Detecting Random Amplified Polymorphic DNA (RAPD) markers to identify cotton fiber mutants was approached. Of 120 random primers, 111 had matching sequences on genomic DNA of the three pairs of sib-lines which were selected for consistent performance in difference of fiber strength for three years. DNA polymorphisms between the two corresponding sib-lines were detected with 22 of the 111 random primers. Of the 22 primers, 6 primers at least resulted in DNA polymorphisms among Gossypium hirsutum acc. TM-1, and two other spontaneous fiber mutants of G. hirsutum, Ligon Lintless(2) (Li(2); genotype, lili) and Immature (lm; genotype, imim).

Screening the 6 primers on F₁ and F₂ populations of (Li(2)xTM-1), (TM-1xlm) and (Li(2)xlm) resulted in segregation of three PCR-amplified DNA fragments matched with the individual's marked phenotype of F₂ population. A PCR-amplified 0.9 Kb DNA fragment only presenting in Li(2) mutant was segregated into (Li(2)xTM-1)F₂ population and appeared on individuals which were homozygous recessive (lili). The other PCR amplified 0.9 Kb DNA fragment presenting in Li(2) and TM-1 mutants was segregated into (Li2xTM-l) F₂ population and also appeared on individuals which were homozygous recessive(lili). Another 0.7 Kb PCR-amplified DNA fragment presenting Li(2) mutant and TM-1 appeared on only individuals which produce normal fluppy fiber(lm_) in (TM-1xlm)F₂ population. Also, this DNA fragment appeared on only individuals which are Ligon Lintless 2 (Li(2)---) in (Li(2)Xlm)F₂ population. These three DNA fragments are being isolated and evaluated as standard RFLP markers.