The effect of nitrogen use efficiency on significant traits of potato starch production

The improvement of nitrogen use efficiency (NUE) in potato (Solanum tuberosum L.) can reduce the required N input. As a result, economic benefits will increase, and environmental pollution will decrease due to N loss. The aim of the study was to determine the NUE of potato genotypes and to evaluate the relationship of NUE with the tuber yield, starch yield, and starch content at different N fertiliser rates. During a two-year experiment, the performance of 19 potato genotypes was evaluated by different farming practices involving the varying levels of N fertiliser rates. These practices included the integrated farming (IF) system with three different N fertiliser rates and the organic farming (OF) system without N fertilisation. The N fertilisation in both farming systems was stated as plant-available N in soil and as N added with a fertiliser. A significant effect of the genotype and the farming system on the tested traits was determined. The potato genotype tuber yield correlation with NUE was high or moderate in the farming system with different N fertiliser rates in both years. The tuber yield of potato grown in the farming system with a comparatively higher N fertilisation usually did not increase significantly; therefore, a decrease in genotype NUE was detected. The correlation between starch yield and NUE was high and strong in both farming systems, although high and moderately strong correlation was determined between tuber yield and starch yield. NUE had a weak correlation with the starch content in potato tubers, so genotype characteristics and growing conditions had the greatest influence on this trait. An increase in N fertilisation did not lead to an increase in starch yield due to a decrease in starch content and a slight insignificant increase in tuber yield. However, genotypes with higher NUE produced a higher tuber yield and starch yield than genotypes with relatively lower NUE, even in the farming systems with different N fertiliser rates in both experimental years.