Evaluation Of Garlic Germplasms Based On Morphological Characters, Induction And Regeneration Of Calluses And Culture Of Protoplasts Of Garlic

A total of 71 garlic(Allium sativum L.)accessions were collected from various parts of China,Korea and European countries.All cultivars were planted at Zhejiang University Experiment Farm in October,2007.Morphological characters were measured before planting and during growth stage.Cluster analysis was used to determine the relationship among three different groups:China,Korea and European countries.The results indicated that the weight of bulb,the days to seedling emergence and the days to flower stalk apperarance were important components for analysis.Four major clusters were revealed by using principal components and cluster analysis procedures,garlics from Korea and European countries were closely related to those from China.Callus induction from stem-disc,shoot tip and other explants from garlic plants was investigated in this experiment.Calluses were induced when the explants were inoculated on MS or B₅ media supplemented with various levels of 6-BA in combination with 2,4-D. Media with different levels of 6-BA and 2,4-D gave significant differences in the induction of calluses.2,4-D was found to be key factor for callus induction and subculture.0.1 mgl^-1 6-BA+1.0 or 2.0 mgl^-12,4-D was favorable to callus induction from stem disc.The results revealed that 1.0 mgl^-12,4-D was suitable for callus propagation and maintaince. Adventitious shoots and roots formed more easily on medium MS+0.1 mgl^-16-BA+1.0 mgl^-1NAA,approximately 8 shoots and 6 roots produced per explant.The survival rate of plantlets under ex vitro condition was 80%in pots filled with a peat:sand(1:1 v/v)mixture after 15d.Results from this study demonstrated that plantlet regeneration of garlic could be reached using calluses derived from stern-disc.The protoplast culture was also studied using calluses,young leaves and embryogenic cell suspension culture of garlic.Embryogenic suspensions had been found to be a better source of material for protoplast isolation and 0.5mol 1^-1mannitol was more benefit to protoplast isolation.This study emphasized on enzyme combinations and digestion duration for protoplast isolation by calculating the yield of protoplasts and assessing viability of protoplasts.The results showed the best enzyme combination was 2%cellulase Onozuka R-10 and 0.2%pectinase Y-23 for 6h.No callus formation was observered from the protoplasts until now.