Effects Of Wide-Narrow Row Spacing Configurations On Photosynthetic Characteristics, Yield And Quality Of Potato

In order to reveal the changes and differences of potato growth and development,photosynthetic characteristics,chlorophyll fluorescence characteristics,key enzymes of photosynthetic regulation,yield and quality under different wide-narrow row spacing configurations,finally to get potato’s optimum wide-narrow row spacing configurations for high yield and good quality.Based on the simple cultivation conditions adopted the split-zone test design.It was through the different combinations of three planting densities and six wide-narrow rows spacing configurations to mainly explore the effect of wide-narrow row spacing configurations on potato photosynthesis physiology,yield and quality.The main results were as follows:1.Effects on LAI and dry matter mass of potatoAs the wide line spacing becomes larger,the LAI increased first and then decreased.The B4 treatment was significantly higher than other treatments,followed by B5 treatment.As the planting density increases,the LAI showed an increasing trend.The A3 density of both test points was significantly higher than the A1 density.It is indicated that the two wide-narrow row spacing of B4 and B5 at medium and high density are necessary for improving the leaf area index of potato.The dry matter mass increased first and then decreased with the wide line spacing becomes larger.There was an optimal wide-narrow row spacing configuration B4,followed by B5,which was significantly higher than other wide-narrow row spacing.As the planting density increased,the dry matter quality gradually decreased,and A1was the highest,followed by A2 and A3,and the three reached a significant level.In summary,the wide-narrow row configuration and planting density can significantly affect the accumulation of dry matter quality.Low density and suitable wide-narrow row configuration are conducive to the accumulation of dry matter quality per plant.2.Effect on photosynthetic characteristics of potatoAs the wide line spacing becomes wider,the chlorophyll content increased first and then decreased,and the B4 and B5 treatment were significantly higher than other treatments.The chlorophyll content increased gradually with the planting density,and the difference between the three densities was not significant in the test site of Weituo Town.The density of A3 was significantly higher than that in A2 and A1 in Jianshan Town.It is indicated that the wide-narrow row configuration has a greater influence on the chlorophyll content than the planting density,and the two wide-narrow rows of B4and B5 are effective measures to increase or maintain the chlorophyll content of potato leaves.As the wide line spacing became wider,the leaf net photosynthetic rate（Pn）,transpiration rate（Tr）and stomatal conductance（Gs）increased first and then decreased,and B4 and B5 treatments were higher,which were significantly higher than other treatments.With the increase of planting density,Pn,Tr and Gs showed a decreasing trend.The Pn values of A1 and A2 density were significantly higher than those of A3.The Tr value was not significantly different between the three densities,and the Gs value of A1 density was significantly higher than the A2 and A3 densities.It is indicated that the suitable wide-narrow row configuration and medium and low density are beneficial to the net photosynthetic rate,transpiration rate and stomatal conductance of the leaves,and the wide-narrow rows of B4 and B5 treatments are optimally configured.As the wide line spacing becomes wider,the intercellular CO₂ concentration first decreased and then increased,and the B4 and B5 treatments are the lowest,which were significantly lower than other treatments.It is indicated that the suitable wide-narrow row configuration can reduce the intercellular CO₂ concentration of potato leaves.The intercellular CO₂ concentration exhibited a density between three densities of A1<A2<A3,and A2 and A3 were significantly higher than the A1 density.As the wide line spacing becomes wider,the maximum light energy conversion efficiency（Fv/Fm）,the actual photochemical quantum efficiency（Y（II））,and the photochemical quenching coefficient（qP）increased first and then decreased.Wide-narrow row configuration compared to equal row spacing configuration,the Fv/Fm,Y（II）and qP were higher,and the B4 and B5 treatment were more significant,indicating that the suitable wide-narrow row configuration is beneficial to the chlorophyll fluorescence of the leaf.Different wide-narrow row configuration had a greater impact on the activity of Rubp carboxylase and sucrose phosphate synthase（SPS）.Rubp carboxylase and SPS activity showed a single-peak curve as the wide line spacing became wider.It is indicated that the wide-narrow row configuration is beneficial to increase Rubp carboxylase and SPS activity in potato leaves,and this wide-narrow row configuration of B4 treatment is optimal.3.Effects on potato yieldAnalysis of variance in potato yield showed that there was a significant difference between A factor（planting density）and B factor（width and narrow row configuration）in potato yield,with wide-narrow rows being the most influential.As the wide line spacing became wider,the potato yield increased first and then decreased,and the yield of B5 treatment was the highest,followed by the B4 treatment,which were significantly higher than the equal line spacing B1 treatment.The yield of potato increased with the increase of planting density.When the density increased to a certain level,the yield did not continue to increase,but decreased.The density of A2 and A3were significantly higher than that of A1.This indicates that planting density and wide-narrow row configuration can significantly affect potato yield,and reasonable close planting and field allocation are effective ways to increase potato yield.4.Effect on the quality of potato tubersThe starch content,soluble protein content and vitamin C content of potato tuber increased with the increase of wide line spacing became wider.The starch content and soluble protein content were higher in B4 and B5 treatments,and vitamin C content in B3 and B4 treatments.It is indicated that the too large wide line spacing and the narrow line spacing are not conducive to the accumulation of tuber quality.The content of each quality index showed a decreasing trend with the increase of planting density.The overall performance was A1>A2>A3,indicating that low density is more conducive to improving the quality of potato tubers.The rate of commercial potato increased first and then decreased with the wide line spacing became wider,and increased with the increase of planting density.It shows that both the planting density and the wide-narrow row configuration have an impact on the commercial potato rate,and there is an optimal planting density and a combination of wide-narrow rows.The medium-density and wide-narrow rows have a higher commercial potato rate.