유채 잡종 1세대의 소포자 배양에 의한 배가반수체 집단 선발 및 지방산 조성 분석

Production of doubled haploid population derived from the microspore culture of rapeseed (Brassica napus L.) F1 generation and analysis of fatty acid composition

Brassica napus, an oil crop that produces rapeseed oil, is an allotetraploid (AACC, 2n = 38) produced by natural hybridization between B. rapa and B. oleracea. In this study, microspore was cultured using the F1 developed from a cross between ‘EMS26’ line with high oleic acid content and ‘J8634-B-30’ lines. The flower bud size showing the nuclear development at the late uninucleate and binucleate stage with high embryogenesis rate was 2.6 ~ 3.5 mm. Microspores were cultured using only this size and after then most microspore embryo developed into secondary embryos and then regeneration plants obtained from the developed multilobe. The analysis of the ploidy of the plants revealed that 66.7% and 27.8% of the total lines were tetraploids and octoploids, respectively. The sizes of stomatal cells in tetraploids, octoploids, and diploids were 25.5, 35.6, and 19.9 μm, respectively, indicating that ploidy level was positively correlated with cell size. Furthermore, 62 tetraploid doubled haploid (DH) lines were selected. The average oleic acid (C18:1) and linolenic acid (C18:3) concentrations of DH were 72.3% and 6.2%, respectively. Oleic acid and linolenic acid concentrations exceeded the two parental values in 5 and 14 DH lines, respectively, suggesting that these two fatty acids had transgressive segregation. Therefore, the DH population can be utilized for the biosynthesis of unsaturated fatty acids in rapeseed and related genes. It can also be used as a breeding material for varieties with high oleic acid concentrations.