花椰菜—黑芥体细胞杂种的性状演变和对黑腐病抗性的转育

以对黑腐病(Black rot)感病的花椰菜(Brassica oleracea L.var.botrytis L.,2n=18,CC)‘Korso’和抗病的黑芥(B.nigra,black mustard,2n=16,BB)‘G1/1’的体细胞杂种(简称PFCN,protoplast fusion of cauliflower and Brassica nigra)高代自交及回交后代为材料,根据表型特征将其分为4大类:性状介于花椰菜和黑芥之间的中间型材料(M)、向花椰菜过渡的过渡型(M-K)、偏花椰菜型(-K)和花椰菜型(K)。连续5年的黑腐病人工接种鉴定结果显示:‘Korso’的病情指数在44~57之间,表现为耐病到感病;‘G1/1’在12~32之间,表现为抗病,从M、M-K、-K至K型,杂种后代病情指数总体上呈逐渐升高的趋势,其中M型和M-K型材料表现为高抗至抗病,-K型材料表现为抗病至耐病,K型材料表现为耐病。对2014年的15份典型-K至K型材料进行了形态演变及黑腐病抗性变化追溯:总体上,偏花椰菜的形态转变发生在S1BC4、S5、S1BC3和BC3(S为自交,BC为回交)世代中,伴随着形态的转变,黑腐病病情指数急剧升高;同一年中来源相同或者相近的株系病情指数相差不多。2015年进一步对2014年25个单株的自交后代进行黑腐病抗病性跟踪鉴定:整体上病情指数呈下降趋势,仅少数株系表现上升;来源相同的衍生株系变化趋势几乎一致,且差异不大,说明这些材料系内对黑腐病抗病性逐年趋于稳定。目前获得了6份相对于受体亲本‘Korso’表现出了对黑腐病抗性显著提高的材料:PFCN14-15-4.1、PFCN14-15-5.1、PFCN14-29-1.1和PFCN14-29-1.2,连续3年病情指数呈下降趋势,并最终稳定在30左右;PFCN14-14-1.1和PFCN14-14-1.2则连续6年保持在20~38之间。

The Phenotype Evolution and Transfer Breeding of Black Rot Resistance in Somatic Hybrids Between Cauliflower and Black Mustard

Black rot is one of the main diseases of cauliflower（Brassica oleracea L. var. botrytis L.， 2n = 18，CC）. Somatic hybrids were obtained by asymmetric cell fusion between susceptible cauliflower cultivar‘Korso’and resistance black mustard line‘G1/1’（B. nigra，2n = 16，BB）. Different advanced generations were got after years of selfing and backcrossing. According to the characters of the plants such as leaf morphology and flower curd，the somatic hybrids were classified into four types. Type M：having characters between cultivated‘Korso’and wild species‘G1/1’. Type M-K：having traits between two parents and bias to‘Korso’. Type -K：having most cauliflower-like phenotypes. Type K：exactly cauliflower-like type. The results of resistance identification from year 2010 to 2014 showed that disease index （DI）of‘Korso’were in 44–57，and DI of‘G1/1’were in 12–32 for the inoculated pathogenic bacterium. The DI were gradually increased in hybrids from type M to type M-K，type -K and type K displaying the high resistance，resistance to tolerance degree，respectively. The results of phenotype evolution and resistance tracing showed that cauliflower-like morphology changes occurred in S1BC4，S5， S1BC3 and BC3，and along with the morphology changes，DI of black rot increased sharply. Little DI difference was detected among lines with the same or similar derivation. Further resistance identification was carried out in 2015 in the selfed progeny lines. Overall，the DIs showed a downward trend in most of the lines and only increased in a few lines. Plants from the same derivation showed the similar changing trend indicating that the disease resistances in the progenies became stable after years’ selection. Up to now，six promising lines displaying significant black rot resistance compared with the receptor parent ‘ Korso ’ were obtained ，which including PFCN13-15-4.1 ， PFCN13-15-5.1 ， PFCN13-29-1.1 ， PFCN13-29-1.2，PFCN13-14-1.1 and PFCN13-14-1.2，respectively.