Submitted to: Journal of Cotton Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 28, 2011
Publication Date: April 20, 2011
Citation: Romano, G.B., Taliercio, E.W., Turley, R.B., Scheffler, J.A. 2011. Fiber initiation in eighteen gossypium cultivars and experimental lines. Journal of Cotton Science. 15:61-72. Interpretive Summary: Cotton is the most important natural fiber. To maximize fiber production and quality it is essential to understand and perhaps modify the process of fiber development. A new technique was used to study the initial stage of fiber development in several cultivars of upland and Pima cotton, most of which have not been analyzed before. This technique uses a fluorescent dye and a regular optical microscope and makes this type of study accessible to more scientists because it is less expensive and labor intensive than the usual electron microscopy imaging. Differences were found among cultivars in the fiber density measured and the pattern of development of those fibers on young seeds. It was concluded that this technique is as useful as electron microscopy to study the beginning of fiber development on cotton seeds. This technique provides a less inexpensive and accessible tool to assess early fiber development; therefore it enables the selection of desirable new cotton lines.
Technical Abstract: A new technique was developed to study the fiber initiation process and fiber initial densities. The objectives were to assess whether the fiber initiation patterns reported for some G. hirsutum and G. barbadense cultivars extend to a more diverse range of cultivars/lines; and to test if there is a relationship between fiber initials density, lint percentage and fiber characteristics. This study was performed in seventeen cultivars and experimental lines of Gossypium hirsutum L. (upland cotton) and G. barbadense L. (Pima cotton) and in one G. arboreum L. cultivar. The ovules were extracted from the flowers at the day of anthesis and 1 and 2 days thereafter, stained with a fluorescent dye, DiOC6(3) (3,3’-dihexyloxacarbocyanine iodide), and observed under an optical microscope. Staining cotton fiber initials with DiOC6(3) enabled the evaluation of a greater number of samples than the more time-consuming SEM microscopy protocols to assess the fiber initiation process. There were significant differences in fiber initial densities among cultivars and lines but these did not cluster into “upland” and “Pima” types as had been expected. Upland and Pimas fiber initiation occurred at the time of anthesis while Sea Island Pimas initiation was delayed by a day. A delay in fiber initiation was also confirmed in fuzzless mutant lines. Fiber initial densities were not found to be useful predictors of lint percentage.