Estirpes de Bradyrhizobium em simbiose com guandu‑anão em casa de vegetação e no campo

The objective of this work was to evaluate the symbiotic efficiency of nitrogen‑fixing bacterial strains, from the genus Bradyrhizobium, with dwarf pigeon pea. The experiments were carried out in Leonard jars, in pots with soil and in the field. In Leonard jars, 11 strains were tested, and the most effective in promoting pigeon pea growth were evaluated in pots with soil (Oxisol and Cambisol) and in the field (Oxisol). In all experiments, treatments were compared to two positive controls (strains approved as inoculants for pigeon pea cultivars, BR 2003 and BR 2801) and to two controls without inoculation, one with a high concentration of mineral N, and the other, depending on the experiment, without mineral N (soil) or with low N concentration (Leonard jars). Some strains have provided plant growth similar or superior to the reference strains and to the controls in Leonard jars. In the pot experiment with soil, the soil type influenced the treatments. In the field, there was no difference among treatments, and the native strains promoted a good plant growth. Dwarf pigeon pea is able to establish a symbiotic association with nitrogen‑fixing bacteria, and the strain UFLA 03‑320 has the potential to be recommended for this crop together with the BR 2801 strain.O objetivo deste trabalho foi avaliar a eficiência simbiótica de estirpes de bactérias fixadoras de nitrogênio do gênero Bradyrhizobium com guandu‑anão. Os experimentos foram conduzidos em vasos de Leonard, em vasos com solo e em campo. Foram testadas 11 estirpes em vasos de Leonard, e as que apresentaram maior eficiência em promover o crescimento do guandu‑anão foram avaliadas em vasos com solo (Latossolo Vermelho‑Amarelo e Cambissolo) e em campo (Latossolo Vermelho‑Amarelo). Em todos os experimentos, os tratamentos foram comparados a dois controles positivos (estirpes aprovadas como inoculantes para as cultivares de guandu‑anão BR 2003 e BR 2801) e a duas testemunhas sem inoculação, uma com alta concentração de N mineral, e a outra, a depender do experimento, sem N mineral (solo) ou com baixa concentração de N (vasos de Leonard). Algumas estirpes proporcionaram crescimento vegetal semelhante ou superior às estirpes‑referência e às testemunhas em vaso de Leonard. Em vasos com solo, o tipo de solo influenciou os tratamentos. No campo, não houve diferença entre os tratamentos, e as estirpes nativas promoveram bom crescimento. O guandu‑anão é capaz de estabelecer associação simbiótica com bactérias fixadoras de N2, e a estirpe UFLA 03‑320 apresenta potencial para ser recomendada para a cultura junto com a estirpe BR 2801

Viabilidade da inoculação líquida com Rhizobium etli no sulco de semeadura do feijoeiro-comum

The objective of this work was to evaluate the viability of liquid medium inoculation of Rhizobium etli in the planting furrow and to certify the efficiency of its strain UFLA 02-100 as a potential inoculant for common bean (Phaseolus vulgaris). The treatments consisted of three application rates of liquid inoculant applied in the planting furrows and one rate applied in common bean seed, besides two controls without inoculation. The inoculant contained 109 cells of Rhizobium etli mL-1. Regardless of the application method, the yield obtained with the inoculation was equivalent to that of N from urea; however, the application in the furrows, at 0.6 L ha‑1, is more advantageous due to the operational practicality and reduced costs. O objetivo deste trabalho foi avaliar a viabilidade da inoculação líquida de Rhizobium etli no sulco de semeadura e certificar a eficiência da estirpe UFLA 02-100 como inoculante potencial para o feijoeiro-comum (Phaseolus vulgaris). Os tratamentos consistiram de três doses do inoculante líquido aplicadas aos sulcos e uma dose aplicada às sementes de feijão-comum, além de dois controles sem inoculação. O inoculante continha 109 células de Rhizobium etli mL-1. Independentemente do método de aplicação, a produtividade obtida com a inoculação foi equivalente à da aplicação de N da ureia, mas a aplicação ao sulco, com 0,6 L ha-1, é mais vantajosa pela praticidade operacional e redução de custos.

Grain technological quality of common beans cultivars in the rainy crop season<br>Qualidade tecnológica de grãos de cultivares de feijão-comum na safra das águas

