Pilose (T(1)), the dominant allele at the t(1) locus, is characterized by a high density of trichomes on the leaf surface and the presence of trichomes on the carpel wall. Previous reports have stated that pilose has a pleiotropic effect on fiber traits, most notably increased micronaire. In 1987 a line of pilose-like plants, 39-17/6, derived from a single plant selection of pilose-expressing plants with an Empire genetic background, was found with (atypically) low micronaire values. Experiments were undertaken to determine if close linkage between T(1) and a locus influencing micronaire had been interpreted as pleiotropy. A second line, 250-14/2, was concurrently selected with 239-17/6 to act as a control. It is characterized by a typical pilose phenotype and high micronaire. After two additional years of testing, these lines proved to have stable fiber properties. 239-17/6 was checked for the T(1)-phenotype by counting leaf trichome density and inspecting fruits for trichomes. To determine if 239-17/6 actually carried the T(1), allele, 239-17/6 was crossed to 250-14/2 and to plants homozygous for the normal pubescence (t(1)) and glabrous plant (T(1)(sm)) alleles of t(1). Similar crosses were made between 250-14/2 and homozygotes for alleles at t(1). Segregation data for all crosses was taken from F₂ seedlings. The agronomic performance of the 239-17/6, 250-14/2, Empire and FTA (low micronaire check) were measured for two years in a completely randomized design with six replicates. Yield, lint percent, and the fiber traits of elongation, maturity, micronaire, perimeter, span length, strength and wall thickness were measured. 239-17/6 and 250-14/ had greater leaf trichome density than normally pubescent plants: an average of 4.95 x 10⁶ and 1.06 x 10⁶ trichomes M^-2, respectively. The pilose line and pilose-like line had trichomes on the fruit, whereas the others did not. All 238 F₂ seedlings from the cross of 239-17/6 x 50-14/ and 227 seedlings from the reciprocal had tomentose leaves. The F₂ seedlings of 239-17/6 x t(1) and 250-14/2 x t(1) showed non-significant deviation from a segregation ratio of 3-tomentose plants to 1-normally pubescent plant. Heterogeneity chi-square showed that the two sets of crosses were homogeneous. Similar results were obtained when the F₂ seedlings of crosses with T(1)(sm) were scored: a ratio of 3-tomentose plants to 1-glabrous plant was found, and heterogeneity chi-square was non-significant. The 250-14/2 line had significantly greater maturity, higher micronaire and thicker walls than the three other lines. Importantly, the 239-17/6 was not distinguishable from either Empire or FTA for these wall traits. The pilose lines, however, had shorter fiber than the normally pubescent lines, which was expected from previous reports. The low micronaire, pilose-like line 239-17/6 was shown to have the phenotype of T(1) and behave genetically like T(1). However, the maturity, micronaire and wall thickness of 239-17/6 resembled the recurrent parent, Empire. Since T(1) was associated with both high and low micronaire values, the pleiotropic effect of T(1) on micronaire appears unlikely. Linkage of T(1) to a gene or block of genes that influence micronaire appears likely.