【作者】 王之旭；

【导师】 雷财林； 韩勇；

【作者基本信息】 中国农业科学院 ， 作物， 2009， 硕士

【摘要】 本研究选用辽宁省60年代以来大面积推广的黎明、丰锦、辽粳5号、辽粳326、辽粳454、辽粳9号和辽星1号为试材,从产量结构、株形特点、生理特性和生长发育动态几个方面入手,在不同肥力水平和不同栽培密度下,对不同品种的生理性状差异进行比较研究。以探寻在品种更替及产量提高过程中水稻植株形态和生理特性的演进规律及栽培调控的作用,揭示超高产的生理基础及增产的内在生理机制,为辽宁省粳稻高产育种和栽培提供参考依据。研究结果表明：1.随着品种的更替,水稻品种单产不断提高,较高的肥力和较密的种植有利于直立穗和半直穗品种产量的发挥,尤其是对近年育成的新品种。在不同肥力和密度试验试验处理中,产量较高的品种大部分为上世纪90年代后期至今所育的品种,而上世纪60-70年代应用的品种,多数产量较低,表明近些年应用的直立穗和半直立穗品种较60-70年代应用的弯穗形品种更易获得高产。但在中低肥水平下,弯穗形老品种通过调节栽培密度,也可获得较高的产量,表明在品种更新的过程中,栽培肥力与栽培密度起了决定性的作用,新品种更适于高肥力条件下栽培,否则难以发挥其应有产量潜力。2.随着品种的更替,品种的穗粒数明显增加,而穗数则有所降低,粒重变化不明显。在高肥区,60-70年的品种虽然有较多的穗数,但由于穗粒数较少,产量都显著地低于90年代后期应用的品种。这意味着穗粒数的增加是产量不断提高的直接原因。近年育成的辽星1号品种在高肥时易获得高产,主要是因为其穗数和穗粒数都较多。相关分析表明,穗数和穗粒数对产量的直接作用均为显著的正效应,而穗数通过穗粒数对产量为负效应,穗粒数通过穗数对产量也为负效应。如何协调二者之间的矛盾仍是育种和栽培研究的主要目标。3.生物产量与稻谷产量呈极显著的正相关,随着品种的更替,生物产量也在增加,而收获指数的表现出“先升后降”的变化趋势。在高肥条件下,80年代后的直立穗和半直立穗品种的生物产量和收获指数表现出同时增加,相关分析表明,其生物产量与收获指数呈显著的正相关,这为品种产量的提高创造了物质基础。在高肥条件下,在水稻孕穗前,不同年代水稻品种的干物质生产量和干物质积累速率差别不明显。从始穗期开始,60-80的品种在经过一个较快的增长过程后,很快进入平缓增长过程,到生育后期干物质积累速率较低,而90年代后育成的水稻品种,在生育后期干物质积累速率仍较高。在密植条件下,60-70弯穗型品种水稻在出穗灌浆期群体密闭,不利于通风和透光,使用水稻在后期的光合生产能力受到影响。4.随着品种的更替,新品种叶片的光合速率最高并逐渐提高,其原因是新品种具有较大的气孔导度和CO2同化能力(胞间CO2浓度最低),同时新品种叶片的叶绿素含量较高。早期品种光合速率的衰减值和衰减速度都要大于90年代后的品种,表明早期品种在生育后期的抗衰性及生理机能较差。近期育成品种的净光合速率普遍高于老品种的净光合速率。而光合速率的衰减率方面则相反,近期育成品种光合速率的衰减率值要小于老品种的光合速率衰减值。5.株高随着育成年代的推进表现为“高—低—高”的趋势。早期品种平均株高为最大,之后品种的株高有所下降,到了90年代后期株高又逐渐增加。早期品种的叶片较大且披散,这种叶片形态能够适应肥力较低的栽培条件,利于光能的接收。但在高肥条件下,由于叶片互相遮挡,易造成群体密闭。新品种株型较紧凑,这种冠层结构,能最大程度地利用光能,有利于中后期光合作用。6.随着品种的更替,水稻的穗部性状也发生着变化,60-70年代品种的穗长较大,一次枝梗和二次枝梗数最少,着粒密度小,成熟后穗弯曲角度最大。80-90年代品种穗长明显降低,每穗的枝梗数也明显增加,着粒密度也增大,而90年代后期育成品种穗长和枝梗数量几乎没有变化,但着粒密度明显有所降低。相关分析表明,水稻的产量与一次枝梗数量呈正相关与着粒密度呈负相关,增加枝梗数量和着粒密度可以提高穗粒数,但显著降低了水稻的结实率和千粒重,进而影响到产量,而且稻米品质也会随着枝梗数量的增加而有降低的趋势。更多还原

