Influence of the sex of flowers on androgenesis in Aesculus hippocastanum L. anther culture

Flowers of Aesculus hippocastanum L. are bisexual and zygomorphic, and are positioned on a 20-30 cm long inflorescence. Those located in the basal par t of the panicle are female and fertile (segment A), flowers in the middle are bisexual (segment B), and those on top of the panicle are male (segment C). Androgenesis was achieved in anther culture which originated from thre e types of flowers cultured on modified Murashige and Skoog medium containi ng 2,4-dichlorophenoxyacetic cid (4.5 muM) and kinetin (4.6 muM) Difference s in viability of uninuclear microspores were found between female (90.0%) and other flowers (bisexual 61.1%; male 72.7%). Both the percentage of embr yogenic anthers and the number of androgenic embryos formed per inflorescen ce differed according to the segment of origin. The highest embryogenic res ponse was obtained in segment A (47.3%) and the lowest in segment C (24.1%) . A significant difference was found between the number of androgenic embry os formed per inflorescence in segments A (921.0) and C (286.7). The highes t germination percentage (21.3%) and plantlet formation (41.0%) were obtain ed on woody plant WPM liquid medium supplemented with 1% activated charcoal . Acclimation and regeneration were Lest from plantlets originating from fe male flowers (62.5%). Plantlets originating from bisexual and male flowers have much poorer survival (29.3 and 22.2%, respectively).