In recent 35 years, climatic warming and rainfall decreasing occurred in tillering to jointing stages, but that are disadvantageous conditions of increasing mature spike number.

The results showed that the yield increased significant applying of "Jiulongsheng" and " Banzhongji". The best treatment is "Jiulongsheng" seed dressing, and secondary root increased 0.4 per plant, tiller increased 1.1 per plant, heads increased 28.0×104/hm2, kernel increased 0.3 per head, yield increased 702.9kg/hm2.

In order to gain optimum number of panicls for high yielding inrice prodention, a experimental formula was set up as: X=Y/(1+t_1)〔1+(N-n-SN-1-a)r_1〕+t_2r_2In the formula, X stands for the number of basic seedlings needed pemu, Y stands for the optimum number of panicles, N-n stands for thecritical leaf-age-period of effective tillers, SN for the leaf age of theseedlings fransplanted, t_1 for the number of tillers having more than 1leaves, t_2 for the number of tillers being less than two leaves. The r_1and r_2...

In order to gain optimum number of panicls for high yielding inrice prodention, a experimental formula was set up as: X=Y/(1+t_1)〔1+(N-n-SN-1-a)r_1〕+t_2r_2In the formula, X stands for the number of basic seedlings needed pemu, Y stands for the optimum number of panicles, N-n stands for thecritical leaf-age-period of effective tillers, SN for the leaf age of theseedlings fransplanted, t_1 for the number of tillers having more than 1leaves, t_2 for the number of tillers being less than two leaves. The r_1and r_2 represent the rate of effective tillers occured in main tillers andthe rate of survived small tillers respectively. With different vepresentative rice varieties an 1 different treatmentssuch as the sowing norms, the seedlings being of different leaf-age-per-iod, the forms of transplanting different densities of plants transplantedand different fertility levels, the experiment weve carried out in variousecological districts in Jiangsu Province. It was confivmed that the formulaconld be comprehensively used to determine the desirable number ofpanicles developed per seedling the panicles which depend on the mainstems or on the tillers and the proportion of panicles which shoulddevelop from tillers, and that the formula was feasible to direct riceproduction.

We investigated and quantitatively described the rule of ear formation per plant and the interrelationships among ears per plant, number of spilelets, grains per ear and weight of 1000 grains in winter wheat Yangmai No.5 under different sowing time and baise seedlings. The result showed that under the condition of basic seedlings 4～20 x 10~4 per mu and sowing time from October 9 to November 9 the less the basic seedlings and earlier sowing time, the larger the potential of single plant which gave more ears per...

We investigated and quantitatively described the rule of ear formation per plant and the interrelationships among ears per plant, number of spilelets, grains per ear and weight of 1000 grains in winter wheat Yangmai No.5 under different sowing time and baise seedlings. The result showed that under the condition of basic seedlings 4～20 x 10~4 per mu and sowing time from October 9 to November 9 the less the basic seedlings and earlier sowing time, the larger the potential of single plant which gave more ears per plant, more seeded spikelets, less sterils spikelets more grains per spikelet, larger ear and higher weight of 1000 grains. The relationship between ears per plant (x) and grains per ear (y) could be deseribed by equation (?)= ax~b. The relationship between number of seeded spikelets per car (x) and grains per ear (y)could be described by equation (?)= ax + bx~2. The relationship between number of sterile spikelets per ear (x) and grains per ear (y) could be described by equation (?)= ac~bx.

A regression design(Table 1)was adopted with Yangmai 5, a wheat cultivar of spring habit, as the material in order to find an optimized combination of sowing date, sowing rate and nitrogen application to win wheat yields as high as 6000 kg per hm2 or more. The results are summarized as follows. ①Earlier sowing and less seedlings per hectare could increase the leaf number per main stem(Table 2).②The ear number per plant was increased with decreasing seedlings per hectare, especially when the seedling number...

A regression design(Table 1)was adopted with Yangmai 5, a wheat cultivar of spring habit, as the material in order to find an optimized combination of sowing date, sowing rate and nitrogen application to win wheat yields as high as 6000 kg per hm2 or more. The results are summarized as follows. ①Earlier sowing and less seedlings per hectare could increase the leaf number per main stem(Table 2).②The ear number per plant was increased with decreasing seedlings per hectare, especially when the seedling number was less than 1.5 million per hm(Fig. 1).③The filled grain number per ear was increased and the 1000-grain weight decreased with the increase in the ear number of per plant(Fig. 2). The decrease in 1000-grain weight could cause the decrease in the volume weight of grains(Fig. 3).④The wheat yield was increased with the increased amount of accumulated dry matter after anthesis(Fig.4, Table 3).⑤When the proportion of nitrogen fertilizer applied as basic fertilizer, tillering fertilizer and heading fertilizer was 5: 2: 3, the wheat yield was the highest(Table 4). Through frequency analysis,an optimized combination of cultural factors for a target yield Of more than 6000 kg/hm in average Climatic conditions was established, i. e., sowing date Oct. 12-15, seedling number 0. 75-0. 90 million/hm, total nitrogen application 300 -345 kg/hm(Table 5). In view of the difficulty in carrying out low sowing rate in practice, it would be better to set the per hm seedling number at about 1.2 million and the ear number per plant at 3-4, when the combination technology is applied to high yielding fields. If this technology is applied to common fields,it may be advisable to keep the seedling number per hm at about 1. 5 million and the average ear number per plant at 3, on the basis of an earlier sowing date and a reasonable increase in nitrogen application.