Retrocruzamentos visando à obtenção de resistência do maracujazeiro-azedo à virose do endurecimento dos frutos, auxiliados por marcadores moleculares / Backcrossing aiming the resistance of sour passion fruit to woodiness passion fruit virusis resistance assisted by molecular markers

AUTOR(ES)

Kenia Gracielle da Fonseca

DATA DE PUBLICAÇÃO

2008

RESUMO

Brazil is an expoent in passion fruit production, however, the average productivity is quite below its potential. Among the reasons for low productivity are the phytosanitary problems, that compromise the production and the quality of the fruit. Breeding programs that use intra and interspecific crossings have been conducted to overcome these problems. The objective of the present work is to obtain, evaluate and characterize plants of the fourth and fifth backcrossing generation (RC4 and RC5, respectively) originated from the base interspecific crossing between species Passiflora setacea and P. edulis) regarding the woodiness virus disease and the recovery of recurrent genome based on Random Amplified Polymorphic DNA (RAPD) markers. The experiment was carried out at Embrapa Cerrados. Ten leaves per RC4 and RC5 plant and three plants per genitor (P. setacea and P. edulis) were randomly collected, at different time points, for evaluation of virus symptons. They were classified into highly resistant, resistant, susceptible and highly susceptible, according to a visual scale of grades. Artificial inoculation was held under controlled conditions and the incidence of this disease in 60 plants RC5 and their genitors was evaluated. The resistance of P.setacea and the susceptibility of RC plants and P.edulis species were verified. To characterize RC4 and RC5 plants and the recover of the recurrent genome based on RAPD markers, 17 RC4 plants and 16 RC5 plants were collected, based on virusis resistance (evaluation as before mentioned). Leaves of three P. setacea and P. edulis plants were also used. DNA samples of each genetic material was amplified to obtain RAPD markers. The greatest genetic distance was observed between the two genitors (P. edulis and P. setacea), with a large percentage of polymorphisms. RC5 plants showed greater recovery of the recurrent genitor and greater genetic distance to the resistant genitor when compared with RC4 plants. Among RC4 and RC5 plants were selected those with greater resistance to virusis and genetically closer to the recurrent genitor to provide pollen for successive generations, in order to decrease the time spent on the recurrent genome recovery.

ASSUNTO(S)

vírus do endurecimento dos frutos p. setacea passiflora edulis f. flavicarpa passiflora edulis f. flavicarpa recurrent genome ciencias agrarias wood genoma recorrente p. setacea

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