The Genetics of Withering or Deciduous Bracteoles in Cotton.

The character Withering Bracteole in Gossypium hirsutum is shown to be controlled by a single recessive gene bw. This gene has a pleiotropic action causing leaf crumpling and also sterility to a greater or less extent. Pollen grains carrying bw appear to have an advantage in fertilization. At a low modifier level F2 ratios of 2.1 Normal: 1 Withering Bract were obtained, and bwbw plants were more or less sterile and had severely crumpled foliage. At a higher modifier level F 2 ratios rose to 7 2: 1, presumably because many of the bwbw plants were indistinguishable from normal. In such families the deleterious effects of bw were largely masked, but as a result the bracteoles also failed to wither effectively. This gene is therefore considered to be useless as a means of removing the bracteoles to facilitate mechanical picking.