The effect of ovule age on ovary-slice culture and ovule culture in intraspecific and interspecific crosses with Tulipa gesneriana L.

The efficiency of two embryo rescue techniques, direct ovule culture and ov ary-slice culture followed by ovule culture, is studied in crosses with Tul ipa gesneriana as maternal genotype. The germination percentages increased, in most cases, significantly with increasing ages of te ovary-slices and o vules at the start of the cultures. The low number of embryos recovered at early culture dates is caused by a higher rate of embryo abortion and by re tarded embryo development. The germination percentages for ovary-slice cult ure followed by ovule culture was mostly comparable to direct ovule culture . Unique hybrids have been obtained from the crosses T. gesneriana x T. age nensis and T. gesneriana x T. praestans.