In vitro method for early evaluation of nitrogen use efficiency associated traits in potato

The objective of the present study was to characterize various traits associated with nitrogen uptake and utilization in a range of potato cultivars. For this purpose an in vitro test system was developed which allows analyzing specific stress responses in a highly controlled environment. Shoot tips were grown fixed in perforated stainless steel plates in 500 ml glass vessels in liquid culture medium at four nitrogen levels, i.e. 60, 30, 15 and 7.5 mmol L-1. At the end of a three weeks' culture period plant developmental traits were determined and nitrogen uptake and assimilation were analyzed. Reduction of nitrogen in the culture medium differentially affected morphological and physiological features. Highly significant differences were found between different N-levels and cultivars as well as for genotype x nitrogen level interactions. Three groups of cultivars (high, low and intermediate) were distinguished with respect to biomass production and crude protein yield under nitrogen-sufficient conditions of 60 mmol L-1. Genotypes with a low biomass production at full nitrogen availability responded with increased root development under nitrogen deficiency stress and increased their nitrogen utilization capacity in relation to the other cultivars.