| With the varieties of mid-maturing hybrid rice Chuanxiang3hao and Fuyou838, late-maturing hybrid rice Fyou498and Gangyou725as the materials, the experiment mainly studied the effects of different seedling ages(21d,28d,35d) on seedling quality, the mechanical transplanting quality, the growth and development of population and yield. The main results are as follows:1. Using the seedling tray of hachikata blanket raising seedling, the best seedling quality is21days after sowing, with the seedling age extension, the seedling quality decreased, especially the seedling age of35d, in seedling morphological characteristics manifested as seedling number per unit area decreased significantly, the plant height increase rapidly, while W/H and the root-shoot ratio significantly decreased. The total rooting number and root length have no growth28days after sowing, the rooting ability and seedling regularity decreased, the seedling aging is increasing. In seedling physiological and biochemical indexes manifested as the content of MDA and POD are increasing, while the content of CAT and SOD are declining and the C/N is declining too. The seedling quality of the late-maturing hybrid rice are better than the mid-maturing hybrid rice, and the variety Fyou498is best. In mechanical transplanting quality, with the seedling age extension, the miss planting rate, floating seedling rate, tipping rate, damaged seedling rate and folded seedling rate increased significantly, but the maximum seedlings per litter reduced significantly. Fyou498is better than the other three varieties in mechanical transplanting quality indexes, and is suitable for mechanical transplanting than the other three varieties.2. Seedling age affected the yield and yield components of the transplanting rice with machine significantly. With the increase of seedling age, the yield decreased gradually for 21d>28d>35d. Among those,the late-muturing hybrid rice(Fyou498) under the Seedling age of21days had a highest yield with9.66t/hm2. Under the same seedling age, the late-maturing hybrid rice varieties(Fyou498) and (Gangyou725production was significantly higher than the mid-maturing varieties (Chuanxiang3) and (fuyou838). Between the late-maturing varieties, the (Fyou498)’s yield was significantly higher than (Gangyou725)’s. In addition,(Fyou498) remained a higher yield when extending the seedling age appropriately to28days. Under the seedling age for21days, the measures to improve the rice yield was raising the numbers of effective panicles and grain mumber per panicle namely total number of spikelets at the same time. so only under the premise of high panicles,until we got a high rice yield increasing the number of grains per panicle. Late-maturing varieties (Fyou498) will get a higher yield with a reasonable yield components.3. With the seedling age extension, the highest tillering age and effective tillering stage in mechanical transplanting hybrid rice will be advanced, and the highest seedlings and effective panicle reduced significantly. The time to reach the highest tillering age is almost same for the four varieties. Fyou498’s tiller increase faster, tillering potential high, tillering ability strong. Mechanical transplanting stem and tiller increase faster than hand planting,the tillering amount is large and reduced quickly in the late. The rate of productive tillers is low, Among the productive tillers of21d is highest, significantly larger than the treatment of28d and35d. In the rate of productive tillers of four varieties, Fyou498is the best. There is no significant difference at main stem panicle length, primary panicle and secondary panicle manifested as the treatment of21d and28d significantly larger than35d. In the three seedling ages, the primary branch numbers in primary panicle and secondary panicle are not significantly different. In secondary branch numbers, main panicle, primary panicle and secondary panicle manifested as21d>28d>35d. Two late-maturing hybrid rice are better than two mid-maturing hybrid rice in the panicle traits.In the contribution of different tiller position to yield, primary panicle> main panicle> secondary panicle, mechanical-transplanting is significantly lager than hand-transplanting in the contribution of different tiller position to yield.4. In booting stage, full-heading stage and maturity stage, with the seedling age extension, dry matter accmulation continuously decreased. The difference in dry matter weight per plant on seedling age at different growth stages, botting stage is less and full-heading stage and maturity stage after heading show relatively large. With the seedling age extension, the treatment of harvest index decreases gradually, in variety, late-maturing hybrid rice is better than mid-maturing hybrid rice in dry matter accmulation and harvest index, especially Fyou498. EPSS and TPSS decreased significantly as the seedling age extension, Fyou498> Gangyou725, Fuyou838> Chuanxiang3hao. LAI reached its maximum in booting stage, in booting stage and full-heading stage, LAI decreases gradually with the seedling age extension, but in maturity stage35d is significantly large than21d and28d. Efficient leaf area ratio shows that it significantly decreases with the seedling age extension. The late-maturing varieties LAI are more suitable, leaves area growth and decline speed more reasonable. In full-heading stage,15days after full-heading and30days after full-heading, the photosynthetic rate of flag leaf significantly decreases with the seedling age extension, which the21d photosynthetic rate of flag larger18.05%and34.32%than28d and35d. At different varieties, Fyou498is the maximum, Fuyou838is less, shows that the two varieties photosynthetic ability more strong, accumulated more photosynthetic products.5. With the seedling age extension, the time to turning green is increased, initial heading date is delayed, and so full-heading stage and maturity stage. The late-maturing varieties the days which delayed is more than the mid-maturing varieties, especially Gangyou725. The total growth period shows trend that21d<28d<35d, two late-maturing varieties is larger than two mid-maturing varieties in grown period, the grown period of Fyou498is less than Gangyou725, and Fuyou838is least. Compared hand-transplanting with mechanical-transplanting, the date of turning green delay, the total grown period is longer than21d seedling age while shorter than the seedling age of28d and35d. |
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