The effect of low nitrogen supply on yield and water-use efficiency of sweet potato (Ipomoea batatas L.)

Abstract

A pot experiment was conducted in a tropical mid-elevation environment to evaluate sweet potato clones of different origin and breeding intensity for traits related to growth phenomena, nitrogen use efficiency (NUE), and transpirational water use efficiency (WUE) as affected by different levels of N fertilisation. Genotypes with small canopies were associated with a consistently positive response to increasing N supply and with efficient translocation of dry matter and N to storage roots. Genotypes with high canopy net assimilation rates had a high proportion of sun leaves and high chlorophyll content in leaves. N stress lead to increased transpiration per unit leaf area and decreasing WUE. We found clear effects of genotype and nitrogen supply on WUE.