VIEW ARTICLE

Etiology

Hardcore Development in Sweetpotatoes A Response to Chilling and its Remission as Influenced by Cultivar, Curing Temperatures, and Time and Duration of Chilling. Robert H. Daines, Professor and Research Specialist, Department of Plant Biology, Rutgers University-Cook College, New Brunswick, New Jersey 08903; David F. Hammond(2), Norman F. Haard(3), and Michael J. Ceponis(4). (2)Postdoctoral Fellow, Department of Plant Biology, Rutgers University-Cook College, New Brunswick, New Jersey 08903; (3)Associate Professor, Department of Food Science, Rutgers University-Cook College, New Brunswick, New Jersey 08903; (4)Research Plant Pathologist, USDA Agricultural Research Service, Rutgers University-Cook College, New Brunswick, New Jersey 08903. Phytopathology 66:582-587. Accepted for publication 7 August 1975. DOI: 10.1094/Phyto-66-582.

The physiogenic disorder, hardcore, can be induced in Centennial and Jewel sweetpotatoes (Ipomoea batatas) by chilling the roots at 1.5 to 10 C. Centennial sweetpotato roots cured at 27 C developed much less hardcore following chilling than did fleshy roots cured at ambient temperatures (about 15.5 C). Centennial sweetpotatoes cured at 27 C and chilled early in their storage life (November) possess the ability to recover from hardcore, whereas similar fleshy roots chilled later (March) demonstrated only slight recovery capacity. Centennial sweetpotatoes cured at ambient temperatures, and exposed to chilling temperatures in January and March, exhibited some corrective capacity in January. Although the susceptible Centennial cultivar exhibited little or no such capacity in March, Jewel sweetpotatoes still recovered from hardcore at that late date. The development or disappearance of the hardcore symptom appeared to be related to modification of the pectic substances of the root tissue, in particular, protopectin.