Tomato Leafs Yellow Curl Virus (TYLCV) is one of the most world important begomovirus. It predominates in Cuban tomato producing regions and can caused losses of 100%.Variability stidies have proved the presence of an unique isolated of TYLCV-Israel corresponding to the one previously identified. Genetical control is the best alternative.

The present work includes: the characterization and recommendation of resistence genetical sources; Lycopersicon chilense resistence introgression; the established conditions for a technique to interespecific embryos in vitro rescue; the agroinoculation of viral DNA and the molecular diagnose for the rapid and precise detection of asymptomatic plants and the resitence testing in promissory genetical materials.

The genetical efficiency of the proposed improving model was validated through the estimation of genetical and statistical parameters for resitence indicators (severity and incidence before TYLCV) and the agronomical characteristics, as well as through the practical confirmation, by means of the obtention, for the first time in Cuba , of 4 resitent lines, asymptomatic after getting infected by viruliferous vectors and grafting, and with low accumulation of viral DNA (0.09 ng, inferior than what was informed as Israel, a pioneer in improvement, up to 1ng).

Resitence heritage model was determined, with incomplete dominance, controled by Ty—1 gene. The presence of such gene was confirmed in 3 of the selected lines, using RFLPs type markers revealed by TG 97 y TG 297, reported in literature due to its relation to this locus. A second variant conditioning the asymptomatic resistence in a comercial hybrid and in the other selected line, results of genetical and improving interests.

The obtained resistent lines showed a remarkable climatic adaptation, non affected by the infection, according to the agronomical tests; one of these was released in 2000 as a resistent variety (“Vyta”) in absence viral vector chemical control. This variety produced an economic effect of 354 00 USD during the last season. The selected lines were used in the obtention of eight Cuban F1 hybrids, which have been validated abroad (Italy, Spain, Trinidad and Tobago and Martinique) and are under extending process in protected cropsd national facilities.

There were published: 10 articles in scientific journals (from them, 2 with high impact factor and 5 prestigious foreigner journals), 1 scientific work with an international group of authors and 2 handbooks.