SUSCEPTIBILITY OF SOME DATE-PALM CUL TIV ARS TO THE ROOT-KNOT NEMATODE, MELOIDOGYNE INCOGNITA Eissat, M.F..; EI-Sherier, M.A.; AbdeI Gawadt,M.M., YoussefM.M.A!.; Ismailt,A. A. and EI-Nagdi1,W.M.A. 1. Nematology unit, Plant Pathology Dept., National Research centre. 2. Nematology Dept., Fac. Agric.; Cairo Univ. ABSTRACT Seventeen date-plam cultivars were screened to determine the effect of the tested date-palm seedlings on development and reproduction of Meloidoyne incognita. The nematode development and reproduction varied according to the tested cultivar. Zanati was the only immune cultivar as nematode infestation did not survive on its roots. Six highly resistant cultivars; Aynat, Malakabi, Orabi, Sakkoti, Samani and Seqii were recorded in this study. Other cultivars presented different degrees of resistance. Production of phenols and/or inhibitory hormones and/or toxins to the parasitizing nematodes are probably responsible of resistance mechanism in early growth stage of date-plam. INTRODUCTION The world produce 4.4 Million tons of date (FAO, 1997) 97.1% of the World date production are from Arabian and Islamic countris. Date-plam is not only valuable as economic and social aspects; but also it is documented in relegions, history and arts. Several nematode pests were recorded as parasites to date-plam roots causing losses in the early stage of growth (Nurseries). The root-knot nematodes, Meloidogyne spp. are some of the most comon wide-spread nematodes all-over the World (Sasser, 1989). These pests act as endoparasites and have hundreds of hosts under field conditions. Few studies have been conducted on host reaction of date-plam cultivars to detect their relative susceptibility to root-knot nematode species. Carpenter (1964) tested 50 date-palm cultivars against Meloidogynejavanica infection. The cultivars Braim, Hayany and Honey were rated as susceptible cultivars to the nematodes, but Amhat and Deglet Noor were ranked as tolerant to nematode infection. Lamberti and Greco (1977) reported that four cultivars of date-palm, Le., Bou Feggous, Kabkab, Medijool and Deglet Noor, were screened for resistance to three populations of both Meloidogyne incognita and M javanicap. Deglet Noor cultivar was generally rated as poor host to nematode infection. Griffth and Koshy (1990) stated that young seedlings of 50 date-palm cultivars were susceptible to infection by root-knot nematode. Moreover, 90% of the tested seedlings were killed prior to emergence when s~eds were sownin heavlyinfectedsoil. 282 ---- --------- - --- -
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SUSCEPTIBILITY OF SOME DATE-PALM CULTIVARS TO THEROOT-KNOT NEMATODE, MELOIDOGYNE INCOGNITA
Eissat, M.F..; EI-Sherier, M.A.; AbdeI Gawadt,M.M., YoussefM.M.A!.;Ismailt,A. A. and EI-Nagdi1,W.M.A.
1. Nematology unit, Plant Pathology Dept., National Research centre.
2. Nematology Dept., Fac. Agric.; Cairo Univ.
ABSTRACT
Seventeen date-plam cultivars were screened to determine the effect ofthe tested date-palm seedlings on development and reproduction of Meloidoyneincognita. The nematode development and reproduction varied according to thetested cultivar. Zanati was the only immune cultivar as nematode infestation didnot survive on its roots. Six highly resistant cultivars; Aynat, Malakabi, Orabi,Sakkoti, Samani and Seqii were recorded in this study. Other cultivarspresented different degrees of resistance. Production of phenols and/orinhibitory hormones and/or toxins to the parasitizing nematodes are probablyresponsible of resistance mechanism in early growth stage of date-plam.
INTRODUCTION
The world produce 4.4 Million tons of date (FAO, 1997) 97.1% of theWorld date production are from Arabian and Islamic countris. Date-plam is notonly valuable as economic and social aspects; but also it is documented inrelegions, history and arts.
Several nematode pests were recorded as parasites to date-plam rootscausing losses in the early stage of growth (Nurseries). The root-knotnematodes, Meloidogyne spp. are some of the most comon wide-spreadnematodes all-over the World (Sasser, 1989).These pests act as endoparasitesand have hundreds of hosts under field conditions.
