|Stewart, J. Mcd|
Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: 1/5/2004
Publication Date: 1/5/2004
Citation: Stewart, J.McD., Ulloa, M., Garcia-C., E.A., Godoy-A., S., Soto, J.C. 2004. The gossypium of mexico: observations from recent collections expeditions. National Cotton Council Beltwide Cotton Conference. p. 1044.
Technical Abstract: Germplasm collection expeditions were conducted in Feb.-Mar. and late April 2003 in the parts of the Mexican states of Colima, Guerrero, Jalisco, Mexico, Michoacan and Nayarit. This was the second year in a planned series of three to 1) document the remaining diversity and in situ status of G. hirsutum landraces, 2) document the range and diversity of the wild diploid Gossypium species of Mexico, and 3) to collect seed samples of all Gossypium encountered for ex situ preservation. Both the center of origin and the center of diversity of G. hirsutum are in Mexico, and 11 of the 13 described diploid Gossypium species of the Western Hemisphere are endemic to Mexico. During the Feb.-Mar. expedition, 56 Gossypium seed accessions were collected that included four species: G. aridum (9 accessions), G. hirsutum (33 accessions), G. lobatum (11 accessions) and G. schwendimanii (1 accession). MU and JMS returned to Nayarit in late April and collected 5 additional accessions of cotton, including three grown by the Huichol and Cora Indians in the NE area of Nayarit. Two seed accessions were also obtained of G. aridum located in this same area in the interior of the Sierra Madre Mts. In addition G. aridum was collected from two populations in the upland center of the state. As was determined from the 2002 collection effort, indigenous cotton (G. hirsutum) seems to survive only as a curiosity in garden plots or as escaped plants from garden plots. Almost all cotton plants in Michoacán were of the race Palmeri type, however, in western Michoacán, Colima, Jalisco and Nayarit the genotypes were normal-leaf types. A considerable range of morphological diversity was noted among the non-Palmeri accessions collected during this expedition. Gossypium aridum, as currently circumscribed, is the most widely distributed wild Gossypium in Mexico, occurring from Sinaloa to Oaxaca. Morphological diversity is extensive among accessions of G. aridum from different locations and/or ecological niches. Particularly noted were the distinctions between coastal ecotypes and highland ecotypes of Colima and of Jalisco. The coastal ecotypes of Colima and Jalisco were similar to each other, but the highland accessions of the two states were not similar. The G. aridum of the more northerly states (Jalisco, Nayarit) blooms and fruits considerably later than that of the southern states. No G. laxum population was encountered in 2003, however, several new populations of G. lobatum were encountered in Michoacan. As a result of the recent expedition, the known range of G. lobatum has more than doubled, and it is now recognized that there is significant morphological diversity within the species. One accession of G. schwendimanii was collected that was sympatric with G. lobatum. None of the arborescent species of Gossypium appear to be threatened at this time. However, the status of G. trilobum is less certain. Visits to five locations where this species previously had been collected as a herbarium specimen failed to locate any plants. Urbanization and agricultural activities appear to have destroyed the habits.