芥蓝和结球甘蓝分别与甘蓝型油菜杂交的后代结实性及Rfo传递效率比较

Comparison of Seed-setting and the Transmission Rate of Rfo During the Distant Hybridization of Chinese Kale × Brassica napus and Cabbage × B. napus

为明确甘蓝与甘蓝型油菜种间杂交的生殖隔离程度是否与甘蓝的变种类型有关,以2份Ogura CMS芥蓝和4份Ogura CMS结球甘蓝为母本,分别与2份含有Ogura CMS育性恢复基因Rfo的甘蓝型油菜杂交,获得的种间杂种加倍后,再分别与母本芥蓝和结球甘蓝回交,调查F_1、BC_1两个世代材料的结实性和Rfo基因的传递效率。结果表明,芥蓝与甘蓝型油菜种间杂交F_1代、BC_1代的亲和指数都显著高于结球甘蓝(P<0.05),是结球甘蓝的2倍以上,且在芥蓝材料中Rfo基因的传递效率高于结球甘蓝。进一步比较BC_1回交后代Rfo阳性单株的育性、遗传背景回复率,芥蓝的育性大多显著好于结球甘蓝(P<0.05),26株BC_1单株遗传背景回复率在0.50~0.84之间;而结球甘蓝两个BC_1单株(15Y1和15Y4)遗传背景回复率分别为0.53和0.59。上述结果说明,芥蓝较结球甘蓝更易与甘蓝型油菜杂交获得后代,且异源目的片段的传递效率更高,因此芥蓝可作为结球甘蓝与甘蓝型油菜杂交的桥梁材料,加速甘蓝型油菜中优异性状的转育进程。

In order to determine whether the seed-setting of distant hybridization between Brassica napus and B. oleracea is affected by different B. oleracea sub-species or not,in this study,two Chinese kale and four cabbage materials with Ogura CMS cytoplasm were crossed with two homozygous rapeseed restored lines harboring the Ogura CMS fertility-restored gene Rfo. The F_1 interspecific hybrid plants with doubled chromosome were backcrossed with Ogura CMS Chinese kale and cabbage to produce BC_1 plants,respectively. The seed-setting and the transmission rate of Rfo of Chinese kale × rapeseed cross combinations（CKR）and cabbage × rapeseed cross combinations（CR）were investigated in two generations,respectively. The results suggested that the compatibility index of CKR was two folds higher than that of CR,with significant difference between CKR and CR in two generations（P 0.05）. In addition,the Rfo gene transmission rate of CKR was higher than that of CR. The pollen viability and recovering ratio of genetic background（RRGB）of all BC_1 Rfo-positive individuals obtained from CKR and CR were assessed. The pollen viability of most BC_1 Rfo-positive individuals obtained from CKR were significantly higher than that of the two Rfo-positive individuals obtained from CR（P 0.05）. The RRGB of 26 Rfo-positive individuals obtained from CKR were 0.50–0.84. While the RRGB of two Rfo-positive individuals（15 Y1 and 15 Y4）obtained from CR were 0.53 and 0.59,respectively. Our results revealed that compared with cabbage,Chinese kale is much easier to produce progenies when crossed with B. napus and the transmission rate of alien fragment was much higher. Therefore,Chinese kale could be used as a bridge to accelerate the process of the beneficial agronomic traits transfer from B. napus to cabbage.