Field performance of new cowpea cultivars inoculated with efficient nitrogen-fixing rhizobial strains in the Brazilian Semiarid

The objective of this work was to evaluate the contribution of efficient nitrogen-fixing rhizobial strains to grain yield of new cowpea cultivars, indicated for cultivation in the Brazilian Semiarid region, in the sub-medium of the São Francisco River Valley. Two experiments were set up at the irrigated perimeters of Mandacaru (Juazeiro, state of Bahia) and Bebedouro (Petrolina, state of Pernambuco). The treatments consisted of single inoculation of five rhizobial strains - BR 3267, BR 3262, INPA 03-11B, UFLA 03-84 (Bradyrhizobiumsp.), and BR 3299T(Microvirga vignae) -, besides a treatment with nitrogen and a control without inoculation or N application. The following cowpea cultivars were evaluated: BRS Pujante, BRS Tapaihum, BRS Carijó, and BRS Acauã. A randomized complete block design, with four replicates, was used. Inoculated plants showed similar grain yield to the one observed with plants fertilized with 80 kg ha-1 N. The cultivars BRS Tapaihum and BRS Pujante stood out in grain yield and protein contents when inoculated, showing their potential for cultivation in the sub-medium of the São Francisco River Valley.

Interspecific hybrids between the homothallic Phytophthora sojae and Phytophthora vignae

An interspecific cross was attempted between two homothallic species of Phytophthora, P. sojae and P. vignae. From 1640 single-oospore cultures isolated, DNA was extracted from 800, and two interspecific F-1 hybrids (F(1)1121 and F(1)1426) were putatively identified using RAPD markers. The true hybrid nature of these F-1 hybrids was confirmed using additional AFLP analysis. Single- zoospore cultures were generated for each F-1 hybrid and one single-zoospore culture of each was used in pathogenicity and virulence tests. Both F-1 hybrids were pathogenic to soybean and cowpea, causing symptoms including lesions, wilting and death of susceptible soybean and cowpea cultivars. However, the aggressiveness of the F-1 hybrids was reduced and was substantially more variable when compared with that of the parental isolates on their respective hosts. The F-1 hybrids were reisolated from infected seedlings and their hybrid nature confirmed using RAPD and AFLP analysis. These results provide a basis for further research aimed at obtaining an increased understanding of the genetics of host specificity in the Oomycetes.

Elaboração e validação de escala diagramática para avaliação da severidade do carvão da folha do caupi

O carvão da folha, causado pelo fungo Entyloma vignae, é uma doença comum do caupi no Nordeste brasileiro. Considerando a inexistência de métodos padronizados para quantificação dessa doença, foi elaborada uma escala diagramática com os níveis 1,5; 3,5; 7,0; 14,5; 27,0 e 45,0% de área foliar lesionada, testando-se a acurácia, a precisão e a reprodutibilidade das estimativas de severidade do carvão da folha com e sem a utilização desta. Na validação da escala diagramática, 48 folíolos de caupi com diferentes níveis de severidade da doença, mensurados previamente com o programa AutoCAD®, foram avaliados por 10 pessoas, sem e com a utilização da escala diagramática. Foram realizadas duas avaliações com utilização da escala, com intervalo de sete dias, onde seqüências diferentes das mesmas folhas foram estimadas visualmente pelos mesmos avaliadores. A acurácia e a precisão de cada avaliador foram determinadas por regressão linear simples, entre a severidade real, mensurada eletronicamente, e a estimada pelo avaliador. Sem a escala, a maioria dos avaliadores superestimou a severidade da doença. Com a escala, os avaliadores obtiveram melhores níveis de acurácia e precisão, com os erros absolutos concentrando-se na faixa de 10%. Os avaliadores apresentaram boa repetibilidade (90%) e reprodutibilidade (84%) das estimativas com a utilização da escala. A escala diagramática proposta demonstrou ser adequada para avaliação da severidade do carvão da folha do caupi.

Dictionarium Ciceronianum, olim a Francisco Priscianense inchoatum : nunc vero a Ioanne Francisco Besutio ciue mediolanensi absolutum. : in quo omnia vocabula ciceroniana leguntur, atque italice explicantur ...

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