Effects Of Shading Treatment On Physiology Yield And Quality Of Potato

Potato is an important grain and vegetable crop,which is planted in different ecological regions of China.There are certain differences in the planting season and mode of potato in each region.Therefore,the light adaptability of varieties is one of the important factors that limit its promotion area.Potato varieties planted in the southern winter planting area require good light resistance;the intercropping in the southwest mixed cropping area and the facility cultivation in the central plains secondary cropping area also required the weak light resistance of varieties.Potato varieties planted in the northern monoculture have no special requirements for light intensity.The pot experiment was conducted to compare the changes of plant growth,related physiological indexes and chlorophyll fluorescence parameters of 12 potato varieties under three shading treatments at multiple growth stages,as well as the yield and some quality performance at harvest.The research results accumulated data for the identification and utilization of potato germplasm resources with weak light tolerance,screened basic materials for subsequent gene mining,and provided reference for the cross-regional promotion of different varieties.The main research results are as follows:(1)Different varieties grew differently under shading treatment.The plant height and node spacing of double shading treatment were significantly higher than that of no shading treatment,and the stem diameter was significantly lower than that of no shading treatment.Under shading treatment,the SOD activity and transpiration rate of leaves increased first and then decreased,and the MDA content increased and the photosynthetic rate decreased.With the increase of shading degree,SOD activity decreased first and then increased,MDA content,photosynthetic rate and transpiration rate decreased significantly.(2)The chlorophyll fluorescence parameters of different varieties varied under shading treatment.Double shading increased Fv / Fm,NPQ and light use efficiency,but ETR decreased significantly.The Fv / Fm values of Kexin 23,Yanshu 4,Dongnong 303 and Youjin under different shading treatments were significantly different,and the changes of other varieties were similar.NPQ and ETR showed a downward trend with the advancement of fertility,and the utilization rate of light energy showed an upward trend.The difference between different shading treatments was significant.(3)The effects of shading treatment on yield and quality were different.Compared with no shading treatment,double shading treatment significantly reduced yield per plant,tuber number per plant and large tuber rate.The dry matter content of tubers under no shading and single shading treatments was significantly higher than that under double shading treatments;there was no significant difference in crude protein content of tubers among different shading treatments.Properly reducing light intensity would increase crude protein content.(4)Seven principal components with eigenvalues greater than 1,contribution rate greater than5 and cumulative contribution rate greater than 90 were obtained by principal component analysis,which represented potato yield,nutritional quality,physiological indexes,growth and photosynthetic efficiency,and chlorophyll fluorescence efficiency,respectively.It was concluded that the main evaluation indexes of weak light tolerance were yield per plant,dry matter content,MDA and photosynthetic rate.Cluster analysis showed that Kexin 19,Dongnong 322,Atlantic and Zhongshu 5 were low light tolerant varieties.Eugene,Dongnong 317,Dongnong 314,Yanshu 4and Kexin 23 were tolerant to low light.Yanshu 9,Dongnong 303 and Dongnong 310 are weak light sensitive varieties.This experiment provided a theoretical basis for studying the effect of shading treatment on the growth of potato,and provided technical support for the breeding of potato varieties and strains resistant to weak light.