Seleção precoce em plantas segregantes de feijoeiro para resistência à murcha de Curtobacterium

Abstract

Early selection in segregating common bean plants for resistance to bacterial wiltThe objective of this study were both the estimation of the efficiency of selection in segregating populations of common bean for the resistance to Curtobacterium and also the indication of the best time of the cycle to make the selection of resistant plants. To this end, we used converging crosses between IAC-Carioca Aruã x SCS Guará, IACCarioca Pyatã x IAC-Carioca and SCS Guará x Pérola, originating filial generations (F 1 , F 2 , F 2:3 and F 3:4 ) which were subsequently inoculated with Curtobacterium flaccumfaciens pv. Flaccumfaciens, isolate 2634, and evaluated according to a scale related to the common symptoms of the disease at 20, 40 and 60 days after inoculation. The results showed that the segregating generations of Aruã x Guará, Pyatã x Guará and Pyatã x Pérola had similar behavior in relation to resistance to the Curtobacterium symptoms. The selection is effective for the coming generations of Aruã x Guará and Pyatã x Pérola and the favorable time for distinguishing and selecting reliably segregating plants occurs between 40 and 60 days after inoculation.

Reaction and colonization of common bean genotypes by Curtobacterium flaccumfaciens pv. Flaccumfaciens

“…However, in the cultivars IPR Juriti, IPR Graúna, IPR Saracura, IPR Chopim, and IPR Gralha, whose resistance levels were described as good (Comissão 2012), susceptibility was observed in this study (Table 2). This variation in the behavior of these cultivars may be due to differences in aggressiveness between Cff isolates (Rava et al, 2006), or to other factors that may influence the expression of resistance or susceptibility (Bergamin Filho et al 1984, Rava et al 2006, Krause et al 2009, Morais et al 2012). …”