Submitted to: American Journal of Potato Research
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/21/1998
Publication Date: N/A
Citation: Interpretive Summary: Potato is the top vegetable in the US. But a good crop depends on high rates of fertilizer application, which is not only costly to farmers in time and money (which farmers in developing countries may not be able to afford), but also can have environmental impact. A notable example is nitrogen, which can contaminate surface water and wells. This research examined exotic potato relatives for ability to use nitrogen more efficiently than current varieties. We found that some wild potato species produce much more growth than most varieties when nitrogen is limited, and this was particularly true when plants are grown under stress. Identification of these nitrogen-efficient wild potato relatives provides new genetic resources for breeders. We now know the best exotic materials to use as parents for the ultimate goal of breeding high nitrogen-use efficiency into new varieties which will compose the crop of the future.
Technical Abstract: Modern potato varieties (Solanum tuberosum L.) require high rates of fertilizer nitrogen (N). This practice is costly and can pose a serious threat to surface and groundwater. Previous evaluation of wild potato germplasm demonstrated the existence of species capable of producing high total biomass under low N conditions, with the ability to make maximum muse of added N. Therefore, a two-year field experiment was conducted to investigate the response of selected wild potato accessions and their hybrids with the haploid USW551 (USW) to low and high N environments. The haploid USW and cultivars Russet Burbank, Red Norland, and Russet Norkotah were also included in the study. Uniform propagules and seedlings from the various Solanum species were subjected to two N treatments: 0 and 225 kg N ha-1. At harvest, total dry biomass of wild and hybrid potato germplasm was equal to or higher than that of the cultivars. Cultivar biomass partitioning in percent was roots: 1, shoots: 15, fruits: 0, and tubers: 84, whereas wild potato species partitioned percent biomass to roots and stolons: 18, shoots: 52, fruits: 23, and tubers: 7. Hybrids were intermediate, allocating their percent biomass to roots plus nontuberized stolons: 9, shoots: 39, fruits: 14, and tubers: 38. Nitrogen-use efficiencies for many of the species and crosses were comparable to that of Russet Burbank and greater than those of Red Norland and Russet Norkotah. Of the wild species tested, S. chacoense accessions had the highest biomass accumulation and N uptake efficiencies and may be the best source of germplasm for improving nitrogen-use efficiency in a potato breeding program.