不同大葱品种耐寒性鉴定与越冬栽培效果

以章丘大葱为对照，测定了日本引进的春味、长宝2个大葱品种丙二醛含量、保护酶活性、叶绿素含量、光合速率及根系活力等抗性生理指标，并运算其隶属函数，鉴定了不同大葱品种的耐寒性及小拱棚越冬栽培效果.结果表明，大葱越冬栽培过程受低温环境的胁迫，使大葱叶片的丙二醛含量及电解质渗透率在1月15日达到最高值，叶绿素含量和光合速率则降至最低，此时春味、长宝及章丘大葱各生理指标的隶属函数值分别为0.452、0.364、0.226，表明春味大葱耐寒性较强，长宝大葱次之，章丘大葱耐寒性较差.收获时，春味、长宝和章丘大葱的抽薹率分别达0、35.2%和81.0%，因此，尽管长宝大葱的生物产量分别比春味及章丘大葱高25.67%和52.94%，但经济产量则以春味大葱最高，达5.49 kg·m^-2，比长宝大葱增产18.57%，章丘大葱经济产量最低，仅为0.86 kg·m^-2，表明春味大葱适宜小拱棚越冬栽培，而章丘大葱冬性较差，不适宜越冬栽培.  

洋葱大葱种间杂种鉴定方法建立与应用

以洋葱、大葱及其杂种F1为材料，利用PCR-RFLP技术对其核糖体DNA内部转录间隔区（ITS）和细胞质线粒体DNA的srRNA基因V7进行分析，试图建立洋葱大葱种间杂种的鉴定方法。结果显示：大葱ITS序列没有DdeⅠ酶切位点；而洋葱被DdeⅠ酶切成两个大小不同的片段；F1杂种具有两亲本的ITS序列酶切模式。细胞质线粒体srRNA基因的V7区域的扩增表明F1杂种和亲本有大小一致的单一片段，经RsaI酶切后，大葱有约0.3 kb条带，比洋葱的稍小，两亲本都含有另外一条小条带（约0.1 kb）。对25份杂种材料进行鉴定，22份的母本为大葱，3份为假杂种。本研究在分子水平上建立了洋葱大葱种间杂种的鉴定方法，快速、准确的辨别杂种一代的真假性。  

Fumonisin B1 production by Fusarium proliferatum strains isolated from Allium fistulosum plants and seeds in Japan

Aims:  To test the fumonisin B₁ - producing ability of Fusarium proliferatum strains isolated from Welsh onion ( Allium fistulosum ) plants and seeds of commercial cultivars in Japan and to examine the applicability of PCR-based assays to discriminate between fumonisin B₁-producing and nonproducing isolates.
Methods and Results:  Fumonisin B₁ levels in 20 Fusarium isolates obtained from Welsh onion plants and seeds of seven commercial cultivars were determined by HPLC. Thirteen of the 20 isolates produced fumonisin B₁. PCR assay with FUM1 gene-specific primers amplified a DNA fragment (700 bp) only from fumonisin-producing isolates.
Conclusions:  Fusarium proliferatum isolates that can produce fumonisin B₁ were often associated with wilted Welsh onion plants and seeds of some commercial cultivars. The PCR assay with FUM1 gene-specific primers has the potential to discriminate between fumonisin B₁-producing and nonproducing isolates.
Significance and Impact of the Study:  This study revealed that F. proliferatum producing fumonisin B₁ is associated with Welsh onion plants and that commercial cultivar seeds may be contaminated with the fungus. PCR amplification of FUM1 gene can be a useful tool for the rapid identification of fumonisin B₁-producing F. proliferatum isolates.