INFLUENCE OF CROP MANAGEMENT FACTORS ON CHIPPING POTATO MATURITY AND STORAGE PROCESSING PERFORMANCE

Russet Burbank, Norchip, and Gemchip potatoes were grown under three n itrogen fertilizer levels to study the relationship between physical/p hysiological maturity components and long-term storage processing perf ormance. Potatoes from all treatment combinations were physiologically mature for processing (ie sucrose less than 1.5 mg g(-1) tuber fresh weight basis) at harvest while physical maturity differences (periderm shear strength, vine appearance and tuber size) were evident during t he growing season and harvest. A quadratic regression model, using dat e and (date)(2) as regressors, provided the best description for potat o chip color variation over a 13-month storage period compared to line ar, logarithmic, and higher order polynomial models. The optimal proce ssing date (date in which the lightest chip color was predicted to occ ur during storage) for each nitrogen fertilizer by cultivar treatment combination was correlated with field maturity components. Russet Burb ank and Gemchip potatoes that were less physically mature, indicated b y vine appearance and periderm shear strength, resulted in optimal pro cessing dates later in the storage season. Tuber size was negatively c orrelated with optimal processing date for Norchip tubers. These resul ts suggest that physical and physiological maturity measures taken at or shortly before harvest may augment chemical maturity data for the p urpose of selecting potato lots for long-term storage.