The environment during the growing season is a major determinant of fiber quality and, therefore, of price in upland cotton (Gossypium hirsutum). Water deficits during fruit (boll) formation and seed and fiber maturation increase the number of underdeveloped seeds (motes), decrease fiber maturity, and increase fiber thickness (and micronaire). All of these changes associated with inadequate water supply lower cotton fiber quality. Plant mapping techniques have been used to determine the effects of two types of row-irrigation on mote frequency, fiber/seed maturity, and fiber quality with respect to boll position and ovule position within cotton locules. These preliminary population statistics are used in the development of predictors of the abnormal seed and fiber development and the probability of undyed fabric "white specks" associated with the presence of motes and immature fiber.