Development of interspecific Solanum lycopersicum and screening for Tospovirus resistance

Tospovirus has emerged as a serious viral pathogen for several crops including tomato. The tomato production is being severely affected worldwide by Tospovirus. Some reports have been published about the association of plant virus and development of human disease either by direct or indirect consumption. Resistance to this virus has been identified as good source in wild tomato species (Lycopersicum peruvianum). But the introgression of resistance genes into cultivated tomato lines and the development of interspecific hybrid are hampered due to incompatibility, fertilization barriers and embryo abortion. But this barrier has been broken by applying the embryo rescue methods. This study describes the development of interspecific hybrid tomato plants by highly efficient embryo rescue method and screening for Tospovirus resistance. The interspecific hybrid tomato plants were developed by making a cross between wild tomato species (L. peruvianum) and cultivated tomato (Solanum lycopersicum). The immature embryos were cultured in standardized medium and interspecific hybrids were developed from embryogenic callus. The immature embryos excised from 7 to 35 days old fruits were used for embryo rescue and 31 days old embryos showed very good germination capabilities and produced the highest number of plants. Developed plants were hardened enough and shifted to green house. The hybrid nature of interspecific plants was further confirmed by comparing the morphological characters from their parents. The F1, F2 and F3 plants were found to have varying characters especially for leaf type, color of stem, fruits, size, shapes and they were further screened for virus resistance both in lab and open field followed by Enzyme linked Immunosorbant Assay confirmation. Finally, a total of 11 resistant plants were selected bearing red color fruits with desired shape and size.