ARS | Publication request: THE OXIDATIVE INDEX AS A MEASURE OF PHYSIOLOGICAL AGE OF POTATO TUBERS

Submitted to: American Journal of Potato Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 5, 1997
Publication Date: N/A

Technical Abstract: The degree of oxidation of a tuber extract was used as a rapid measure of physiological age to predict sprouting behavior of Russet Burbank (RB) seedlots. The oxidative index (OI) was defined as the absorbance at 405 nm of a clarified tuber homogenate after 24 hours. In 1994 the oxidative index was correlated with field maturity (r=0.68, p=0.01) for 27 Russet Burbank fields, but subsequent sprouting was not monitored. The OI was compared in 1995 with the length of growing season, growing degree days, per cent dextrose and sucrose at harvest, and sprouting after 4 Centigrade and 10 Centigrade storage. Six RB lots were tested from 3 different growing areas representing short (86-95 day), intermediate (107-124 day), and long (137-140 day) seasons. The oxidative index correlated (r=0.86) with sprouting from 4 Centigrade storage, which was measured as the sum of the primary and secondary sprouts times maximum sprout length after sprouting at 20 Centigrade for 4 weeks. The sprouting index was also related to growing degree days and per cent dextrose and sucrose at harvest. A multiple linear regression analysis with sprouting index as dependent variable, and percent dextrose and oxidative index as independent variables, gave an r 2 of 0.95 for the small group of fields tested. The usefulness of the oxidative index as a predictive measurement for physiological age is being tested on grower seedlots.