Near isogenic F₂ (NIF₂) population frequently developed by conventional backcross has dramatically contributed to QTL identification in plants. Developing such a NIF₂ population is time-consuming. Thus, it is urgent to rapidly produce a NIF₂ population for QTL cloning. Here, we proposed a rapid QTL cloning strategy by generating a Pseudo-near isogenic F₂ population (Pseudo-NIF₂), which segregates at the target QTL but is fixed at other QTLs for the target trait. Nineteen QTLs for GL, GW, and TGW were detected in the F₂ population from the cross between Zhenshan 97 and Egy316. To verify the efficiency of Pseudo-NIF₂ in QTL quick cloning, the novel moderate QTL qGL10.1 which explained 9.1% and 5.6% of grain length variation in F₂ and F_2:3 populations was taken as an example. An F₂ plant (F₂-120), which segregated at qGL10.1 but fixed at other 8 QTLs for grain length, was screened to generate a Pseudo-NIF₂ population by selfing cross. In the Pseudo-NIF₂ population, the segregation ratio of plants with long grains to short grains fits 3:1, indicating that one gene controlled the variation of grain length. Based on the Pseudo-NIF₂ and its progeny, qGL10.1 was fine mapped to a 19.3-kb region, where a gene OsMADS56 was verified as the candidate by functional polymorphism between parental alleles. Pseudo-NIF₂ strategy is a rapid way for QTL cloning, which saves 3 to 4 cropping seasons compared to the conventional way. Applying the method for cloning QTL with moderate or major effects is promising.

通过传统回交频繁开发的近等基因F ₂ (NIF ₂ )群体对植物中QTL的鉴定做出了巨大贡献。开发这样的 NIF ₂群体非常耗时。因此，迫切需要快速产生用于QTL克隆的NIF ₂群体。在这里，我们提出了一种快速QTL克隆策略，通过生成伪近等基因F ₂群体（Pseudo-NIF ₂），该群体在目标QTL处分离，但固定在目标性状的其他QTL处。镇山97与Egy316杂交F ₂群体中检测到19个GL、GW和TGW QTL 。_{为了验证Pseudo-NIF 2}在QTL快速克隆中的效率，以解释F ₂和F _2:3群体粒长变异9.1%和5.6%的新型中等QTL qGL10.1为例。F ₂植物(F _{2 -120)在}qGL10.1处分离，但在粒长方面固定于其他8个QTL，经筛选以通过自交杂交产生伪NIF _2群体。在Pseudo-NIF ₂群体中，长粒与短粒的分离比符合3:1，表明一个基因控制了粒长的变异。基于 Pseudo-NIF ₂及其后代，qGL10.1被精细定位到 19.3 kb 区域，其中基因OsMADS56通过亲本等位基因之间的功能多态性被验证为候选基因。Pseudo-NIF ₂策略是QTL克隆的一种快速方法，与传统方法相比可以节省3至4个种植季。应用该方法克隆具有中等或重大效应的QTL是有希望的。