INTRODUCING NEW GENES INTO 'THOMPSON SEEDLESS' GRAPES

Abstract

'Thompson Seedless' is the major common grape cultivar in Egypt for its adaptation to local environmental condition in addition to its widely acceptance by local consumers. New introduced colored seedless cultivars such as 'Beauty Seedless', 'Flame Seedless' and others exhibit good appearance but with less acceptable taste therefore it was of great importance to introduce color and flavor of the new cultivars into 'Thompson Seedless'. Hybridization of seedless seedless will result in seedless hybrid and needs a tool such as embryo rescue to germinate the aborted embryo. The objectives of this study were to rescue embryos of 'Thompson' and 'Beauty Seedless' grape cultivars and to define the optimal age and size to isolate the embryo as well as the best media for planting under in vitro conditions. Embryo germination reached its maximum values at the 7 th and 8 th week after fruit set. MS, WP and B5 plant media produced the highest percentage comparing to WH and NN ones on the period from the third week till the 9 th week after fruit set. WPM induced the highest embryo germination (85%) at the 7 th week AFS. A correlation study was made between embryo length and embryo survival and germination for both cultivars. Embryo formation appeared two weeks after fruit set and developed normally until it reached its maximum length at 7 and 8 weeks after fruit set. Embryo abortion clearly occurred 9 and 10 weeks after fruit set when embryo length dropped until it completely degraded.