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Investigation Of Microspore Culture In Brassica Juncea

Posted on:2014-09-19Degree:MasterType:Thesis
Country:ChinaCandidate:X K GuFull Text:PDF
GTID:2253330401478701Subject:Vegetable science
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As an important method of genetic breeding and basic research, isolated microspore culturetechnique has been widely applied in Brassica crops. However, the study on microspore culture inBrassica juncea started relatively late and is still in the preliminary exploration stage. Relevantresearches were less and mainly focused on oil mustard. In order to further improve the microsporeculture system and promote its application in breeding and basic research in Brassica juncea,36genotypes were used as experimental materials to study the main internal and external factors thataffected the results of microspore culture in Brassica juncea (L.) Czern. Some factors includinggenotypes, heat shock, plant growth condition and exogenous ABA were investigated in microsporeculture in Brassica juncea. Flow cytometer (FCW) was used to identify the ploidy of two populations ofmicrospore-derived plants. The results are as follows:1. Microspores in the late uninucleate stage were prismatoidal and characterized with three obviousgerminal furrows. Their size was bigger than those in mid-uninucleate stage. Thesecharacterizations can be used for microscopic examination to identify the microspores in lateuninucleate stage.2. Generally,2~3mm buds were suitable for microspore culture in Brassica juncea. But theappropriate length of buds depended on genotypes.3. The ability of embryo yield was quite different among36different genotypes. Sixteen of themproduced embryos. The ratio of embryo induction was44.4%. V03B0097and A12959gave5.87embryos per bud and5.54embryos per bud respectively, the highest among the16genotypes. Theother14genotypes yielded relatively less embryos. Genotype was the key factor that determinedthe results of microspore culture in Brassica juncea.4. The appropriate heat shock condition was genotype-dependent. Different genotypes had their ownoptimal heat shock condition. Relatively,35℃heat shock for3days was appropriate formicrospore culture in Brassica juncea. But it was not suitable for all genotypes.5. Low growing temperature-25.7℃/14.25℃(average maximum temperature/average minimumtemperature)-of donor plants was appropriate for microspore culture in Brassica juncea.6. Genotypes responded to exogenous ABA differently: Compared with control, V03B0097had ahigher rate of embryogenesis after treated with10uM ABA and V03C0001had a lower rate ofembryogenesis at any level of ABA in the experiment. As for V03A0223, V03C0021and A10801,there were no significant differences between ABA treatment and control. Long-term treatment withexogenous ABA was harmful for microspore culture in Brassica juncea.7. Microspore-derived plants from V03B0097and A12959consisted of haploids (1n), diploids (2n)and chimaera (1n+2n). The natural doubling rate of Brassica juncea was low. The rate ofV03B0097was21.52%and the rate of A12959was5.39%.
Keywords/Search Tags:Brassica juncea, Microspore culture, Genotype, Heat shock, Exogenous ABA, Ploidy identification
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