|Kakani, A - ALABAMA A&M|
|Sapra, V - ALABAMA A&M|
|Zipf, A - ALABAMA A&M|
|Stelly, D - TEXAS A&M|
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 9, 1998
Publication Date: N/A
Interpretive Summary: For more effective manipulation of the plant reproductive system, including cotton, information about genes governing gametophyte (pollen or egg) development along with their genetic map relations and chromosomal locations are needed. We have combined the power of haploid analysis with the advance technique of confocal laser scanning microscopy to identify and understand the genetic mechanism of pollen development in cotton. Cytogenetic-deficient stocks of cotton were used to locate genes for cotton pollen development to chromosomes and chromosome arms. Pollen of the two tetraploid species were found to be morphologically distinct as pollen size and spine pattern were significantly different between TM1 (Gossypium hirsutum) and Pima 3-79 (G. barbadense). Gene(s) responsible for pollen spine development were located on the long arm of chromosome 12. Pollen size and spine formation must be, at least, partially controlled by the gametophyte generation since these morphological characters segregated during pollen grain development. There is no report of chromosomal location gametophytic - specific gene(s) in cotton. Knowledge, similar to our results, regarding pollen development should augment our ability to cytogenetically and genetically manipulate the cotton genome for both basic, scientific and applied purposes.
Technical Abstract: Genetic manipulation of plant reproduction is limited by the lack of knowledge of genes controlling gametophyte development. A study was made on the differential effects of specific chromosomal deficiencies on the morphology of mature cotton pollen. Pollen of the two tetraploid species (G. hirsutum L. and G. barbadense L.) was found to be morphologically distinct. Confocal microscopy was used to construct a three dimensional image of the fluorochrome-stained pollen grains. Cytogenetic-deficient stocks of cotton were used for locating genes for pollen development to chromosomes and chromosome arms, respectively. Results indicated that the pollen size and spine pattern were significantly different between TM1 (G. hirsutum) and Pima 3-79 (G. barbadense). Comparative analysis of pollen morphology of parental and interspecific hybrid, monosomic and monotelodisomic plants indicated that gene(s) responsible for pollen spine development were located on the long arm of chromosome 12. The segregating nature of pollen morphological features indicated that the gametophytic gene(s) of the microscope partially controlled the pollen size and spine formation during pollen grain development.