Few studies have been conducted on host reaction of date-plam cultivarsto detect their relative susceptibility to root-knot nematode species. Carpenter(1964) tested 50 date-palm cultivars against Meloidogynejavanica infection.The cultivars Braim, Hayany and Honey were rated as susceptible cultivars tothe nematodes, but Amhat and Deglet Noor were ranked as tolerant tonematode infection. Lamberti and Greco (1977) reported that four cultivars ofdate-palm, Le., Bou Feggous, Kabkab, Medijool and Deglet Noor, werescreened for resistance to three populations of both Meloidogyne incognita andM javanicap. Deglet Noor cultivar was generally rated as poor host tonematode infection. Griffth and Koshy (1990) stated that young seedlings of 50date-palm cultivars were susceptible to infection by root-knot nematode.Moreover, 90% of the tested seedlings were killed prior to emergence whens~edsweresownin heavlyinfectedsoil.
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The present article investigates the susceptibility of 17 date-palmcultivars, at their early stage of growth, to M incognita.
MATERIALS AND METHODS
Under greenhouse conditions, 17 date palm cultivars were screened toM incognita infection. The tested cultivars were Aglani, Amhat, Aynat, Bent-Eisha, Gondela, Hayany, Malakabi, Orabi, Saidi, Sakkoti, Samani, Seqii,Shamya, Sokarya, Wardy, Zaghlool and Zanati. Seeds of each cultivar weresoaked in renewable tap water for one week, then incubated in wetted clothfor two weeks. Sprouted seeds were planted in 20 cm diameter clay pots filledwith sterilized sandy loam soil. Two weeks later, five replicates from eachcultivar were inoculated with 200 newly hatched purified M incognitalarvae/pot. Other five non inoculated pots from each cultivar kept as untreatedcontrol. The pots were watered regularily for 10months.
Nematode extraction followed Jenkins (1964) technique. Nematodecounting was done by 1 ml Hawksley eclworm counting slide. Nematodeidentification followed (Mai & Lyon,1975).
Roots were stained for further examination (Franklin and Goodey,1949).Data were recorded for number of root galls (G), developing larvae stages(D.S.), females (F) and egg-laying females (E.F.) per root system wereestimated. Rate of nematode penetration, maturation, reproduction, potentialeggmassesproduction,potentialpopulationdensity,rateof susceptibilityandbuild-upwerecalculatedaccordingto the followingformula(Oostenbrink,1966):-
-Rate of penetration (R.P.) =
-Rate of maturation (R.M.)=
Count of total nematodes in root tissuesCount of nemetodes used for inoculation
Total count offemales+egg-Iaving femalesTotal count of nematodes in the root tissues
XlOO
XlOO
-Rate of reproduction (R.R.)= Countofegglayingfemales X100Total count of females +egg-Iaying females
- Potential eggmasses production (P.E.P.)= Numberofeggmasses/cultivar X100Number of eggmasses/potential cultivar
-Potential population density (P.Pop.)= Totalfinalpopulationlcultivar XIOOTotalfinalpuplationof potentialcultiver
-Rate of susceptibility (R.S.)= Average ofP.E.P.+P.pop.
