陕A群、陕B群选育的玉米自交系氮效率评价

为阐明不同类型玉米自交系氮效率差异特征,筛选氮高效的玉米自交系,以陕A群、陕B群选育的33份玉米自交系为材料,以4份骨干自交系(‘郑58’、‘昌7-2’、‘PH6WC’和‘PH4CV’)为对照,调查了2种施肥条件下[0 kg(N)·hm?2、180 kg(N)·hm?2]玉米自交系的穗位叶SPAD值、叶面积、干物质积累量、叶片、茎秆和籽粒氮含量等生理指标。利用主成分分析和模糊隶属函数,采用逐步回归分析方法建立最优回归方程,筛选耐低氮性综合评价指标。结果表明:穗位叶SPAD值、吐丝期绿叶面积、吐丝期茎干重、吐丝期叶干重和籽粒氮含量,可作为玉米自交系耐低氮能力的第2性状筛选指标。以产量作为第1性状指标,可将37份玉米自交系划分为14份高产氮高效型,5份低产氮高效型,15份低产氮低效型和3份高产氮低效型。以耐低氮能力综合值D值筛选,将37份玉米自交系可分成3种类型,其中耐低氮能力较强的15份(D值≥0.5),耐低氮能力中等的15份(0.35≤D值0.5),耐低氮能力较差的7份(D值0.35)。综合分析,2种施氮条件下,‘KB215’、‘KB417’、‘KA225’、‘KB081’和‘L123098-2’5份玉米自交系具有吐丝期绿叶面积大,吐丝期茎叶干重、籽粒氮含量高和籽粒产量高,耐低氮能力强的特点。因此,强化育种环境的选择压力,实施低氮选择策略,可有效提高玉米种质对氮肥的利用效率。

Evaluation of nitrogen efficiency for selected Shaan A and B maize inbred lines

AbstractThis study was set up to explore the characteristics of nitrogen (N) use efficiency (NUE) of different groups (Shaan A group and Shann B group) of maize inbred lines, and to screen high N-efficient maize inbred lines. A total of 33 maize inbred lines from the Shaan B and Shaan A groups were used along with 4 elite inbred lines (‘zheng58’, ‘chang7-2’, ‘PH6WC’, ‘PH4CV’) as the control. The study analyzed SPAD value, green leaf area, dry matter accumulation as well as N uptake in stem, leaf and grain of maize inbred lines under no nitrogen [N0, 0 kg(N)·hm-2] and normal N [N180, 180 kg(N)·hm-2] levels. Based on principal component analysis (PCA), fuzzy membership function (FRF), stepwise regression analysis and the optimal regression equation, evaluation indexes for low N tolerance of maize inbred lines was established. The results indicated that SPAD value, green leaf area, stem dry weight and leaf dry weight at silking and grain N uptake were reliable secondary indicators for comprehensive evaluation of low N resistant ability of maize inbred lines. Using yield as primary index, among 37 maize inbred lines, 15 lines were determined as high yield with high N efficiency, 5 lines as low yields with high N efficiency, 15 lines as low yields with low N efficiency and 2 lines as high yields with low N efficiency. According to the integrated value of low N resistance (D) calculated using the secondary indexes, 37 maize inbred lines were also divided into three types — 15 lines of strongest resistance to low N withD ≥ 0.5, 15 lines of stronger resistance to low N with 0.35 ≤D < 0.5, and 7 lines of poor resistant to low N withD < 0.35. Comprehensive analysis of two N levels showed that ‘KB215’, ‘KB417’, ‘KA225’, ‘KB081’ and ‘L123098-2’ had higher green area and stem and leaf dry matter at silking stage, greater grain N content and higher yield, and the strongest resistance to low N. Thus strengthening selection process of breeding environment and low N use effectively improved the utilization efficiency of N fertilizer of maize germplasm.