The Selection Of New Germplasm And The Construction Of The Isolated Regeneration System

Common bean,an edible bean originating from South America,possess the second largest cultivated area only after soybean in the world.Common bean mainly distribute in Asia,America,eastern Africa,western and southeastern Europe.It is also widely planted in China,where in the crop production areas,common bean can be mutually introduced and cultivated.Common bean is one of the main export agricultural products in China,with the annual export volume amounting to 1 million tons.At present,there are few researches on screening and in vitro regeneration of drought-resistant common bean germplasm in China.In this study,we firstly analyzed the 30 common beans drought resistance by the drought resistance index method.Then using the selected drought-tolerant cultivars we constructed an in vitro regeneration system,which can be used for the transgenic study of drought-resistant common bean.The main results of this research are listed below.1.The drought-related indicators are distinctively different among different materials,such as seed germination rate,fresh weight of above-ground parts,fresh weight of underground parts,leaf water content,conductivity,chlorophyll fluorescence and so on.The association degree between the 7 indices(germination rate,fresh weight,fresh weight,the whole plant fresh weight,conductivity and Fv/Fm)and the comprehensive drought resistance index are greater than 0.8.This result indicates that these indices are closely related to the comprehensive drought resistance index,which can be used as the main indicators in the identification of the drought resistance of common bean seedling.2.The results of fuzzy membership function analysis show that the drought-resistance value of barley bean(F3370)and black eel bean(F4845)are more than 0.6,indicating its the stronger drought resistance germplasm.The drought-resistant value of Dajinhuadou(F3260),Xiaozadou(F0666),Sijidou(F0708),Hongzhuangdou(F0671),Bihuadou(F3010)are less than 0.4,indicating its water sensitive material.3.The seeds pollution rate was significantly deduced when common bean seeds were treated with high concentrations of mercuric chloride for longer time in during common bean seeds germination stage.But this treatment seriously damaged the seeds and reduced the germination rate.The desirable treatment was 0.1% mercuric chloride for 5min,witch maintained the seed contamination rate below 24% and seed germination rate above 80.7%.4.Medium significantly affected the seed germination.The seed germination in 1×MSB5,1×MS and 1×B5 were 83%,76.7%,69.3%,respectively.5.Hormones promotes induction shooting from common bean embryonic tip and cotyledon node.The best hormone added to MSB5 medium was 1.0 mg/L 6BA for the cotyledon node shooting induction,which can get the highest shooting rate(73%).The best embryo germination induction rate(81%)can be achieved by supplementing 1.0mg/L of 6BA and 0.5mg/L of NAA in the MS medium.6.The callus induction rate was different in different explants treated with different hormones in 1×MSB5 mediums.When 0.2 mg/L 6BA and 3mg/L 2,4-D were added into medium,the maximum induction rate of hypocotyls is 76.3%.When 0.3 mg/L NAA and 1.0 mg/L 2,4-D are added into medium,the maximum induction rate of cotyledon node is 28.7%.When 0.3 mg/L NAA and 1.0 mg/L 2,4-D are added into medium,the maximum induction rate of embryonic tips is 32.7%.7.Hormones promote the proliferation of the adventitious buds from embryonic tip and cotyledon.The best medium for the proliferation of the adventitious buds from cotyledon node was MSB5 medium added 1.0 mg/L of 6BA,the highest proliferation rate was 73%.The best medium for the proliferation of the adventitious buds from embryo was MS medium added 1.0 mg/L of 6BA and 0.5 mg/L of NAA,the highest proliferation rate was 81%.8.When adventitious buds are transferred to 0.5×MS agar medium supplemented with 0.5 mg/L of IBA and 1.5g/L of activated carbon,most of the adventitious buds can root,the maximum rooting rate was 81.3% for embryo adventitious buds,and 77% for cotyledon node adventitious buds.