利用回交法快速选育高油酸花生新品系

以普通花生品种花育22为母本、高油酸花生品种开农176为父本杂交得到F1杂种,筛选油酸含量高于60%且同时含有FAD2a和FAD2b位点的F1为杂交父本,以花育22为轮回亲本(母本)连续回交得到BC1F1~BC4F1代回交种。利用近红外光谱仪测定F1及BC1F1~BC4F1籽粒的油酸、亚油酸含量,选择油酸含量大于60%的种子,用刀片切取种子小部分子叶提取DNA,以F0.7/R3为引物进行PCR扩增及测序,根据测序峰图差异表现筛选出同时含有FAD2a和FAD2b位点的种子作为下一代回交的父本。切去部分子叶的种子切口用石蜡封闭,播种前浸泡于40℃温水中催芽,对12 h后未露白的种子用100 mg L–1乙烯利浸泡4 h后再转入40℃温水浸泡至24 h,发芽率可达到98%。2013年春季开始杂交,2016年春在青岛播种BC4F2代种子,取幼苗期幼叶鉴定基因型,筛选出基因型为aabb的单株,收获时选留农艺性状类似于花育22的优良单株,再利用近红外光谱仪测定所选单株油酸含量,获得油酸含量在70%以上、油酸亚油酸比值大于7.0的单株24个。这些单株与花育22相比,农艺性状基本相同,称为改良花育22高油酸花生新品系。

Breeding New Peanut Line with High Oleic Acid Content Using Backcross Method

F1 hybrids and BC1F1–BC4F1 backcross generation were obtained by cross and backcross with peanut variety HY22 as female parent (recurrent parent) and Kainong176 with high oleic acid content as the donor parent. The contents of oleic acid and linoleic acid of F1 and BC1F1 to BC4F1 were determined by Near infrared spectrometer. The seeds with oleic acid content higher than 60% were selected and their partial cotyledon was cut off for DNA extraction. The loci FAD2a and FAD2b in these seeds were detected by sequencing absorption peaks of PCR products with F0.7/R3 as primers, and those seeds with both FAD2a and FAD2b were used as the male parent in following backcross. The incision in these seeds whose cotyledon was cut off was sealed by paraffin oil, and these seeds were soaked in water for sprouting at 40°C. Those seeds that did not germinate within 12 hours were soaked in 100 mg L–1 ethephon solution for four hours, then immersed into water till 24 hours at 40°C by which 98% seeds could germinate. Four to five times of backcross every two years were finished in spring in Qingdao, 1–2 times in autumn and winter in Sanya, by which the breeding process might be accelerated. The backcrossing work began in the spring of 2013 and BC4F2 seeds were sowed in Qingdao in the spring of 2016. The young leaves were used for genotyping and these plants with aabb genotype and similar agronomic characters with Huayu 22 were selected and harvested, whose oleic content was then confirmed by NIR. Twenty single plants with similar characters of Huayu 22 whose oleic content was higher than 70% and oleic/linoleic ratio was higher than 7.0 were regarded as a new improved HY22 strain with high oleic acid content.