Research On Establishment And Optimization Of Regeneration System From Different Explants Of Proso Millet

Proso millet(Panicum miliaceum L.)was the oldest crop originated from China.Recently,proso millet also was the important dominant crop and featured crop of dry farming region in northern China.Its grains were rich in nutrients and become a healthy food source to improve the dietary structure.But it was the adjustment of crop-planting structure and the difficulties in cross breeding of proso millet,which caused the decrease of proso millet yield and the limitation of the production level.At present,the tissue culture of proso millet was the exploration stage,and unable to meet the actual production needs.Hence,it would be an efficient method that the establishment of in vitro culture and regeneration system of proso millet by using the plant tissue culture technology.In the study,the young spike,immature embryo and young leaf of Shaanmi 1 and Shaanmi 2 were used for explant,and they would be placed the MS medium and N6 medium with different kinds and concentrations of hormones,in order to induce callus,differentiation,and rooting,the result showed:(1)In the callus induction of proso millet from young spike,the MS medium had an advantage of inducing callus of young spike.This study proved that adding a content of KT could improve the callus embryogenic capability.The highest callus induction frequency of young spike was reached when 2,4-D was 2.5 mg/L and KT was 1.0 mg/L,and the calli induction frequency of Shaanmi 1 and Shaanmi 2 were up to 85%.(2)Study on callus induction of immature embryos of proso millet showed: the callus induction effect of MS medium is better than that of N6 medium.The 4 ℃ pretreatment of3 days could increase the callus induction frequency of young spike efficiently.The optimal medium was MS+2,4-D(3.0 mg/L)+KT(1.0 mg/L)to induce callus of immature embryo of Shaanmi 1 and the optimal medium was MS+2,4-D(3.0 mg/L)+KT(0.5 mg/L)to induce callus of immature embryo of Shaanmi 2.(3)In the callus induction of proso millet from young leaf,the culturing time of asepsis seedling could influence on the callus induction,and we found that the highest frequency of callus induction was obtained when the culturing time was 7 days.The N6 medium had an advantage of inducing callus of young leaf.The callus of Shaanmi 2 was induced in the N6 medium without 2,4-D,and the callus induction frequency was 6.45%,meanwhile the callus induction of Shaanmi 1 was 0.Compared all the treatment,the optimal medium to induce callus of young leaf of proso millet was N6+2,4-D(3.0mg/L)+KT(0.5 mg/L),and the calli induction frequency of Shaanmi 1 and Shaanmi 2 were64.33%,68.67% respectively.(4)In the callus diffierentiation and regeneration of proso millet from young leaf,the optimal differentiation medium was MS+6-BA(1.0 mg/L)+NAA(0.5 mg/L),and the rate of differentiation of Shaanmi 1 was 87.78% and that of Shaanmi 2 was 96.29% respectively.Adding proline of 600 mg/L was conducive to callus differentiation.The optimal rooting medium of proso millet was 1/2MS+NAA(0.1 mg/L)and the rooting rate was 100%.