Genetic transfer from several apomictic tetraploid Paspalum species to an elite group of sexual plants

Basic findings from classical genetic studies are available for exploiting apomixis in the breeding of several forage grass genera. Most Paspalum species are multiploid with a sexual diploid cytotype and conspecific apomictic polyploid (mainly tetraploid) cytotypes. Experimental tetraploidized diploids reproduce sexually and, when crossed with natural apomictic tetraploids, yield hybrid populations that segregate for reproductive mode. Genetic studies indicated that apomixis is inherited as a monogenic dominant factor. We recombined 50 selected sexual hybrids obtained from crosses between a tetraploidized sexual genotype of P. plicatulum and 9 natural apomictic tetraploid accessions of 6 species of the Plicatula group. A synthetic sexual tetraploid population (SSTP) of 600 individuals from mixed seed of the 50 intercrossed hybrids was space-planted in the field. Based on evaluations of plant vigor, seed set, ergot tolerance, regrowth after flowering, and cold tolerance, 31 plants were selected. Crosses between most selected plants and two testers, which belonged to P. guenoarum, were performed, and the generated progeny was planted into the field following a randomized block design with 3 replications. The progeny test was evaluated for seed fertility, biomass yield, and cold tolerance. This procedure allowed selection of 10 elite plants from the SSTP. These plants should contain genes recombined from six apomictic species, without the genetic determinants for apomixis. They may be polycrossed to generate an improved sexual population, or crossed with other apomictic genotypes to obtain improved apomictic hybrids.Fil: Novo, Patricia Elda. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; ArgentinaFil: Acuña, Carlos Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; ArgentinaFil: Urbani, Mario Hugo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; ArgentinaFil: Galdeano, Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; ArgentinaFil: Espinoza, Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; ArgentinaFil: Quarin, Camilo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; Argentin

Chromosome Numbers in Bolivian Grasses (Gramineae)

Volume: 81Start Page: 768End Page: 77

Regeneracíon de plantas de Paspalum (Gramineae) por cultivo in vitro de anteras

International audienc

Agronomic characterization of <i>Paspalum atratum</i> Swallen and <i>P. lenticulare</i> Kunth

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

Unravelling the ambiguous reproductive biology of Paspalum malacophyllum: a decades old story clarified

In a recent manuscript published by our group we analyzed the reproductive biology of the grass Paspalum malacophyllum by using traditional embryological techniques combined with current cytological and molecular methods. Our findings confirmed apparent contradictions regarding the reproductive behavior of P. malacophyllum from six independently published reports over the past six decades. Herein we summarize the main findings, conclusions, and validations of all previous studies, highlighting the need for multiple approaches to characterize reproductive systems when using apomictic plants in a breeding program.Fil: Hojsgaard, Diego Hernan. Universitat of Gottingen; AlemaniaFil: Burson, B. L.. Texas A&M University; Estados Unidos. United States Department of Agriculture; Estados UnidosFil: Quarin, Camilo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Nordeste. Instituto de Botánica del Nordeste (i); Argentina. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias; ArgentinaFil: Martínez, Eric Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Nordeste. Instituto de Botánica del Nordeste (i); Argentina. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias; Argentin

Segregation for Sexual Seed Production in Paspalum as Directed by Male Gametes of Apomictic Triploid Plants

Background and Aims: Gametophytic apomixis is regularly associated with polyploidy. It has been hypothesized that apomixis is not present in diploid plants because of a pleiotropic lethal effect associated with monoploid gametes. Rare apomictic triploid plants for Paspalum notatum and P. simplex, which usually have sexual diploid and apomictic tetraploid races, were acquired. These triploids normally produce male gametes through meiosis with a range of chromosome numbers from monoploid (n = 10) to diploid (n = 20). The patterns of apomixis transmission in Paspalum were investigated in relation to the ploidy levels of gametes. Methods: Intraspecific crosses were made between sexual diploid, triploid and tetraploid plants as female parents and apomictic triploid plants as male parents. Apomictic progeny were identified by using molecular markers completely linked to apomixis and the analysis of mature embryo sacs. The chromosome number of the male gamete was inferred from chromosome counts of each progeny. Key Results: The chromosome numbers of the progeny indicated that the chromosome input of male gametes depended on the chromosome number of the female gamete. The apomictic trait was not transmitted through monoploid gametes, at least when the progeny was diploid. Diploid or near-diploid gametes transmitted apomixis at very low rates. Conclusions: Since male monoploid gametes usually failed to form polyploid progenies, for example triploids after 4x × 3x crosses, it was not possible to determine whether apomixis could segregate in polyploid progenies by means of monoploid gametes.- Methods Intraspecific crosses were made between sexual diploid, triploid and tetraploid plants as female parents and apomictic triploid plants as male parents. Apomictic progeny were identified by using molecular markers completely linked to apomixis and the analysis of mature embryo sacs. The chromosome number of the male gamete was inferred from chromosome counts of each progeny. - Key Results The chromosome numbers of the progeny indicated that the chromosome input of male gametes depended on the chromosome number of the female gamete. The apomictic trait was not transmitted through monoploid gametes, at least when the progeny was diploid. Diploid or near-diploid gametes transmitted apomixis at very low rates. - Conclusions Since male monoploid gametes usually failed to form polyploid progenies, for example triploids after 4x 3x crosses, it was not possible to determine whether apomixis could segregate in polyploid progenies by means of monoploid gametesFil: Martínez, Eric Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; ArgentinaFil: Acuña, Carlos Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; ArgentinaFil: Hojsgaard, Diego Hernan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; ArgentinaFil: Tcach, Mauricio Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; ArgentinaFil: Quarin, Camilo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; Argentin

Registration of "Boyero UNNE" bahiagrass

‘Boyero UNNE’ (Reg. No. CV-5, PI 676021) bahiagrass (Paspalum notatum Flüggé) was registered with the National Register of Plant Cultivars and the National Register of Property for Plant Cultivars, Ministry of Agriculture, Livestock Exploitations, and Fisheries of Argentina, Resolution no. 276 in August 2012 (Reg. No. 3213) and released by the National University of the Northeast (UNNE), Faculty of Agricultural Sciences (FCA), Corrientes, Argentina. Boyero UNNE is a tetraploid, highly apomictic F1 hybrid developed between an experimentally obtained female parent, reproducing sexually, and an apomictic, wild bahiagrass genotype. It is the first registered cultivar of a tetraploid apomictic P. notatum developed by breeding through a sexual × apomictic hybridization scheme, exploiting apomixis and plant selection in the F1 progeny. The new cultivar has a more upright growing habit than tetraploid bahiagrass cultivars currently in use or wild tetraploid biotypes. It can produce approximately 19% more forage dry matter than its apomictic male parent, largely exceeding (20–51%) the wild bahiagrass type currently found in natural pasturelands of northeastern Argentina, and it produced 4 to 26% more than the cultivar Argentine at three locations in Florida, USA.Fil: Urbani, Mario Hugo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; ArgentinaFil: Acuña, Carlos Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; ArgentinaFil: Doval, D. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; ArgentinaFil: Sartor, Maria Esperanza. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; ArgentinaFil: Galdeano, Florencia. Universidad Nacional del Nordeste; ArgentinaFil: Blount, A. R.. North Florida Research And Education Center;Fil: Quesenberry, K. H.. University of Florida; Estados UnidosFil: Mackowiak, Chery L.. North Florida Research And Education Center;Fil: Quarin, Camilo Luis. Universidad Nacional del Nordeste; Argentin