| Based on the theory of Rice Precise and Quantitative Cultivation (RPQC) and the erect eco-type environment in Yunnan province, China, the study on mechanism and quantitative cultivation of high-yielding rice were carried out from 2008 to 2012. By analyzing the climate data of 33 counties with different altitude and latitude in Yunnan province, three eco-type environments and five sub-zones of rice in Yunnan province were divided and the meteorologic characteristics of different environment were compared. The process of leaf age, leaf number and elongation internode number of 53 varieties were studied to build the leaf age model for erect environment, meanwhile to analyze the effect of temperature on total leaf mumbers and growth period. Two key techniques of RPQC, which were nitrogen application rate and basic seedlings quantitative, were researched. The contrast experiments for different mature types of rice varieties between RPQC and traditional high grain yield cultivation were carried out at 5 sub-zones to appraise the adaptability and the mechanism of increased grain yield. The results were shown as fellow:1. The subdivision of erect eco-type environment in Yunnan province, ChinaIn order to divide the rice ecology by analyse the characteristic of different environment, the climate data from March 1st to October 31stof 33 counties in Yunnan province from 1998 to 2007,which was the whole rice period, were collected and analyzed. According to daily average temperature, the rice zones could be divided into indica region, japonica region, and indica-japonica cross-region. The main limiting factors in indica region were humidity and rainfall. According to them, indica region could be divided into humidity indica sub-zone (HISZ) and dry indica sub-zone (DISZ). Because the temperature was also the main limited factor in Japonica region, japonica region also could be divided into warm-japonica sub-zone (WJSZ) and cool-japonica sub-zone (CJSA). The mean and active accumulated temperature during rice growth period in indica region, indica-japonica cross region and japonica region were>23℃, 19-23 ℃ and 15-19℃C, andv>5000℃,4650-5000℃ and 3500-4650 ℃, respectively. The mean temperature of DISZ, HISZ, IJSZ, WJSZ and CJSZ during rice growth period were>24℃,23-24℃, 19-23℃,17-19℃,15-17℃, respectively, The active accumulated temperature of DISZ, HISZ, IJSZ, WJSZ and CJSZ were>5500℃,>5000℃,4650-5000℃,4000-4650℃,3500-4000℃, respectively.2. Study on the traits of rice growth period under five sub-zones in Yunnan ProvinceFifty-tree varieties were classed by different ecological sub-zones and mature types to analyze the growth period traits. The results were shown:The growth period of rice varieties were from 140 d to 219 d. The difference was 70 d. So, seven mature types were divied by per 10 d. They were extreme early, very early, early, middle, late, very late, extreme late mature type. With the altitude rising, the rice period was longer and the mature type was delayed. The rice period in HISZ was from 140 to 155, and the varieties belonged to extreme early and very early mature types. The rice period in DISZ was from 170 to 195, and the varieties belonged to middle, late, and very late mature types. There were Indica and Japonica varieties planted in IJSZ, the period of indica varieties was from 170d to 185 d, which belonged to middle and late mature types; the period of Japonica varieties was from 160 d to 195 d, which belonged to early, middle, late and very late mature types. The period of rice in WJSZ was from 186 d to 200 d, which belonged to late and very late types. The period of rice in CJSZ was from 191 d to 219 d, which belonged to very late and extreme late types. The active accumulated temperature and effective accumulated temperature for Indica varieties were from 3500℃ to 4950℃, and from 1550℃ to 2610℃, respectively. Those for Japonica varieties were from 3100℃ to 3850℃, and from 1200℃ to 1900℃, respectively. With the altitude or latitude rising of sub-zone, the active and effective accumulated temperatures were decreased. At the same sub-zone, the active and effective accumulated temperatures were increased with the longer period.3. Research on nitrogen application ratio of high-yielding rice at five sub-zones in Yunnan province, ChinaIn order to look for better method to application nitrogen to improve grain yield of rice and the nitrogen use efficiency, the field experiments were carried out at 5 sub-zones inYunnan province. Six ratios of basal-tiller nitrogen and panicle nitrogen under the same total nitrogen dose were used to study the differences of grain yield, yield component and nitrogen use efficiency. The results indicated that postponing nitrogen application was in favor of increasing grain yield. T3 (6:4) had got the highest grain yield under dry-indica, wet-indica and warm-japonica sub-zones, and T4 (5:5) had got the highest grain yield under indica-japonica, and cool-japonica sub-zones. So the optimum ratio of basal-tiller and panicle nitrogen to increase grain yield and use efficiency of nitrogen were 6:4 or 5:5. The ratio of basal and tiller nitrogen, and promotion and sustaining nitrogen were 5:5, respectively, so the nitrogen application method that the ratio of basal nitrogen, tillering nitrogen, spiliket promotion nitrogen and spiliket sustaining nitrogen were 2.5:2.5:2.5:2.5 or 3:3:2:2, was named balanced applied nitrogen method (BANM).By this method, the panicle number, spikelet number per panicle and grain weight were increased to get high yield, and mature nitrogen agronomic efficiency (MNAE) and partial factor productivity of applied N (PFP) were increased.4. Research on quantifying seedlings of high yielding rice at five sub-zones in Yunnan province, ChinaIn order to provide basic theory for rice high yield cultivation by determining seedlings, the field experiments about plant density and basic seedling with the main varieties were carried out at 5 sub-zones inYunnan province in 2009 and 2010. The results showed that basic seedlings of high yield Indica varieties was less than that of Japonica, which was 22.5-36 seedlings and 72-75 seedlings per square meter, respectively. For the same basic seedlings, grain yield by transplanting single seedling was higher than that by double seedling. Effective panicles and spikelet number per unit land were increased with rising basic seedlings, but spikelet and filled grain per panicle were reduced, seed rates and thousand-grain weight were less affected. With rising basic seedlings and plant density, the maximum tiller number was increased significantly, but the percentage of effective panicles was reduced.5. Research on the mechanism of increased grain yield by RPQC at five sub-zones in Yunnan province, ChinaFrom 2008 to 2009, the contrast experiments for different mature type varieties between RPQC and traditional cultivation were carried out at 5 sub-zones. The major local varieties were selected as experimental materials. The order of rice yield by traditional cultivation at 5 sub-zones DISZ>IJSZ >WJSZ>CJSZ>HISZ changed to DISZ>IJSZ>HISZ>WJSZ> CJSZ by RPQC. Compared with traditional cultivation, by RPQC rice yield was significantly increased from 4 percent to 36 percent. In addition, effective panicle, spikelet per panicle, filled grain per panicle, spikelets per unit land, seed rates and grain weight were increased by RPQC. Although the increased amplitude of single factor was no significant level, but increase of all components promoted the significant increase of rice yield. There were two main reasons that RPQC had been produced more rice. One was to obtain more effective panicle by reducing basic seedlings and basic-tiller nitrogen to contral the maximum tiller number, and to increase the ratio of panicle and maximum tiller number, the other was to increase spikelets number per unit land significantly by applying more panicle nitrogen to promote large panicles.6. Built the regulation of RPQC under erect-ecological sub-zone in Yunnan provinceAccoding to the research, the high yielding model of RPQC were built for 5 sub-zones. |
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