Regeneration Of Rosa Chinensis 'Old Blush' And Studies On Cross Breeding For Rejuvenation Rose Group

Being one of ancient rose species with the recurrent flowering trait, Rosa chinensis'Old Blush'is one of the most important parentages for modern rose cultivars. This study on regeneration of Rosa chinensis'Old Blush'is the basis of understanding the characteristic of seasonal flowering through transformation of roses. Rejuvenation Rose Group, the brand-new rose species with higher stress resistance and aesthetic value, would be cultivated through interspecific hybridization between Chinese native wild species and modern rose cultivars and lay the foundation for further breeding study.During the study period,487 rose species introduced by Beijing botanical garden with the form characteristics and parentages of 423 were documented and the wild fertility were observed for 266 species.The tests of interspecific hybridization were conducted between Rosa sp. (R. spontanea,R. primula,R. xanthina,R. hugonis,R. laevigata) and modern rose cultivars.802 flowers were obtained out of 90 combination in 2008, but only 15 fruits (87 seeds) and one hybrid seedling were harvested due to artificial cutting damage to the fruits.43 fruits (304 seeds) were reaped from more than 1344 flowers by 93 combinations in 2009.A protocol for in vitro propagation using direct induction of shoot buds from leaf explants of in vitro-raised shoots of Rosa chinensis'Old Blush' was carried out. Nodal explants were cultured on a solid initial medium [MS+2.5mg/L 6-BA+0.15mg/LNAA]. Elite plants maintained for half year in vitro on a shoot multiplication Murashige and Skoog(MS) medium supplemented with 1.Omg/L 6-BA and 0.1mg/L IBA were used. Petioles from fully developed young leaves were found to be ideal for regeneration of shoots. The highest shoot regeneration response (9.5%) when shoots were kept in the induction medium [MS+1.5mg/L TDZ+0.05mg/L NAA+10mg/L AgNO3+100mg/L CH+600mg/L L-proline] for 30d under the weak light (113.2-114.51ux). Then adventitious buds were raised on shooting medium [MS+0.5mg/L 6-BA+0.01mg/L NAA] and inducted to root on the rooting medium[half-strength MS+O.1mg/L IBA]. The best callus (100%) was obtained on the induction medium [1.0mg/L TDZ+0.2mg/L NAA+20mg/L AgNO3+150mg/L CH or 1.Omg/L TDZ+0.3mg/L NAA+20mg/L AgNO3+150mg/L CH] for 8d under the weak light. Callus was maintained on a multiplication medium [MS+1.0mg/L 6-BA+0.1mg/L NNA+20mg/L Ads or MS+2.0mg/L 6-BA +0.15mg/L NNA+20mg/L Ads].