Temperature And Solar Ecological Basis And Response To Cultivation Regulation Of Spatial Distribution Of Seedcotton Biomass Per Boll And Fiber Properties In Cotton

Based on the achievements in physiological and ecological mechanisms of seedcotton biomass per boll and fiber properties,the experiments were carried out in Nanjing in 2010-2013.In this study,we investigated the spatial distribution of seedcotton biomass per boll and fiber properties within a cotton plant,and the effects of cultivars,eco-factors,drought,N supply and K supply on the distribution of seedcotton biomass per boll and fiber properties.The main results are as follows:1.Characteristics of spatial distribution of seedcotton biomass per boll and fiber propertiesThe difference of seedcotton biomass per boll and fiber properties among different boll locations within a cotton plant was:seedcotton biomass per boll>micronaire>fiber length>fiber strength.With the fruiting branches up,seedcotton biomass per boll and fiber properties showed a tendency to rise first and then decrease.The tendency of seedcotton biomass per boll,fiber strength and micronaire of the same fruiting branches:FNI>FN2>FN3.The tendency of fiber length:FN2>FN1>FN32.Effects of planting dates and shading on the spatial distribution of Seedcotton biomass per boll and fiber propertiesSeedcotton biomass per boll,fiber strength and fiber micronaire decreased as planting date delayed and shading enhanced.Fiber length of cotton bolls was longer in planting date of 25 May than other planting dates.Shading had a positive effect on fiber length in the planting date of 25 Apr,whereas shading had a negative effect on fiber length in 25 May and 10 Jun.The interaction effect of late planting and shading had a significantly effect on fiber length and micronaire and were more than late planting or shading only.The best fruiting branch for seedcotton biomass per boll and fiber properties turmed from the middle fruiting branch to the lower fruiting branch as planting date delayed.Seedcotton biomass per boll and fiber properties on FN3 were more sensitive to late planting and shading than those on FN1 and FN2,especially for micronaire.Late planting and shading increased the variation of seedcotton biomass per boll and fiber properties within a cotton plant.Seedcotton biomass per boll and fiber properties of Sumian 15 were more sensitive to late planting and shading than Kemian 1.3.The effect of ecological factors on seedcotton biomass per boll and fiber properties on different boll locationsThe main eco-factor varied among different boll locations.The effect of temperature factors on seedcotton biomass per boll and fiber proberties were greater than that of light factors in most parts.MDR affects seedcotton biomass per boll of all boll locations except FB1-3FN1,and fiber strength and micronaire of all boll locations.The lint yield and fiber properties of entir cotton plant were mainly affected by the bolls at the late growth stage.MDTmax and MDSR had the most significant effect on seedcotton biomass per boll of later period bolls.The optimum MDTmax was 29.9-32.4oC,and the optimum MDR was 15.8-17.5 MJ m-2 for seedcotton biomass per boll.The optimum MDTmax was about 26.7°C,the minmum GDD thresholdwas 207-216?,the optimum MDR was 14.2 MJ m-2 for fiber proberties.Micronaire reached it's maxmum when MDR was 22.9MJ m-2.When the superior fiber quality achieved,the boll weight may be inhibited.4.Effects of sustained soil drought during flowering and boll-forming period on the spatial distribution of Seedcotton biomass per boll and fiber propertiesDrought shorten boll maturity period,decreased seedcotton biomass per boll,fiber length and fiber strength.W45 decreased fiber micronaire,but the effect of W60 varied with years.Seedcotton biomss per boll and fiber properties at different positions differed in their response to drought.FB7-9 and FB10-12 were more pronounced than FB1-3 and FB4-6.Drought increased the variation of seedcotton biomass per boll and fiber properties within a cotton plant.5.Effects of nitrogen rate on the spatial distribution of Seedcotton biomass per boll and fiber propertiesThe optimum N rate was 240kg hm in both Nanjing and Anqing.Seedcotton biomass per boll and fiber properties firstly increased than decreased as N rate increased between 0-360/480.Nitrogen application decreased the variation of seedcotton biomass per boll within a cotton Plants whereas had little effect on the variation of fiber properties.N rate could decreased the varitiation of fiber length between FNI and FN3 in the same fruiting branch.6.Effects of potassium rate on the spatial distribution of Seedcotton biomass per boll and fiber propertiesPotassium application decreased the variation of seedcotton biomass per boll and fiber properties within a cotton plant.Seedcotton biomass per boll and micronaire of the bolls on the upper fruiting branches was more influenced by potassium application than those of the middle and the lower fruiting branches.Seedcotton biomass per boll and fiber properties of bolls on FN3 was more sensitive to potassium application than FN1 and FN3.