中国不同年代玉米亲本自交系的灌浆特性与氮素运转

大田试验条件下，选择我国1960s、1980s、2000s三个年代在生产中大面积应用的玉米亲本自交系为试验材料，比较分析了遗传改良过程中玉米骨干自交系灌浆特性及氮素运转的演变特征。结果表明，当代玉米品种及其亲本自交系的产量显著高于其他年代品系(P<0.05)，且不同年代品种产量提高与其亲本产量密切相关(P<0.05)，亲本自交系产量提高与其穗粒数相关性不显著，而与粒重呈显著正相关(P<0.05)。对粒重变化研究表明，当代亲本自交系的灌浆速率呈先慢后快的趋势，籽粒灌浆的积累起始势(R₀)较高，灌浆最大速率出现时间(T_max)延迟，灌浆速率最大时生长量(W_max)和最大灌浆速率(G_max)明显较高。当代亲本自交系具有较高的干物质积累和日增干重，其茎鞘物质输出率和茎鞘物质贡献率均高于1960s自交系，且在高密度条件下优势更为明显。当代亲本自交系具有较高的氮素积累总量(P<0.05)，氮素输出率、贡献率的优势不明显(P>0.05)，而氮素利用效率及氮收获指数显著高于1960s自交系(P<0.05)。表明遗传改良过程中玉米骨干自交系籽粒产量及氮效率得到同步提高，这与其自身较高的籽粒灌浆能力和物质运转效率密切相关。

Characteristics of Grain Filling and Nitrogen Translocation of Maize Parent Lines Released in Different Eras in China

The purpose of this study was to investigate the evolution characteristic of grain filling and nitrogen translocation in maize hybrids parents released in different eras, which provides the critically important information for nitrogen efficient cultivar. Sixteen elite parent lines released in 1960s, 1980s, and 2000s with widely popularized and utilized in China were used in 2007–2008 to analyze the changes in grain filling traits and nitrogen efficiency associated with yields in genetic improvement during the past four decades. The results showed that compared with 1980s and 1960s hybrids and their parents, the modern hybrids and parent lines had higher grain yield significantly, and the correlation analysis indicated that the yield increasing of hybrids closely related to that of their parents (P < 0.05). However, the yield of parents was not significantly related with their ear numbers, and was significant positively correlated with 100-kenerl weight (P < 0.05) in different eras. Compared with 1980s and 1960s hybrids parents, their contemporary parents had higher initiation potential(R₀), delayed time of the highest filling rate, and higher growth amount at biggest filling rate (W_max) and the highest grain filling rate (G_max). Also, the modern hybrids parents maintained higher dry matter accumulation, stem-sheath matter exportation rate, and stem-sheath matter contribution. As far as nitrogen translocation, the modern hybrids parents had higher N accumulation amount (P < 0.05), without obvious advantages in transportation rate and contribution rate, and higher nitrogen utilization efficiency (NUE) and higher nitrogen harvest index (NHI) (P < 0.05). These demonstrated that the modern hybrids parent lines maintain higher grain yield and nitrogen efficiency, which is closely correlated with stronger grain filling ability and organic matter accumulation efficiency.