Abstract

MASELLI, Anna; ROSALES, Ligia Carolina; GUEVARA, Yolanda  and  SUAREZ H, Zoraida. REACTION OF THE GENERA Carica AND Vasconcellea MATERIALS TO Erwinia papayae, Meloidogyne incognita AND Rotylenchulus reniformis. Rev. Protección Veg. [online]. 2010, vol.25, n.3, pp. 157-165. ISSN 2224-4697.

The bacterial canker and the attack of nematodes are serious obstacles to the extension of Carica papaya L. crop. The main objective of this work was the selection of both commercial and wild genotypes resistant to the above mentioned pathogens. To assess the response to the bacterial canker caused by Erwinia papayae, eleven accesions of C. papaya, Vasconcellea goudotiana y V. cauliflora were selected and ten plants of each genotype were inoculated with a bacterial suspension with a concentration of 10⁸ CFU.mL^-1 . The plants were inoculated by wounds on the stems of the healthy plants. The controls were similarly treated but with sterile distilled water. Two trials were carried out to evaluate the resistance to nematodes. In the first trial, materials of C. papaya and V. goudotiana were inoculated with a mixed population of Meloidogyne incognita race 1 and Rotylenchulus reniformis, with 2000 eggs+juveniles. 1000 cm^-3 in sterile soil-sand. In the second trial, V. cauliflora, V. cundinamarcensis, V. microcarpa var. microcarpa and V. microcarpa var. pilifera, in addition to the genotypes previously used, were inoculated only with M. incognita race 1, with 2500 eggs+juvenils.1000 cm^-3. After 12 weeks, the final population was calculated and the fresh and dried weights of the aerial parts and roots were determined. The results of the reaction of the genotypes towards the bacterium determined that V. goudotiana and V. cauliflora did not get the disease, what differed from the Carica genus, where all the plants resulted susceptible, a result that was similar to the evaluation to nematodes, where all the genotypes of C. papaya and V. goudotiana were susceptible and non-tolerant to the attack of the mixed populations of M. incognita race 1 and R. reniformis, since the agronomic variables were affected while most materials of V. cundinamarcencis and of V. microcarpa resulted resistant to the attack of M. incognita race 1. These results allow to direct the search for genes of resistance in wild materials, which could be incorporated into improved or commercial genotypes. This would permit a better management of the mentioned pathogens, which are serious limiting factors in the papaya crop in Venezuela.

Keywords : nematodes; bacterioses; papaya; Erwinia papayae; Meloidogyne incognita; Rotylenchulus reniformes.

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