【作者】 马均；

【导师】 周开达； 朱庆森； 杨建昌；

【作者基本信息】 四川农业大学 ， 作物遗传育种， 2002， 博士

【摘要】 高产是水稻育种、栽培研究的永恒主题。目前，增大库容量，提高单穗重已作为实现水稻超高产所选择的一个重要的目标性状。重穗型超高产育种途径已成为水稻超高产育种的重要技术路线之一，并已培育出一大批重穗型品种在生产上大面积推广，取得了良好的增产效果。2000-2001年，用16-18个不同穗重型品种在四川温江、江苏扬州进行试验，对不同穗重型品种的形态、生理生化特性和高产潜力进行了系统而全面的研究，以期为水稻超高产育种、栽培提供理论依据。主要研究结果如下： 1．重穗型品种的产量及产量潜力均比中穗型品种高10％左右，而后者又高于轻穗型品种15％以上。重穗型品种比中、轻穗型品种较易获得更高的产量和具有更大的增产潜力，且其产量水平也较稳定。重穗型品种高产的原因是有效穗数有所减少，但穗粒数、库容量有较大幅度的提高，结实率并未降低。 2．重穗型品种穗大粒多，强、弱势粒异步灌浆明显，弱势粒灌浆启动慢，但其生长活跃期长，灌浆时间延后，后期仍有较强的灌浆。如后期生长条件正常，其籽粒充实也能达到中、轻穗型品种的正常水平。 3．重穗型品种的LAI比中、轻穗型品种有适当降低，但齐穗后其LAI的衰减较慢，高效叶面积率、粒／叶(cm~2)比有显著提高。重穗型品种在齐穗后其上部3叶的叶绿素降解较慢，SOD酶活性较高、下降较缓，叶片中光合产物向穗部的输出效率高；重穗型品种在齐穗后剑叶的净光合速率显著高于中穗型品种，而后者又显著高于轻穗型品种，其净光合速率增加的直接原因是其Rubisco酶活性的提高及叶绿素含量的增加；与中、轻穗型品种相比，重穗型品种具有在高、低光强、高温和低CO~2浓度下对CO~2有较强的同化能力的优势，光合“午休”现象较轻，能保持较高的净光合速率，显示其对环境有较强的抗逆性；气孔开度积(单位面积上的气孔密度乘以其气孔开度)大是重穗型品种净光合速率高的重要生理基础。因此，重穗型品种在“源”方面已具备了高产、超高产的潜力。 4．穗颈节间组织包括维管束数目、面积、韧皮部面积、茎横切面面积、茎壁面积及穗部各部位枝梗维管束数目与面积等均是重＞中＞轻穗型品种；随着穗型的增大，韧皮部的库容负荷量并未对籽粒充实产生“结构障碍”；穗颈节间和穗部枝梗输导组织特征与空壳率的大小无关，但它是籽粒充实的重要前提和解剖学基础；穗颈节间茎的粗度、茎壁的厚度与维管束数目、维管束面积、韧皮部面积、每穗总粒数、单穗重呈显著或极显著 如b 个问穗至型水稻的彤态、生理生化特性及产量潜力的研究2 正相关，茎壁面积’。茎横切面积之比与籽粒充实率呈极显著正相关。 5．提高灌浆前期籽粒中 ATP、IAA含量，可加速籽粒灌浆，IAA对籽粒灌浆的调控作用 更明显；灌浆汕期籽粒中ADPG焦磷酸化酶、淀粉合成酶、分枝Q酶的活性高，则籽粒 的灌浆起步早、灌浆迅速，且提高灌浆前、中期籽粒中上述3种酶的活性与灌浆期中各 种酶的平均活性，将有助于促进籽粒灌浆和籽粒充实。重穗型品种弱势粒灌浆启动慢、 起步迟，与其籽粒广的生理活性低有关，要进一步提高其籽粒的充实，关键是提高灌浆 前。中期弱势粒）车的牛理活性，加速其灌浆和籽粒充实。 6．重、中、轻型品朴在抽穗前的物质积累差异甚小，但重穗型品种在抽穗后具有较强 的光合生产力，物质积累优势显著，其总生物产量显著高于中、轻穗型品种。且重穗型 品种茎鞘物质向穗部的运转率、运转量和转化率也极显著高于中、轻穗型品种，所以其 了t 大“库”与“源”供应基本相适，但增“源”仍有增产余地。 7．重穗型品种的株高有所增加，但主要是在上部第I、2个节间，基部节间长度与中、 轻穗型品种差异甚个，且茎秆粗壮、机械组织发达、坚韧性强，虽弯曲力矩增加，但茎 秆的抗折力也相应提高，故而倒伏指数并未增大。说明其株高与茎秆物理性状的优化组 合可使株高与倒伏和生物产量的矛盾在更高产量水平上得到统一？重穗型品种冠层3叶 的长度、宽度、面积均显著大于中、轻穗型品种，且它们均与每穗粒数、实粒数、单穗 重呈显著或极显著正相关；重穗型品种剑叶叶角小而挺直，倒2。3叶叶角顺次适当增 大，且上3叶叶位均有所提高，尤其是剑叶，这种较优的叶层结构利于形成较为理想的 受光姿态，提高光能利用率。 8．本研究结果表明，聚合各种优良基因、配合理想的株型因于、注重后代选择的重穗 型水稻品种选育是水稻超高产育种的重要途径之一，而三系重穗型杂交稻育种是目前比 较成功的重穗型水稻品种选育方法。本研究还讨论了有关重穗型品种的栽培技术问题。更多还原

