Study On Mature Wheat Embryos Culture In Vitro

Mature wheat embryos of new wheat varieties R57(ChuanNongl7) and R59(ChuanNongl2) which are important cultivar in Sichuan Province were used as explants for culture in vitro.And the mature embryos of other wheat genotype"Bobwhite" were also used to culture. When mature embryos were inoculated ,some embryonic buds of RS9 and Bobwhite' s mature embryos were removed.The purpose of this study is to construct a high effective system of plantlet regeneration for mature wheat embryos.In this study,the response of RS7 and RS9 to culture was compared with the response of Bobwhite to culture.The general result is following:In this study,a high effective wheat plantlet regeneration system was built. This experiment showed that the callus induction medium supplemented with 2mg/l 2,4-D,callus induction time of 14 days and regeneration medium with Smg/1 KT were the best combination and the best explants were mature embryos with embryonic buds.R57 and R59 have a good response to culture.The rate of callus formation of R57' s mature embryos is 77.28%~97.58%,as for R59,the rate is 79.22%-99.33%.The highest frequency of plantlet regeneration of callus initiated from R57' s mature embryos is 73.63%,as for R59,the highest frequency is 89.23%.Few researchers got the same result in previous studies.Harvesting time and treating by low temperature had effect on callus formation.The rate of callus formation of mature embryos excised from seeds harvested hi 2002 was higher than that of mature embryos excised from seeds harvested in 2001 .There was no significant difference in different callus induction media for callus formation of mature embryos harvested hi 2001.But great difference hi different callus induction media wasobserved for callus formation of mature embryos harvested in 2002.During the callus induction, the germination of mature embryos was affected by harvesting time and low temperature treat. It is the first time to report this kind of result The rate of germination of mature embryos harvested hi 2002 was by far higher than that of mature embryos harvested in 2001. In this study,high density of 2,4-D could prevent mature embryos from germinating,but KT could prompt germination.Embryonic bud profited callus formation and differentiation.For R59,significant difference between mature embryos with embryonic buds and those without embryonic buds was observed for callus initiation and differentiation.For Bobwhite,there was no difference between the two kinds of mature embryos for callus formation,but great diference was observed for plantlet regeneration.There were no reports about the effect of embryonic bud on callus initiation and plantlet regneration in previous studies.There was great difference between RS7 and Bobwhite for callus initiation and plantlet regeneration from mature embryos with embryonic bud.Bobwhite was better than R57.But for the same case.there was no great difference between R59 and Bobwhite.So far as mature embryos without embryonic buds was concerned,there was no significant difference between R59 and Bobwhite for callus formation,but great dufference was observed for plantlet regeneration and Bobwhite was better than R59.The new wheat varieties R57 and R59 have an excellent character for culture in vitro.And they have good agricultural trait.So they are good acceptors for transgenic wheatThe method of mature wheat embryos culture in vitro found in this study can be reference for other researchers.