杂交水稻超多蘖壮秧超稀栽培的增产作用及机理研究

本文以杂交中稻冈优22、D优95为材料，研究了超多蘖壮秧超稀栽培的增产机理及本田最栽植密度．结果为：秧苗素质优良、单株带蘖10个以上的超多蘖壮秧实行超稀栽培，单株分蘖多而全田茎蘖数及叶面积发展平缓，从而提高了分蘖成穗率，减少了无效分蘖，改善了稻田通透条件，稻株个体生长健壮，光合生产率高，干物质积累快而多，尤其是生育后期的干物质积累量及速度均明显地优于常规栽培，且光合产物向穗部的运转率也高，为大穗高产提供了物质条件．所以，超多蘖壮秧超稀栽培能明显地改善稻田穗、粒结构，比常规栽培增产10％以上，而大穗多粒是其高产的主要原因．而且得出：超多蘖壮秧本田的最佳栽植密度为11．25-15．00万穴／公顷，过稀过密均不利于其产量构成因素的协调发展而增产．且在分蘖力不同的两品种间主要效应是一致的．

STUDY ON THE EFFECT AND MECHANISM OF YIELD INCREASE OF THE MAXIMUM-TILLERING SEEDLING AND MINIMUM-DENSITY CULTIVATION IN HYBRID RICE

The maximum- tillering sedling and minimum-density cultivation in hybrid rice is a new culturing method by which the nutritive area of the single seedling in the nursery bed is 100 cm2 to grow the maximum- tillering seedling with over 10 tillers and the minimum-deusity cultivation is practised in the paddy field to increase the grain yield and save the cost. This. paper reports the reseatch results of the mechanism of yield increase and the optimum cultural praetices of this new method using rice hybrids Gangyon 22 and Diyou 95. The results indicated that the maximum- tillering seedling and minimum-density cultivation inereased the number of tillers per plant, slowed down the increase of the colong and leaf area at early growth stage and maintained that at lata growth stage, raised the ear-bearing tiller percentage, decreased the number of nonbearing tillers as eompared with the traditional cultivation. The maximum-tilleting seedling and min imum-density cultivation improved the ventilative and lightpervions condition, promoted the photosynthetic activity nad the rate of material production and the efficiency of matter transportation especially in the late growth stage as compared with the trtditional cultivation, thus laid the material bases for bigger yanicles and higher grtin yield. The maximum-tillering seedling and minimum-dens ity cultivation obviously promoted the spikelet-panicle structure and iucreasel the grain yield by over 10 pereent as compared, with the traditional cultivation. The main reason for the grain yield increase was found to the increase of filled sFikelets Per pauicle. And it was proved that the optimum density in the paddy field of the maximum- tillering seedling and minimum-density cultivation is 112500 to 150000 hills per hectare. The results mentioned above showed no difference between two rice hybrids with different tillering ability.