Resumen Panicum coloratum var. makarikariense es una gramínea perenne nativa de África. Se adapta a un amplio rango de ambientes y posee uso potencial como forraje en distintas regiones tropicales y semiáridas del mundo. El estudio tuvo como objetivo evaluar el efecto del modo de polinización sobre la producción de semilla viable y la supervivencia de la progenie. Se evaluaron progenies de autopolinización y de polinización cruzada en diferentes accesiones midiendo la producción de semillas, germinación, tasa de germinación y supervivencia de plántulas, y se obtuvieron perfiles moleculares con Secuencias Simples Repetidas (SSR). La progenie obtenida mediante polinización cruzada mostró significativamente mayor producción de semillas llenas y supervivencia de plántulas que la de autopolinización. Esto indica que las accesiones evaluadas dependen en gran medida de la alogamia y que la contribución de la descendencia por autofertilización a la población sería escasa. Los perfiles moleculares SSR mostraron que, en promedio, 85% de la progenie (obtenida a partir de polinización cruzada) presentó marcadores específicos paternos y 100% de ella difirió del genotipo materno. Todas las plantas examinadas presentaron 4x = 36 cromosomas. En conjunto, los resultados indican que la var. makarikariense puede generar progenie altamente polimórfica a través de la segregación y recombinación. Este estudio provee información útil para el diseño de estrategias de conservación, manejo del germoplasma y programas de mejoramiento.

Abstract Panicum coloratum var. makarikariense, a perennial grass native to Africa, is adapted to a wide range of soil and climatic conditions with potential to be used as forage in tropical and semi-arid regions around the world. Our objective was to understand how the pollination mode affects viable seed production and further survival of the progeny. We evaluated self- and open-pollinated progenies from different accessions by measuring the seed production of the parents and their germination performance, germination rate and seedling survival. Parents and progeny were also fingerprinted with Simple Sequence Repeats (SSR). Progeny produced through open-pollination resulted in significantly more filled seeds and superior seedling survival than self-pollination. These results indicate that accessions studied here rely heavily on cross-pollination, whereas the contribution of self-pollinated offspring to the population is likely to be low. SSR profiles showed that, on average, 85% of the progeny (arising from cross-pollination) possessed paternal specific markers and 100% of them were genetically different from the maternal genotype. All plants examined had 4x = 36 chromosomes. Overall, our findings indicate that var. makarikariense is able to generate highly polymorphic progeny through segregation and recombination. This study provides reference information for the formulation of appropriate strategies for pasture germplasm management, conservation and development of breeding programs.

Eight isozyme systems were used in this study: acid phosphatase (ACP), alcohol dehydrogenase (ADH), esterase (EST), glutamate dehydrogenase (GDH), malate dehydrogenase (MDH), phosphoglucoisomerase (PGI), 6-phosphogluconate dehydrogenase (PGD), and phosphoglucomutase (PGM). The polymorphism of these enzyme systems was studied in 25 elite inbred lines. A total of 19 loci were identified, but only eight of them were polymorphic in the germplasm tested. The polymorphic index for the eight informative markers ranged from 0.08 to 0.57, with a mean value of 0.36. Five isozyme loci were mapped in F2:3 populations with existing RFLP data. Est-1, Gdh-2 and Pgi-2 were mapped to linkage groups 3, 14 and 9, respectively. As in previous reports, an ACP locus and a PGD locus were found to be linked, both located in linkage group 2 of the public sunflower map.