Effect Of Row Spacing And Plant Density On Growth And Yield,Fiber Quality Of Cotton

The experiment was conducted at the Science and Technology Demonstration Park of the Dezhou Academy of Agricultural Sciences in 2015.In the open field,two kinds of transgenic insect-resistant cotton varieties(SCRC6269 with the short fruit and the compact plant type,SCRC28 with the more loose plant type)were selected to study the effects of different population structure formed by planting densities,seedling cultivation and spacing on plant growth,yield and quality using three-factors split-plot design.The main results were as follows:1.Effect of row spacing and plant density on growth and development of cottonPlant height of cotton increased in low density at the later stage of CRC6269 and earlier stage of SCRC28 and at the method of leaving seedling doubly.But only plant height of SCRC28 increased in narrow row spacing.Stem diameters of SCRC6269 and SCRC28 decreased with the increase of plant density and the number of the left seedling in each growth period of two varieties.The stem diameters of these varieties were the highest in the treatment of B1C1D1.The first fruiting branch node of the two types of cotton significantly improved in high density,and the first fruiting branch node of SCRC6269 significantly improved at the method of leaving seedling doubly,so the first fruiting branch node of the two varieties were the highest with B2C2D1.The first fruiting branch heights of two varieties were positively correlated with the planting density,which inceased at the method of leaving seedling doubly,and were the highest with B2C2D1 treatment.Cotyledon node height of SCRC6269 was negatively correlated with planting density,while the trend of SCRC28 was opposite.Fruiting branch number of the two types of cotton decreased with the increase of plant density and the number of the left seedling.2.Effect of row spacing and plant density on bolls of different stages and rot bolls of cottonThe ratio of hot summer bolls of SCRC6269 increased in high density and wide row spacing,and the ratio of hot summer bolls and late autumn bolls of SCRC28 in wide row spacing increased.Meanwhile the ratios of late autumn bolls of the two varieties increased at the method of leaving seedling doubly.For compact cotton varieties,leaving seedling doubly and wide row spacing was suitable for improving ventilation and light transmittance of cottonand reducing the rate of boll rot under the same density,but leaving seedling singly and wide row spacing was better for the loose varieties with the specific density.3.Effect of row spacing and plant density on canopy light interception of cottonWith the increase of planting density,the canopy of the light energy utilization rate increased,and the leakage loss decreased.Compared with the wide row spacing,the narrow row spacing improved the light utilization rate,and reduced leakage loss.The lower leaves by light in the low density significantly improved with leaving seedling doubly.4.Effect of row spacing and plant density on quality of cotton bolls and fiber in different fruiting branch of cottonThe change of the boll weight in different fruiting branch of the two varieties with different treatments were the same,which inner bolls were more than outer bolls,and bolls in middle branches were more than bolls in the upper branches,more than bolls in lower branches.Seed cotton yield per boll in middle and upper branches significantly increased in wide row spacing and in low denstiy.On the high-density conditions,seed cotton yield per boll in middle branches of SCRC6269 significantly increased with leaving seedling singly.The lint percentage was the highest in OBL,followed by IBL and IBM,and the lowest in OBU in different fruiting branch of the two varieties with different treatments.The lint percentage of SCRC6269 decreased with the increase of density.On low-density condition,the lint percentage of SCRC6269 planted decreased with leaving seedling doubly and wide row spacing,but the lint percentage of SCRC28 reduced only with wide row spacing.On high-density conditions,the lint percentage increased with leaving seedling doubly for SCRC6269,and with leaving seedling singly for SCRC28,and with wide row spacing for these two varieties improved.The seed indexes of inner bolls were more than those of outer bolls of the two varieties in different fruiting branch with different treatments.The seed index of SCRS6269 was lower in high density.The seed indexes of two varieties in the low density improved with leaving seedling doubly and wide row spacing.On high-density conditions,the seed index increased with leaving seedling singly and wide row spacing for SCRC6269,and it increased with combination leaving seedling singly with narrow row spacing and combination leaving seedling doubly with wide row spacing for SCRC28.With the increase of density,the fiber length of the two varieties showed the increasing trend.There was no significant effect on the fiber quality indexes of two varieties by the way of leaving seedling and row spacing.The fiber micronaire and fiber uniformity of inner bolls were more than outer bolls in the same fruiting branch of two varieties.According to the performance of fiber quality,the treatment of B2C2D1 and B2C1D1 were better for SCRC6269;and the treatment of B2C2D1 and B2C1D2 were better for SCRC28.5.Effect of row spacing and plant density on yield and yield components of cottonDensity had a significant effect on yield components of cotton.With the increase of density,bolls per plant and the seed cotton yield per boll of all the two varieties decreased,and the number of bolls per unit area increased.Bolls per plant,the number of bolls per unit area and the lint percentage of cotton in high density improved with the wide row spacing.The effects of the way of leaving seedling on yield components were different in the two varieties.Density and row spacing significantly affected seed cotton and lint yield of two varieties,which in high density was more than those in low density,and with narrow row spacing more than with wide row spacing.But seedling leaving mode had no significantly effect on seed cotton and lint yield.According to lint yield,the treatment of B2C2D1 was the best and followed by B2C1D1 for SCRC6269,and B2C1D1 was also the best for SCRC28,and followed by B2C1D2.6.Effect of row spacing and plant density on biology yield and ratio of seed cotton to straw of cottonThe biological yield of the two varities significantly increased in high density.On lowdensity condition,the biological yield of two varities improved with narrow row spacing.On high-density conditions,SCRC6269’s the ratio of seed cotton to straw of cotton improved with leaving seedling singly and narrow row spacing.This index of SCRC28 in low density increased with leaving seedling doubly.From the results above,we could conclude that if we want to improve the production and quality of cotton,the higher planting density should be selected,which it was the base of higher production.Secondly,on high-density condition,the rational field arrangement was neccessary to fully expand the potential of individual growth and development,and to promote the coordinated development of individuals and groups,then to ensure high yield and good quality.Combined high yield with good quality,the density of 67500 plants per hm2 and the treatment of C2D1 was more suitable for SCRC6269,and the density of 67500 plants per hm2 and C1D2 of were the best for SCRC28 in the experiment.