Relationships Among Individual Fiber Tensile Properties and Fiber Bundle Tensile Properties

This study was performed on the 104 reference cottons for maturity described by Hequet (2006). The samples were tested with the FAVIMAT, HVI, AFIS, and Cottonscope. For the FAVIMAT data, the examination of the results shows that there is an excellent linear relationship between elongation-at-break and work-to-break (r² = 0.804) and a relatively poor linear relationship between force-to-break and work-to-break (r² = 0.399). It appears that, on this set of samples, the main contributor of the work-to-break is the elongation-at-break. For elongation-at-break the range of variation among samples is quite large (from 6.1% to 12.7%) while it is narrower for force-to-break (from 3.59 to 6.1 g). It confirms that there is a wide range of variability available in the current cotton germplasm for fiber elongation (the 104 cottons were commercial cotton bales). Unfortunately, at this time, most of the cotton breeders concentrate their effort on improving strength and ignore elongation. It is of interest to note that the relationship between force-to-break and elongation-at-break is quite weak (r² = 0.162) and positive while it is well documented that with bundles tests such as HVI (High Volume Instruments) the same relationship is weak and negative. This negative relationship is one of the reason why the cotton breeders do not work on elongation. They are concerned that improving elongation will result in lower tenacity and possible discounts.