Study On The Relationships Among Main Quantitative Characters Of Different Cotton Varieties

Cotton is the most important cash crops in the China,and it is also a very important natural fiber crop.With the rapid development of textile industry technology and the increasing population demand,the demand for cotton varieties yield and fiber quality is becoming higher and higher.Cotton with high yield,long fiber,suitable strength,fiber fineness and high regularity that can satisfy the demands of human beings for durability of cotton textiles.In this study,159 cotton germplasm resources from different provinces in China were used as materials,Fifteen traits were investigated and determined in the field?Anyang?.Through a large number of data and statistical methods,the relationships among the main quantitative traits were interpreted in order to cultivated high-yield,stable-yield and excellent fiber quality,create specific and outstanding germplasm to provide material and theoretical basis.The main results are as follows:1.159 materials were clustered into 6 groups based on 15 agronomic traits,group I for varieties in Yangtze River valley,group II for varieties in northwest inland region,group III for varieties in Liaoning region,and group IV,V,VI contain varieties in the Yellow River valley.Varieties in the same ecological region were clustered into a group as a result of natural selection.During the long-term breeding process,the selection of yield and quality traits of varieties have high positive correlation under the same ecological conditions.Clustering results show that it is the genetic background determines the distance between varieties.The traits of varieties in the Yellow River valley are similar to those in the northwest inland region.It indicates that the distance between geographical location has high correlation with the main quantitative traits similarity of varieties in these regions.2.Analysis of main quantitative traits showed that among the yield components and coefficient variation of number of bolls per plant was 28.57%,followed by lint percentage and boll weight;the coefficient of variation of specific strength was 9.79%and the coefficient variation of elongation was 1.35%in qualitative traits;Among other traits,the coefficient of variation of Verticillium wilt index was 38.69%and as followed by flowering stage was 4.12%.3.Principal component analysis demonstrated that the first five principal component eigenvalues of 159 germplasm with 15 traits were more than 1.It can reflect the genetic information of most quantitative traits in cotton.4.The correlation analysis showed that the correlation degree of lint yield was boll number,lint percentage,boll weight,plant height,fruit branch number,growth period,flowering period and seed index respectively.The relationship between agronomical and qualitative traits showed that the plant height was extremely positively correlated with fiber length and micronaire value,meanwhile siginificant correlated with specific strength and elongation;fruit branch number was positively correlated with micronaire value and elongation,and siginificant correlated with uniformity;there was a significant positive correlation between fiber length,specific strength,elongation and uniformity,the elongation and uniformity were extremely positively correlated with fiber length and specific strength respectively;verticillium wilt index has no significant correlation with seed index,and it was negatively correlated with yield components and quality components,and negatively correlated with lint yield and lint percentage.5.Path analysis and optimal regression analysis showed that boll number had the great effect on lint yield,followed by fruit branches number,plant height,lint percentage and boll weight.The optimum regression equation Y=-0.579+0.036X₁+0.058X₂+0.007X₃.6.According to yield trait the boll weight is greater than 5.7g are four varieties,followed by lint percentage with 43%in four varieties and four varieties with 15.8 boll number per plant were selected among the yield traits;Four varieties with length greater than 30mm,eight varieties with specific strength greater than 34cN/tex and three varieties with micronaire belonging to A-level range were selected according to fiber quality traits.