male sterile
Nebenkern
nucleus & spermatid
spermatid
spermatozoon
Y chromosome loop
Mutant spermatocytes have a fragmented kl-3 Y-loop, while the morphology of the other Y-loops is normal. Defective spermatids with micro- and macro-nuclei and irregular nuclei-Nebenkern associations are seen. Non-motile sperm are seen.