Common bean (Phaseolus vulgaris L.) is a nutrient-rich food and the main protein source in the Brazilians’ diet, chiefly of the low income population. The sort of bean most consumed in Brazil is the carioca and it is also the most produced. Recently, breeding programs have made new cultivars available with beans of other commercial groups, but the enablement of its adoption by the farmers demands, in addition to the adequacy of the current production systems, evaluations of the technological quality of the beans produced. The purpose of the work was evaluating the technological quality of beans of cultivars of different commercial groups of bean harvested in the rainy season crop, which in general produces lower quality beans. For this purpose, the beans obtained were submitted to different laboratory analyses, adopting the randomized block design with five treatments (cultivars BRS Radiante, Ouro Vermelho, BRS MG Talismã, BRS Supremo and Bolinha) and five replicates. The technological quality of bean beans ranged according to the cultivar, except in relation to the water imbibition percentage by the beans after cooking and percentage of whole beans. Cultivar BRS MG Talismã, of the carioca group, presented shorter cooking time, less electric conductivity and higher volumetric expansion rate. Cultivar Bolinha, of yellow group, demanded longer cooking average time.O feijão-comum (Phaseolus vulgaris L.) é um alimento rico em nutrientes e a principal fonte protéica na dieta dos brasileiros, principalmente da população de baixa renda. O tipo de grão mais consumido no Brasil é o tipo carioca, também o mais produzido. Recentemente, programas de melhoramento têm disponibilizado novas cultivares, com grãos de outros grupos comerciais, mas a viabilização da sua adoção pelos produtores requer, além da adequação dos atuais sistemas de produção, avaliações da qualidade tecnológica dos grãos produzidos. O objetivo do trabalho foi então avaliar a qualidade tecnológica de grãos de cultivares de diferentes grupos comerciais de feijão-comum colhidos na safra das águas, que geralmente produz grãos de qualidade inferior. Para tanto, os grãos obtidos foram submetidos a diferentes análises laboratoriais, assumindo-se um delineamento em blocos casualizados com cinco tratamentos (cultivares BRS Radiante, Ouro Vermelho, BRS MG Talismã, BRS Supremo e Bolinha) e cinco repetições. A qualidade tecnológica de grãos de feijão-comum variou com a cultivar, exceto em relação a porcentagem de embebição de água pelos grãos após o cozimento e porcentagem de grãos inteiros. A cultivar BRS MG Talismã, do grupo carioca, apresentou menor tempo médio de cocção, menor condutividade elétrica e maior taxa de expansão volumétrica. A cultivar Bolinha, do grupo amarelo, demandou maior tempo médio de cozimento

Bradyrhizobium spp. Strains in Symbiosis with Pigeon Pea cv. Fava-Larga under Greenhouse and Field Conditions

ABSTRACT: Optimization of symbiosis between nitrogen-fixing bacteria and legumes has been extensively studied, seeking agricultural sustainability. To evaluate the symbiotic efficiency of nitrogen-fixing bacterial strains belonging to the Bradyrhizobium genus with pigeon pea (Cajanus cajan (L.) Millsp.) cv. Fava-Larga, experiments were conducted in Leonard jars (axenic conditions), pots with soil, and in the field. Ten strains were tested in Leonard jars, and three strains, in addition to BR 29, were selected according to their ability to promote the growth of pigeon pea, for further tests in pots with different soil types (Inceptsol and Oxisol) and in the field (Oxisol). Treatments were compared with strains BR 2003 and BR 2801 (approved as inoculants for pigeon pea), with a non-inoculated control with mineral N fertilization, and with another non-inoculated control (absolute control) with low mineral N concentration (Leonard jars) or without mineral N fertilization (soil). The efficiency of Bradyrhizobium strains in axenic conditions varies among strains, being higher when pigeon pea cv. Fava-Larga establishes symbiosis with the strains UFLA 03-320, UFLA 03-321, UFLA 04-212, BR 2801, and BR 2003. The soil type influences the symbiotic efficiency of Bradyrhizobium-pigeon pea in soil in the greenhouse, mainly in Inceptsol, in which strains UFLA 04-212, BR 2801, and BR 2003 increased N accumulation in the plant. The strain UFLA 03-320 increased shoot dry matter and N accumulation in the shoot equivalent to the mineral N treatment under field conditions. UFLA 03-320, BR 29, UFLA 03-321, and UFLA 04-212 promoted yields similar to those of the reference strain (BR 2801), and of the mineral N treatment with 70 kg ha -1 urea-N. These results confirm that pigeon pea establishes efficient symbiosis, which provides the N required for its growth. All strains, except for BR 2003, show potential for recommendation as inoculants for grain production. The strain UFLA 03-320 also shows potential for use in green manure crops

Bradyrhizobium spp. Strains in Symbiosis with Pigeon Pea cv. Fava-Larga under Greenhouse and Field Conditions

ABSTRACT: Optimization of symbiosis between nitrogen-fixing bacteria and legumes has been extensively studied, seeking agricultural sustainability. To evaluate the symbiotic efficiency of nitrogen-fixing bacterial strains belonging to the Bradyrhizobium genus with pigeon pea (Cajanus cajan (L.) Millsp.) cv. Fava-Larga, experiments were conducted in Leonard jars (axenic conditions), pots with soil, and in the field. Ten strains were tested in Leonard jars, and three strains, in addition to BR 29, were selected according to their ability to promote the growth of pigeon pea, for further tests in pots with different soil types (Inceptsol and Oxisol) and in the field (Oxisol). Treatments were compared with strains BR 2003 and BR 2801 (approved as inoculants for pigeon pea), with a non-inoculated control with mineral N fertilization, and with another non-inoculated control (absolute control) with low mineral N concentration (Leonard jars) or without mineral N fertilization (soil). The efficiency of Bradyrhizobium strains in axenic conditions varies among strains, being higher when pigeon pea cv. Fava-Larga establishes symbiosis with the strains UFLA 03-320, UFLA 03-321, UFLA 04-212, BR 2801, and BR 2003. The soil type influences the symbiotic efficiency of Bradyrhizobium-pigeon pea in soil in the greenhouse, mainly in Inceptsol, in which strains UFLA 04-212, BR 2801, and BR 2003 increased N accumulation in the plant. The strain UFLA 03-320 increased shoot dry matter and N accumulation in the shoot equivalent to the mineral N treatment under field conditions. UFLA 03-320, BR 29, UFLA 03-321, and UFLA 04-212 promoted yields similar to those of the reference strain (BR 2801), and of the mineral N treatment with 70 kg ha-1 urea-N. These results confirm that pigeon pea establishes efficient symbiosis, which provides the N required for its growth. All strains, except for BR 2003, show potential for recommendation as inoculants for grain production. The strain UFLA 03-320 also shows potential for use in green manure crops