Researches On The Related Technology Of The Germplasm Innovation Of Disease Resistance In Turnip (Brassica Campestris L.ssp.Rapifera Sinsk)

Turnip (Brassica campestris L. ssp. rapifera Sinsk, syn. B. rapa L. ssp. rapifera), a subspecies of Brassica genus in Cruciferae, is one of the vegetables and feed crops in China, and is widely cultured in Wenzhou, Zhejiang province. However, its yield and quality is affected badly because of the infection of turnip mosaic virus (TuMV). So far, conventional measures such as chemical control and crop rotation can not control the virus effectively, and the traditional breeding for resistance can not solve this problem because of the lack of the resistant materials. With the use of the new breeding strategies such as building the genetically modified plant by transgenic approach, heterosis breeding using male sterile lines and molecular assisted selection in the innovation of the germplasm, the breeding of virus resistance in turnip will be more effectively.In this study, a resistant inbred line 'Naibing 98-1' built by our laboratory, 'Whenzhou-pancai' and other varieties of turnip were used. The regeneration system of turnip ' Wenzhou-pancai' was established by tissue culture, and the disease resistant Ogura CMS lines and the maintenance lines of turnip were obtained by interspecific hybridization and successive backcrosses, and DNA differences between TuMV-resistant and TuMV-sensitive turnip were analyzed by Amplified Fragment Length Polymorphism (AFLP). The main results are as follows:(1) The regeneration system of turnip 'Wenzhou-pancai' was established on 1/2NH/ MS medium (2 % sucrose, 0.8 % agar) supplemented with different combinations of BAP, 2,4-D and AgNO3. The results revealed that MS medium containing 4 mg L-1 BAP, 0.1 mg L-1 2,4-D, and 5 mg L-1 AgNO3 gave the best result for plant regeneration, and the regeneration frequency reached 16.7%.(2) Three disease resistant Ogura CMS lines with fine traits and stable male sterility 'Ogu00-NB-NB-NB-NBA', 'Ogu00-NB-MJ-MJ-NBA', 'Ogu00-NB-MJ- MJ-MJA' and maintainer lines 'Ogu00-NB-NB-NB-NBB', 'Ogu00-NB-MJ-MJ-NBB', 'Ogu00-NB-MJ-MJ-MJB' in turnip were obtained, by interspecific hybridization between Ogura CMS line in Brassica napus and the turnip inbred line 'Naibing 98-1' and the F1 subsequent backcrossing with the inbred lines 'Naibing 98-1' and 'Baimanjing' successively.(3) Based on the responses to TuMV infection, F2 individuals gained from a cross between the TuMV-resistant inbred line 'Naibing 98-1' and the TuMV-sensitive species 'Wenzhou-pancai' were divided into TuMV resistant DNA pool and TuMV sensitive DNA pool by the Bulked Segregant Analysis (BSA). And then the different bands related to the TuMV-resistant gene in turnip were obtained by AFLP analysis of these two DNA pools.