Cucurbit Genetics Cooperative Report 1:20 (article 20) 1978
M. Pitrat
Station d’Amelioration des Plantes Maraicheres, I.N.R.A., Domaine Saint Maurice, 84140 Montfavet-Avignon (France)
Cucumber mosaic (CMV) is a very common and severe virus on melon in the Southeast of France. While observing different lines in the field to study their resistance, it appears that PI 161375 (received from the Southern Regional Plant Introduction Station, Georgia) was the most resistant one (2). After artificial inoculation with CMV, other lines as LJ 34340, LJ 90436 or Freeman’s cucumber were as resistant as PI 161375. After the description of the watermelon mosaic virus (WMV II) in our area (1), we have thought that PI 161375 was more resistant than the other lines to this virus.
After artificial inoculation on the two cotyledons with different isolates of WMV II, a vein-banding with distortion of the leaves appears 12-15 days later on a susceptible cultivar. In PI 161375 distinct vein-banding appears on the first (and sometimes the second) leaf but the following ones are free of symptoms.
We inoculated the two cotyledons of a susceptible line, ‘Charentais T’ and PI 161375 with two isolates of WMV II. The first symptoms on ‘Charentais T’ appeared 12 days after inoculation. Fresh and dry matter weights were made weekly. Until the fourth week there were no differences between the inoculated and non-inoculated plants. Five weeks after inoculation, the fresh and dry matter of the inoculated ‘Charentais T’ was 50-60% of that of the non-inoculated check, whereas the growth of PI 161375 was not significantly affected (Table 1).
Table 1. Dry matter (in grams), 4 or 5 weeks after inoculation with WMV II (2 isolates) of two lines of melon.
Isolates WMV II |
||||
Cultivar |
Time of measurement |
MAR |
V 107 |
Non-inoculated |
| Charentais T | 4 weeks | 0.85 | 1.23 | 1.06 |
| 5 weeks | 1.16** | 1.30** | 2.16 | |
| PI 161375 | 4 weeks | 0.47 | 0.70 | 0.63 |
| 5 weeks | 0.87 | 1.22 | 1.12 | |
** Difference (Prob. < 0.01) between the inoculated and non-inoculated plants (Student’s test).
After artificial inoculation, the symptoms on PI 161375 were less severe and its growth was less affected than ‘Charentais T’. PI 161375 possesses tolerance to WMV lI.
Literature Cited
- Luis, Arteaga, M., J. B. Quiot, J. P. Leroux. 1976. Mise en evidence d’une souche de watermelon mosaic virus (WMV II). dans le sud-Est de la France. Ann. Phytopathol. 8:347-353.
- Risser, G., M. Pitrat, J. C. Rode. 1977. Etude de la resistance du Melon (Cucumis melo L.) au virus de la Mosaique du Concombre. Ann. Amelior. Plantes 27:509-522.