Study On The Identification Of Guava Root-Knot Nematodes In Hainan Island

Root-knot nematodes are a group of heavely harmful obligate plant pathogens parasitizing on almost every higher plant species. According to the papers published in home and broad,more than ninthy nominal species have been described so far. Psidium guajava is cultivated as a kind of rare fruit special for tropic in Hainan Island,and it is heavenly damaged by root-knot nematodes(Meloidogyne spp.).We randomly invested the three years older orchard with fruit,the orchard and tree's rate of disease are both 100%,root-knot index is above 3.0.25 root-knot nematode populations on Psidium guajava were collected from Hainan island. Based on morphology,isoenzyme and mtDNA,25 populations of 28 populations purified are identified as Meloidogyne zhanjiang,2 populations as M.panyu and 1 population as M.incognita. Therefore, M.zhanjiang is the predominant species. The technology and methods of identification on root-knot nematode were discussed in the paper.Finally,we get the resolution that M.zhanjiang is the prevalent species .So we can take the effective prevention measures in time.Applying common PAGE,esterases,malate dehydrogenase of yong females of 28 purified populations is analysised .According to papers of Esbenshade,etc(1985,1990) and Liaojinglin(Doctoral dissertation,2001),of 28 populations,esterase patterns of 25 populations are VS1-S1,dehydrogenase patterns are Nla,the two enzyme patterns are the same as the M.zhanjiang published; esterase patterns of 2 populations are S1-M1-F1,, dehydrogenase patterns are Nlp,the two enzyme patterns are the same as the M.panyu published; esterase pattern of 1 population is II, dehydrogenase pattern is N1,the two enzyme patterns are the same as the M. incognita published.mtDNA of 28 populations is amplified,amplified fragment length of 25 populations is 0.7kb, amplified fragment length of 2 populations is 0.5kb; amplified fragment length of 1 populations is 1.7kb,according to Meloidogyne mtDNA identification standard of Powers (Powers et al,1993) and identification results of two new species of Doctor Liao(Doctoral...