ABSTRACT

We investigated the relationship between the polymeric molecular weight distributions and strength of cotton fiber in different genotypes. Fiber samples from the new higher strength cotton variety for the MidSouth, Mississippi Delta 51 ne (MD51) were assayed and compared with the popular Deltapine 90 (DPL90). The F1 cross (MD5 1 x DPL90) and two selected BC-3 (backcrosses) F2/F3 progenies were evaluated from progeny rows in three replicates at Stoneville, MS.

Conventional strength evaluations have shown MD51 to be -11% higher in strength than DPL90. Previously, we reported that single fiber strength (tenacity) for MD51 was higher than DPL90 by -30%. Gel permeation chromatography (GPC) was used to determine the molecular weight distributions of cotton fiber samples dissolved directly in dimethylacetamide/lithium chloride. Samples of MD51 have a greater proportion of higher molecular weight material than DPL90. The most significant difference is apparent in the molecular weight range of 1,000,000-10,000,000.