Development of an empirical relationship for chemical mutagen induced lethality in zygotic embryos and microspore embryogenesis from mutant donor plants of Indian mustard (B. juncea)
The haploid mutagenesis has not been exploited for crop improvement in Indian mustard (Brassica juncea) as yet and information for LD50 of chemical mutagens is not available. The present study was thus undertaken to understand the relationship between mutagen concentration, exposure duration and survival of zygotic embryos along with evaluation of microspore totipotency of the mutant donor plants. Three Indian B. juncea genotypes, Pusa Bold, Varuna and BIO-902, were tested for varying mutagen concentrations (5-50 mM) and exposure durations (10-50 h) of three chemical mutagens, Ethyl methanesulfonate (EMS), Ethyl nitrosourea (ENU) and Ethidium bromide (EtBr), to study the effect of mutagen exposure on zygotic embryos. The seeds, after mutagen treatment, were rinsed with sterile water, cultured on Murashige and Skoog basal medium, incubated at 25 ± 2 ℃/16 hours photoperiod, and scored for percent survival afer 15 to 20 days. Exposure to EtBr resulted in 100％ mortality. The survival data from ENU and EMS treatments was subjected to orthogonal contrast partioning ANOVA for determining the relationship between the dependent (survival) and the independent variables (concentration, linear to quartic and duration, linear to cubic orthogonal polynomial). Both genotypes showed a similar response for percent survival after EMS/ENU treatment, however, significant variation was caused individually and by interaction of the concentration and exposure duration for both the mutagens. The mutagen concentration for both mutagens had a linear relationship with percent survival while the exposure duration had a non-linear relationship with the latter. Multiple regression analysis was carried out to develop prediction functions for EMS/ENU treatment survival and this revealed that log transformation of the percent survial data resulted in linearizable non-linear regression equations that adequately explained the relationship between the dependent and the independent variables. Using these equations the LD50 for zygotic embryo mutagenesis for 20h exposure duration ranged from 3.5mM for ENU to 6.8mM for EMS. This information was used to generate mutant donor plants for microspore culture. The microspores from ENU treated donor plants, irrespective of the genotype, were recalcitrant to embryogenesis, while 48.8％ EMS mutant donor plants produced 2.9 ± 0.36 embryos per Petri dish (total 943 embryos). Genotype comparison revealed that mutant donor plants of the three genotypes had similar microspore embryogenic response.
Indian mustard Brassica juncea LD50 multiple regression haploid mutagenesis
Deepak Prem Kadambari Gupta Gautam Sarkar Abha Agnihotri
Plant Biotechnology, TERI, Darbari Seth Block, IHC Complex, Lodhi Road, New Delhi, 110003, India
国际会议
第十二届国际油菜大会( The 12th International Rapeseed Congress)
武汉
英文
360-363
2007-03-26（万方平台首次上网日期，不代表论文的发表时间）