Collect fibers from twenty random cottonseeds and weigh (W1). 2. Randomly pick six fiber bundles (1–2 mg each), tease, and weigh (W2). If the weight is inconsistent, repeat the bundle picking and weighing steps. 3. Separate the ring and cap from a micro-centrifuge tube. 4. Fix fibers with the cap to the ring. 5. Boil fibers for 10 min, cool to room temperature, store in 45% acetic acid (2–3 days). 6. Dry fibers, cut into segments (1–2 mm). 7. Separate snippets in six drops (20 μl each) of 45% acetic acid. 8. Observe and photograph snippets using a stereo-microscope. If the images are not clear, repeat the observation and photography steps. 9. Count snippets using Image-Pro® Plus, determine fiber number (N2). 10. Calculate mature fibers per seed (N1) using N1 = (W1/20) / (W2/N2). If the calculation is not accurate, repeat the counting and calculation steps.