Variation, Evaluation Of Nitrogen Use Efficiency Of Triticale In Genotype And Its Physiological Characteristics

In order to release the stress of population, getting the higher harvest and keeping it, the excessive of nitrogen fertilizer input to farmland is the best way in China. As the excessive input of nitrogen fertilizer to field, it not only leads to increased the yield cost,decreased the nitrogen use efficiency but also urged the environment pollution. Some report showed that there were universal different of the same crop about nitrogen use efficiency in different genotypes. So we can get the high nitrogen use efficiency genotype from itself to reduce the supplies of nitrogen fertilizer, deduce the nitrogen use efficiency of the crops, and research the characteristics of high nitrogen use efficiency genotypes for getting german. Therefore, evaluation of nitrogen use efficiency of triticale in genotype was studied in this research. Then, the experiment of soil culture with different N levels were carried out to research the difference in dry matter production, N accumulation, distribution, and physiological characteristics at different growth by using two triticale genotypes of high nitrogen use efficiency PI429186 and low nitrogen use efficiency CIxt74 as materials. The main results were as bellowing:(1) The nitrogen use efficiency and the correlative indexes of 31 triticale cultivars were investigated at the tillering, jointing and heading stages under low and normal N supplies based on pot experiment. The results show that the nitrogen use efficiencies were different for the triticale genotypes under the two N levels. The variation coefficient of triticale at the heading stage was bigger than that at other stages, which was 19.07% under the low N level and 19.50% under the normal N level. The triticale cultivars can be divided into three genotypes, high nitrogen use efficiency genotype, low nitrogen use efficiency genotype and the middle genotype. The high nitrogen use efficiency genotypes of triticale were CIxt82, PI429186 and PI429228, and the low nitrogen use efficiency genotypes were CIxt74, CIxt75, CIxt76, PI428955, PI587238 and PI587241. The plant height and shoot biomass of the high nitrogen use efficiency genotypes were higher than those of the low nitrogen use efficiency genotypes. The plant height and shoot biomass were significantly correlated with the nitrogen use efficiency, which can be used as the indirect indexes to evaluate nitrogen use efficiency of triticale. (2) To investigeat the characteristics of triticale dry matter production, N accumulation and translocation at different growth stages (tillering, jointing and heading stage), a potted experiment was carried out under four N levels comprising 0 mg/kg(N0),16.67 mg/kg(N1),33.33 mg/kg(N2) and 66.67 mg/kg(N3) by using two triticale genotypes of high nitrogen use efficiency PI429186 and low nitrogen use efficiency CIxt74 as materials. The results showed that at each growth stage N application increaded dry matter production. At the same N supplies under different growth stages, the high nitrogen use efficiency genotype PI429186's dry matter production was significant higher than low nitrogen use efficiency genotype CIxt74 N application increased the N accumulation and N accumulation progress of triticale genotypes in root, stem and leaf, while decreased the content of N in each organ. At the same N supplies under different growth stages, the high nitrogen use efficiency genotype PI429186's N accumulation and N accumulation progress in root, stem and leaf were higher than that of low nitrogen use efficiency genotype CIxt74. The N accumulation was higher in stem and leaf than that of root. At heading stage the N accumulation in leaf was transferred into stem, but the amount of N accumulation of root was keeping comparatively tranquilization. There was no significant different in two nitrogen use efficiency genotypes in the distribution of N accumulation.(3) To discussion the effects of nitrogen on root physiology, protective enzyme activities and lipid peroxidation in triticale leaves at different growth stages (seeding, tillering, jointing and heading stage), a potted experiment was carried out under four N levels comprising 0 mg/kg(N0),16.67 mg/kg(N1),33.33 mg/kg(N2) and 66.67 mg/kg(N3) by using two triticale genotypes of high nitrogen use efficiency PI429186 and low nitrogen use efficiency Clxt74 as materials. The results showed that:At the same N supply under different growth stages, the indexes of root physiology including root oxidation ability of a-NA, root reducing ability of TTC, active absorbing surface area of root in high nitrogen use efficiency genotype PI429186 were higher or significant higher than those in low nitrogen use efficiency genotype Clxt74 During the period of seeding, the activities of superxoide dismutase (SOD), peroxidase (POD), and catalase (CAT) in leaves of high nitrogen use efficiency were higher than those of low nitrogen use efficiency genotype at the same N supplies. Contrarily, the content of malondialdehyde (MDA) was lower in high nitrogen use efficiency genotype than that in low nitrogen use efficiency genotype significantly. It could be concluded that, the root physiology was vigorous in high nitrogen use effiviency genotype, it ensures the efficient absorption and utilization of N from soli, and the protective enzyme of high nitrogen use efficiency genotype can cooperated with each other to eliminate reactive oxygen species, inhibit the membrane lipid peroxidation to increase the photosynthesis and get higher yield.