Early evaluation of black leaf streak resistance by using mycelial suspensions of Mycosphaerella fijiensis

Abstract:

A standardized method for the early evaluation of resistance to black leaf streak on in vitro Musa plants was developed using mycelial suspensions of Mycosphaerella fijiensis. Seven cultivars:'FHIA-18','FHIA-01''FHIA-21','Grande naine','Yangambi','Calcutta 4'and'Niyarma yik'were tested in a greenhouse. Inoculum was adjusted to io5cfu/ml and applied to the lower surfaces of the first three open leaves. Plants were evaluated 15 days after inoculation and at 15-day intervals until 60 days. A standardized scale of leaf symptoms ensured consistency between evaluators. All cultivars except'Yangambi', showed a similar response to M. fijiensis in natural conditions. Partial resistance expressed in FHIA cultivars was characterized by a slow rate of symptom development with'Calcutta 4'the slowest.'Grande naine'and'Niyarma yik'gave a susceptible reaction and their symptoms were more severe. Artificial inoculation of in vitro plants with mycelial suspensions was an easy, rapid and practicable method to determine resistance to M. fijiensis. An inoculum adjusted to an appropriate concentration gave uniform symptoms on the inoculated leaf. The method has promise for the evaluation of in vitro plants in breeding programmes. Resumen-Evaluacion temprana de la resistencia a la raya negra de la hoja mediante el uso de la suspension del micelio de Mycosphaerella fijiensis

Año de publicación:

2002

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