摘要
甘蓝型油菜品种奥罗×蓝花子杂种Ｆ-１，平均配对构型为１２．１Ⅰ＋６．５３Ⅱ＋０．４１Ⅲ＋０．１８Ⅳ＋０．１８Ⅴ，Ａ、Ｃ染色体组与Ｒ染色体间存在配对，它们之间具有一定的同源性。在甘蓝型油菜与蓝花子的杂种Ｆ-１代中，存在一种染色体不配对的减数分裂类型。这一类型中有少量可形成平衡的不减数配子。提供了油菜与蓝花子远缘杂种回交结实的细胞学根据。在ＭＳ＋０．２ｍｇ／ＬＮＡＡ＋３ｍｇ／ＬＢＡ＋１ｇ／Ｌ秋水仙碱＋３０ｇ／Ｌ蔗糖＋８ｇ／Ｌ琼脂的培养基中，接种甘蓝型油菜奥罗与蓝花子的杂种Ｆ-１进行加倍处理，经快速繁殖后，获得大量的染色体数为２ｎ＝５６的双二倍体幼苗。上述双二倍体自交结实，在减数分裂中绝大多数细胞形成２８个二价体，个别形成２６个二价体和１个四价体。上述技术在油菜与蓝花子远缘杂交中首次解决了用常规方法不易获取远种杂种稳定双二倍体的难题。甘蓝型油菜品种Ａｌｔｅｘ×蓝花子杂种Ｆ-１代，长时间的快速繁殖后，出现了染色体丢失和加倍，有形成１９条染色体的配子回复到甘蓝型油菜染色体组成的趋势。在油菜远缘杂种中发现了类似于球茎大麦远缘杂种中染色体丢失的现象。
In the F_1 obtained from the cross between B.napus cv Oro and R.Sativus var.oleifera,the average meiotic association was 12.11+6.35Ⅱ+Ⅲ+0.18Ⅳ+0.18Ⅴ,the mean number of pairing chromosomes was 15.9.The chromosomes of genome A and C may make pairing with those of genome R.The genes may be exchanged between A or C genome and R genome.Another type of meiosis was found in the F_1 PMC,where no chromosome pairing could be detected.Some balanced or nearly balanced gametes might be formed in this type.This might be the reason why progenies could be obtained after backcross.In another F_1 hybrid obtained from the cross between B.napus cv.Altex and R.sativus var.oleifera,23-28 bivalents were found in the PMC.At the anaphaseⅠ,19 chromosomes gathered in one pole.They may rescome back to the genome of B.napus.F1 hybrids obtained from the cross between B.napus cv.Oro and R.sativus var.oleifera were cultured on the medium(MS+0.2mg/L NAA+3mg/L BA+1g/L colchicine+30g/L sugar+8g/L agar)to douoble the chromosomes.After 5 days,many plantlets containing 56 chromosomes were obtained.This was the first time in obtaining stable amphidiploids in the hybridization between Brassica and related species which were difficult to be obtained with the conventional method.In the PMC of the amphidiploids 28 bivalents were formed and occasionally 26 bivalents and 1 quadrivalent were also found.This may be due to that there are homologous or homoeolgous chromosomes with in one genome or between two genomes of the amphidiploid.
关键词
甘蓝型油菜
蓝花子
双二倍体
远缘杂交
Biassica napus,Raphanus sativus var.oleifera,Partical amphidiploid,Wide hybridization
