Cucurbit Genetics Cooperative Report 13:25-26 (article 9) 1990
Mark E. Herrington and Svenning Prytz
Redlands Research Station, OI Box 327, Cleveland, Queensland, 4163, Australia
Losses of Cucumis melo to zucchini yellow mosaic virus (ZYMV) have increased in Queensland where there are at least two distinct isolates of the virus (1). Resistance available in PI 414723 has been overcome by some variants (2). We are therefore seeking other sources of resistance which may be more stable. In early tests we found that line 91213, which has a low rate of multiplication of WMV-2 (3), was also resistant to ZYMV. This was not surprising as 91213 and PI 414723, which have similar reactions, are derived from PI 371795.
The results of an initial survey of a sample of PIs from USDA Ames are reported here. Plants were manually inoculated twice on the cotyledons with ZYMV in phosphate buffer (pH 7.0). ‘Doublon’, PI 414723 and ‘Planters Jumbo’ were included as controls.
PI lines with infection percentages less than about 70% (Table 1), PI 390451 and PI 470252 warrant further evaluation and may provide sources of ZYMV resistance or tolerance. Fifteen of the 60 lines tested reacted with symptoms similar to those on ‘Doublon’.
Lines PI 321005 and PI 164825 also showed a high degree of resistance to natural infections by powdery mildew (Sphaerotheca fuliginea) while PI 381803 showed a moderate level of resistance.
We are attempting to produce self-pollinated seed from survivors of the ZYMV evaluations to allow further testing and inheritance studies. PI 207662 is particularly interesting with a mild reaction and low frequency of infection. Some of the lines identified should provide additional sources of resistance to ZYMV.
This work was funded by Research Grant 4.54 from the Committee of Direction of Fruit Marketing (COD) and the Horticultural Research and Development Corporation.
Table 1. Percentage of Cucumis melo plants infected following inoculation with ZYMVz.
Cultivar (PI) |
% of plants infected |
|||
| 136173 (10/10)y | 390452 (8/8) | 435992 (10/10)w | 446930 (8/8) | |
| 255478 (8/8) | 401704 (2/2)w | 476337 (9/9)w | 470252 (8/8)u | 100% |
| 255479 (1/1) | 426627 (10/10)w | Doublon (5/5)w | 476336 (10/10) | |
| 381803 (10/10) | 435086 (10/10)w | 438684 (7/7) | Planters Jumbo | |
| 390451 (8/8)v | 435087 (10/10)w | 438685 (10/10) | (14/14) | |
| 102077 (3/3) | 126099 (1/1)w | 255953 (3/3) | 357824 (3/3) | |
| 124100 (3/3) | 251516 (3/3)w | 266934 (1/1) | 385965 (3/3) | |
| 266943 (3/3)w | 268227 (2/2) | 439745 (3/3) | ||
| 280548 (2/2)w | 269368 (2/2) | 500362 (3/3) | ||
| 288236 (1/1)w | 277283 (3/3) | 502328 (3/3) | ||
| 296119 (3/3)w | 279366 (3/3) | 502329 (3/3) | ||
| 344411 (3/3)w | 357800 (3/3) | 504526 (3/3) | ||
| 161375 (5/6) | 249560 (8/9) | 435289 (8/9) | 470253 (11/12) | 71-99% |
| 200819 (7/9) | 321005 (5/6) | 435941 (8/9) | PI414723 (10/13)v | |
| 355056 (5/9)w | 296345 (1/2) | 164796 (2/3) | 164825 (3/5) | 41-70% |
| 224786 (1/2)w | 505936 (1/2) | 266935 (2/3) | ||
| 503325 (2/3)w | 357827 (2/3)x | |||
| 164797 (1/3) | 207662 (3/10)x | 11-40% | ||
| 289876 (0/1) | 436533 (0/2) | 0-10% | ||
zSown 18 September 1989; inoculated with G4 strainof ZYMV 26 September and 11 October. Final assessment was on 20 November. Lines with more than five plants were from duplicated pots.
yParenthesis indicates the number of plants showing symptoms/number inoculated.
xMild reaction.
wNecrosis as in Doublon.
vPartial recovery; slow symptom development.
uPartial recovery; tolerant cucumber present in seed lot.
tHypersensitive spotting as PI414723, stem necrosis.
Literature Cited
- Greber, R. S., D. M. Persley, and M. E. Herrington. 1988. Some characteristics of Australian isolates of zucchini yellow mosaic virus. Australian Journal of Agricultural Research 39:1085-1094.
- Lecoq, H. and M. Pitrat. 1984. Strains of zucchini yellow mosaic virus in muskmelon (Cucumis melo L.). Phytopath Z 111:165-173.
- Moyer, J. W., G. G. Kennedy, and L. R. Romanow. 1985. Resistance to watermelon mosaic virus II multiplication in Cucumis melo. Phytopathology 75:201-205.