谷子苗期氮高效品种筛选及相关特性分析

Evaluation of Nitrogen Efficient Cultivars of Foxtail Millet and Analysis of the Related Characters at Seedling Stage

【目的】评价不同基因型谷子苗期氮素吸收利用差异性,筛选谷子氮高效利用基因型材料,为谷子氮高效利用品种选育和机理研究提供理论依据。【方法】采用沙培盆栽试验,以具有代表性生态类型的79个谷子品种为材料,分析其在低氮(0.2 mmol·L^(-1))和高氮(6 mmol·L^(-1))处理下茎叶干物重、含氮量、氮素吸收量、氮素吸收与利用效率的差异及相关性,并划分不同生态类型品种的氮效率类型。【结果】供试谷子品种在2个氮素水平条件下的茎叶干物重(CV_(N0.2) 35.39%和CV_(N6) 50.83%)、氮素含量(CV_(N0.2) 11.52%和CV_(N6) 11.22%)、氮素吸收量(CV_(N0.2) 32.82%和CV_(N6) 48.46%)、氮素吸收效率(CV_(N0.2) 32.82%和CV_(N6) 48.45%)、氮素利用效率(CV_(N0.2) 11.53%和CV_(N6) 11.27%)和氮效率(CV_(N0.2) 35.35%和CV_(N6) 50.61%)均存在较大差异。不同生态类型谷子品种的氮素吸收和利用效率差异显著,西北春谷类型氮素吸收效率的变化(CV_(N0.2) 39.99%和CV_(N6) 54.38%)显著高于华北夏谷类型(CV_(N0.2)29.31%和CV_(N6) 45.68%)和东北春谷类型(CV_(N0.2) 29.49%和CV_(N6) 40.30%),而氮素利用效率以华北夏谷类型品种间差异最大(CV_(N0.212.03%和CV_(N6) 12.70%)。茎叶干物重与氮素吸收和氮素利用效率呈极显著正相关(P<0.01),相关系数分别为R^2_(N0.2)=0.1827**和R^2_(N6)=0.1027**及R^2_(N0.2)=0.8985**和R^2_(N6)=0.9442**;氮效率与氮素吸收量极显著正相关,与氮含量极显著负相关,相关系数分别为R^2_(N0.2)=0.8985**和R^2_(N6)=0.9442**及R^2_(N0.2)=0.1962**和R^2_(N6)=0.0998**;氮素利用效率与氮含量极显著负相关,相关系数分别为R^2_(N0.2)=0.9924**和R^2_(N6)=0.9910**。氮素吸收效率与氮素含量和氮素利用效率间无显著相关性。以两氮素水平条件下茎叶干物重和氮效率的平均值为标准,将3种生态类型的谷子品种划分为4种氮效率类型,双高效型、双低效型、高氮高效型和低氮高效型。其中,东北春谷双高效型和高氮高效型品种所占比重最高(P_(东北)52.9%>P_(西北)36.0%>P_(华北)29.7%和P_(东北)23.5%>P_(华北)18.9%>P_(西北)4.0%),双低效型比重最低(P_(东北)17.6%<P_(华北)32.4%<P_(西北)36.0%),而低氮高效型在西北春谷类型中所占比重最高(P_(西北)24.0%>P_(华北)18.9%>P_(东北)5.9%)。【结论】不同谷子品种苗期氮效率差异显著,且西北春谷类型品种间氮素吸收效率差异最大,华北夏谷类型品种间氮素利用效率差异最大;氮素吸收效率和利用效率之间无显著相关性,应作为2个独立的氮效率指标进行评价和改良。

【Objective】The objective of this experiment was to probe genetic variation of nitrogen uptake efficiency（Nup E） and nitrogen utilization efficiency（Nut E） of foxtail millet cultivars at seedling stage and screen N efficient cultivars, which could provide a theoretical basis for the development of new N efficient varieties and N efficient mechanism study. 【Method】In this study, a sand culture pot experiment was conducted with 79 foxtail millet cultivars from three typically ecological types, shoot biomass, nitrogen concentration, nitrogen content, Nut E and Nup E were assessed under low nitrogen（0.2 mmol·L^（-1）） and high nitrogen（6 mmol·L^（-1）） supply, nitrogen use efficiency（NUE） types were also classified. 【Result】Large genetic variation was observed in shoot biomass, shoot N concentration, shoot N content, Nup E, Nut E and NUE at seedling stage. Among the three ecological types, northwest spring foxtail millet cultivars had the highest genetic variation of Nup E, followed by north summer and northeast spring foxtail millet cultivars, while the genotypic variation of Nut E in north summer type was more than that in northwest and northeast spring foxtail millet cultivars. Shoot biomass was significantly and positively correlated with Nup E and Nut E（P0.01）, and correlation coefficients were R^2_（N0.2）=0.1827＊＊ and R^2_（N6）=0.1027＊＊, R^2_（N0.2）=0.8985＊＊ and R^2_（N6）=0.9442＊＊, respectively. NUE was significantly and positively correlated with nitrogen content and negatively correlated with nitrogen concentration, and correlation coefficients were R^2_（N0.2）=0.8985＊＊ and R^2_（N6）=0.9442＊＊, R^2_（N0.2）=0.1962＊＊ and R^2_（N6）=0.0998＊＊, respectively. Nup E was negatively correlated with nitrogen concentration, and the correlation coefficients were R^2_（N0.2）=0.9924＊＊ and R^2_（N6）=0.9910＊＊. There was no significant correlation between Nup E and nitrogen concentration, and between Nup E and Nut E. According to means of shoot biomass and NUE of 79 foxtail millet cultivars, foxtail millet cultivars from three ecological regions were classified into four types, respectively, both higher than the average under low nitrogen and high nitrogen level（HLHH）, both lower than the average under low nitrogen and high nitrogen level（LLLH）, higher than the average under low nitrogen and lower than the average under high nitrogen level（HLLH）, and lower than the average under low nitrogen and higher than the average under high nitrogen level（LLHH）. HLHH and LLHH types were dominant cultivar types in northeast spring foxtail millet, and the percentage of LLLH types was the lowest in northeast spring foxtail millet（P_（NW）17.6%P_（NS） 32.4%P_（NE）36.0%）. However, HLLH types were the main cultivar types in northwest spring foxtail millet（P_（NW） 24.0%P_（NS） 18.9%P_（NE） 5.9%）. 【Conclusion】There was a significant NUE genetic variation of seedlings in different foxtail millet cultivars. Genetic variation of Nup E was the highest in northwest spring foxtail millet cultivars, and north summer foxtail millet cultivars had the highest genetic variation of Nut E. There was no significant correlation between Nup E and Nut E, indicating that the evaluation and improvement of N uptake and utilization should be undertaken independently.