Adaptability Evaluation Of Medium Indica Hybrid Rice For Mechanical Transplanting And Its High Yield Characteristics Based On Daily Yield

This study started with the lack of selection criteria and evaluation methods of suitable machine-transplanted indica hybrid rice varieties in Sichuan region.In 2017,34 medium indica hybrid rice varieties were used as materials,and single factor randomized block field experiments were used to collect data.Combined with actual production and cluster analysis,the daily yield,plant type characteristics,material production characteristics and nitrogen absorption and utilization of medium indica hybrid rice varieties under machine transplanting cultivation were studied,and the feasibility of daily yield as an index for screening medium indica hybrid rice varieties under machine transplanting cultivation was discussed.On the basis of 2017,the varieties that are prone to lodging in actual production and whose whole growth period is too long or too short were excluded.In 2018,a total of 20 varieties were selected to conduct studies on plant type characteristics,population material production,nitrogen absorption and utilization of machine-inserted indica hybrid rice.Correlation analysis,principal component analysis and multiple linear regression analysis were used to analyze the relationship between plant type index,material production characteristics index,nitrogen absorption and utilization index and daily yield.The indexes closely related to daily yield were screened out,and the advantages of daily production efficiency level,yield formation,population growth characteristics and nitrogen absorption and utilization of machine-transplanting indica hybrid rice in Sichuan region were identified.The main results are as follows:1、In this experiment,the actual production stubble features and daily yield characteristics of the tested varieties were discussed,and the daily yield of the tested varieties was analyzed by cluster analysis.It was confirmed that daily yield can be used as one of the main indexes for screening machine-transplanted medium indica hybrid rice varieties.Six varieties suitable for machine transplanting in Sichuan were screened,namely Tianyouhuazhan,Fanyou 609,Jingliangyou 534,Y Liangyou 1,C Liangyouhuazhan and F You498.Compared with low daily yield varieties,high daily yield varieties have the characteristics of appropriate whole growth period,large grain number per panicle,sufficient effective panicle,high population spikelet amount and high seed setting rate,which make up for the disadvantage of small 1000-grain weight,thus achieving high yield by mechanical transplanting.Therefore,the machine transplanting indica hybrid rice in Sichuan region should choose varieties with suitable full growth period and coordinated panicle and grain,which is more conducive to increasing the number of grains per panicle to expand the sink and increase the yield under the condition of effective panicle sufficient.2、Compared with the low daily yield varieties,the high daily yield varieties have shorter plant height,stem length,N3 internode length and N4 internode length,higher grain density,but no obvious difference in upper three leaf length and leaf width.Correlation analysis showed that plant height,stem length,N3 internode length and N4 internode length were significantly negatively correlated with daily yield,grain density was significantly positively correlated with daily yield,flag leaf length and width were positively correlated with daily output,and inverted two and three leaf length and width were weakly negatively correlated with daily yield,but the difference was not significant.The results showed that there was a close relationship between stem type,spike type and daily yield,Meanwhile,the results of principal component analysis and multiple linear regression analysis showed that stem type(partial correlation coefficient r=-2.641**)and spike type(partial correlation coefficient r=4.951**)had significant effects on daily yield,therefore,plant height,stem length,N3 internode length,N4 internode length and grain density can be used as the reference indexes for screening high daily yield variety in the field.3、Compared with the low daily yield varieties,the high daily yield varieties had higher shoot and root growth 8 days after transplanting,and the difference was significant;Transplanting to the effective critical stage of tillering has a higher population growth rate,low consumption at ineffective tillering stage,and the population dry matter accumulation and population growth rate increase significantly in the middle(jointing to full heading stage)and later(full heading to mature stage),especially after full heading,the dry matter accumulation in the panicle has a larger advantage,and after full heading,it has a higher apparent output,output rate and conversion rate of stem sheath and leaf(That is to say,the middle and late stage has the characteristics of high accumulation and high transformation).The total nitrogen accumulation(especially the nitrogen accumulation in the panicle)of the plant at the full heading stage and after full heading is relatively large,and has relatively high nitrogen harvest index,nitrogen grian production efficiency and relatively low nitrogen uptake of 100 kg grain.Correlation analysis,principal component analysis andmultiple linear regression analysis show that the above indexs have significant impact on daily yield,indicating that dry matter,nitrogen accumulation and transportation related indexs in the middle and late stages can be used as important indexs for screening variety with high daily yield,and the characteristics of early growth and rapid development in the early stage can also be used as basic index for auxiliary screening.