|CHRISTENSEN, CHRISTIAN - University Of Florida|
|ZOTARELLI, LINCOLN - University Of Florida|
|COLEE, JAMES - University Of Florida|
Submitted to: American Journal of Potato Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/8/2017
Publication Date: 7/14/2017
Publication URL: http://handle.nal.usda.gov/10113/5886682
Citation: Christensen, C.T., Zotarelli, L., Haynes, K.G., Colee, J. 2017. Rooting characteristics of Solanum chacoense and Solanum tuberosum in vitro. American Journal of Potato Research. https://doi.org/10.1007/s12230-017-9597-x.
Interpretive Summary: Commercial potato cultivars have shallow root systems. As a result, much of the fertilizer applied is lost and becomes a source of groundwater contamination. In this study, root formation was examined under tissue culture conditions and the wild potato species Solanum chacoense was shown to produce a larger root system than commercial cultivars. The incorporation of a larger root system into commercial cultivars would decrease the amount of lost fertilizer and may even result in growers having to apply less fertilizer. This would have both an environmental and economic benefit. This research will benefit public and private potato breeders developing new improved potato varieties.
Technical Abstract: Increases in root biomass and length have been linked to increased plant nitrogen (N) accumulation; however it is difficult to measure these parameters in soil environments. In vitro methods may aid in elucidating potato-rooting characteristics in relation to N use efficiency (NUE) due to a high level of environmental control. Solanum chacoense Bitt. (chc), a wild diploid species relative of the commercially cultivated tetraploid S. tuberosum L. (tbr), has demonstrated increased plant biomass partitioning towards roots and stolons and may serve as a genetic resource for improved NUE potato breeding. The objectives of this research were to 1) determine the phenotypic variation in root morphological responses of Solanum chacoense Bitt. (chc), 2) root morphological responses of hybrid families of diploid chc, Solanum tuberosum Group Phureja – Solanum tuberosum Group Stenotomum (phu-stn) and Solanum tuberosum L. (tbr) to limited N supply in vitro, and 3) identify chc genotypes with superior root production for future breeding and development of NUE improved potato cultivars. Forty-nine diploid chc clones, 30 diploid phu-stn clones, and nine tbr cultivars were grown under two N rates (1.0 and 0.5 of the recommended N rate) in vitro for 28 days. A reduction in N rate significantly increased root length density (RLD), root surface area density (RSAD), and root tip density (RTD) but not root volume density (RVD). Chc produced the longest roots with the most surface area and number of tips. Furthermore, chc genotypes exhibited the greatest range of performance with five genotypes common to two accessions (PI-537025 and PI-320286) performing in the top 25% for root length suggesting the development of new cultivars with improved NUE may be possible through the introgression of superior N foraging responses in chc. This research will benefit growers and the environment.