Evaluation of the susceptibility of some local hybrids of Capsicum to infection with Tomato yellow leaf curl virus (TYLCV) in protected cultivation condition

The research was carried out at the Scientific Agricultural Research Center in Lattakia Governorate during the 2020-2021 agricultural season within a greenhouse under protected conditions. The aim of the research was to study the effect of Tomato yellow leaf curl virus (TYLCV) on some growth indicators of several hybrids of locally grown pepper under protected cultivation conditions in the Syrian coast. In this experiment, 4 hybrids of pepper were used, 2 Hot (Lahab and Sirad), and 2 Non-Hot/ Sweet (Nevada and Dallas), where a completely randomized block design was followed, the experiment included 8 treatments, 3 replicates, 5 plants per one replicate. The results of the experiment showed that the tomato leaf curl virus infects pepper plants in early stages and that the symptoms resulting from infection at this age stage are severe and increase more with the age of the plant. Non-Hot/Sweet (Nevada and Dallas) were more sensitive and affected by the tomato yellow curl virus than the hot hybrids (Lahab and Sirad), without any significant differences between the hybrids. The edges of the leaves to the top, their small size and the fall of the flowers, which leads to a lack of fruit production and low quality (Dallas), and the effect of the virus differed in terms of symptoms of infection. The Nevada hybrid did not show any outward symptoms, and the effect of the virus on it in the indicators of vegetative growth and productivity (number of flowers, percentage of flower knots and leaf area) was clear compared to other hybrids with non-significant differences. The Dallas, Sirad, and Lahab camels showed symptoms of infection on the leaves of the infected plant, and the infection rate was 93.33, 80, 80%, respectively, in addition to the virus’s effect on them in the previous criteria in varying proportions. After 30days of infection 48.17, 53.06, 16.45, 36.6%, respectively, and also for the decrease in the flowering number of hybrids Nevada, Dallas, Sirad and Lahab after 45 days of infection 33, 31.10, 10.23, 5.07%, respectively, as well as for a decrease of Flower knots 77.39, 20.87, 23.33, and 66.68%, respectively. The percentage of decrease in the wet shoots of the Nevada, Dallas, Sirad and Lahab hybrids was 17.97, 54.99, 5.36, 35.00%, respectively, and in the wet root total of 69.01, 68.65, 26.71, 61.87%, respectively. The virus also caused a decrease in the quality of fruits, both quantitatively and qualitatively, where the highest percentage of decrease in fruit weight was recorded in the hybrid Dallas 70.21% and the lowest in the hybrid Nevada 36.74% within significant differences.