Genotypic dependence of wheat species in nitrogen uptake determines by root morphology at maturity

Abstract

The root system is essential for taking up nutrients while providing anchorage to the plant. The controlled environment experiment was conducted to study root morphological traits, plant growth, yield and nitrogen (N) up-take in different wheat species. Seven genotypes including cultivated emmer (Triticum dicoccum), spelt (T. spelta L.) and modern bread wheat (T. aestivum) under three N levels were examined. A split-plot design was used in the experiment where the main plot factor was N levels and the sub-plot factor was genotypes and replicated three times. Root samples at five depth layers were scanned and analysed using WinRHIZO software at anthesis and maturity. Total root length, root volume, root biomass, root diameter, root length density, rooting depth and root N uptake efficiency were recorded. Plant N uptake, N uptake efficiency, N utilisation efficiency and N use efficiency were calculated at maturity (excluding N in roots). Neither interaction effect between main factors nor N level were significant for all measured root traits except N uptake efficiency of roots. Similar results were observed for growth and yield traits together with plant N uptake, N uptake efficiency, N utilisation efficiency and N use efficiency. All measured parameters were significantly different among genotypes. Spelt genotypes recorded the highest total root length, root volume, root biomass and root length density at all depth layers while emmer genotypes recorded the greatest root N uptake efficiency. Plant N uptake was significantly different between genotypes where all spelt genotypes had high plant N uptake followed by bread wheat and emmer. Plant N uptake of the genotypes had a very strong positive correlation with total root length, root volume, root biomass and rooting depth of the genotypes. Therefore, it could be concluded that the high plant N uptake of spelt may be due to the robust and vigorous growth of root systems.