菜心和芥蓝种间杂交创制异源四倍体蔬菜种质

通过菜心和芥蓝的种间杂交可丰富遗传背景,创新种质资源,但由于受精合子发育障碍,需对种间杂种进行胚挽救,才能获得后代。以菜心作为母本,芥蓝作为父本,进行种间杂交,于杂交后取种间杂种胚进行人工培养,设置5种不同胚挽救培养基,6个不同取材时间,4种不同生根培养基,3种不同染色体加倍方式,筛选适合的种间杂种胚挽救方式、增殖扩繁方式、染色体加倍方式,提高种间杂种获得率。结果显示,ERM₄(MS+0.5 mg·L^-1 6-BA+0.5 mg·L^-1 NAA+1.0 mg·L^-1 KT+1 g·L^-1 AC)出胚率为10.47%,为最佳胚挽救培养基;授粉后12 d为最佳取材时间,出胚率为26.32%;RM₄(1/2MS+0.5 mg·L^-1 IBA)生根率最高、生根时间最短,为最佳生根培养基;秋水仙碱涂抹生长点5次,染色体加倍率可达62.26%,为最佳染色体加倍方式。通过形态学鉴定、染色体分析、倍性鉴定等方法,对F₁代杂种植株进行鉴定,结果显示,所得杂种为真杂种,可育株为异源四倍体。异源四倍体蔬菜种质的成功创制为后续育种研究奠定了基础。

Creation of allotetraploid vegetable germplasm by interspecific hybridization of Brassica rapa L. ssp chinensis var. utilis Tsen et Lee and Brassica oleracea var. Alboglabra

Hybridization between Brassica rapa L. ssp chinensis var. utilis Tsen. et Lee and Brassica oleracea var. Alboglabra can enrich genetic background and innovate germplasm resources. However, due to the dysplasia of fertilization zygote, embryo rescue of the interspecific hybrid is necessary to obtain the offspring. The interspecific hybridization was performed using Brassica rapa L. ssp chinensis var. utilis Tsen. et Lee as female parents and Brassica oleracea var. Alboglabra as male parents. Hybrid embryos were harvested for artificial culture after crosses. In this experiment, five kinds of mediums, six different sampling time, four kinds of rooting mediums and three kinds of chromosome-doubling manner were set. Suitable interspecific hybrid embryo rescue methods, proliferation and expansion methods, and chromosome doubling methods were selected to improve the hybrid acquisition rate. The results showed that embryogenesis rate of ERM₄ (MS+0.5 mg·L^-1 6-BA+0.5 mg·L^-1 NAA+1.0 mg·L^-1 KT+1 g·L^-1 AC) was 10.47%, used as the optimal embryo rescue medium. 12 d after pollination was the best sampling time since the embryogenesis rate was 26.32%. RM₄ (1/2MS+0.5 mg·L^-1 IBA) had the highest rooting rate and the shortest rooting time, which was the best rooting medium. The method that applied at growth points 5 times with colchicine, was the best chromosome-doubling manner, in which chromosome doubling rate reached to 62.26%. And then the F₁ generation hybrids plants were identified through morphological identification, chromosome analysis and ploidy identification. The results showed that the hybrids obtained in the experiment were true hybrids, and the fertile plants were allotetraploidy. The successful creation of allotetraploid vegetable germplasm laid a foundation for subsequent breeding research.