【作者】 牛兴奎；

【导师】 李少昆；

【作者基本信息】 中国农业科学院 ， 作物信息科学， 2012， 博士

【摘要】 为探明春玉米产量提升过程中产量性能与群体结构的变化,本研究以我国不同年代的代表性春玉米品种为试验材料,种植在不同密度(37500、52500、67500和82500plants/ha)、不同施氮水平(0、150、225和300kg/ha)条件下,研究其产量的增益、冠层结构特征的变化,以期为建立合理的高产群体,实现春玉米高产提供理论依据。主要研究结果如下(1)本试验条件下,中国春玉米产量增益为每年120.34kg/ha,品种、种植密度及施氮量等主要因素均对春玉米产量影响显著,现代品种具有较高的产量优势,且在高肥、高密条件下更能发挥其产量潜力。在当前一般管理水平下(225kg/ha纯N和67500plants/ha),品种对产量的贡献为45.37%,栽培措施的贡献为30.94%,品种×栽培措施互作的贡献为23.69%；在高产水平下(300kg/ha纯N和82500plants/ha),品种对产量的贡献为31.30%,栽培措施的贡献为36.23%,品种×栽培措施互作的贡献为32.47%。随着生产水平的提高,农艺措施及农艺措施×品种互作对玉米产量增加的作用更大。(2)产量结构分析表明,空秆率随着品种更替显著降低,早期品种白鹤的空秆率为15.99%,现代品种先玉335和郑单958空秆率分别是0.23%和0.35%,随着种植密度的增加,现代品种的亩穗数增加明显；在本研究范围内,随着品种的更替,穗粒数和千粒重以每年2.86粒／穗和1.194克的速度增加,穗数、穗粒数、千粒重的共同作用提升了产量。穗粒数的增加不是花丝数增加,而是成粒率的提高所致。随着密度增加,穗粒数和千粒重减少,现代品种降低幅度小于早期品种。(3)物质生产与分配结果表明,玉米植株干物质积累量随品种更替显著提高,现代品种先玉335比早期品种白鹤提高58.76%;从物质分配角度分析,现代品种花后物质积累量显著增加,早期品种白鹤为46.83%,现代品种郑单958和先玉335花后物质积累比例分别为51.59%和53.17%；伴随产量的提升,收获指数增加,白鹤收获指数为0.41,先玉335为0.53。现代品种花前积累干物质向果穗的转移率较低,更多依靠花后干物质生产来提高产量。随着密度的增加,单株干物质量下降,群体干物质增加,现代品种变动幅度小于早期品种。(4)不同年代品种间冠层结构差异显著,现代品种单株叶倾角逐渐变小,先玉335比白鹤平均减小27.1%,叶向值变大,增加55.1%,叶型上部趋于紧凑,下部趋向松散,更有利于光的透射与分布。现代品种获得最高产量的种植密度增加、叶面积指数增加,白鹤适宜种植密度为37500plants/ha,叶面积指数为3.7,郑单958则为82500plants/ha,叶面积指数为6.2,先玉335则为82500plants/ha,叶面积指数为6.1。和早期品种相比,现代品种的抗倒能力显著增加,白鹤倒伏率为12.6%,郑单958和先玉335分别为1.1%和2.2%,不同年代发放品种的植株倒伏率受种植密度和施氮量的影响,但主要是由品种自身的遗传特性决定的。更多还原

【Abstract】 The objective of this study was to provide a theoretical basis for maize production research by analyzing the maize yield gain characteristics by analyzing the population structure characteristics and yield capability of spring maize resulted of productivity improvements. Six varieties of maize were selected for the study; each selection is representative of a typical or commonly used maize variety from a specific decade, beginning from the1950’s and continuing through each decade into the2000’s. Each variety was planted under four different densities (37500,52500,67500, and82500plants ha-1) and four different nitrogen applications (0,150,225, and300kg ha-1) to study the effects on yield gain and Population Structure characteristics. The main results were as follows:(1)The obtained results demonstrated that there was a maize yield Grain yield has increased at a linear rate of120.34kg/ha between the1950’s variety and the2000’s variety. The effects of maize variety, nitrogen application, and planting density on yield were all significant. Modern Chinese maize varieties had a higher yield advantage. They also displayed the additional potential to acquire higher yield under increased planting densities and nitrogen applications. At the present cultivation levels (planting at67500plants ha-1with225kg ha-1nitrogen application), the contribution types and corresponding yield increase percentages were as follows:genetic improvement,45.37%; agronomic-management improvement,30.94%; and genotype x agronomic-management interaction,23.69%. At high-yielding cultivation levels (planting at82500plants ha-1with300kg ha-1nitrogen application), the contribution types and corresponding yield increase percentages were as follows: genetic improvement,31.30%; agronomic-management improvement,36.23%; and genotype x agronomic-management interaction,32.47%. The contribution of agronomic-management and genotype x agronomic-management interaction to yield increase would be larger with the corresponding management improvement. To further increase maize grain yield in China, researchers should further examine the effects of agronomic-management on maize yield and the adaptation of variety to agronomic-management.(2) The yield components were analyzed, which showed that plant barren ratio was decreased significantly with variety replacement, the plant barren ratio of Baihe was15.99%, and that of Xianyu335and Zhengdan958were0.23%和0.35%, Ear number per mu of modern varieties was increased significantly with increase of density; in this condition, kernel number per ear has increased at a linear rate of2.86grains, thousand kernel weigh has increased at a linear rate of1.194g with variety replacement, the yield was in increased of the combined action of ear number、 kernel number and thousand kernel weigh. The increase of ear number was not because of increase of silks number, but because of increase of rate of granulation. Ear number and thousand kernel weigh were decreased with increase of plant density. The decrease of modern varieties’ was less than early varieties’.The results of dry matter production and distribution showed that dry matter accumulation was increased with variety replacement, the increase of modern variety Xianyu335was higher than early variety Baihe58.76%. The dry matter accumulation of modern variety after anthesis was increased significantly. Dry matter accumulation of Xianyu335and Zhengdan958were51.59%、53.17%respectively, that of early variety Baihe was46.83%. The harvest index was increased with the yield increase. The harvest index of early variety Baihe was0.41, that of modern variety Xianyu335was0.53. The transfer rate of modern variety dry matter accumulation before anthesis to ear was lower than that of early varieties. The yield of modern variety was increased by producing more dry matter after anthesis. With the increase of density, the dry matter per plant was decreased but population dry matter production was increased, the changeable range of modern varieties was less than that of early varieties.(4) The difference of canopy structure between varieties released in different years. Leaf angle of modern varieties was decreased, the average leaf angle of modern variety Xianyu335was decreased by27.1%than that of early variety Baihe. LOV of modern varieties was increased, the average LOV of modern variety Xianyu335was increased by27.1%than that of early variety Baihe. The upper side leaves of plant became compact, lower part leaves of plant became loose, it was beneficial to transmission and distribution of light. The plan density and LAI of modern varieties with the highest yield were increased, such as suitable planting density of Baihe was37500plant/ha and the LAI of Baihe was3.7, suitable planting density of Zhengdan958was82500plant/ha and the LAI of Zhengdan958was6.2; suitable planting density of Xianyu335was82500plant/ha and the LAI of Xianyu335was6.1; the capacity for the resistance to lodging of modern varieties was improved significantly, Lodging rate of early variety Baihe was12.6%, Lodging rate of modern varieties Xianyu335and Zhengdan958were2.2%、1.1%respectively. Although it was also affected by plant density and nitrogen application, lodging rate of varieties released in different years was mainly determined by the genotype of variety.更多还原