Abstract

At the Cotton Breeding Station, Coimbatore, a few sterile plants (Plate 1, Fig. 1) without any pods were observed in the year 1930, among the progenies of single plant selections. During 1931, their appearance was more common, and again in the following season, their percentage occurrence was as high as fifteen in certain fields sown with unselected bulk. As the presence of such a large proportion of sterile plants would considerably reduce the yield of crop, a detailed study of these sterile plants was made with regard to the modifications of their floral parts, and the causes of their occurrence. The sterile plants (Fig. 1) had their floral parts metamorphosed or virescent, and were distinguished by their characteristically stunted and bushier habit, by the smaller and more greenish leaflets, and by the upright gynophores with empty carpels. Sometimes a plant had only a few branches, or portions of a branch displaying this abnorma- lity. The various monstrosities observed in the flower, might now be dealt with under the various types of floral structures.

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