-Rate of build up (R.B.)= To~a.1final counts of nemetodes in r~ot and .soil(Pr) XIOOInItial count of nematode used for inoculation (Pi)
RESULTS AND DISCUSSION
Susceptibility of seventeen date-palm cultivars to M incognita wastested. Data on number of galls, nematode developmental stages, rates ofreproduction and population build-up were recorded, ten months after theinoculation (Tables 1-3). Host susceptibility or resistance rates were alsodeterimned (Table 4). Reactions to M incognita infection differed remarkablyamong date-palm cultivars. Aglani, Bent-Eisha and Zaghlool cultivars showedthe highest M incognita root gall index of four (Table 2). While, Aynat andMalakabi had the lowest index of 1.2. The other cultivars showed moderate
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root-gall indices. Zaghlool cultivar supported the highest M. incognita rate ofbuild-up comparing to cultivar Orabi which showed the lowest rate (Table 3).Based on number, relative number of galls, developmental larval stages, matureand egg-laying females host susceptibility of cultivars was determinedaccording to Hadisoeganda and Sasser (1982). The average of theaforementioned rates for each cultivar defmed its host suitability category tonematode infection (Table 4). In this respect, cultivars Aglani, bent-Eisha andZaghlool were rated as highly susceptible and cultivars; Amhat, Hayany andSlkarya were considered moderately susceptible. On the other hand, cultivarsAynat, Malakabi, Orabi, Saidi, Sakkoti, Samani and Seqii were categorized ashighly resistant. The most promising cultivar was Zanati which proved to beimmune to the tested M incognita population. The nematode population densityin soil were generally not always in consistence with their densities in the rootsystem.Growth response of date-palm cultivars to infection with Meloidogyneillcognita:
The impact of M incognita infection on the growth of 17 date-palmcultivars was studied. data on number ofleaves, lengths and weights of bothshoots and roots were recorded (Table 5). It is obvious that growth of all plantswas greatly affected by the nematode infection. The reduction in number ofleaves of most inoculated plants was not significant except for cv. Zaghloolwhich was 20.9%. The shoot length of all inoculated plants was notsignificantly different from uninoculated plants except for cvs. Aglani, Bent-Eisha and Saidi which were 27.5, 16.4 and 20.8% reduction, respectively. Theshoot fresh weight reduction in all inoculated cultivars were not significantexcept for cvs. Amhat, Aynat, Shamya and Wardy which were 33.9,34.4,21.8and 20.7% reduction, respectively. Shoot dry weight in all inoculated cultivarswere not significantly different from control plants except for Amhat, Aynat,Bent-Eisha and Malakabi which showed reduction of 28.9, 32.9, 21.5 and16.4%, respectively. On the other hand, root length of most inoculated cultivarswere significantly different from respective checks. However, reduction in rootfresh weight and dry weight of most inoculated cultivars was not significantexcept for cultivars Aglani and Zaghlool.
Results indicated that most of the examined date-palm cultivars wereinfected with M incognita. The tested cultivars, however, varied in theirsuitability as hosts to this nematode pest. They were classified into five groupsstarting from immune to highly susceptible. Immune and resistant date-palmcultivars may be cosidered the most economical components for M incognitamanagement. In this respect, one immune cultivar, Zanati, and six highlyresistant cultivars; Aynat, Malakabi, Orabi, Sakkoti, Samani and Seqii wereidentified in the present study. The resistant cultivars probably produce phenols,enzymes, inhibitory hormones and/or toxins to nematode which prevent itsdevelopment.
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LITERATURE CITED
- Carpenter, J.B. (1964). Root-knot nematode damage to date-palm seedlingsin relation to germination and stage of development. Date Growers Inst.,Ann. Rept., 44: 10-14
- FAO (1997). Agricultural Statistics of 1996.FAO Rome.
- FrankIin, M.T. and J.B. Goody (1949). A cottonblue-lactophenoltechniquefor mounting plant-parasitic nematodes. 1.Helmintol., 23: 175-178.
- Griffth, R. and P.K. Koshy (1990). Nematode parasites of coconut andother palms. In: Plant Parasitic Nematodes in Subropical and TropicalAgriculture (M. Luc, R.A. Sikora and J. Bridge (eds.). C.A.B. International,363-386.
- Hadisoeganda, W.W. and J.N. Sasser (1982). Resistance of tomato, bean,southern pea and garden pea cultivars to root-knot nematodes based on hostsuitability. Plant Disease, 66: 145-150.
- Jenkins, W.R. (1964). A rapid centrifugal flotation technique for separatingnematodes from soil. PI. Dis. Reptr. 18:692. "
- Lamberti, F. and E.N. Greco (1977). Pathogenicity of two species ofMeloidogyne on four varieties of date-palm.Nematol.Medit., 5: 159-172.
- Mai, W.F. and H.H. Lyon (1975). Pictorial key to genera of plant-parasiticnematodes. Ithaca, CorneIIUniversity Press, 220 p.
- Oostenbrink, M. (1966). Major characteristics of the relation between nematodes
and plants.Meded.Landbouwhogesch,Wageningen,66-4, 46 pp.
- Sasser, J.N. 1989 Plant Pavasitic Nematodes, the fanner's Hidden Enery.Bull. PI. Path. Dept. N.C. state Univ., pp. 115.
