. The cotton plant in Egypt, studies in physiology and genetics. Cotton; Cotton. I 62 THE COTTON PLANT IN EGYPT chap. some approaching the long narrow boll of the Sea Island type. The form is expressed as t. A cross of Upland with a mean form of 075 and a width of 31 mm., upon an Egyptian with a form of 0"58 and a width of 27 mm., gives an Fi with a form of 0"60 and a width of 32 mm. In other words, the long narrow form is dominant though very much larger than the long narrow parent. (Figs. 61 and 62). The Fa of such a cross ranges up to the Fi width and form, but includes plants the
. The cotton plant in Egypt, studies in physiology and genetics. Cotton; Cotton. I 62 THE COTTON PLANT IN EGYPT chap. some approaching the long narrow boll of the Sea Island type. The form is expressed as t. A cross of Upland with a mean form of 075 and a width of 31 mm., upon an Egyptian with a form of 0"58 and a width of 27 mm., gives an Fi with a form of 0"60 and a width of 32 mm. In other words, the long narrow form is dominant though very much larger than the long narrow parent. (Figs. 61 and 62). The Fa of such a cross ranges up to the Fi width and form, but includes plants the boUs of which may be as narrow as 0'44 and 22 mm. So far as mere width is con- cerned, this might well be due to auto- genous fluctuation, but the new form of the extremely narrow boUs cannot be attributed to this cause. As in the case of leaf-form, we are probably dealing with a compound inheritance, and the new forms are the result of recombinations of allelomorphs. A side-light on this interpretation is provided by plotting the correlation table of form against width in F^. While the general trend of the diagram indicates positive correla- tion between wider boll and more spherical boll, yet on comparing such a diagram with that from a pure strain, it becomes clear that the Fj family is heterogeneous. Again, families have been raised in F4 which showed no more fluctuation in width than the parent strain, while the. 20 25 30 35 mm. Fig. 61.—Width of the Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Balls, William Lawrence, 1882-. London, Macmillan and Co. , Ltd.
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