| With 12 typical hybrid mid-season rices as test materials, the effects of seedling growth, planting quality, planted recovering, population structure at full heading stage, grain growth, yield and rice quality were studied in mechanical transplanted. The main results were as follows:1. According to the results of the whole growth stage dynamic cluster analysis during tow years, we divided the 12 rice varieties into four types. One type is the whole growth stage of 137 days, including D you 261. The second type is the whole growth stage of 145-146 days, including Chuanxiangyou 425, T you 8086 and Fuyou 838. The third type is the whole growth stage of 155-156 days, including Gangyou 99-14, Gangyou 305, Gangyou 906, Gangyou 725 and Neixiang 8156. The last type is the whole growth stage of 160-162 days, including II you 498, Chuanxiang 9838 and Rongdao 415.2. The rice seedling quality decreased at 4.1-leaf stage (34 days after sowing). The result showed that the basic stem diameter became slow, the root did not grow, the number of yellow leaves increased, and the root shoot ratio reduced. Though the root number increased, there was a disharmony between the growth of the aboveground and underground, because of the increasing of aboveground growth and the rapidly decline of the root vigor. The growth stage was longer, the phenomenon was more obvious. The seeding height and aboveground dry matter of long growth stage rice variety all continued to improve with the longer seedling age. But the dry matter of seeding and the rice seedling quality decreased. The leaf color of longer and shorted growth stage rice varieties became light. And the aboveground nitrogen content decreased persistent and the C/N rose fast to above 1.0.3. The main factors which influenced mechanical transplanting were no-seedling in hill and injured-seedling. At the stage of regreening and recovery growth, the content of the aboveground proline (Pro) and malondialdehyde (MDA) showed a peak value first and than reduced. The leaf color deepened and the dry matter continued to increase fast. It showed that the leaf color deepened and the content of aboveground Pro and MDA decreased with the recovery of seedlings. From the view of recovery rate, the longer and shorter growth stage rice varieties recovered slowly relatively.4. In the case of similar basic seedlings, peak tillers larger and the average rate of tiller larger, while the percentage of effective tiller lower. There was not only relatively higher effective panicles and also higher percentage of effective tiller for the type that had lower rate of tiller. Appropriate basic seedlings, peak tillers and the appropriate rate of tiller had direct importance to increase effective panicles. Thus, to control the amount of peak tillers, to select the hybrid mid-season rice that had moderate tillering ability, played an important role to high-yield.5. Light transmittance and leaf area index (LAI) were gradually decreased, and significantly different in different Varieties. The LAI difference in different Varieties reached the highest level after heading 30 days, the longer whole growth stage type had smaller LAI decline rate. The light transmittance of middle and bottom layer had significant impact to yield and quality, yield was mainly affected by top and middle layer LAI. Shorter whole growth stage varieties and types had smaller leaf to grain ratio, had relatively low yield, while longer whole growth stage varieties and types had larger leaf to grain ratio, had relatively high yield. In addition, head milled rice rate had significant correlation with LAI of middle and bottom layer and light transmittance of bottom layer after heading 30 days. LAI and light transmittance had significant correlation with RVA eigenvalue.6. The type that had stronger dry matter accumulation power, and had longer whole growth stage. The correlativity between dry matter accumulation and yield reached significant level in booting stage, and then were positive correlativity. Varieties'dry matter distribution ratio of stem-sheath in booting stage was first increased and then decreased, green leaf dry matter distribution ratio was continuously decreased, while the rate of ear dry matter distribution was to continue growing. The stem-sheath and ear had different dry matter distribution in differnet types, and the dry matter accumulation power of stem-sheath in booting stage had important effect to yield.7. The whole growth stage was longer, and its yield was relatively higher than the type that had shorter whole growth stage. Except 1000-grain weight, different rice type had different grain-filling index, and different varieties and types had different grain-filling characters. The type had larger grain-filling index, and had larger grain-filling percentage too. The whole growth stage of 155 days type had largest grain-filling percentage and grain-filling index was, the second grain-filling percentage and grain-filling index type was 146 days, and the shortest whole growth stage had least grain-filling percentage and grain-filling index.8. The head milled rice rate difference was best significant in different hybrid mid-season rice type, and higher of shorter whole growth stage types. Rice milling quality difference was more different in which had different length of whole growth stage. The rice length to width ratio was greater, chalkiness rice rate was lesser in the type that had longer or shorter whole growth stage, there had lowest chalkiness rice rate in the type that whole growth stage was 137 days. The main difference of RVA eigenvalue of different varieties and types was reflected by hot paste viscosity, cool paste viscosity, setback and pasting temperature.9. Correlation between some indices and yield reached significant or very significantly. These indices included root to shoot ratio, leaf age, the number of yellow leaf, C/N ratio before transplanting, damaged seedling rate, leaf SPAD in 12 days, MDA content of aboveground part in 6 days, Pro content of aboveground part in 15 days after transplanting, leaf SPAD, dry weight aboveground part, dry matter distribution ratio of stem-sheath in booting stage, plant height, flag leaf length, inverse 2nd leaf length and inverse 3rd lesf splay angel in heading stage, LAI and light transmittance of middle layer in 30 days when heading stage, the maximum growth rate of strong grain and initial growth power. The main components was composed of damaged seedling rate, leaf SPAD in booting stage, dry matter distribution ratio of stem-sheath in booting stage, flag leaf length and inverse 2nd leaf length in heading stage, leaf age, the number of yellow leaf, light transmittance of middle layer in 30 days when heading stage. There were three indices independent of each other that could be used as reference index about yield, were dry matter distribution ratio of stem-sheath in booting stage, inverse 2nd leaf length in heading stage, light transmittance of middle layer in 30 days when heading stage.10. In considering the succeeding crop and climatic conditions, the hybrid mid-season rice type which has 145-156 days of the whole growth stage is more suitable for long seedling age rice transplanting with machine after rape (wheat) in Sichuan Basin, that has some characteristics, such as leaf age is less than 4.75, plant height is shorter than 22.0cm, root to shoot ratio is greater than 0.36, sugar nitrogen ratio of about 1.5, has better transplanting quality and more reasonable population structure, yield more stable and so on.
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