Evaluation location: Wisconsin, United States
A vigorous root system could be related to traits desired in the potato crop such as efficient water and fertilizer use. Because wild species are adapted to a broad range of soil environments, they may contain useful variation not available in the cultivar breeding pool. Roots are very difficult to measure, especially in field conditions. We grew 75 accessions (3 accessions of each of 25 species) in Perlite as seedling replicates in clay pots in a summer screenhouse. They were harvested at the same time, all being at about the same physiological maturity (just reaching full flowering). Roots were separated from the rest of the plant (top). The tissue was air, then oven dried and weighed. These results appear to have a relationship with those of Errebhi et al. who measured nitrogen uptake efficiency. S. chacoense and S. microdontum had the highest total biomass production in N-deficient growing conditions and the greatest N uptake efficiency. In our study, S. chacoense had by far the most root production and microdontum ranked 7th of 25. Errebhi et al. found a large difference between the two accessions of kurtzianum they tested for the two parameters mentioned above. Our results with these same accessions found the poor N user produced only 60% as much roots as the efficient N user. More work and analysis needs to be done in this area. However, preliminary indications suggest that screening for root dry weight of pot-grown plants might have usefulness as a relatively simple way to predict field performance of germplasm with respect to use of soil resources.
Reference:
Errebhi et al. 1998. Screening of exotic potato germplasm for nitrogen uptake and biomass production. AJPR 75:93-100.