拔节期淹水对不同株高夏玉米产量、形态特征及物质生产的影响

选择不同株高夏玉米品种登海661(DH661,矮秆品种)和登海605(DH605,高秆品种),设置两个种植密度(52 500株/hm~2和75 000株/hm~2),比较研究因自然降雨引起拔节期淹水对玉米植株形态和物质生产的影响及其与产量的关系。结果表明,拔节期淹水后,两个类型品种子粒产量均显著降低,穗粒数明显降低,千粒重降幅较小。淹水后不同株高夏玉米各个节间干物量显著降低,玉米株高、穗位高降低,各节间长及茎粗均变小,其中,第3节间及穗位节间降幅最大,高秆品种高密度条件下更为显著。相关分析表明,淹水处理后株高、穗位高、平均节间长与产量显著负相关,粒叶比、冠根比与产量相关不显著。表明夏玉米子粒产量降低主要是淹水胁迫降低了植株茎秆中物质积累量(特别是第3节间和穗位节间),明显抑制了穗分化而导致穗粒数减少所致。

Effects of Waterlogging at Jointing Stage on Grain Yield, Plant Morphology and Dry Matter Production in Different Plant Height of Summer Maize

This study chooses summer maize(Zea mays L.)(i.e. dwarf Denghai661, DH661; and high stem Denghai605, DH605) at the different plant height; and set the high and low planting density(52 500 plants/ha and 75 000 plants/ha) to analyze characteristics of plant morphological and material production, and relationship between them and yield at jointing stage under waterlogging caused by rainfall. The results showed that compared with no waterlogging treatment, grain yield of DH661 and DH605 were significantly decreased in two planting density, and kernel number were significantly decreased. The decline increased along with the density increase in the dry matter accumulation of each internodes and reduced plant height, ear position height, the internodes length in waterlogging, and the length of the third internode reduced as the largest proportion in two planting density. The results of correlation analysis between main characters and grain yield showed that plant height, the internode length and stem dry weight had significant positive correlation. Overall, the main reason for summer maize subjected to waterlogging to reduce yield is that waterlogging stress reduced dry matter accumulation in the stem,and significantly inhibited the ear differentiation and resulted in the decrease of kernel number.