Made available in DSpace on 2016-04-28T14:57:33Z (GMT). No. of bitstreams: 1 Gislanne Brito Barros.pdf: 2326172 bytes, checksum: 73f275a11542cb2e428f8d2e36262f20 (MD5) Previous issue date: 2010-08-05 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Several diseases caused by different pathogen species can affect the cowpea culture, causing considerable reduction in its productive potential. Among the diseases of large occurrence are the viral illnesses. The viruses caused by the families Comoviridae and Potyviridae, represented by the species Cowpea severe mosaic virus (CPSMV) and Cowpea aphid-borne mosaic virus (CABMV) respectively, are considered of great importance. Considering the efficiency of the genetic resistance in the control of these diseases, this work was carried out aiming at the obtenttion and characterization cowpea plants with resistance to viruses CPSMV and CABMV, in order to obtain new and essentially derived cultivars. Eight crosses were performed using the line TE 97-309G-9 and the cultivar Patativa as parental donors of resistance to CPSMV and CABMV, and cultivars BR3-Tracuateua, BRS-Urubuquara, BRS-Novaera, BRS-Guariba and the landrace Pretinho as recurrent parents. The isolated virus used in the inoculation of F2 and F2RC1 plants were collected in Embrapa Meio-Norte experimental field, and maintained in differential lines. The purity of the isolated was evaluated and confirmed in the Laboratory of Fitovirologia, of Biological Institute, in S?o Paulo. Biparental crosses and triple were made to obtain F1 generations, and then submitted to self pollinated to develop F2 seeds. These F2 plants were inoculated with the mixture of the viruses CPSMV (sorotype I and II) and CABMV. Afterward, the resistant F2 plants were backcrossed with the respective recurrent parent to obtain F1RC1 seeds. The plants of F1RC1 generation were self pollinated to develop F2RC1 seeds. The F2RC1 plants were also inoculated with the same mixture of the viruses, as previously mentioned, and resistant plants were characterized. The following characters were used: number of days to the first flower; pod length; number of seeds per pod; weight of 100 seeds; seed color; and seed yield per plant. The segregation of the F2 generation of biparental crosses and triple and the F2RC1 were analyzed to check the expected frequency of 15 susceptible plants: 1 resistant plant by the ?2 (Qui square) test. All the F2 biparental crosses and F2RC1 backcrosses were adjusted to the expected frequency of 15:1. The characters evaluated in parents and F2RC1 were submitted to statistical analysis. The averages of the resistant plants F2RC1 in each backcross were compared with the average of respective recurrent parent by the t-test and the averages within crosses were compared by the Scott-Knott test. The existence of great genetic variability within and among backcrosses were detected based on all characters. It can be concluded by this study that all backcrosses are promising for obtaining essentially derived cultivars resistant to the viruses CPSMV and CABMV and that the backcrosses who obtained as recurrent parents cultivars BRS-Urubuquara and BRS Novaera are very promising for obtaining new cultivars with multiple resistance to the viruses CPSMV and CABMV. / Diversas doen?as causadas por diferentes esp?cies de pat?genos podem afetar a cultura do feij?o-caupi, promovendo redu??o consider?vel do seu potencial produtivo. Dentre as doen?as de larga ocorr?ncia se destacam as viroses, merecendo maior ?nfase as causadas pelos v?rus das fam?lias Comoviridae e Potyviridae, com as esp?cies Cowpea severe mosaic virus (CPSMV) e Cowpea aphid-borne mosaic virus (CABMV), respectivamente. Considerando a efici?ncia da resist?ncia gen?tica no controle dessas doen?as, esse trabalho foi conduzido com o objetivo de obten??o e caracteriza??o de plantas de feij?o-caupi com resist?ncia aos v?rus CPSMV e CABMV, visando o desenvolvimento de cultivares essencialmente derivadas e de novas cultivares. Foram realizados oito cruzamentos utilizando a linhagem TE 97-309G-9 e a cultivar Patativa como parentais doadores dos genes de resist?ncia aos v?rus CPSMV e CABMV, e as cultivares BR3-Tracuateua, BRSUrubuquara, BRS-Novaera, BRS-Guariba e a cultivar local Pretinho como parentais recorrentes. Os isolados virais usados nas inocula??es das plantas das gera??o F2 e F2RC1 foram coletados no campo experimental da Embrapa Meio-Norte, e mantidos em linhagens diferenciadoras. A pureza dos isolados foi avaliada e confirmada no laborat?rio de Fitovirologia, do Instituto Biol?gico, em S?o Paulo. Cruzamentos biparentais e cruzamento triplo foram realizados para a obten??o da gera??o F1 e submetidos ? autofecunda??o para a obten??o de sementes F2. As plantas da gera??o F2 foram inoculadas com a mistura dos v?rus CPSMV (sorotipos I e II) e CABMV. Em seguida, as plantas F2 resistentes foram retrocruzadas com o respectivo parental recorrente para a obten??o de sementes F1RC1. As plantas da gera??o F1RC1 foram autofecundadas para a obten??o de sementes F2RC1. As plantas F2RC1 foram tamb?m inoculadas com a mistura dos v?rus, como mencionado anteriormente e as resistentes foram caracterizadas. Foram avaliados os seguintes caracteres: n?mero de dias para o in?cio da flora??o; comprimento da vagem; n?mero de gr?os por vagem; peso de cem gr?os; produ??o de gr?os por planta. As segrega??es das gera??es F2 dos cruzamentos biparentais e cruzamento triplo e F2RC1 foram analisadas pelo teste ?2 (Qui-Quadrado) para verificar a freq??ncia esperada de 15 plantas suscet?veis: 1 planta resistente. Todas as F2 dos cruzamentos biparentais e cruzamento triplo e F2RC1 ajustaram-se a freq??ncia esperada de 15:1. Os caracteres avaliados nos parentais e nas gera??es F2RC1 foram submetidos a an?lise estat?stica. As m?dias das plantas F2RC1 resistentes, de cada retrocruzamento, foram comparadas com a m?dia do seu respectivo parental recorrente pelo teste t e as m?dias dos retrocruzamentos foram comparadas pelo teste de Scott-Knott. Foi detectada grande variabilidade gen?tica entre e dentro os retrocruzamentos para todos os caracteres. Pode-se concluir com base nos resultados que todos os retrocruzamentos s?o promissores para obten??o de cultivares essencialmente derivadas resistentes aos v?rus CPSMV e CABMV e que os retrocruzamentos que obtiveram como parentais recorrentes as cultivares BRS-Urubuquara e BRS Novaera s?o muito promissores para a obten??o de novas cultivares com resist?ncia aos v?rus CPSMV e CABMV.