The invention discloses an early-maturing high-ginning-outturn cotton line breeding method which comprises the steps: A, utilizing early-maturing
gene resources to
breed an early-maturing novel material in a growth period: performing middle 5168 parent selection of an early-maturing variety; B, increasing
spacetime selection pressure and breeding a very early-maturing cotton novel material with high pre-
frost yield, high yield and stable yield; 1) increasing time selection pressure; 2) increasing space selection pressure; C, a breeding method in which low-generation mixed selection, high-generation single selection and Hainan island progeny planting are combined: 1) performing low-generation mixed selection; 2) performing high-generation single selection; D, a
molecular marker screening method of middle 5168: utilizing identified SSR markers of HAU3318, MGHES-73 and NAU3913 related to early-maturing characters to distinguish the middle 5168 from short season cotton varieties like middle 425, China cotton research institute 16, China cotton research institute 36 and China cotton research institute 74 and spring cotton varieties like deltapine cotton 15, Shandong
research center 28,China cotton research institute 12, China cotton research institute 41, China cotton research institute 45 and Shandong cotton
research center 1. The method has the advantages of easiness, practicability, convenience in operation, quick selection speed and high selection efficiency; the selected novel variety has the characteristics of early maturity and high ginning outturn.