【Abstract】 The higher grain yield is the eternal subject for the breeding and cultivation of rice .At present, to increase the sink capacity and panicle weight per panicle is a key factor in super high-yielding breeding and cultivation of rice. The breeding model of heavy panicle type of rice (HPTR) has been considered as one of the main methods in breeding rice for super-high-yield, and with this model many varieties with heavy panicle and high yield have been bred and utilized widely in rice production. Sixteen to eighteen varieties(oryza sativa subsp . indica ) were used in the experiments conducted both in Wenjiang, Sichuan andYangzhou, Jiangsu in 2000 and 2001 . The morphology and the characteristics of physiology andbiochemistry and high-yielding potential of different panicle weight type of rice were studied to supply theorial and practical directions for the super-high-yielding breeding and cultivation of rice. The major results were as follows:l.Both the grain yield and yield potential of HPTR varieties was 10% higher than those of medium panicle type of rice (MPTR) varieties and the latter were over 15% higher than light panicle type of rice (LPTR) varieties. The HPTR varieties could easily harvest higher grain yield and possessed higher yield potential and had a stable grain yield between different ecological regions. The reason for the high grain yield of HPTR varieties was a little less effective panicle number, larger spikelet number per panicle, larger sink capacity per unit area and stable seed setting in compared with those of MPTR and LPTR varieties. 2.The grain-filling processes of HPTR varieties were obvious asynchronous between the strong and week potential grains, its vigorous filling phase was late, but had the long active grain-filling phase and grain-filling duration. If the growing condition was regular at the later grain-filling stage the grain-filling of HPTR varieties could also reach the normal level of MPTR and LPTR varieties.3.The leaf area index (LAI) of HPTR varieties was a little lower than that of MPTR and LPTR varieties, but its decreasing rate of LAI after heading was slower and had much higher percentage of efficient LAI and grain-leaf area (cm2) ratio in comparison with MPTR and LPTR varieties. The chlorophyll content and SOD activity in leaves of HPTR varieties were higher and decreased slowly after heading than those of MPTR and LPTR varieties. There was a high efficiency of assimilate’s transportation to panicle in leaves of HPTR varieties. The net photosynthetic rate (Pn) of HPTR varieties was significantly higher than that of MPTR varieties and the latter was significantly higher than that of LPTR varieties due to the corresponding change of Rubisco activity and chlorophyll content. In comparison with MPTR and LPTR varieties, HPTR varieties had an ability of keeping high level photosynthesis and Pn under high or low light intensity, high temperature and low CO2 concentration. The results showed that HPTR varieties were resistant to poorclimate conditions. For the stomatal characteristics, it was found that higher Pn mainly resulted from its higher total quantity of stomatal opening degrees of HPTR varieties. So, HPTR varieties showed a potential ability of super-high-yield in its supply of source.4.The number of vascular bundle, the area of vascular bundle, phloem, xylem, cross section of stem, culm wall and pith in the first internode and the number and area of vascular bundle in the branches of HPTR varieties were larger than those of MPTR varieties and the latter were larger than those of LPTR varieties. The vascular bundles had the similar load of spikelet number and sink capacity among HPTE, MPTR and LPTR varieties. The characteristics of the conducting tissue in the first internode and the branches were not related to the empty-grain percentage, but played an important role to the grain-filling, and were a basic structural factor to good grain-filling. The number of vascular bundle, the area of vascular bundle andphloem, total sink capacity per更多还原