Study On Population Light Distribution And Light Interception Characteristics Of Corn With Yield Potential Of 22.5t/hm~2

On the basis of identifying the plant type and canopy characteristics of Denghai 618(DH618),a typical variety with yield potential of 22.5t/hm2,and combining with the dynamic changes of photosynthetically active radiation(PAR),a canopy dynamic analyzer was developed for the determination of maize canopy light radiation.It was used to explore the spatio-temporal variation characteristics of light interception and light distribution in dense planting and high-yield maize canopy,providing theoretical support for the breeding of high-light-efficiency varieties.The research results were as follows:1.The canopy dynamic analyzer is different from previous studies in the measurement and calculation methods of canopy light interception.The device can simulate the growth morphology of corn in the field,and multiple photosensitive probes parallel to the leaf surface can truly record the light intensity of the whole leaf,and the light interception efficiency is calculated using the total day light amount.The results of the four treatments(DH618-5K,DH618-8K,SC704-5K,SC7048K)measured by the canopy dynamic analyzer at the spinning stage were 86,46%,92,59%,90.30%,97.98%,respectively.The results of Sunscan canopy were 82.38%,90.21%,92.81%and 99.16%,which were close to each other.Plant type and measurement time were the main factors of difference.The results measured by canopy dynamic analyzer at maturity stage were 68.19%,63.15%,51.81%and 52.64%,respectively,and those by Sunscan canopy analyzer were 81.45%,85.85%,91.34%and 92.51%,respectively.Leaf senescence was the main factor of difference between the two,and the results measured by canopy dynamic analyzer were more accurate.2.Two varieties of different plant types,DH618 and SC704,were selected,among which DH618 was compact and had a yield potential of 22.5t/hm2,while SC704 was semi-compact and had a yield potential of 15t/hm2 as the control.The effects of different plant types and densities on population light interception and their relationship with yield were analyzed.The results showed that DH618 had a high light interception efficiency under dense planting conditions,and the group light interception efficiency reached 92.47%in spinning stage,65.27%,20.86%and 7.70%in upper,middle and lower leaves,respectively,and remained at 63.15%in maturity stage.The light interception efficiency of SC704 was 97.98%and 0%at spinning stage and mature stage,respectively,and 68.73%,22.70%and 3.99%at different leaf layers.DH618 canopy light distribution is more reasonable,the upper canopy light intensity decreased significantly at noon,the ear position and the lower leaves can also maintain a high light intensity,the upper,middle and lower leaves at noon the average light intensity of 338.2,229.0,104.1μmol/(m2·s).SC704 is 409.3,188.0,76.3μmol/(m2·s),the upper part of the light is stronger,the middle part is weaker.