Evaluation and analysis of fiber quality characteristics of different maturity cotton varieties

Fiber quality traits of different maturity cotton varieties were analyzed with Grey Multidimensional Comprehensive Assessment (GMCA). Data sets were collected from the cotton national regional trials from 2005 to 2014, including early-maturing, early-medium maturing, and medium maturing variety trials, in three cotton areas of China-the Northwest Inland Valley (NWIV), the Yellow River Valley (YeRV), and the Yangtze River Valley (YaRV). It is of great significance for establishing dominant cotton production areas and ascertains the distribution, ecological breeding, and quality improvement methods for all cotton varieties. Results showed that:1) there were 0.54% and 12.63% of all candidate varieties of medium maturity cotton divided into the high yield and good quality (type Ⅰ) and common quality (type Ⅱ) according to the national cotton fiber quality standards, respectively. The proportions of early-maturing cotton were 7.09% and 18.44%, and proportions of early-medium maturing cotton were 0.57% and 17.14%, respectively. 2) Fiber length and strength of the tested varieties was higher in grey correlation coefficient with those of ideal varieties characters, followed by spinning consistency index, again for micronaire. 3) By comparing fiber quality to ideal trait via grey relational analysis, we found that the fiber quality of medium maturing varieties in the YeRV were better than those of medium maturing varieties in the YaRV. The comprehensive characteristics of fiber quality of early-maturing cotton were the best in the NWIV, and followed by the medium maturing cotton in the YeRV and YaRV. 4) Medium-maturing varieties were mainly distributed in the YeRV and YaRV in China, though medium maturing cotton varieties had increased in the NWIV over the past 5 years. Overall, the range of fiber length for medium maturing varieties was 28.7-30.3 mm, which reached standards for high quality yarn. In recent years, there had been a downward trend on fiber length and strength of cotton varieties in the YeRV, with a strength range of 29.6-31.0 cN·tex^-1, at medium to upper level. Micronaire in three cotton areas with different maturity types exhibited significant difference; the micronaire of the YaRV was higher than that of the YeRV, and that of YeRV from medium maturing varieties was higher than that of the NWIV for early-medium maturing varieties. The micronaire in the YeRV had greatly improved from 2010 to 2014, where more than 6.0 micronaire had been observed. 5) This study showed that the accumulated temperature of above 10℃ was the primary factor affecting fiber quality of conventional and hybrid cotton of medium-maturing varieties. The order of meteorological factors affecting cotton fiber length and micronaire was accumulated temperature above 10℃, rainfall, and sunshine hours; however, that impacting strength and spinning consistency index was accumulate temperature above 10℃, sunshine hours, and rainfall.