【Abstract】 Six rice cultivars, Liming, Toyonishiki, Liaojing 5, Liaojing 326, Liaojing 454, Liaojing 9 and Liaoxing 1, were selected as experimental materials that have been extended by large area since 1960s in this study. have been studied The yield structures, plant type traits, physiological characteristics and dynamics of growth and development of these cultivars under different fertilization levels and cultivation densities so as to discuss the evolutional discipline of plant morphology and action of cultivation regulation during the process of cultivar alternations and yield increase, reveal physiological basis and internal physiological mechanism of super yield, and provide reference for japonica high-yielding breeding and cultivation in Liaoning province.The research results indicated:1. Higher fertilizer level and thicker planting are beneficial for yield increase of erect-panical and semi-erect panical cultivars with alternation of cultivars. In the experiment of different fertilizer levels and transplanting densities, most of the cultivars bred since late 1990s showed higher yield thanmost of those released in the 1960s and 1970s. Under the mid-low fertilizer level, loose-panicle cultivars could still get higher yield by adjusting transplanting density,indicating that fertilizer level and density played key roles during the process of cultivars replacement. New bred cultivars are suitable for higher fertilization,otherwise it is hard to reach their yield potential.2.With alternation of cultivars, grain number increased markedly, panicle number decreased and grain weight did not change obviously. Grain number increase per panicle was the direct reason for the cultivars released in the late 1990s to continue improving yield. Correlation analysis indicated that panicle number and grain number have significant positive effect on yield, but panicle number has negative effect on yield through grain number, and grain number per ear does so through panicle number. How to coordinate conrtradiction between them is the major objective for study of breeding and cultivation.3. Biological yield had top significant positive correlation with economic yield, and biological yield increased with alternation of cultivars, but harvest index showed the trend of first raise then fall. Under high fertilization, biological yield and harvest index improved simultaneously, and correlation analysis showed the both are significant positive correlation. Under high fertilization, difference between dry matter output and dry matter accumulation rate for different-year cultivars was not obvious before rice booting stage. From early heading stage, dry matter accumulation rate of cultivars released between 1960s and 1980s first increased fast, then to a smooth increase, and the rate is very low at late growth and development; however, that of the cultivars bred in the late 1990s still showed higher at this stage. Under thick transplanting, loose panicle cultivars released between 1960s and 1970s had large and thick population, which was not good for ventilation and light transmission,and production of photosynthesis is affected at late growth stage.4. With cultivar alteration, the max photosynthesis rate of new cultivars gradualy improved, for the reason that new cultivars had greater stomatal conductivity and CO₂ assimilation ability （lowest CO2 concentration between cells）, while keeping higher content of chlorophyll in new cultivars’leaves. Early cultivars had a larger decrease value and decrease speed of photosythesis than those cultivars bred in 1990s, that means they have a poor resistant to aging and a bad physiological function during later stage. New cultivars have a higher net rate of photosynthesis than old cultivars, while decreasing value on the contrary. New bred cultivars had smaller decreasing value in photosynthesis compared with old cultivars.5. Plant hight showed a trend of "High-Low-High" with the rice cultivars bred date moving. Early cultivars had the highest average plant hight, then moved some lower, and then gradualy increased in later 1990s. The early cultivars had larger loose leaves which was suitable for lower fertilizer condition and benifitial for light energy intake. However, with input amount of fertilizer increase, leaves covered each other, and easily created a airtight community. New cultivars had a compact plant type, which could consist a canopy using light energy to its most extent, and that was benifitial for photosynthesis in later stage.6.With cultivars alteration, rice panicle traits altered, too. Cultivars in 1960-1970s had longer panicle length, the lest first and second branches, lower grain density, and the greatest panicle curve angle after ripening. Cultivars in 1980-1990s had panicle length decreased significantly, branches on each panicle increased significantly, and greater grain density. While cultivars bred in late 1990s had nearly no changes on panicle length and branch numbers, but a significant decrease on grain density. Relative analyse showed that rice yield has a positive relation with first branches and a negative relation with grain density. By increasing branches number and grain density, grain numbers on each panicle could be improved. But that would decrease rice seed-setting rate and thousand seed weight, and hence affect yield. Rice quality tended to decease with increase of branch number.更多还原