Effect of preplant calcium applications on calcium concentration, yield, and incidence of internal brown spot in potatoes (cv. Atlantic) grown under greenhouse conditions

The study was conducted from 2004-2005 to investigate the relationship between the incidence of internal brown spot (IBS) and tuber Ca concentrations in potato (Solatium tuberosum L.), cv. Atlantic, a widely cultivated chipping variety in Korea. Calcium sulfate was used as a Ca source with or without irrigation. Calcium sulfate was applied at rates of 0 and 400 kg/ha directly in the top of the hill before planting. Results showed that Ca fertilization significantly increased total or marketable tuber yields. It also increased tuber Ca concentrations, decreased IBS incidence, and affected specific gravity compared with the non Ca-treated controls. The incidence of IBS was relatively high (16.7-28.0% in tubers with tissue Ca 370 μg·g^-1 dry weight) in control plots compared with 10.0-14.7% IBS incidence in tubers with tissue Ca 470 μg·g^-1 dry weight in Ca-treated plots. The effect of Ca fertilization on IBS incidence was more evident in irrigated soils than in non-irrigated soils. Specific gravity was significantly higher in tubers receiving Ca fertilization under non-irrigated conditions. These results show a potential of Ca fertilization in the production of high quality chipping potatoes.