GENETIC IMPROVEMENT OF PASPALUM SPECIES IN NORTHEASTERN ARGENTINA

ESPINOZA FRANCISCO; NOVO PATRICIA; ACUÑA CARLOS ALBERTO; BRUGNOLI ELSA ANDREA; MARCON, FLORENCIA; URBANI MARIO HUGO; ZILLI ALEX LEONEL; QUARIN CAMILO LUÍS

Lake Buena Vista, FL, USA

Conferencia; Internation forage and turf breeding conference; 2019

The purpose of the Paspalum breeding program located in Corrientes, Argentina has been to develop subtropical forages with improved cool-season growth, cold tolerance, seed yield, forage quality and persistence. Three breeding methods were used within the program for polyploid species: ecotype selection, hybridization, and recurrent selection. A total of 135 ecotypes belonging to 15 different species were evaluated. The evaluation of natural diversity present in these species allowed for the identification of germplasm well adapted to the subtropics with outstanding characteristics that were unknown for some species, such as late flowering for P. simplex, good adaptation to acid soils for a biotype of P. dilatatum, and high cattle preference for an accession of P. atratum. Two cultivars were generated using this method, i.e. P. atratum cv. Cambá FCA and P. guenoarum cv. Chané FCA.Hybridization within the tetraploid germplasm was possible for a few species because of the availability of induced sexual tetraploid plants. Highly apomictic hybrids were generated in a large enough number that allowed for selection in P. notatum, P. simplex, and from the interspecific cross P. plicatulum x P. guenoarum. Several hybrids for P. notatum exhibited a combination of high forage yield and good ground cover. Superior cool-season growth, cold tolerance, and seed set were observed for some of the interspecific hybrids. A cultivar named Boyero UNNE was developed using this technique for tetraploid P. notatum.Two sexual tetraploid synthetic populations were created with the objective of using recurrent selection. One population was generated for P. notatum by 1) hybridizing a few sexual clones with a group of apomictic genotypes collected from different parts of the species distribution area, and 2) polycrossing the sexual hybrids. Another sexual population was created for the Plicatula group with the main difference that 8 species were crossed with an induced sexual genotype of P. plicatulum in the first hybridization phase. Recurrent phenotypic selection and recurrent selection based on combining ability were successfully used for these populations with the objective of accumulating additive and non-additive genetic effects in each cycle. In conclusion, several genetic lines of Paspalum were selected considering a group of desirable forage traits by exploring the natural diversity, using hybridization at the tetraploid level and recurrent selection on the novel sexual germplasm.