596 Location and Rootstock Effects on Sheepnosing in Grapefruit

Abstract

Two-year field studies at three sites in the Lower Rio Grande Valley of Texas were conducted to evaluate the effects of location, rootstock, and irrigation on sheepnosing of `Rio Red' grapefruit (Citrus paradisi Macf.,) on sour orange (Citrus aurantium L.) rootstock. Based on the equatorial/polar diameter ratio, grapefruit grown in Weslaco had significantly higher percentage of sheepnosed fruits (62.66) than fruit grown in Mission (57.32), while Bayview had a negligible percentage of sheepnosed fruit (4.07). In a second study, `Rio Red' grapefruit grown on Carrizo [C. sinensis (L.) Osbeck × Poncirus trifoliate (L.) Raf.] had significantly higher percentage of sheepnosed fruit (59.46), compared to `Rio Red' grown on Swingle (C. paradisi × P. trifoliata) (47.83). In a third experiment, grapefruit with microjet irrigation had a significantly higher percentage of sheepnosed fruit (53.40), compared to flood irrigation (42.68). Although sheepnosed fruit had significantly greater peel thickness and a lower juice content, fruit quality was better because of higher soluble solids: titratable acidity ratio compared to normal shaped fruits. While significant, the irrigation and rootstock appear have a minor effect on sheepnosing less than growing location.