Regional distribution characteristics of cotton fiber quality in main cotton production areas in China

The significant regional differences in cotton fiber characteristics have been well recognized in not only traditional main cotton production areas, but also in the corresponding subregions in China. The evaluation of cotton fiber quality characteristics in each cotton production region is obviously benefical for understanding current developing conditions of cotton fiber quality. This can contribute to the intensification of superior cotton production areas and the development of cotton production areas with special fiber qualtiy characteristics. The GGE biplot experimental design was used to explore the interaction pattern between subregional environments of cotton and cotton fiber quality traits in three main cotton production areas (Changjiang River Valley, Huanghe River Valley and Northwest Inland) and their subregions. Data for the study were collected from the national cotton regional trials during the period 2011–2015. The results indicated that: 1) at main cotton production area scale, fiber length and strength in Changjiang River Valley (CRV) performed the best in the three main cotton production areas. Although all of these areas reached the Class II level of national cotton variety registration standard, there were medium performances for micronaire value and spinning consistency index. Fiber length and strength for the Huanghe River Valley (HRV) were better, while micronaire value was higher than desirable. On the other hand, micronaire value and spinning consistency index were best for the Northwest Inland cotton production area. Both fiber length and micronaire value reached Class II level of national cotton variety registration standard, although fiber strength was the lowest in the three main cotton production areas. 2) For subregions within three main cotton production areas, fiber length was the highest in the lower and upper reaches of CRV, slightly poor in the Loess Plateau region and relatively good in other subregions. Strength performed well in the middle and lower reaches of CRV, Huaibei Plain, Nanxiang Basin and the Loess Plateau. It was relatively poor in the upper reaches of CRV and the Northwest Inland regions. Conversely, micronaire value performed ideally in the upper reaches of CRV and the Northwest Inland regions, but not so satisfactory in the subregions of the Loess Plateau, Huaibei Plain, North China Plain and the lower reaches of CRV. 3) For comprehensive fiber quality trait performance, the upper and lower reaches of CRV and the Northwest Inland regions were the most ideal subregions, followed by Huaibei Plain, Nanxiang Basin and the middle reaches of CRV. Then the North China Plain and the Loess Plateau were less satisfactory in terms of comprehensive fiber quality trait performance. This study demonstrated the effectiveness of “environment vs. trait” biplot in evaluating ecological regionalization of cotton fiber quality. It also provided a reference for the prioritization of development of high-quality cotton production areas and raw cotton selection strategy for the textile industry and also set the guidlines for further ecological regionalization of cotton fiber quality in China.