Twenty-four varieties each of Gossypium hirsutum and Gossypium arboreum species from the Indian Agricultural Research Institute's farms at New Delhi and its substation at Sirsa, respectively, were studied for their bundle strength on a Pressley strength tester using zero gauge length and for crystallite orientation using X-ray diffraction. The crystallite orientation was expressed in terms of 40% and 50% angles and the Hermans orientation factor; from the latter an average orientation angle α m was computed. Correlations between bundle strength and these orientation parameters were calculated.

The crystallite orientation angle obtained from x-ray diffraction patterns can be used for varietal characterization of cotton at the molecular level. The 40 and 50% x-ray angles are usually taken as representative parameters to correlate with the strength of the fiber. Although the 50% x-ray angle has some theoretical justification, like the use of the half-width of spectral lines, the choice of the 40% x-ray angle is arbitrary. From the study of 24 Gossypium hirsulum cotton varieties reported in this paper, it is observed that the average angle of orientation αm evaluated from the Hermans orientation factor fc gives better correlations with mechanical properties than the 40 and 50% x-ray angles con ventionally used.

No abstract

No abstract

No abstract