ResumoO rendimento do feijão-caupi pode ser afetado por diversos fatores, em especial as viroses. As principais espécies de vírus que infectam o feijão-caupi, no Brasil, são: Cucumber mosaic virus (CMV), Cowpea aphid-borne mosaic virus (CABMV), Cowpea severe mosaic virus (CPSMV) e o Bean golden mosaic virus (BGMV). Este trabalho foi realizado em duas etapas e teve como objetivo avaliar a reação de genótipos de feijão-caupi quanto à resistência à infecção simples pelo CMV e mista nas combinações CMV+CABMV, CMV+CPSMV-I e CMV+CABMV+CPSMV-I. Inicialmente, foram incluídos 57 genótipos, sendo três avaliações em gaiolas com tela antiafídeos sob infecção controlada, e uma em condição de campo sob infecção natural. Em seguida, foram selecionados 18 genótipos para serem desenvolvidos em nove ensaios, oito em gaiolas com tela antiafídeos sob infecção controlada, e um em campo sob infecção natural. Nesses ensaios, avaliaram-se os efeitos qualitativos e quantitativos resultantes das infecções. No ensaio de campo, foram avaliados o número de plantas assintomáticas, comprimento de vagem, número de grãos por vagem, massa de cem grãos e produtividade. As coinfecções reduziram a altura da planta e a massa seca. Além disso, nas infecções envolvendo os três vírus ocorreu a morte prematura de alguns genótipos. Os genó-tipos BR17-Gurguéia, Epace V-96, TE97-309G-9, TE97-309G-22, TE97-309G-24 e Patativa, além de bom comportamento diante das coinfecções virais, têm sementes com padrão comercial, podendo ser empregadas diretamente em programas de melhoramento.Palavras-chave: Vigna unguiculata, resistência a vírus, efeito sinérgico. Reaction of cowpea genotypes reveals resistance to co-infection by Cucumber mosaic virus, Cowpea aphid-borne mosaic virus and Cowpea severe mosaic virus AbstractMany factors can affect the yield of cowpea, especially viruses. The main species of viruses infecting cowpea in Brazil are Cucumber mosaic virus (CMV), Cowpea aphid-borne mosaic virus (CABMV), Cowpea severe mosaic virus (CPSMV) and Cowpea golden mosaic virus (CPGMV). This study aimed to evaluate the reaction of cowpea genotypes for resistance to CMV in single or in co-infections (CMV+CABMV, CMV+CPSMV-I and CMV+CABMV+CPSMV-I), which was accomplished in two steps. Firstly, 57 genotypes were evaluated in four evaluations: three in aphid proof cages with infection under controlled conditions, and one in field-grown plants under natural infection. To perform the second step, we selected 18 genotypes to be conducted in nine trials, with eight under aphid proof cages control infection, and one under natural infection. The qualitative and quantitative effects resulting from infections were evaluated. In the field trial, we assessed the number of asymptomatic plants, pod length, number of grains per pod, 100-grain mass and yield. Mixed infections reduced the plant height and dry weight, and premature death of some genotypes was observed in infections involving the three viruses. The genotypes BR17-Gurguéia, Epace V-96, TE97-309G-9, TE97-309G-22, TE97-309G-24 a...

