Dissimilarity between Andropogon lateralis ecotypes under different defoliation frequencies and heights

Abstract

Andropogon lateralis Nees is a native grass of southern Brazil and is one of the most frequent specie found in native grasslands. The species is widely distributed and has a high degree of phenotypic plasticity, which makes it highly adaptable to different edaphoclimatic conditions and management. This study aimed to evaluate the behavior of twelve ecotypes of A. lateralis, collected in different regions of the state of Rio Grande do Sul and cut to three different heights and subjected to two different defoliation frequencies. From September to February, the ecotypes were evaluated for total dry matter, leaf and stem yields. In addition, total, vegetative and reproductive tillers and plant height were measured. These characteristics are important for the selection of superior genotypes in terms of genetic variability and forage production. Total dry matter and leaf dry matter are characteristics with agronomic importance and they showed the highest correlation (r = 0.77), enabling an indirect selection for one of these characteristics. The natural selection of plants resulted in distinct structural, morphological and productive characteristics with heterogeneity that allows the selection and grouping according to the characteristics, ecotypes with superior agronomic characteristics can be included in breeding programs.

Genetic parameters, prediction of selection gains and genetic diversity in Andropogon lateralis Nees ecotypes

“…Furthermore, by gaining more knowledge about the biological and ecological factors that can affect the distribution of genetic diversity among, and within, populations of a given species over time and space are fundamental for the successful implementation of management and conservation strategies (Liddell et al, 2020). This information is especially important for grasses from the Pampa biome, such as A. lateralis Nees, which is present in the upper stratum of the natural grasslands in southern Brazil (Barros et al, 2022). Methods that increase our knowledge of the extent of existing diversity within a species, combined with the understanding of biological and ecological factors that govern ecotype distribution, form the fundamental basis for the formulation of solid strategies for germplasm conservation.…”

“…In South America, natural pastures are the primary feed source for extensive livestock production systems and also provide a range of ecosystem services (Weyland et al, 2017;Jaurena et al, 2021). The species Andropogon lateralis Nees is particularly important due to its presence in the upper stratum of the natural grasslands of southern Brazil (Pampa and Atlantic Forest biomes) when they are managed under adequate grazing intensities the equivalent of 12 cm (Barros et al, 2022). The species is a clump-forming, perennial, C4 grass native to South America (Zanella et al, 2021) with gray-green foliage and feathery inflorescences.…”

“…A. lateralis Nees has been identified as a species worth including in genetic improvement programs for inclusion in native grazed pastures (Barros et al, 2022). However, current evaluations have been focusing on a restricted set of genetic parameters.…”

Characterization and genetic diversity in Paspalum notatum Flügge accessions: Morphological and geographical distance

“…The Tocher (original and sequential) and hierarchical (UPGMA) methods showed large concentrations of genotypes in groups I and II, regardless of the distance used (geographic or morphological). It was expected that accessions from different regions, microclimates, and natural selection would result in heterogeneous morphological characteristics and allow differentiation and clustering for breeding purposes (Barros et al, 2022). The large number of accessions in a single cluster demonstrate that they are more closely related and have less genetic variation among themselves (Kaur et al, 2018).…”

“…The large number of accessions in a single cluster demonstrate that they are more closely related and have less genetic variation among themselves (Kaur et al, 2018). This shows that morphological characterization is a valuable source of information for breeding programs (Boczkowska et al, 2014), in addition to being commonly used to assess genetic divergence among accessions (Barros et al, 2022). However, they have limitations to estimate genetic diversity (Kaur et al, 2018).…”