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Stockpiling forage (i.e., deferring grazing) is one way to provide forage for livestock during intervals of low pasture growth, but there are trade-offs as nutrient content declines with increasing forage maturity. Phosphorous (P) concentration, crude protein (CP) content and organic matter digestibility (OMD) were evaluated in two C3 and four C4 grasses native to the South American Campos grasslands. These were: Bromus auleticus (BROAUL) and Nasella neessiana (NASNEE) as C3 grasses and Andropogon lateralis (ANDLAT), Mnesithea selloana (MNESEL), Paspalum dilatatum (PASDIL), and Paspalum notatum (PASNOT) as C4 grasses. The grasses were grown in pots during five stockpiling periods (450, 900, 1350, 1800 and 2250 degree days, approximately 20, 40, 60, 80 and 100 days). As the forage deferment increased, the nutritional value decreased more in C4 than in C3 grasses. Short rest periods (approximately 40 days) are recommended for PASDIL and MNESEL, and medium rest periods (approximately 80 days) for ANDLAT and PASNOT. However, the C3 grasses BROAU and NASNEE maintained high P and CP concentrations and may be the most appropriate option for long rest periods (≥100 days). This information is important to manage different Campos grassland communities for the optimal rest period according to the dominant species.

The native grasslands of southern Brazil have sustained livestock farming for many years; however, decline in pasture areas has led to the loss of genetic diversity of forage species. The development of forage grass cultivars adapted to different environments, will contribute to forming new cultivated pastures or recovering degraded areas. The aim of this study was to assess the herbage accumulation of selected intraspecific hybrid progenies of bahiagrass (P. notatum Flügge) in two different environments (Depressão Central and Campanha region) to estimate their agronomic value. The results indicated variability for the main forage traits studied (leaf dry mass, stem dry mass, inflorescence dry mass, total dry mass, leaf: stem ratio, plant height and population density of tillers). All the hybrids producing more forage mass than the ‘Pensacola’ cultivar in the municipality of Eldorado do Sul and the majority also superior in the municipality of São Gabriel. The production of leaves in the forage was correlated with total dry mass (84%), suggesting that genotype selection for forage mass also selected for production of leaves. The selected hybrids should be indicated for new steps of assessment within the P. notatum breeding program.

Genetic improvement of native forage species is a sustainable alternative for maximizing livestock production. Paspalum notatum Flügge is the most important forage grass in the native grasslands of southern Brazil, with substantial potential available for further genetic improvement. The objective of this study was to quantify a range of genetic parameters and predict yield gains in a population of P. notatum intraspecific hybrids. Results indicated intraspecific hybrids of P. notatum had high magnitudes of heritability in the broad and average sense of genotype, plus high selective accuracy and genetic variation for all forage characteristics evaluated. This indicated REML/BLUP can contribute useful information for plant selection in future plant breeding programs. The genetic material studied showed high genetic variability for forage production. Analysis indicated hybrids 336, 332, 437, 132 and male parent ‘30N’ should be included in new crosses to increase the dry matter production of P. notatum. Parents need to be selected from different groups in order to maximize genetic variability and heterosis. In addition, these parents must be included in diallel crosses. The results obtained in this study provide important information for the future breeding of improved P. notatum cultivars for commercialization.

ABSTRACT: The goal of this study was to assess the variability of Paspalum plicatulum x P. guenoarum interspecific hybrids in terms of agronomic performance and their tolerance to cold conditions, as well as to estimate the correlation of different phenotypic characters associated with forage production. Twenty hybrids plants were used, besides one access P. guenoarum , one of P. plicatulum and the cultivar 'Pensacola' ( P. notatum ). Assessments were performed on individual plants, in a completely randomized design with five repetitions. Paspalum genotypes presented variability in total dry matter, leaf dry mass, leaf: stem ratio, and tolerance to cold. We suggest selection of the hybrids 08Q01 and 08Q44 for new stages within a forage improvement program. Estimates of phenotypic correlation may aid in the selection of genotypes with better agronomic traits.