三角形强化栽培条件下移栽秧龄和密度对杂交稻Ⅱ优498结实期生理和产量的影响

  以杂交水稻组合Ⅱ优498为材料，在三角形强化栽培(TSRI)条件下，研究移栽秧龄和栽插密度对水稻结实期一些生理特性及产量形成的影响。结果表明，在TSRI下，栽培密度的补偿效应可以改善不同移栽秧龄处理下杂交稻Ⅱ优498结实期的一些形态及生理特性，进而获得高产。当移栽秧龄为2叶1心、栽植密度为40 cm × 40 cm时，在一定数量有效穗数的前提下，控制水稻无效分蘖的数量，能够使结实期水稻群体获得较高的叶面积指数(LAI)和高效LAI，延缓了结实期水稻叶面积的下降，而且生育后期根系不早衰，有利于促进茎鞘物质输出，增加茎鞘物质输出率及转化率，其每穗实粒数、千粒重、结实率存在优势，产量最高，且极显著高于其他处理，为此试验TSRI下最佳的移栽秧龄和栽插密度组合。移栽秧龄为8叶1心和栽插密度为50 cm × 50 cm的处理均会造成有效穗数显著降低，影响水稻结实期正常的生理机能，导致产量显著下降。结合产量表现，5叶1心移栽，栽插密度以30 cm × 30 cm ~ 40 cm × 40 cm为宜，可供缓解作物间茬口矛盾的情况下参考；大苗移栽容易加快结实期水稻衰老进程，产量显著降低，大苗移栽应加大移栽密度，本研究条件下栽植密度以30 cm × 30 cm为宜。

Effects of Different Seedling Ages and Planting Densities on Physiological Characteristics and Grain Yield of Hybrid Rice ⅡYou 498 under Triangle Planted System of Rice Intensification During Filling Stage

The grain yield formation and some physiological  characteristics  were investigated during filling stage under triangle planted system of rice intensification (TSRI) at different transplanting seedling ages and planting densities with Ⅱyou 498 as material. The results showed that  obvious compensation effect of planting density to transplanting seedling age of rice under TSRI   improved some morphological  and physiological characteristics during grain filling stage and promoted yield. Transplanting  2 leaf age seedlings at a suitable planting density (40 cm × 40 cm) was the best, which increased effective tiller number of plant population, gained reasonable structure of populations, had high leaf area index (LAI) and much higher percentage of efficient LAI, delayed the descending rate of LAI, and enhanced root activity, consequently, promoted dry matter accumulation and transportation during grain filling, and was helpful to coordinate the conflict among filled grain number per panicle, seed setting rate and 1000 grain weight.  Effective panicle number and grain yield  significantly decreased as seedlings were transplanted at 8 leaf age stage and lower planting density (50 cm×50 cm). For  5 leaf age seedlings, the suitable planting  density  ranged from 30 cm × 30 cm to 40 cm × 40 cm, alleviating  the contradiction of crop  rotation. In addition, transplanting high leaf age  seedlings was easy to accelerate the  senescence process of rice during grain filling stage and decreased yield. It was noteworthy that   high leaf age seedlings should be transplanted at relatively high planting densities, and the optimum planting density was 30 cm × 30 cm for the  8 leaf age seedlings.