Submitted to: 2003 Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: April 16, 2003
Publication Date: April 16, 2003
Citation: Turley, R.B., Kloth, R.H. 2003. The Inheritance Model for Fiberless Upland Cotton (Gossypium hirsutum L.) Line SL 1-7-1: Variation on a Theme. 2003 Beltwide Cotton Conference, January 6-10, 2003, Nashville, TN. p.871. Technical Abstract: Segregating populations were developed to evaluate the inheritance of the fiberless seed phenotype of upland cotton (Gossypium hirsutum L.) line SL 1-7-1. It has been established that fiberless lines do not produce lint or fuzz, whereas, fuzzless lines produce lint but no fuzz. The alleles which eliminate fuzz, i.e., N1, n2, and n3 are often involved in the production of fiberless lines. One example is MD 17 fiberless (N1N1n2n2). We report the segregation patterns of SL 1-7-1 fiberless with crosses to the wildtype line DP 5690 (n1n1N2N2N3N3), Mexican fuzzless seed UA 3-3 (n1n1n2n2n3n3, MOVC accession 143), Ballard fuzzless seed line (N1N1N2N2n3n3, MOVC accession 243) and MD 17 fiberless. Data from the F2 and F2:3 populations derived from the SL 1-7-1 X DP 5690 cross fit a three loci model for expression of the fiberless seed phenotype. The F1 population of the SL 1-7-1 X DP 5690 consisted entirely of fuzzless seed, indicating that SL 1-7-1 was homozygous for the dominant fuzzless seed allele N1. The other two alleles involved in production of the fiberless phenotype of SL 1-7-1 were found to be recessive. Various tests were used to verify whether these recessive alleles in SL 1-7-1 were allelic to the fuzzless seed alleles n2 and n3. A collection of F2 plants (SL 1-7-1 X DP 5690) with fuzzy seed (n1n1) were grown in the F2:3 populations. If SL 1-7-1 possessed n2 and n3 some of the F2:3 progeny would have fuzzless seed. The lack of plants expressing the fuzzless phenotype demonstrated the absence of alleles n2 and n3. The absence of n2 and n3 in the SL 1-7-1 genotype was confirmed in the F2 population of the 143 X SL 1-7-1 cross as about 25% of the progeny possessed fuzzy seed (theoretically, 100% would be fuzzless seed if SL 1-7-1 possessed n2 and n3). The homozygous combination of the two recessive alleles in the SL 1-7-1 line do not produce progeny with a fuzzless seed coat, therefore, they cannot be classified as fuzzless seed alleles. Therefore, we have designated these alleles as en1 and en2, or recessive enhancers of N1 to produce fiberless seeds. With this model of SL 1-7-1, a common theme is proposed for the production of fiberless cotton. Three of the four fiberless lines described in the literature possess at least one of the fuzzless seed alleles, SL 1-7-1 (N1), MD 17 fiberless (N1 and n2) and XZ142w (n2).