Avaliação da resistencia genetica de Coffea SPPa Perileucoptera coffeella (Guerin-meneville, 1842) (Lepidoptera-lyonetudae)

AUTOR(ES)
DATA DE PUBLICAÇÃO

1989

RESUMO

A leaf disk method was developed to evaluate resistance of Coffea germplasm to coffee leaf miner (Perileucoptera coffeella) described as follows: leaf discs 3,14 cm diameter are kept on moist sponge inside plastic boxes closed with a glass lid. The boxes are maintained under artificial light at 22 +- 2ºC with photoperiod of 12 hours. Each box fits 144 leaf discs. Uniform disk infestation is obtained by the introduction of 150 pupes. Contrarily to the field conditions, where the first and second leaf pairs are the least infested, it was not observed insect preference for any leaf pair, in the laboratory. Presence of mid rib in the discs not influence lesion development. According to subjective visual ratings, number of discs with lesions, damaged foliar area and caterpillar consumption, c. stenophylla, c. salvatrix, C. liberica and C. brevipes can be considered as extremely resistant to the insect, with small or no lesions at alI. C. Kapakata, C. eugenioides, C. racemosa and C. devewrei can be classified as resistant, C. canephora and C.congenesis as susceptible and C arabica cv´s Catuai and Mundo Novo as susceptible or very susceptible. Both in field or lab conditions, the C. racemosa x C. arabica derivate C1195-5-6-2 showed high resistance. The genetic resistance of this plant was expressed in F1, F2 and BC1 generations of crosses with susceptible cultivars. In these generations, segregation occurred in ratios compatible with the hypotesis of resistance being inherited as single dominant trait. The reliability of the devised lab method evidenced by high correlations with field tests in addition to its advantages, claim for- its routine use as a screening method in breeding programs. A practical strategy for evaluation of large segregant populations is also suggested

ASSUNTO(S)

cafe - doenças e pragas

ACESSO AO ARTIGO

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