Relationship Between Seed Coat Fragments Count and Fiber Attachment Force in Cottonseeds

A recent report published in 2014 by the International Textile Manufacturers Federation (Cotton Contamination Survey 2013) revealed a noticeable jump in seed-coat fragments (SCF) contamination. Forty-two percent of cotton spinners worldwide claim that they have encountered moderate or significant amounts of seed-coat fragments in the cotton growths consumed against 38% in 2011. This represents an eleven percentage points jump since the all-time low of 31% in 2009. It can be hypothesized that this increase in reported incidence of seed coat fragments is on the rise because of changes that have occurred gradually over the past few decades:

• Ginning: increase in processing speed and number of mechanical devices to remove foreign matter from seedcotton and lint making ginning more aggressive;
• Spinning: increase in processing speed and competition with man-made fibers make spinners more demanding. They look for more homogeneous raw material free of contaminations.

One hypothesis relates SCF generation to the attachment force of the lint to the seeds. Therefore, for this work, our hypothesis is that when the attachment force is excessive, the seed coat may break and form a seed coat fragment. A universal testing machine was used to test this hypothesis. Bundle of fibers from 1200 cottonseeds from 5 different commercial varieties were pulled from the seed (mid-region) and the force required to separate the bundle of fibers was measured. After the test was performed, for each seed, the fiber bundle was visually examined and the presence or absence of SCF was recorded. The proposed method showed a good positive correlation between the formation of seed coat fragments and the attachment force. This procedure has the potential to be used as a screening tool to quantify the seed coat fragment formation in breeding programs.

Keywords: Seed Coat Fragments, Cotton Breeding, Fragile Tegument, Attachment Force, Universal Testing Machine