The Paspalum genus includes several species that are important for livestock in Rio Grande do Sul, such as P. notatum and P. guenoarum, typical of native pastures of the Pampa biome. The aim of this study was to investigate forage production and chemical composition of four ecotypes of these species in relation to the cv. 'Pensacola' (P. notatum). Ecotypes of P. guenoarum (Azulão and Baio) and P. notatum (André da Rocha and Bagual) and the cv. 'Pensacola' were evaluated for two years, during which four cuts/year were made. The work was carried out under field conditions at the Agronomic Experimental Station of the Federal University of Rio Grande do Sul (30°05'S; 51°39'W), in a completely randomized design. P. guenoarum stood out for higher productivity and greater tolerance to cold; the Azulão ecotype showed more autumn production in relation to the other ecotypes. Crude protein content ranged from 14 (Baio) to 15% ('Pensacola'); for neutral detergent fiber, the variation was 68 (Azulão) to 71% ('Pensacola') and for acid detergent fiber there was a variation of 38 ('Pensacola') to 43% (Baio). The data demonstrates the potential of native genotypes for use as cattle feeding in southern Brazil.

For many decades, animal production in southern Brazil has been based on native forage grasses. Paspalum notatum Flügge (bahiagrass) is one of the most frequently used native grass in southern Brazil. The native germplasm of P. notatum is tetraploid and displays apomictic reproduction; hence, chromosome doubling of sexual diploid accessions is required to facilitate hybridization. The main goal of this study was to evaluate forage production and other agronomical evaluation of P. notatum intraspecific hybrids in order to obtain new varieties that could be registered and/or protected and launched as new cultivars in the future. Three tetraploid sexual genotypes were crossed with the ecotypes Bagual and André da Rocha. Biomass production (leaf, stem, and inflorescence fractions), plant growth habit, plant height, number of tillers, and frost damage were evaluated in the resulting hybrids. The general combining ability (GCA) and specific combining ability (SCA) were calculated for the six families generated. We evaluated 196 hybrids and the most productive yielded 42 % more total dry mass than the most productive parent (ecotype Bagual), and Bagual production was seven-fold higher than that of cultivar 'Pensacola'. The highest GCA values were observed for Bagual and Q4205. No correlation was observed between leaf coloration and the frost effect or regrowth in the following winter.Similarly, no correlation between plant growth habit and dry mass production was observed. The reproduction mode of the most productive hybrids are currently being analyzed in larger plots to identify apomictic and sexual genotypes for future registration and protection.

The goal of this study was to assess the variability of Paspalum plicatulum x P. guenoarum

RESUMOO objetivo deste estudo foi avaliar o desempenho forrageiro e estimar as correlações fenotípicas de caracteres agronômicos de híbridos interespecíficos de Paspalum, em duas regiões fisiográficas distintas. Avaliaram-se 20 híbridos, dois ecótipos de P. guenoarum, um de P. plicatulum e a cv. Aruana de Panicum maximum, utilizada como testemunha. O delineamento foi em blocos ao acaso, com três repetições. Os caracteres mensurados foram: produção de matéria seca total, produção de matéria seca de folhas, produção de matéria seca de colmos, produção de matéria seca de inflorescência, relação folha: colmo, altura, diâmetro de cobertura das plantas e numero de perfilhos. Os híbridos 10E4026, 10E5052, 08Q01, 10E43, 10E40104, 10E6086, 10E4025, 10E5017, 10E4041, 10E4071 e 10E31 apresentaram desempenho forrageiro superior nos dois ambientes, e são indicados para novas etapas dentro de programas de melhoramento de forrageiras. A alta correlação positiva entre a massa seca de folha com a massa seca total, diâmetro de cobertura das plantas e altura, torna a estimativa das correlações fenotípicas uma importante ferramenta na seleção de híbridos com caracteres agronômicos superiores. Palavras-chave: ambiente, apomixia, hibridação, melhoramento genético ABSTRACTThe objective of this study was to evaluate the forage performance and estimate the correlations of agronomic traits of interspecific hybrids of Paspalum in two distinct physiographic regions. They evaluated 20 hybrids, two ecotypes of P. guenoarum, one P. plicatulum and cv. Aruana of Panicum maximum, used as a control. The design was a randomized block design with three replications. The traits measured were: total dry matter yield, leaf dry matter yield, stem dry matter yield, inflorescence dry matter yield, leaf: stem ratio, height, plant coverage diameter and number of tillers. The hybrids 10E4026, 10E5052, 08Q01, 10E43, 10E40104, 10E6086, 10E4025, 10E5017, 10E4041, 10E4071 and 10E31 showed higher forage performance in both environments and are suitable for new steps in forage breeding programs. The high positive correlation between the leaf dry mass with the total dry mass, plant coverage diameter and height, makes the estimation of correlations an important tool in selecting hybrids with superior agronomic traits.