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Brazil is the second-largest producer and the first exporter of beef, with herds mainly raised in extensive pastures, where Megathyrsus maximus occupies over 30 Mha. About 70% of the pastures are under degradation, and using plant growth-promoting bacteria (PGPB) may contribute to reversing this scenario. We investigated the effects of PGPB on the growth of six cultivars of M. maximus—Tanzania-1, Massai, BRS Zuri, Mombaça, BRS Tamani, and BRS Quênia—under greenhouse conditions. Plants were inoculated, or not, with the elite strains of Azospirillum brasilense CNPSo 2083 + CNPSo 2084, Bacillus subtilis CNPSo 2657, Pseudomonas fluorescens CNPSo 2719, or Rhizobium tropici CNPSo 103. At 35 days after emergence, plants were evaluated for ten root growth traits, shoot dry weight, and the levels of macro and micronutrients accumulated in shoots. Several root traits were increased due to inoculation in all genotypes, impacting plant growth and nutrient uptake. Despite the differences in effectiveness, all genotypes benefited from PGPB to some degree, but Mombaça and BRS Zuri were more responsive. Scanning electron microscopy indicated that bacterial species differed in their capacity to colonize seeds and rootlets. The results show that inoculation with elite PGPB strains may represent an important strategy for the sustainability of M. maximus pastures.

Estimates are that land area occupied by grass pasture far exceeds that of other crops; at least half are at some stage of degradation. The use of elite plant-growth-promoting microorganisms (PGPM) as inoculants represents an important strategy to achieve qualitative and quantitative improvements in forage biomass, increasing the productivity and sustainability of livestock production. Several studies have reported the benefits of PGPM in grass pastures, with an emphasis on bacteria of the genera Azospirillum, Pseudomonas, Bacillus, rhizobia, and on arbuscular mycorrhiza fungi (AMF). The main grasses studied are Urocholoa (syn. Brachiaria), Megathyrsus (syn. Panicum), Paspalum, Cynodon, and Agropyron. Several microbial processes associated with improvements in root and shoot growth, nutrient content in biomass, and other benefits have been described. Promotion of plant growth has been associated with the synthesis of phytohormones and enzymes regulating several steps of plant development, nutrient mineralization by release of microbial molecules, biological nitrogen fixation, nutrient uptake facilitation by means of molecules such as exopolysaccharides, amongst others. Outstanding benefits of increased root growth, resulting in higher uptake of water and nutrients, either by phytohormones released by bacteria or by expanding root surface by AMF, have been reported. Biocontrol is another important property of PGPM, by a variety of mechanisms, including the synthesis of antimicrobial molecules, lytic enzymes, siderophores, and the release of specific inhibitory compounds such as hydrogen cyanide. Although improvements in forage management can enhance microbial performance, as shown for AMF, in general, inoculation with elite strains positively impacts growth parameters. Globally, the use of microbial inoculants has significantly increased in the past few years, but their application is still modest on grass pastures, which are generally degraded and would need special use of microbial inoculants for reclamation. Efforts towards increasing the use of PGPM in pastures can have deep positive environmental, economic, and social impacts worldwide.

In Colombia, the highest cassava production comes from the semi-arid region of the Atlantic Coast with relatively low yield for fresh consumption (≤11 t/ha). Development of improved varieties is based on a plant ideotype which integrates a group of desirable traits independently measured in the field. However, selecting high performance genotypes for several traits simultaneously is a complex process. Sixteen genotypes were evaluated under four environmental conditions (localities) of the Colombian Caribbean region (Cereté, Carmen de Bolivar, Agustín Codazzi, and Sevilla), and two production cycles (2016/2017–2017/2018) in order to assess phenotypic expression of selected traits, their stability, and utility in genotype selection. Selection of promising genotypes should consider both their superiority and stability. Genotypes SM3106-14, GM1692-56, CM9456-12, and GM214-62 were selected based on their agronomic performance. In addition, frequency analysis of sensorial data showed that genotypes CM9456-12, SM1127-8, SM3553-27, and SM3562-32 were preferred by panelists who assessed, color, flavor, texture, and root shape. Determination of superiority through across-environments, multi-trait selection index allows identifying genotypes with superior performance. However, selection was improved when local multi-trait selection indices were included—phenotypic stability determination (through Lin and Binns index and AMMI model) supported an adequate selection of superior and stable cassava genotypes. The inclusion of palatability response and quality features determination in cassava genotypes can be recommended to identify genotypes with higher adoption rates by farmers and consumers.