that could not be meaningfully interpreted. This study indicates that factors other than Ca and B nutrition are responsible for determining incidence of BF and application of Ca and B fertilisers is unlikely to reduce incidence