In vitro assay for screening of Areca spp. for Phytophthora resistance

Fruit and crown rot, diseases caused by Phytophthora meadii in arecanut (Areca catechu L.), leads to huge yield losses to the growers and remains one of the greatest challenges to arecanut productivity. Developing an arecanut variety with Phytophthora resistance, therefore, is of prime significance. Areca triandra and A. concinna, which are close relatives of arecanut, are possible candidates to develop disease resistant inter-specific hybrids. It is thus imperative to have an effective screening assay for disease resistance. A detached leaf assay is often used to characterize disease susceptibility and screening for resistance to a particular pathogen. Influence of external biotic and abiotic factors in these assays pose potential challenge apart from the biosecurity risks which it carries. In the present study, two approaches were followed to screen for phytophthoral resistance in A. triandra and A. concinna. In the first approach, challenge inoculation was carried out in embryo cultured plantlets, whereas in latter, it was done on leaf segments of adult field grown plants cultured in Eeuwens Y3 media. Results indicate that in vitro assay, involving challenge inoculation on either entire plantlet or leaf segment, is an easy and rapid for disease screening.