|Nzaramba, M. ndambe|
|Miller, jr., J|
Submitted to: American Journal of Potato Research
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/31/2007
Publication Date: 8/1/2007
Citation: Nzaramba, M., Ndambe, M., Bamberg, J.B., Miller, Jr., J.C. 2007. Effect of propagule type and growing environment on antioxidant activity and total phenolic content in potato germplasm. American Journal of Potato Research. 84:323-330. Interpretive Summary: Potato is the most consumed US vegetable, so nutritional improvements could have a particularly big impact on health. Breeders try to keep producing better varieties to meet changing needs of the industry and preferences of consumers. A better understanding of nutritional qualities of potato and how best to measure them would help breeders improve the crop. One such nutritional quality of potato is antioxidant content. A broad spectrum of potato species were grown both in greenhouse pots and in the field. Tubers of some of these species had very high levels of antioxidants—much higher than common varieties. Also, the way the tubers were generated had a significant influence on how much antioxidant was detected. On average, tubers generated in field conditions had even higher levels of antioxidants than their counterparts generated in the greenhouse. But, more importantly, we showed that only for some species do greenhouse pot tubers show the true (field) antioxidant potential. Wild potato species only produce tubers in the field in short-day locations like Hawaii. We showed that the extra effort of producing field tubers in Hawaii is required to get a true picture of which potato relatives have the most potential for breeders to use to improve the potato crop.
Technical Abstract: The potato of commerce has been successfully selected for high yield and adaptability in temperate and tropical environments. Genotype x environment interactions can influence crop productivity and breeding strategies. Thus, it is helpful to investigate the effects of such interactions on performance of crop plants regarding traits of interest. The Potato Variety Development Program at Texas A&M University has demonstrated wide variability for antioxidant activity (AOA) among potato cultivars, and even wider variability among wild potato species. However, the effect of propagation method on AOA and total phenolics (PHEN) in potatoes has not been reported. The objective of this study was to investigate the influence of propagation method and environment on AOA and PHEN in Solanum species. A ‘mini-core’ set of 75 accessions representing 25 wild species was used. Daughter tubers of tuberlings (seed tubers) from a greenhouse in Sturgeon Bay, WI and from a field in Maui, HI, as well as tubers from field transplanted seedlings (TPS) in Hawaii, were analyzed for total AOA and PHEN using the DPPH (2,2-Diphenyl-1-picrylhydrazyl) and the Folin-Ciocalteu methods, respectively. Total AOA and PHEN were significantly affected by species and species x environment interaction effects. Tubers from TPS exhibited significantly higher values than tubers from seed tubers. Thus, plant propagation method and growing environment may influence the relative performance of wild species for tuber AOA and PHEN.