不同时期遮光对棉花纤维品质的影响OA

[Objective]The effects of shading in different stages on cotton fiber quality were studied to provide scientific basis for cotton breeding and cultivation under low light stress.[Method]Cotton field experiments were carried out from 2020 to 2021 in the Yellow River beach area of Zhongmou County.A randomized complete blocks design was employed in this work.The shading treatments were applied at the initial flowering,peak boll setting,initial boll opening,and all three stages of above(three stages),respectively,with no shading as control(CK).The shading intensity was 78％,and each shading lasted 15 days.The effects of shading in different stages on upper half mean length,breaking tenacity,micronaire value,reflectivity,yellowness(+b),breaking elongation,uniformity index and spinning uniformity index were studied for fiber from cotton bolls at the 1st-5th,6th-10th and≥11th fruit branches.[Result]Compared with CK,the upper half mean length of fiber from cotton bolls at the 1st-5th fruit branches significantly shortened by 1.07 mm under the treatment of shading in three stages,and the breaking tenacity of fiber from cotton bolls at the 1st-5th,6th-10th and≥11th fruit branches decreased by 10.82％,6.05％,and 9.64％,respectively,with statistically significant differences.Fiber from cotton bolls at all the fruit branches under all shading treatments exhibited lower micronaire value,but no significant difference was detected.Moreover,the elongation of fiber from cotton bolls at the 6th-10th fruit branches under the treatment of shading in peak boll setting and three stages,and the≥11th fruit branches under the treatment of shading in initial flowering and three stages was significantly higher than CK(except for the three stages shading treatment in 2021).However,the uniformity index of fiber from cotton bolls at all the fruit branches under all shading treatments showed no signifi-cant difference.The reflectivity of fiber from cotton bolls at the≥11th fruit branches under the treat-ment of shading in initial boll opening stage was significantly reduced in 2021.In addition,shading in three stages resulted in a decrease of fiber yellowness(+b)from cotton bolls at the middle and lower part of the fruit branches,but increased the fiber yellowness(+b)at the≥11th fruit branches,and decreased fiber spinning uniformity index.[Conclusion]Shading could decrease upper half mean length and breaking tenacity of cotton fiber,but increase breaking elongation,however has a relatively minor effect on the micronaire value and uniformity index.Shading in three stages exhibited greater impact than that in initial flowering,peak boll setting,and initial boll opening stages,and a slightly greater effect of fiber quality from cotton bolls at≥11th fruit branches was observed.