Interspeci®c hybrids between Lilium nobilissimum and L. regale produced via ovules-with-placental-tissue culture

Reciprocal pollination was made between Lilium nobilissimum and L. regale. Pollen tubes reached the base of style within 144 h after pollination, but no mature seeds were obtained in either cross combination. Explants, or ovules-with-placental-tissue excised from each carpel 30 and 40 days after pollination (DAP), were cultured on a medium composed of major salts of B-5 macronutrient (Gamborg, O.L., Miller, R.A., Ojima, K., 1968. Exp. Cell Res. 50, 151±158), micronutrient, Fe-EDTA and vitamins of MS (Murashige, T., Skoog, F., 1962. Physiol. Plant. 15, 473±497), 5% sucrose and 0.2% gellan gum. In L. regale Lilium nobilissimum, 3% of ovules excised at 30 DAP and 9% of those excised at 40 DAP developed into seedlings. In Lilium nobilissimum L. regale, only 3.6% of ovules excised 40 DAP developed into seedlings, and none of the ovules excised 30 DAP produced any seedlings. Bulbs of L. regale and hybrids transplanted to soil showed some resistance to bulb-rot, leaf-top scorch, browning spots and/or streaking on leaves, but those of Lilium nobilissimum were sensitive to these diseases. Flowering individuals were nearly intermediate between parents in their morphological characteristics. All ̄owering individuals (2n ˆ 24 chromosomes) were identi®ed as hybrids based on karyotype, isozyme and random ampli®ed polymorphic DNA analyses. # 2000 Elsevier Science B.V. All rights reserved.