IBONE   05434
INSTITUTO DE BOTANICA DEL NORDESTE
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Molecular and phenotypic characterization of segregating progenies from crosses between sexual induced tetraploid and apomictic tetraploid genotypes of bahiagrass
Autor/es:
WU H.; CARLOS A. ACUÑA; ANN R. BLOUNT; F. ALPETER; KENNETH H. QUESENBERRY
Lugar:
Buenos Aires, Argentina
Reunión:
Simposio; International Symposium on the Molecular Breeding of Forage and Turf; 2010
Institución organizadora:
INTA
Resumen:
Bahiagrass, (Paspalum notatum Flugge), is a perennial warm-season grass
recognized as one of the most important pasture and utility turf species of
Florida and the southem Coastal Plain region of the United States. This diverse
species contains germplasm with different ploidy levels and linked reproductive
characteristics. Diploids (2n = 2x = 20) reproduce sexually while tetraploids (2n =
4x = 40) reproduce asexually by apomixis. Apomixis bypasses megasporogenesis
and fertilization of the egg to result in asexual seed production following
apospory and pseudogamy. Bahiagrass offers the opportunity for manipulating
apomixis to generate highly productive hybrids that may result in new forage
or turf cultivars. Apospory in tetraploid bahiagrass is believed to be inherited
as a single dominant Mendelian factor with distorted segregation. This factor
is located in a genomic region characterized by suppression of recombination.
Synteny of molecular markers was detected between the apospory controlling
region of bahiagrass and specific regions of rice (0ryzas sativa L .). A segregating
progeny can be generated by making crosses between sexual induced tetraploid
genotypes and apomictic tetraploid genotypes. We generated sexual tetraploid
bahiagrass by treating tissue cultured calluses from the diploid cultivar Tifton
9 with colchicine. A segregating bahiagrass population was generated by
hybridizing selected sexual and apomictic tetraploid genotypes. Our objective
was to evaluate the variation in this type of progeny for traits of agronomic
importante such as flowering pattern, rate of spread, and seasonal growth pattern,
and to also determine the segregation ratio of apomicitic vs. sexual reproduction.
We will present data evaluating mode of reproduction by comparative embryo sac
and molecular marker analysis and present the observed variability for genetic
improvement of growth habit and seasonal growth pattern. Total seasonal yield
and distribution of yield of selected apomictic hybrid progeny will be compared
to the tetraploid cultivar Argentine.