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Table (1): Number of Me/oidogyne incognita developmental stages onseventeen date-palm cultivars +.
+ Means of 5 replicates.+ Cultivars from Saudi Arabian origin.- Data in columns followed by a common letter are not significantly different (P
0.05) accoridng to Duncan's multiple range test (DMRT).
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No. of developmental stages / rootCultivars 2nd 3 rd 4th Mature Total Eggmasses
Table (2): Number of Meloidogyne incognita galls, second stage in soil, totalnematode in root system and gall index on date-palm cuItivars+.
+ Values are means of5 replicates.* Cultivars from Saudi Arabian origin.# Final nematode population/pot containing 2 kg soil where the initial nematode
population. Were 200 larave/pot.Data in columns followed by a common letter are not significantly different(P 0.05) according to Duncan's multiple range test (DMRT).
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No. of 2nd TotalNo. of
stage in nematode Root-gallCultivars Total galls persoil per stages in indexplant root system
root
Aglani 2387# a 2882 a 5269 51 b 4.0Amhat 805 de 680 b 1485 26 cd 3.2Aynat 195 g 3g 198 2h 1.2Bent-Eisha 2422 ab 2119 a 4541 64 a 4.0Gondela 527 def 163 d 690 5th 2.0Hayany 1279 bcd 792 b 2071 45 b 3.8Malakabi 158 th 30 f 188 3h 1.2Orabi 53 g 12 h 65 10 eth 2.2Saidi 0 94 e 94 16 def 2.1Sakkoti 42 g 357 c 399 25 cd 2.0Samani 122h 89 e 211 17 de 2.2Seqii* 48 g 22 f 70 9 eth 2.2Shamya 256 eth 736 b 992 11 eth 2.4Sokarya* 1026 cde 2338 a 3364 32 c 3.4Wardt 431 def 293 cd 724 15 def 2.3Zaghlool 2990 abc 2843 a 5833 56 ab 4.0Zanati 0 0 0 0 0.0
Table (3): Nematode development and reproduction on date-palm cultivarsinfected with root- knot nematode, Meloidogyne incognita.
+ As indicated in materials methods.
· Cultivars fi:omSaudi Arabian origin.
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Rate of Rate of Rate of Rate ofCultivars
. + maturation+ reproduction+ build-up+
penetratIon(RP. ) (RM. ) lRR)
Aglani 1650.5 12.7 75.7 28.4
Amhat 446.5 23.9 8?9 9.2.
Aynat 3.5 57.1 75.0 1.03
Bent-Eisha 1568.0 32.4 74.2 27.8
Gondela 121.0 32.6 69.6 3.8
Hayany 534.5 25.9 69.8 11.7
Malakabi . 28.0 46.4 61.5 1.1
Orabi 11.0 45.5 50.0 0.4
Saidi 83.0 43.4 80.6 0.8
Sakkoti 193.0 7.9 58.6 2.1
Samani 69.0 35.5 69.4 1.3
Seqit 22.0 50.0 63.6 0.5
Shamya 456.0 19.3 72.7 5.8
Sokarya.
1268.5 7.8 58.3 17.8
Wardy 214.5 31.5 74.1 4.3
Zaghlool 1679.0 15.1 71.3 31.7
Zanati 0.0 0.0 0.0 0.0
Table(4): Reproduction and population density of Meloidogyne incognita on 17 date-palmcultivars. . -
D.S. = Developmental 5'...:igeT.F.P.= Total firu:I. pop:.!lation.M.F.=~facure female R.P.= Rate of productionE..M.=Eggmass R.M.= Rate of maturation~1JS = NO.oflarvae in soil R.R= Rate of reproduction.
HR 1-10 %M.R 10-20 %MS. 20-50 %H.S. >50 %
P .E.P= Potentia! egg mass productionP.Pop= Potential populationR.S.= Rate of susceptibility
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Cultivars D.S MF E.M NUS T.F.P RP R.M RR PE.P P.Pop Factor R.S
Figures in parenthesis indicated the percentage of reduction over the check pl:lJ1ts... indicate the signific:lI1t 41l1dhighly signifiC41l1tat p =0.05 and 0.01. respectively.
