Resumen En Corrientes, Argentina, se evaluaron algunas características agronómicas y de calidad de 11 ecotipos de Paspalum atratum y P. lenticulare, especies nativas de Sur América. La producción de forraje fue determinada entre 2011 y 2014, la digestibilidad y concentración de proteína en verano 2014 y la preferencia animal en invierno 2013 y verano 2015. La tolerancia al frío fue estimada en junio de 2012, el momento de floración durante 2013 y 2014, y la producción de semilla y la germinación en 2014. Los ecotipos de ambas especies mostraron un crecimiento estival marcado y la producción anual de forraje varió entre 5 y 12 t MS/ha. La floración ocurrió a comienzos del otoño, la producción de semillas fue de 280 kg/ha en promedio, y la germinación de 16% (P. atratum) y 19% (P. lenticulare). Con excepción de un ecotipo de P. lenticulare el germoplasma evaluado persistió en la época de invierno y se comportó como perenne. No se observaron diferencias entre los ecotipos en la concentración de proteína cruda y digestibilidad; sin embargo el ecotipo P. atratum U44 fue pastoreado preferencialmente. Futuros estudios serán necesarios para determinar la persistencia en pastoreo y la producción animal de los diferentes ecotipos.

Abstract Paspalum atratum and P. lenticulare are perennial grasses, native to South America. The objective was to evaluate seasonal growth, frost tolerance, cattle preference, nutritional characteristics, seed yield and germination of 11 ecotypes of P. atratum and P. lenticulare with regard to their potential as alternatives to introduced species. Forage yield was evaluated during 3 growing seasons between 2011 and 2014. Digestibility and CP concentration were assessed in summer 2014, cattle preference in winter 2013 and summer 2015, frost tolerance after the first frosts in June 2012, flowering time during 2013 and 2014 and seed yield and germination in 2014. A marked warm-season growing period was observed for both species with annual forage yields varying from 5 to 12 t DM/ha. Flowering did not occur until autumn, with mean seed yield of 280 kg/ha and germination of 16% for P. atratum and 19% for P. lenticulare. Most ecotypes were able to tolerate winter temperatures and behaved as perennials. Although no differences were observed for DM digestibility and CP concentration among accessions, cattle preferentially grazed accession P. atratum U44. Further studies are needed to evaluate persistence under grazing and animal performance.

In previous studies we reported the identification of several AFLP, RAPD and RFLP molecular markers linked to apospory in Paspalum notatum. The objective of this work was to sequence these markers, obtain their flanking regions by chromosome walking and perform an in silico mapping analysis in rice and maize. The methylation status of two apospory-related sequences was also assessed using methylation-sensitive RFLP experiments. Fourteen molecular markers were analyzed and several protein-coding sequences were identified. Copy number estimates and RFLP linkage analysis showed that the sequence PnMAI3 displayed 2-4 copies per genome and linkage to apospory. Extension of this marker by chromosome walking revealed an additional protein-coding sequence mapping in silico in the apospory-syntenic regions of rice and maize. Approximately 5 kb corresponding to different markers were characterized through the global sequencing procedure. A more refined analysis based on sequence information indicated synteny with segments of chromosomes 2 and 12 of rice and chromosomes 3 and 5 of maize. Two loci associated with apomixis locus were tested in methylation-sensitive RFLP experiments using genomic DNA extracted from leaves. Although both target sequences were methylated no methylation polymorphisms associated with the mode of reproduction were detected.