Abstract: 【Objective】By using the GGE biplot method, the classification and characteristics analysis of national registered varieties over 30 years recommended from the candidate cotton lines in cotton regional trials in the Yangtze River Valley (YaRV) facilitated us a historical perspective of cotton variety improvement progress to explore the evolution trend of cotton varieties’ type and the corresponding characteristics, and thus to provide theoretical guidelines for current decision making of cotton breeding target characters and cotton evaluation and recommendation for the official registration before commercial release.【Method】In accordance with the cultivar scoring criteria of national cotton registration standard, the corresponding weights were allocated to certain characters of yield and fiber quality, disease resistance, earliness, etc., to build a universal cotton variety evaluation index based on multiple traits. The “genotype vs. trait” view of GGE biplot was adopted to analyze the interaction pattern of 53 national registered cotton varieties in cotton regional trials in YaRV during 1981-2012 and 15 major characters including seed cotton yield, lint cotton yield, boll weight, boll numbers, lint percentage, seed index, fiber length, fiber strength, micronaire value, Fusarirum wilt index, Verticillium wilt index, pro-frost yielding rate, plant height, fruit branch number and evaluation index, and also to implement the classification and feature comparison of registered cotton cultivars. And then the cultivar types and features were evaluated. According to the shift of check cultivars in cotton regional trials in the past, the cotton regional trial datasets since 1981 were divided into five periods. The dynamics of cultivar type’s proportion and the evaluation index scores were evaluated across the five periods. 【Result】The “genotype vs. trait” view of GGE biplot analysis showed that there existed complicated relationships among cotton breeding target traits, which made it necessary to construct evaluation indices for comprehensive evaluation of cotton varieties. On the basis of cotton recommending criteria in national variety registration standard, a variety evaluation index in common was built as: EI = 0.40×(lint cotton yield ) + 0.13×(fiber strength ) + 0.09×(fiber length + micronaire value +Verticillium wilt) + 0.11×(Fusarium wilt) + 0.10×(pre-frost yielding rate). According to the interaction pattern of varieties and characters and their spatial relationships among varieties, 53 national registered varieties were divided into four varietal types with significant special characteristics, respectively. TypeⅠcluster was constituted of certain cultivars with “high yield, more boll numbers and moderate fiber quality”; type Ⅱ was of “high yield, big boll and high micronaire value”; type Ⅲ was of “superior fiber quality, moderate yield and small boll”; while type Ⅳ was weak in major characters and was named as “weak cultivars”. The ordination of variety types sorted by evaluation index was listed as typeⅠ＞ typeⅡ＞ type Ⅲ＞ type Ⅳ. The dynamic of cultivar types shift indicated that type Ⅳ varieties only appeared in “Simian 3” period and the before; type Ⅲ varieties existed in “Simian 3” and “Xiangzamian 2” periods; typeⅠvarieties commenced in “Simian 3” period, and its proportion was on the rise until the decline in “Ezamian 10” period; type Ⅱ varieties were selected firstly in “Xiangzamian 2” period, and the proportion showed a continuous trend up till now.【Conclusion】On the basis of the variety evaluation index and GGE biplot analysis method, 53 national registered varieties were efficiently divided into four variety types with distinct characteristics and historical traces in each. The conclusion of cotton variety improvement effect and development trend in past 30 years in YaRV reminded as that more attention should be paid to the improvement and evaluation of micronaire trait, so as to guide the simultaneous development of high yielding and fiber quality in cotton breeding and registration procedure in YaRV.

Key words: cotton (Gossypium hirsutum L.), GGE biplot, cultivar type classification, the Yangtze River Valley (YaRV), crop regional trial