Leaf water potential of peanut subjected to drought stress is positively related to the oil content of peanut kernels. The aim of this study was to directly screen the high oil mutants of peanut and create the new peanut varieties using hydroxyproline as water potential regulator. In vitro mutagenesis was carried out with the embryonic leaflets of peanut variety Huayu 20 as explants and pingyangmycin as a mutagen added into the somatic embryo formation medium. The formed somatic embryos were successively transferred to somatic embryo germination and selection medium containing 6 mmol/L hydroxyproline (at -2.079 MPa water potential ) to induce regeneration and directionally screen high oil content mutants. After that, these plantlets were grafted and transplanted to the experimental field and 132 high oil mutants with oil content over 55% were obtained from the offspring of regenerated plants. Finally, among them, the oil contents of 27 lines were higher than 58% and of 2 lines were higher than 60%. A new peanut variety Yuhua 9 with high yield and oil content was bred from the regenerated plant progenies combining the pedigree breeding method. The yield was 14.0% higher than that of the control cultivar in the testing new peanut varieties of Liaoning province, and also it has passed the national registration of non-major crop varieties. Yuhua 9 with an oil content of 61.05%, which was 11.55 percentage points higher than that of the parent Huayu 20, was the peanut cultivar with the highest oil content in the world. The result showed that it was an effective way for directional breeding of high oil peanut varieties by means of the three-step technique including in vitro mutagenesis, directional screening by reducing water potential in medium and pedigree selection of regenerated plant progenies.
笔者前期研究发现经干旱胁迫处理后的花生叶片水势与其籽仁含油率呈显著正相关。文中对羟脯氨酸作为水势 (渗透压) 调节物质用于离体定向筛选花生高油突变体及培育花生新品种进行了研究。以花生品种花育20 号胚小叶作为外植体，平阳霉素作为诱变剂添加于体胚诱导培养基上进行离体诱变培养。形成的体胚转移到添加6 mmol/L 羟脯氨酸 (培养基水势为–2.079 MPa) 的体胚萌发和再生培养基上诱导体胚萌发成苗，同时进行高油突变体定向筛选。再生小苗经嫁接移栽田间，从再生植株后代中获得了132 份含油率55%以上的高油突变体，其中27 份含油率超过58%，2 份超过60%。再生植株后代结合系谱育种法育成了高产高油花生新品种宇花9 号，在辽宁省花生新品种备案试验中，籽仁产量比对照品种增产14.0%，并通过了国家非主要农作物品种登记。宇花9 号含油率达61.05%，比亲本花育20 号高11.55 个百分点，是目前国际上含油率最高的花生品种。本研究结果表明，利用离体诱变、培养基低水势定向筛选及其再生植株后代结合常规育种法选择是定向培育高油花生品种的有效方法。.
Keywords: directed screening; in vitro mutagenesis; oil content; peanut; water potential.