Abstract:

Three diploid (Triticum boeoticum, AA; Aegilops speltoides, BB and Ae. tauschii, DD), two tetraploid (T. dicoccoides, AABB and T. dicoccum, AABB) and one hexaploid (T. aestivum, AABBDD) wheats were chosen, and a pot experiment was carried out under different water and nutrition conditions (i) to understand the variation trend of nutrient use efficiency in the evolution of wheat (from diploid to tetraploid then to hexaploid); (ii) to assess the effects of soil water and nutrient condition on nutrient use. Our results showed that with the evolution of wheat, nutrient uptake and uptake efficiency increased, but grain nutrient concentration decreased. Generally, water stress and low nutrient supply resulted in the lower grain nutrient concentration, and nutrient uptake and uptake efficiency. Nutrient use efficiency for biomass and that for grain yield were all different significantly among wheat genotypes, but the differences of the latter were more significantly than those of the former. With the increase of wheat ploidies, nutrient use efficiency for biomass and that for grain yield all increased significantly. Nitrogen and phosphorus use efficiency for biomass (NUTEb and PUTEb) dereased in the same order：Ae. speltoides > T. dicoccum, T. dicoccoides, Ae. tauschii, T. boeoticum > T. aestivum, and potassium use efficiency for biomass (KUTEb): T. aestivum, Ae. tauschii, Ae. speltoides > T. dicoccoides > T. dicoccum > T. boeoticum. All of nitrogen, phosphorus and potassium use efficiencies for grain yield (NUTEg, PUTEg, KUTEg) and harvest index (HI) decreased in the similar order：T. aestivum > T. dicoccum, T. dicoccoides, Ae. tauschii > T. boeoticum, Ae. speltoides. Compared to the other two diploid wheats, Ae. tauschii had significant higher nutrient use efficiency for grain yield, indicating that the genome D may carry genes controlling high efficient use of nutrient. The effects of water and nutrient application on nutrient use for biomass were prominent, but not for that for grain yield, suggesting that wheat nutrient use efficiency for grain yield is mainly controlled by genotypes. Generally, water stress increased nutrient use efficiency for biomass, but higher nutrient application decreased them. Some of these results and their significance for breeding were discussed.

Key words: Diploid, Tetraploid, Hexaploid, Wheat, Nutrient uptake efficiency, Nutrient use efficiency, Water