Micropropagation and sanitation of Citrus sinensis L. Osbeck from CTV-infected fruits

Plant sanitation is an important tool to ensure disease-free plants, particularly for genetic breeding and germplasm conservation programs. Citrus Tristeza Virus (CTV) is a destructive disease that affects the quality of the seed and causes the plant death. Therefore, it is important to develop a protocol for propagating CTV-free Pineapple sweet orange (Citrus sinensis L. Osbeck) plants from infected fruits. When the seed coat was treated with 2% sodium hypochlorite and thermotherapy process at 52°C, not CTV was detected. Similarly, seedlings germinated in vitro were negative for CTV after receiving treatment. In addition, 6.9 adventitious shoots were produced using epicotyl with cotyledons as explants in the culture medium supplemented with 1.0 mg L-1 of 6-BAP + 0.5 mg L-1 of IBA. Furthermore, the highest rate of in vitro rooting percentage was 86% with 4.4 roots per explant using 1.0 mg L-1 of IAA + 0.5 mg L-1 of IBA. The plantlets in vitro rooted and acclimatized showed grafting success with high survival percentages (above 92%). The results of the study allowed us to develop a seed coat sanitation protocol to eliminate the CTV in micropropagated of Pineapple sweet orange plants.