| This study aimed at the main technical problems existing in the developing of rice potted-seedling of mechanical transplanting.The test has been completed in Yangzhou university agronomy external sites for three years in 2011 and 2013.The demonstration base of rice science and technology in Jiangsu province(Jiangyan of Taizhou)chose 4 types of different period of rice varieties(combination)which is promoted to cultivated in large area,a total of six,including four conventional Japonica Rice,one japonica hybrid rice and one japonica hybrid rice to carry out the research of different types of rice conducted by rice potted-seedling of mechanical transplanting yield formation characteristics and several cultivation regulation technology.Test including the suitable planting age and seedlings per hole of different types of rice,analysis of characteristics of rice's yield components,analysis of matter production and photosynthetic characteristics,and the production advantages and main physiological ecology characteristics and so on of rice potted-seedling of mechanical transplanting.Wuyunjing24 was selected as the experimental material to investigate tillers emerging,panicles formation,and yield characteristics under different seedlings per hole The main results of the study are as follows:1.Varieties of the four types under different yields and the seedlings per hole,the output of all have different degree of variation,characterized by hybrid medium indica rice>hybrid late rice>conventional late rice>conventional medium rice.In yield components,the variation of 1000-grain weight is minimal in 4 types of variation.The variation of panicles is the largest in conventional late rice and conventional medium rice,followed by grain per panicle and setting percentage.The variation of grain per panicle is the largest in hybrid medium indica rice and hybrid late rice,followed by setting percentage and panicles.Therefore,it is necessary to arrange reasonable seedling age and seedlings per hole for different types of rice to build a proper production structure,full playing the larger yield potential.Yield components of correlation and path analysis showed that the 1000-grain weight worked and contributed the least to yield of the four types rice.For conventional medium rice,panicles functioned the most,followed by grain per panicle and setting percentage.While for conventional late rice,panicles and grain per panicle contributed a lot to the yield equally,then is the setting percentage.For two varieties of hybrid rice,yield components worked a consistent role to the yield.Grain per panicle affected it greatly,followed by setting percentage and panicles.On high yield cultivation,in varieties of the four types,in consideration of the 1000-grain weight simultaneously,conventional medium rice should further increase panicles,and then increases grain per panicle and setting percentage.Conventional late rice should still put the panicles in the first place,coordinating the grain per panicle and improving setting percentage.While the hybrid rice should point the grain per panicle and setting percentage in the basic of certain panicles.2.In the condition of rice potted-seedling of mechanical transplanting,different types of rice varieties photosynthetic material production has different characteristics.Rice yield trend is consisted with the order of the size of dry matter accumulation from heading date to mature date,and it is different from the dry matter accumulation and harvest index from sowing date to jointing date or jointing date to heading date.Compared with hybrid medium indica rice,in the dry matter production,the group of japonica rice has high quality in growth coordination,with suitable material accumulation from sowing to jointing date and a strong productive ability from jointing date to heading date and heading date to mature date,especially after the heading date of hybrid late rice when the material production capability is strong,which results in a large amount of dry matter accumulation,therefore the rice is in a particular high field.In photosynthetic production side,the advantage of hybrid late japonica rice mainly reveals after the heading date,when the LAI is big,the photosynthetic intensity is high,and both of the late group light transmittance and chlorophyll content is higher.3.The experiment indicated the rules of tillers emergence and panicles formation for rice potted-seedling in mechanical transplanting,.Under the condition of proper seedlings per hole,the rice has had tillers emergence in seedling stage and the re-greening stage is short which belongs to the two peak tiller mode of seedling and field stage.Field stage mainly starts tillering from the fourth tillering position of stem.The main tillers are 4?7 tillers and the secondary tillers of the 4th tillering position.The final panicles mainly from the 5th to 7th