Nitrogen Use Efficiency in Durum Wheat Under Different Nitrogen and Water Regimes in the Mediterranean Basin

Abstract

Improving nitrogen use efficiency (NUE) represents one of the main goals to reduce N input in maximizing crop yield for sustainable agriculture. A NUE key strategy is the exploitation of genetic variation in available germplasm together with the understanding of molecular mechanisms governing this complex trait. Thus, NUE, its components, nitrogen uptake efficiency (NUpE) and nitrogen utilization efficiency (NUtE), and NUE-related traits heritability were evaluated in ancient (Cappelli, Capeiti, Russello, and Mazzancoio) and modern (Messapia, Tiziana, Svevo, and Normanno) wheat genotypes for tackling nitrogen (N) and/or water limitation in both growth chamber and field experiments. Our results exhibited a reduction of NUE, NUpE, and NUtE under water and combined (nitrogen + water) stress in all the genotypes, as expected. The contribution of genetic variability on phenotypic variation was significant for NUtE, harvest index, post-anthesis nitrogen uptake (PANU), and biomass production traits. Moreover, the stress tolerance indexes, calculated and bi-plotted for N and water stresses, exhibited two distinct clusters for many traits as then confirmed by principal component analysis. Although modern varieties showed higher crop yield and NUE under conventional N and water regimes, ancient varieties exhibited best performances to cope with both stresses, mainly under water limitation. Finally, the usage index, which takes into account total biomass increase, underlined that old genotypes were less affected by both stresses during crop cycle. In particular, these genotypes showed the best performances for NUE and its components under both stresses at stem elongation and milk ripening as shown also by PANU. In addition, at these stages, nitrate and ammonium transporter gene expressions in the root were performed, showing the highest activity in ancient varieties. In conclusion, the identification of NUE traits during a specific crop cycle stage, under both N and water limitation, will help in the breeding of more resilient varieties in Mediterranean sustainable agriculture by reducing N supply.

Synchronizing Nitrogen Fertilization and Planting Date to Improve Resource Use Efficiency, Productivity, and Profitability of Upland Rice

“…Crop water productivity was also associated with NUE. Furthermore, AE N , RE N , and NHI were significant and positively associated with crop water productivity, and higher crop water productivity results in enhanced NUE (Ullah et al, 2019 ; Lupini et al, 2021 ).…”

Effect of Trichoderma asperellum on Wheat Plants’ Biochemical and Molecular Responses, and Yield under Different Water Stress Conditions

“…WS was performed by halving irrigation throughout the trial and obtaining a 30% reduction in the field capacity, representing a moderate stress condition, but not one that was drastic enough to bring the plants to final production. Studies in wheat have shown that WS decreases N use efficiency and crop productivity [ 40 , 41 , 42 ]. It has also been reported that the effect of Trichoderma on wheat plants subjected to moderate WS depends on N fertilization levels, and that only growth and biomass were increased under high N inputs [ 43 ].…”

“…WS did not significantly modify the expression levels of the two transporters, AMT-3.1 and PDR1 , but it reduced those of the two N metabolism genes, GS2 and NIA7 . Controversial results on the expression of ammonium transporter genes in WS wheat plants have been reported [ 41 , 47 ]. While a marked induction of ammonium transporters by WS has been described in the vegetative stage [ 47 ], plants in later developmental stages did not show upregulation under WS, but they did so under N deficit [ 41 ].…”

Evaluation of Advanced Backcrosses of Eggplant with Solanum elaeagnifolium Introgressions under Low N Conditions

“…Increasing nitrogen use efficiency (NUE) is one important pathway to enhance sustainability, and several strategies and genetic approaches were described for NUE improvement [45][46][47]. Several efforts for NUE breeding in cereals and others field crops were published in rice [7,[48][49][50], wheat [51,52], maize [53][54][55][56], barley [57], millet [58], and oilseed rape [59]. In potato, breeding for NUE was also reported [60,61].…”