Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/4/2000
Publication Date: N/A
Citation: Interpretive Summary: Internal heat necrosis is a physiological disorder that occurs in potato tubers grown under high temperatures and is characterized by unattractive brown spots in the tuber flesh. These brown spots do not disappear when the tubers are sliced and made into potato chips resulting in potato chips that are objectionable to consumers. In this study scientists at Rutgers University in New Jersey, Virginia Polytechnic Institute and State University in VA and the USDA, ARS in Beltsville, MD found that a large part of the variation observed for internal heat necrosis has a genetic basis which is not related to either the total yield of the crop or the percent dry matter of the tuber. These results suggest that breeding efforts in the future should be successful in developing new, high yielding, and high dry matter potatoes for production in heat stress environments such as the mid- Atlantic states. This information will be useful to potato breeders as the study indicates that breeding high yielding, high specific gravity cultivars for resistance to internal heat necrosis should be feasible.
Technical Abstract: Internal heat necrosis (IHN), a severe physiological disorder of potato tubers, is characterized by brown spots or blotches that first appear towards the apical end of the tuber parenchyma but in severe cases may involve most of the parenchyma tissue. The purposes of this study were to determine the amount of genetic variation for and the stability of IHN in tetraploid potato clones, and the relationships among IHN, specific gravity, and tuber size distribution. Nineteen potato clones (4 cultivars and 15 breeding selections) were grown in Bridgeton, NJ and Painter, VA from 1991 to 1993 in a randomized complete block with 4 replications of 20 hills per plot. The crop was harvested 2 to 3 weeks later than normal harvest time to provide for maximal exposure to heat stress. All tubers were harvested and graded by size. Incidence and severity of IHN were recorded. Several of the more IHN susceptible clones were unstable for IHN both before and after environmental heterogeneity was removed. The correlation between incidence and severity of IHN was very high. There was no correlation between IHN and total yield or specific gravity.