[tomato] Tolerance to tomato yellow leaf curl virus

Pete (Tomato@GlobalGarden.com)
Tue, 14 Dec 1999 20:54:06 -0500

I found this with a search engine, and it seems that TYLCV has been around
for awhile, I'm wondering why I'm just hearing about it now.  Although they
mention breeding a hybrid for tylcv tolerance, I wonder why I've never seen
this advertised.  Anyone know of any varieties that are TOMATO YELLOW LEAF
CURL VIRUS tolerant?  Here is what the website had to say:

>>Tolerance to tomato yellow leaf curl virus.
Pilowsky, M. and Cohen, S.
The whitefly-borne tomato yellow leaf curl virus (TYLCV), a geminivirus,
causes severe damage to tomatoes in the Mediterranean basin. Affected plants
are stunted, their leaflets are rolled upwards and inwards, and are smaller
than those of healthy plants. Fruit set is greatly reduced.

Tolerance to TYLCV was detected in PI 126935 of Lycopersicon peruvanum. A
breeding program was begun in 1977 to incorporate this tolerance into the
cultivated tomato. the interspecific hybridization was made using the
mixture-of-pollen technique (Laterrot, 1983). This technique was also used
to produce seed of the first backcross to tomato. The netted-virescent gene,
nv, was used as a marker to select interspecific and backcross progenies.
This breeding program led to the development of F1 hybrid TY-20, which was
released in 1988 for commercial cultivation in the open field (Pilowsky et
al., 1989).

The inheritance of tolerance to TYLCV was determined by crossing line M-60
(TYLCV-tolerant with line 10 (TYLCV-susceptible). Inoculations were made in
F1, F2, and backcross populations by means of vector, Bemisia tabaci.
Genetic data indicated that tolerance was recessive and controlled by five
genetic factors.

Plants of TY-20 have a determinate vine habit. Fruits are flat- round in
shape, with green shoulders, and have an average weight of 110 g. In
addition to tolerance to TYLCV, TY-20 also carries resistance to
Verticillium dahliae (Ve) and Fusarium oxysporum f. sp. lycopersici (I).

Literature cited:

Laterrot, H. 1983 Use of pollen mixture technique in interspecific cross
between Lycopersicon esculentum and L. peruvianum. Tomato Genetics
Cooperative Report 33:3-4.

Pilowsky, M., S. Cohen, R. Ben-Joseph, A. Shlomo, L. Chen, S. Nahon and J.
Krikun 1989 TY-20 - A tomato cultivar tolerant to tomato yellow leaf curl
virus (TYLCV). Hassadeh 69:1212-1215. (In Hebrew, with English summary)>>