tilling positions while also a little bit low and the secondary tillers.The tillers from the middle positions showed a higher productive tiller percentage,and the tillers were the main source of the final panicles and the tiller panicles.According to the tilling characteristics of rice potted-seedlings,management measures of manure and water should be studied,for giving full play to the middle tillers of main stem to shape a high-yielding group in production.4.The experimental study shows that the field of 4 varieties rice increased 9.58%?13.08%from conventional transplanting rice seedlings to rice potted-seedling of mechanical transplanting.The average yield increase is 10.30%.Yield increase is mainly resulted from the high quality of rice potted-seedling of mechanical transplanting.Which is easy to form a strong stem and big panicles,also a high dry matter accumulation,thus panicles,grain per panicle,spikelet amount of group,setting percentage and 1000-grain weight is all in a high level.Rice potted-seedling of mechanical transplanting group stem tillers dynamics has the characteristics that early tillers emergence fast,medium tillers form a stable group of high photosynthetic efficiency and in the late group stem tillers happens slowly.namely " Fast forward,medium steady,slow down".The leaf area of rice potted-seedling of mechanical transplanting has a certain advantage in the whole growth period except the jointing date.In the whole growth period of rice has a greater weight of dry matter.Meanwhile,all the other growth period has the advantage of dry matter accumulation,especially the high fertility matter accumulation in the middle-late stages which forming enough grouting material and enriching the rice grain except the invalid tillers date.5.The seedling age has a conspicuous influence on yields of different types and varieties of seedlings.The conventional medium rice and hybrid medium indica rice which in a relatively shorter growth period has highest yield in the seedling age of 25?30 d and 25 d.Conventional late japonica's highest yield is in its 30?35 d while hybrid late japonica is 30 d,both of which is late japonica rice with a relative longer growth period and later mature period.Single cavity seedling number has a significant influence on the yield of varieties rice.Conventional rice with a 3 or 4 seedlings per hole may have its highest yield,the production of hybrid rice with 2 seedlings per hole will get its highest yield,in which Japonica Hybrid Rice is 2 or 3 seedlings per hole and hybrid indica rice is 1 or 2 seedlings per hole.Interaction effects of seedling age and single cavity number affect yield of conventional rice varieties significantly.With the extension of yields,the number of plants obtain higher yield of single cavity number has a gradually increasing trend.Interaction effects have no significant influence to the hybrid rice.The optimal combination of high yield in this test of rice potted-seedling of mechanical transplanting of seedling age and seedlings per hole is respectively that,25?30 d,3?4 seedlings per hole for conventional medium rice;30?35 d,3?4 seedlings per hole for conventional late japonica;30 d,2?3 seedlings per hole for hybrid japonica rice;25 d,2 seedlings per hole for hybrid indica rice.6.In seeding rate experiment,as the number increased,the quality of potted-seedlings tended to be inferior while seedling has difficult to form a complete set of transplant.High sowing density always bring rice in poor quality which was not conducive to high yield while seedlings of a low sowing density was difficult to cooperate with the rice transplant.The suitable sowing amount of the conventional japonica rice,Wuyunjing24,with a large fringe,was 45-60 g in each potted tray,and on average,there were 3-4 strains of plants per plastic hole.Regarding the water management,the dry rice seedling had more tiller and higher chlorophyll content than the seedlings in the moist environment.Dry management delayed the stagnant growth period of tiller,and the degradation rate of chlorophyll was low,which improved the seedlings' ability to maintain green.Under the experimental conditions,the seedling ages could be extended to 35 days.Twice chemical regulations,by analyzing the seedling plumpness through the orthogonal design of seedling-strengthening agent,MET,water management,sowing densities,was determined as the optimal combination.Timely and appropriate twice chemical regulations could approve seedling plumpness and quality significantly,and it could achieve the uniformity of seedlings in height.To achieve seedling of the best quality,the optimal method was that in the condition of 45 g per potted tray under dry management,mixing up 100 kg subsoil with a 0.5 kg seedling-strengthening agent,and spraying 0.06g MET per tray in the two-leaf period. |
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