Effect of Densities and Varieties on Yield and Quality of Mechanical-harvested Cotton Interplanted with Wheat

【Objective】 To study the effects of different densities and varieties on yield and quality of cotton under the short-season cotton for the wheat-cotton double cropping system and provided the basis for selection and breeding of suitable densities and varieties of short-season cotton for the wheat-cotton double cropping system. 【Method】 A field experiment was conducted in 2019 with the density gradients of 45，000 plants/hm² （D₁），90，000 plants/hm² （D₂） and 135，000 plants/hm² （D₃） were set up in Anyang，Henan Province，with early maturing varieties Jinke 707 （JK707） and Lumian 2387 （LM2387） as experimental materials. 【Result】 With the increase of densities，the plant height，the number of fruit branches and the ratio of branches gradually decreased，while the Leaf Area Index （LAI） and biomass where gradually increased，the LAI was the largest under D₃，with the maximum of 3.14 and 4.16，respectively. The total biomass of D₂ was increased by 40.4% and 42.0% than that of D₃ and D₁ when compared to the three density treatments of the JK707 varieties and were increased by 65.5% and 85.1% under the three density treatments of the LM2387 varieties. With the increase of densities，the seed cotton yield was first increase then decrease，with the D₂ densities the highest （JK707 and LM2387 were 4 025 kg/hm² and 4 114 kg/hm²，respectively）. Compared to the JK707，LM2387 have more advantages in the medium and high densities. The micronaire value of fiber decreases gradually with the increase of density，and the fiber strength was highest under the D₂ densities. The fiber length，strength and micronaire value of JK707 are better than LM2387. 【Conclusion】 In summary，under the short-season cotton cropping pattern of the wheat-cotton double cropping system in the Yellow River Basin，the varieties JK707 and LM2387 can achieve high quality and high yield under the planting density of D₂ （90，000 plant s/hm²）. Compared with the two varieties，JK707 fiber quality is superior，while LM2387 has a higher lint，more combatively plant type，more concentrated bolls，and were more suitable for mechanized harvesting.