Carlos Lásaro Pereira de Melo

Caracterização fenotípica e molecular de genitores de feijão tipo carioca quanto à resistência a patógenos

Abstract€–€The present study aimed at the phenotypic and molecular characterization of 31€genotypes of thecarioca-type common bean regarding the resistance to anthracnose, rust and angular leaf spot (ALS) pathogens.Thirteen pathotypes of Colletotrichum lindemuthianum , two of Uromyces appendiculatus and seven of Pseudocercospora griseola were inoculated. In the molecular characterization, five molecular markers, identifiedin advance, and linked to the different alleles of pathogens’ resistance, were used. Seven genotypes showedresistance to 12€pathotypes of C.€lindemuthianum . Nine genotypes presented resistance to five pathotypes of P.€griseola . Ten genotypes were resistant to the pathotypes of U.€appendiculatus . The lines VC€2, VC€3 andVC€5, besides Ruda-R (line pyramided with five genes which confer resistance to some pathotypes of anthracnose,rust and ALS), were the stood out for multiple resistance to the pathogens above described. Molecularpolymorphism was detected between the most genotypes with Ruda-R, which indicates the possibility of usingthe molecular markers SCARF10, SCAR Y20, SCARAZ20, SCARH13 and OPX1 1 .Index terms:

Espaçamento entre linhas e severidade da ferrugem-asiática da soja

ABSTRACT A ferrugem-asiatica da soja, causada pelo fungo Phakopsorapachyrhizi Syd. & P.Syd., tem sido, desde sua deteccao no Brasil (25),um dos principais desafios fitopatologicos para essa cultura. Ate omomento, a unica forma de controle da doenca, apos sua instalacao nalavoura, e por meio da aplicacao de fungicidas, o que onera os custosda lavoura. Alem disso, o seu uso continuo, como unica estrategia demanejo, pode causar a selecao de patogenos resistentes ou menossensiveis aos fungicidas utilizados e, por conseguinte, a ineficienciado controle da doenca, com a aplicacao exacerbada de fungicidas eelevacao dos custos de producao.Dessa forma, e necessaria a combinacao de outras praticas agricolaspara o controle mais efetivo das doencas, a fim de garantir a eficienciaeconomica e ambiental da agricultura. Neste contexto, a adocao domanejo integrado torna-se uma estrategia adequada para atender aoproposito de eficiencia e sustentabilidade no controle de doencas. Noentanto, pouco avanco se obteve no conhecimento sobre o manejocultural da ferrugem-asiatica da soja, principalmente com relacao aoarranjo de plantas.O efeito do arranjo de plantas e do espacamento entre linhas desemeadura tem sido estudado por diversos pesquisadores para asmais variadas culturas (3, 4, 5, 8, 11, 12, 13, 14, 15, 16, 17, 22). Nacultura da soja, o espacamento entre linhas interfere na populacao ecrescimento de plantas daninhas (3), no indice de area foliar, navelocidade de fechamento das entrelinhas (13) e no rendimento degraos (12, 14). No entanto, pouco se tem estudado sobre o efeito deespacamento entre linhas na severidade de doencas, principalmente daferrugem-asiatica da soja, exceto pelos trabalhos realizados porMadalosso et al. (15) e Soares & Lonien (22).Sabe-se que o desenvolvimento de uma doenca depende dainteracao entre planta, agente patogenico e fatores ambientais (1, 2, 7,20). Portanto o ambiente, representado tanto pelas condicoesmeteorologicas como pelo micro clima, e um fator relevante nesta

Resistance of soybean genotypes to the reniform nematode in a controlled environment

The aim of this study was to characterize the resistance to the reniform nematode of soybean genotypes derived from crosses with at least one parent resistant to Rotylenchulus reniformis or Heterodera glicynes, or to both. Two experiments in a greenhouse of Embrapa Western Region Agriculture, arranged in a completely randomized design, evaluated 199 genotypes with five replications. Sixty days after artificial inoculation (1000 eggs and larval forms), the nematodes were extracted from the roots and the genotypes evaluated for the number of eggs and larval forms per gram of root (NGR) and for the reproduction factor (RF). Sixty-five genotypes were resistant (RF <1.0), with mean RF significantly equal to M-SOY 8001. The highest number of lines resistant to reniform nematodes, in the different study combinations of crosses, were derived from the genotypes Custer, PI 437654, Fayette, BRSGO Ipameri, BRSMT Pintado, and BRS 262.

BRS Esteio: common bean cultivar with black grain, high yield potential and moderate resistance to anthracnose

BRS Esteio is a common bean cultivar with black grains of excellent cooking quality, suited for cultivation in 21 Brazilian States. In 77 trials of Value for Cultivation and Use, the cultivar had a normal cycle (90 days), an average yield of 2,529 kg ha-1, which is 8.1% higher than that of the control cultivars, a high yield potential (4,702 kg ha-1), upright growth, tolerance to lodging, and moderate resistance to anthracnose.