The document summarizes a study that tested the susceptibility of three Vernonia galamensis accessions (17, 18, and 19) to the root-knot nematode Meloidogyne incognita race 2 under greenhouse conditions. The study found that all three accessions were susceptible to M. incognita, with accession 17 being the most susceptible and accession 19 the least. Future research will screen additional accessions to find ones resistant to nematodes to graft the commercial accessions with.

1. F LIMPOPO
UN YO
I V ERSIT
Faculty of Science and Agriculture
Host-suitability and Host-sensitivity of Vernonia
galamensis accession 17, 18 and 19 to Meloidogyne
incognita race 2 under Greenhouse conditions
Matsobane Mathiba
School of Agricultural and Environmental Sciences
Department of Soil Science, Plant Production
and Agricultural Engineering

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INTRODUCTION
 Alternative vegetable oil: Vernonia oil valued for its
vernolic fatty acid
 Synthetic epoxies of linoleic and alpha-linolenic
acids are common substitutes of the carcinogenetic
acryllic and phthalate products.
 Industrial epoxidation of common fatty acids
increase greenhouse emissions
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Vernonia galamensis in Limpopo Province
 V. galamensis is adaptable to the agronomic
conditions in Limpopo Province, Republic of South
Africa.
 Three accessions: 17, 18 and 19, have shown good
adaptations in Limpopo Province and are therefore
being considered as commercial lines.
 Root-knot nematodes: Meloidogyne incognita race
2 and M. javanica.
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Three types of host-nematode interactions
 Susceptible host: Host allows nematodes to
reproduce and the host suffers yield loss.
 Tolerant host: Host allows nematodes to
reproduce, but the host does not suffer yield
loss.
 Resistant host: Host does not allow
nematodes to reproduce and there is no yield
loss.
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OBJECTIVE
To determine Host-suitability and Host-sensitivity of Vernonia galamensis accession
17, 18 and 19 to Meloidogyne incognita race 2 under greenhouse conditions
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MATERIALS AND METHOD
 Study area: Greenhouse
 Experimental design, treatment and procedure:
 Two 5 x 3 Factorial experiments in RCBD with five replicates.
 Treatments 0, 500, 1000, 1500 and 2000 nematode densities (Pi)
were inoculated on V. galamensis accession 17, 18 and 19.
 Data collection
 Nematode numbers (Pf)
 Shoot mass
 Calculated reproductive factor (Rf) = Pf/Pi
 Data analysis
 Data: ANOVA and Means: LSD
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RESULTS AND DISCUSSION
Accession 17 Accession 18 Accession 19
Inoculation Root Soil Root Soil Root Soil
(Pi) 500 232.5 2407.8 267.7 2075.4 226.4 834.0
1000 151.7 2069.7 128.0 1409.0 159.0 672.4
1500 81.1 1260.8 82.3 1403.4 73.1 409.2
2000 18.5 876.1 32.2 983.6 32.8 313.4
Accession 17 Accession 18 Accession 19
Inoculation Pf RF Pf RF Pf RF
(Pi) 500 2640.2 5.2a 2343.0 4.7a 1065.2 1.97a
1000 2221.4 2.2b 1531.3 1.5b 831.4 0.83b
1500 1342.0 0.9c 1491.3 1.0bc 482.3 0.32bc
2000 894.6 0.5c 1015.9 0.51c 346.2 0.17c
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Accession 17 Accession 18 Accession 19
Shoot Shoot Shoot
Inoculation (Pi) mass (g) Rel* mass (g) Rel* mass (g) Rel*
Control 35.7a - 37.8a - 41.9a -
500 15.0b - 57.98 26.4b - 30.16 30.9b - 26.25
1000 14.7b - 58.82 29.1b - 23.06 27.6b - 34.13
1500 13.0b - 63.59 29.7b - 21.43 32.8b - 21.72
2000 16.3b - 54.34 27.2b - 28.04 31.5b - 24.82
Relative effect = (treatment/control – 1) 100
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CONCLUSION
 V. galamensis accessions tested are susceptible to M. incognita race 2.
 Future research will include screening all available accessions with the aim of grafting the
three commercially used accessions with those with less commercial value but resistant to
nematodes.
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ACKNOWLEDGEMENTS
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