First comprehensive study on distribution frequency and incidence of seed-borne pathogens from cereal and legume crops in Sri Lanka

Abstract

Sri Lanka as an agricultural country requires seed health testing to rnanage crop diseases. So tar no comprehensive research has been can'ied out for the proper identi fication olseed mycoflora af ltcting the seed quality in Sri Lanka. The present sfudy strives to address this issue by identifying seed-borne fungal pathogens from stored seeds usirg morpho-molecular characterization. Fungal pathogens were isolated lrom surface-sterilized and non-surface sterilized seeds of .,lrachis hypogeu, Or1':a sativa. Ligra radiata, andl4gna srnensls. PCR arnplilication and DNA sequencing olthe intemaL transcribed spacer (ITS) region was carried out for molecular identit-rcation of pathogens. The genaination qualiry of each seed vanety was calculated by pot experiments. Distnbution tiequencies. percentage of germination, and seedling vigor were calculated and analyzed tbr each seed variery tested. In total eighteen isolates were recovered fi'om the fbur seed varieties. Molecular characterization revealed that the fungal isolates recovered from all the four seed varieties belong to seven senera: ,lspergillus, Bipolaris, Daldiuia, lrlacroplromirn, Orbilia, Rhi:opus, and Tuluroml,ces. Rhi:opus spp. showed the highest distribution frequency (15%). Arachis hv-pogea showed the lowest gennination percentage (20%) and lowest seedling vigor index (585). The seeds ofOry:a rativd shorved no gennination probably due to their high incidence offungal pathoqens (loul out ol seven genera). This study is tl.re tlrst comprehensive sLudy analyzing the seed-borne pathogens ol the lour most commonly consurned Sri Lankan cereal and legume crops. Results reported in this study helps to identi[y and implement optimum storage facilities and control such fungal pathogens in future agricultural practices.