Production of Sexual Hybrids Nicotiana rustica X N. tobacum via in vitro Culture .of Fertilized ovules.

배주배양에 의한 Nicotiana rustica와 N. tabacum의 잡종식물 육성

The present study examined various environmental and cultural media conditions for in vitro "rescue" of cross-fertilized ovules formed through sexual crosses between Nicotiana rustica and N. tabacum cv. BY4. The response ovules to two cultural procedures was compared; ovules were cultured either separately or left attached to the placenta. Total yield of seedlings and percent of normal seedlings were increased by culturing individual ovules separately, rather than on excised placenta. Total yield of seedlings and number of normal seedlings were produced following in vitro culture of individual fertilized ovules of N. rustica X M tabacum cv. BY4 at four days post-pollination on NN medium containing 2% sucrose. In the in vitro culture of fertilized ovules, high sucrose concentration increased the frequency of seedlings of abnormal appearance. Therefore, sucrose should be supplied to developing ovules at gradually decreased concentrations. Culture of fertilized ovules from three to eight days after pollination gave increased number of seedlings, but with delayed cultral time the number of morphologically normal seedling were decreased. Hybrids were uniform in appearance and showed vegetative heterosis but flower characteristics were generally intermediate between those of the parents. All hvbrids evaluated were self-sterile.f-sterile.