Effects Of Different Hill Spacing And Basic Seeding Per Hill On Plant Morphology And The Field Light Conditions Of Machine-transplanting Hybrid Rice

In order to define the effects of different hill spacing and basic seeding per hill on transplanting quality,plant and leaf shape,canopy light distribution,microclimate environment,photosynthetic production,as well as yield and yield components in hybrid rice,Fyou 498 and Yixiangyou 2115 were choosed in 2016 with basic seedlings of 42×10⁴/hm²（widely used in the production）,and Yixiangyou 2115 was conducted in 2017 with two basic seedlings of 42×10⁴/hm² and 63×10⁴/hm².Three planting patterns were set as:（1）high hills with low seedlings,at 30 cm×12 cm spacing;（2）middle hills with middle seedlings,at 30cm×17 cm spacing;（3）low hills with high seedlings,at 30 cm×23 cm spacing.The main results were as follows:1.Comparing with Fyou498,the single and group stem tillers number,percentage of earbearing tiller,plant convergent index,second upper leaf length and third upper leaf length and width at the heading stage,leaf area and leaf area index per hill,dry matter weight at the tillering stage,colony growth rate from heading to maturity of Yixiangyou 2115 were higher.Fyou 498 had higher tillering angle,plant canopy width,leaf length and width,leaf loose degree,leaf basal and open angle,third upper leaf drooping angle,light penetration rate at the heading stage,stem sheath output rate,dry matter accumulation and proportion after heading.2.Under the condition of high basic seedlings,float seedling rate reduced.While the stem tillers number,leaf area（index）,dry matter accumulation of single hill and group were increased.The flag-leaf open angle and drooping angle,lodging index,leaf and stem-sheath output,output rate,conversion rate after heading,canopy humidity were higher.But percentage of earbearing tiller,tiller angle,stem type index,basal culm diameter,breaking resistance,bending moment,light transmittance,flag-leaf stomatal conductance,intercellular CO₂ concentration,and transpiration rate,assimilation amount and population growth rate after heading,crop growth rate from heading to maturity,as well as harvest index were decreased.3.The planting pattern of low hills with high seedlings could improve the mechanical transplanting quality,stem tillers number per hill,plant canopy width,leaf area and dry matter per hill,crop growth rate,falg-leaf photosynthetic rate,stomatal conductance,and transpiration rate.The canopy temperature was more moderate under the low hills with high seedlings of 42×10⁴/hm² basic seedlings,and the relative humidity at the later stage was lower.4.Under the condition of high basic seedlings,the effective panicle number significantly increased,but the spikelet and grain numbers per panicle decreased,resulting in no significant difference of rice yield.The field density was too high under the basic seedlings of63x10⁴/hm²,which inhibited the mechanical transplanting rice yield potential productivity.The results showed that,the three planting patterns had no significant effect on the rice yield,and the low hills with high seedlings could also achieve high and stable yields.