Abstract: The experiment was conducted with six generation populations derived from crosses between two glanded upland cotton varieties and two glandless ones. The distribution of pigment glands on thirteen organs of the plant was studied, based on whether a plant part was glanded or glandless, ten spatial distribution models of pigment glands were found. The grades of pigment glands densities on whole plant of one model were distinguished from another, and the kinds and numbers of glanded organs contained in various models were varying. The differences between pigment glands densities on variour oergans of the same models and the average values of their population densities were differen. On these grounds four new concepts of priorly developed organs, subsequently developed organs, synchronously developed organs and postponably reproducted organs were put forward. Based on the spatial distribution models, a more reliable methed to select or retain the ideal types in the glandless cotton breeding had been established.

Key words: Upland cotton, Pigment gland, Spatial distribution model, Organ