| Abstract: | The study deals with an investigation of embryo and endosperm development in seeds of interspecific hybridization betwwn Actinidia deliciosa cv. Hayward (6X) and A. eriantha (2X) and an attempt to hybrid embryo rescure. The average seed number per fruit of hybrid com suitable culture media for in vitro embryo growth and subsequent growth of the seedlings are tested for hybrid embryos from normal and abortive seeds. The highest percentage of seed germination and the best growth of early seedlings are obtained op. MS medium supplemented with 0.5 ppm of IAA and 0.5 ppm of GA3; MS supplemented with 2 ppm of 2ip, 0.5 ppm of IAA and 0.5 ppm of GA3; MS supplemented with of 2ip and 0.5 ppm of GA3. When these embryos, as seedlings, were transferred onto MS supplemented with 0.5 ppm of GA3 and then MS without growth regulators, they readily develop into seedlings with normal leaves and roots, A lot of adventitious buds produced from hypocotyl of some normal and abortive embryos on MS supplemented with 2 ppm of BAP and Ms+ 0.5 ppm IAA+0.5 ppm GA3 further grow into hybrid plantlets. Although various percentage of embryos developed from abortive seeds also germinate, but when inoculated onto media as mentioned in Table l, a number of malformed seedlings form subsequently. The remaining embryos on all the media, however, show limited growth, and eventually either form callus or die. The nature of hybrid seedling is confirmed by cytological test. Half of them showed chromosome number as 4X=116 approx., the rest may have 19, 27, 30, 46, 120, 131, ect. In conclusion, according to embryological and cytological observation on hybrid seeds and seedlings: (I) the cross between Actinidia deliciosa cv. Hayward and A. eriantha appears interspecific incompatibility and compatibility to some extent, (2) normal hybrid seedlings are produced by normal hybrid embryos from normal seeds and abnormal embryos from abortive seeds, and (3) both may induce initiation of adventitious buds from hypocotyl. We suggested that these results may be useful for plant breeding program. |