RESUMOPalavras-chave adicionais: Vigna unguiculata, Comovirus, Potyvirus, melhoramento genético.Among the viruses tha t infect cowpea ( Vign a u n gu ic u lata L . Walp.), Cowpea severe mosaic virus (CPSMV) and Cowpea aphidb o rn e mo saic v iru s (CABMV) a re highlighted for their severity a n d wid esp rea d o ccu rr enc e, respe cti vel y. T h ere for e, the a im of t h is st u d y wa s t o o b t a i n a nd e v a l u a t e c o wpe a pl a n t s sh o wi n g resist a nce to CPS MV a nd CABMV in order t o develop n ew a nd e sse n t i a ll y d er i v e d c u l t iv a r s. E i g ht c r o sse s we r e pe r fo r me d , fo llo wed by ba c k cro sse s, u si ng t he lin e T E 9 7 -3 0 9 G-9 a n d t he cu l tiva r Pa ta tiva a s re sista nt pa rent a l do nors, a nd the c u ltiv a rs BR3-Tracuateua, BRS-Urubuquara, BRS-Novaera, BRS-Guariba and Pretinho a s su sceptible pa rents. Generations F2 a nd F2 RC1 were challenged for resista nce by mechanically inocu lating CPSMV a nd CABMV isolates. In F2RC1 genera tions, besides resista nce, other Barros, G.B.; Nogueira, M.S.R.; Oliveira, C.R.R.; Freire Filho, F.R.;Ribeiro, V.Q.; Veiga, C.F.M.; Brioso, P.S.T.; Eiras, M. Obtaining cowpea plants resistant to Cowpea severe mosaic virus and Cowpea aphid-borne mosaic virus. Summa Phytopathologica, v.39, n.2, p.130-136, 2013. traits were evaluated: number of days to the beginning of flowering, pod length, nu mber of seeds.pod-1, weight of 100 seeds, and yield of seeds.plant-1. All F2 and F2RC1 individuals were analyzed by the  2 test a nd fit to the expected frequency of 15 susceptible plants: 1 plant resistant to both viruses. The means of resistant F2RC1 plants, from each backcross, were compared with the mean of their respective recurrent parent by the t-test and means of backcrosses were compared by the Scott-Knott test. Genetic va riability among back crosses was detected for all traits. All backcrosses were considered promising for obta ining essentia lly derived cu ltiva rs resista nt to CPSMV a nd CABMV, and the selected plants have characteristics that allow the selection of lines with highly productive grains of good commercial quality.Dentre os vírus que infectam o feijão-caupi (Vigna ung uiculata L. Wa lp.) desta ca m-se, respectiva mente, pela severidade e ampla ocorrência o Cowpea severe mosaic virus (CPSMV) e o Cowpea aphidborne mosaic virus (CABMV). Portanto, objetivaram-se, no presente tra balho, obter e ava liar plantas de feijão-cau pi com resistência ao CPSMV e ao CABMV, visa ndo a o desenvolvimento de cu ltivares essencia lmente deriva da s e novas cu ltiva res. Rea liza ra m-se oito cruzamentos seguidos de retrocruzamentos, utilizando a linhagem TE 9 7 -30 9 G-9 e a cu ltiva r Pa ta tiva como genitores resistentes, e a s cu ltivares BR3 -Tra cua teu a, BRS-Urubu qua ra, BRS-Novaera, BRSGuariba e Pretinho como genitores suscetíveis. As gerações F 2 e F 2 RC 1 foram desafiadas quanto à resistência por meio de inoculação mecânica com isolados do CPSMV e do CABMV. Nas gerações F 2 RC 1 , além da resistência for...

Cowpea [Vigna unguiculata (L.) Walp.] is an important protein source in diets in Brazil. The preference of consumers is for large, white, light brown and evergreen seeds with rugose coat and small hilum and hilum ring. The Cowpea severe mosaic virus (CPSMV) and the Cowpea aphid-borne mosaic virus (CABMV) are the main pathogens in cowpea plantations in Brazil. This study selected cowpea offspring with (i) white rugose coat seed characteristics that are accepted by markets and (ii) that present resistance to CPSMV (serotype I) and CABMV. The first selection of asymptomatic plants was carried out using seedlings from F 3 seeds mechanically inoculated with a mixture of the two viruses. Offspring F 3:4 went through a second selection process with two stages, one in the field (with natural inoculation), one in trays (with mechanical inoculation). In total, 40 F 3:4 offspring were selected to evaluate agronomic traits in two field assays, one in Teresina, one in Tracuateua (states of Piauí and Pará, respectively) based on a randomized block design with four repetitions. Significant effect of genotype and of the interaction assay x genotype was observed (p ≤ 0.01) for most of the traits evaluated: weight of 100 seeds, yield, seed length, width, and height; length-to-height ratio; width-toheight ratio, and hilum width-to-length ratio. Fourteen offspring produced large seeds (25 -30 g in 100 seeds), and four presented cross-resistance to CPSMV and CABMV, while 36 offspring were resistant only to CPSMV.