栽插苗数对超级稻南粳49冠层和产量的影响

Effect of Seedling Planting Density on Canopy and Yield of Super-rice,Nanjing 49

以南粳49为材料，研究栽插苗数对超级稻冠层和产量的影响。结果表明，南粳49对栽插苗数有较宽的适应范围，在2～4株·穴-1的栽插苗数内，南粳49均可达到较高的产量，而5株·穴-1则产量显著降低。不同的栽插苗数，南粳49有不同适应调节方式：2株·穴-1的植株，可通过增加单株分蘖数、每穗总粒数和提高单叶光合能力，从而增加干物质累积而获得高产；3株·穴-1的植株，则通过增加群体叶面积等提高群体数量的方式，增加有效穗数，而获得高产；在4株·穴-1的植株，则通过增加叶面积指数，以及减少倒2叶的叶基角以增加群体中层截光率，而改善群体质量，从而达到高产。可见，南粳49是具有较强群体调控能力的超高产水稻品种类型，选择2株·穴-1的栽插苗数，产量可以达到（12.63±0.253） t · hm -2，而且可以减少用种量。

Nanjing 49 was used in the experimentation to determine the effect of seedling planting density on the canopy and yield of the super-rice . The results showed that Nanjing 49＆#39;s adaptability to the varying planting density was rather broad .It could reach a high yield at the range of 2 -4 plans · hill-1 . However ,when the planting density was more than 5 plants · hill-1 ,the productivity significantly reduced .It appeared that Nanjing 49 adapted to the varied planting density by different means . For example ,at the rate of 2 plants · hill-1 ,it increased the total dry matters to reach a high yield by increasing its tillers per plant ,total grains per spike ,and photosynthetic capacity per leaf . At 3 plants · hill-1 ,a high yield was achieved through increasing the total leaf area and effective panicles per hill . Then ,when the planting was increased to 4 plants · hill-1 ,it improved the yield by increasing LAI and reducing the leaf＆#39;s base angle of the second leaves to effectively increase the sunlight reception . Therefore , with its high adaptability to the planting density ,Nanjing 49 could provide a yield as high as （12.63± 0.253） t · hm -2 on a reduced number of seedlings · hill-1 （e .g .,2 plants · hill-1 ） to save on the planting cost .