Incidence of blossom-end rot and fruit firmness of tomato affected by irrigation quantity and calcium source

M. D. Taylor, S. J. Locascio, M. R. Alligood

Abstract


'Equinox' tomatoes (Lycopersicon esculentum Mill.) were grown during the spring of 2001 with black polyethylenemulch and drip irrigation on an Arredondo fine sand in Gainesville to study the influence of water quantity and Ca source on fruit firmness, incidence of blossom-end rot (BER), fruit yield, and fruit and leaf Ca concentration. Tensiometers were used to automatically schedule irrigation in main-plots when soil matric potential reached 10 or 25 kPa (10 or 25 cb). Sub-plot nutritional treatments were, no added Ca, Ca(NO[sub3])[sub2], Ca thiosulfate, CaCl[sub2], CaSO[sub4], and K rate reduced by 50% from 168 to 84 kg·ha[sup-]. Tomato plants that received Ca(NO[sub3])[sub2] or reduced K produced lower weights of BER fruit than with no added Ca, Ca thiosulfate, or CaSO[sub4]. Marketable fruit yields and fruit Ca concentrations were significantly greater from plants irrigated at 10 kPa than at 25 kPa and yields were greater with Ca(NO[sub3])[sub2] or CaCl[sub2], than with Ca thiosulfate. Fruit from plants with all nutritional treatments irrigated at 10 kPa had similar firmness, and a 100% lower incidence of BER compared with plants irrigated at 25 kPa. For 10 kPa irrigation, plants that received Ca(NO[sub3])[sub2] had leaf and fruit Ca concentrations higher than plants that received no added Ca or reduced K. Ca content decreased from the stem-end to the blossom-end with both irrigation treatments. In this study, maintaining a soil matric potential at 10 kPa compared to 25 kPa increased marketable yield, reduced BER, and increased fruit Ca concentrations. Supplying drip N as Ca(NO[sub3])[sub2] compared with NH[sub4]NO[sub3] or reducing the K rate reduced the incidence of BER.

Keywords


calcium nitrate; gypsum; calcium chloride; calcium thiosulfate; potassium

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Proc. Fla. State Hort. Soc.     ISSN 0886-7283