Abstract: Cotton is native to tropical and subtropical regions and is an annual or perennial woody shrub. The main cultivated upland cotton and sea-island cotton are gradually selected and cultivated in the long term, and gradually moved north to temperate zone, which has evolved into an annual crop, which has been retained for many years.Cotton is native to tropical and subtropical regions and is an annual or perennial woody shrub. The main cultivated upland cotton and sea-island cotton are gradually selected and cultivated in the long term, and gradually moved north to temperate zone, which evolved into an annual crop, which retains some characteristics of perennial plants and forms a different from perennial plants. Some new fertility and physiological characteristics.? ? (1) Morphological characteristics:? ? The main morphological characteristics of cultivated upland cotton are: broadleaf, with lobes, divided into duck palm leaves, chicken feet and lanceolate leaves according to the depth of the nick; the whole plant has glands (there are individual glandless mutants); the lower part is mostly The unilateral type of vegetative shoots, the upper part of which is mostly pseudo-axis type; the complete flower, each flower has 3 leaves, forming a triangular scorpion, the scorpion leaves are serrated, the flower buds are cup-shaped, the petals are 5 petals, and the stamens are many. The lower part of the filament is combined into a tubular shape, the anther is single chamber, the ovary is 3 to 5 chambers, the style is rod-shaped, the number of stigma lobes is equal to the number of ovary chambers; the fruit is the capsule with a crack on the back, and the bell is divided into round, oval, and long oval. , cones and irregular shapes; seeds are linters (with individual mutated mutants).? ?...