BP Singh

214 Arjun LalTable 3.Some important seed-borne nematodes of quarantineimportanceNematode speciesAnguina tritidAnguina agrostis*Aphelenchoides besseyiAphelencltoides arachidisDitylenchus destructor'Ditylenchus . dipsaci*Pratylenchus brachyurHsRhadinaphelenchus .cocophilus*Common nameSeed gall nematodeBent grass nematodeWhite tip nematodePeanut testa nematodePeanut pod rot nematodeStem & Bulb nematodeLesion nematodeRed ring nematodeHost plantsWheat, barleyBentgrassPaddy, Setaria,Panicum, StylosanthesPeanutPeanutAlfa alfa, onion,. garlic, faba bean,tulip, GladiolusPeanutCoconut, oil palm* Nematode species not yet reported from India.f) Molecular aids to nematode diagnosisAs stated in the beginning, only a few nematode-plantinteractions produce distinctive, readily observable symptoms onroots, stems, leaves, bulbs and seeds. As a result, the diagnosis ofnematode- induced plant damage is dependent upon isolating andidentifying plant parasitic nematodes from infested plant tissuesor soil samples. Over the last two decades, efforts have been madeto diagnose and identify nematodes by analysing proteins, lipids,carbohydrates and most recently DNA sequences. In fact, significantprogress has been made in developing these molecular aids fornematode diagnosis, for example, the use of esterase or malatedehydrogenase phenotypes to separate Meloidogyne arenaria, M.javanica, M. incognita, and M. hapIa; use of monoclonal antibodiesand DNA probes to separate Globodera rostochiensis from G. pallidaland Bursaphelenchus xylophilus from B. mucronatus.Techniques to detect DNA sequences differences betweenorganisms can be divided into three basic approaches: detection ofRestriction Fragment Length. Polymorphisms (RFLPs) 'betweennematode DNA samples; use of DNA probes in dot blot assays andPolymer chain Reactions (peR). In general, most DNA studies forspecies, and race{pathotype separation have made comparisons