Heckenberger M, Bohn M, Frisch M, Maurer H P, Melchinger A E
Institute of Plant Breeding, Seed Science, and Population Genetics, University of Hohenheim, 70593 Stuttgart, Germany.
Theor Appl Genet. 2005 Aug;111(3):598-608. doi: 10.1007/s00122-005-2052-2. Epub 2005 May 26.
Genetic similarities (GS) based on molecular markers have been proposed as a tool for identification of essentially derived varieties (EDVs). Nevertheless, scientifically reliable criteria for discrimination of EDVs and independently derived varieties with GS estimates are scanty, and implementation into practical breeding has not yet taken place. Our objectives were to (1) assess the influence of chromosome number and length, marker density, and distribution, as well as the degree of polymorphism between the parental inbreds on the distribution of GS between parental inbreds and their progenies [GS(P1,O)] derived from F2 and different backcross populations and (2) evaluate these factors with regard to the power for distinguishing F2- versus BC1- and BC1- versus BC2-derived lines with molecular markers. We developed an approach based on statistical test theory for the identification of EDVs with molecular markers. Standard deviations and overlaps of distributions of GS(P1,O) of F2-, BC1-, and BC2-derived lines were smaller with (1) increasing chromosome number and length, (2) increasing marker density, and (3) uniformly instead of randomly distributed markers, approaching a lower boundary determined by the genetic parameters. The degree of polymorphism between the parental inbreds influenced the power only if the remaining number of polymorphic markers was low. Furthermore, suggestions are made for (1) determining the number of markers required to ascertain a given power and (2) EDV identification procedures.
基于分子标记的遗传相似性（GS）已被提议作为鉴定实质派生品种（EDV）的一种工具。然而，利用GS估计来区分EDV和独立派生品种的科学可靠标准却很少，并且尚未在实际育种中得到应用。我们的目标是：（1）评估染色体数量和长度、标记密度及分布，以及亲本自交系之间的多态性程度对亲本自交系及其来自F2和不同回交群体的后代[GS(P1,O)]之间GS分布的影响；（2）就利用分子标记区分F2衍生系与BC1衍生系以及BC1衍生系与BC2衍生系的能力评估这些因素。我们开发了一种基于统计检验理论的方法，用于利用分子标记鉴定EDV。随着（1）染色体数量和长度增加、（2）标记密度增加以及（3）标记均匀而非随机分布，F2、BC1和BC2衍生系的GS(P1,O)分布的标准差和重叠变小，接近由遗传参数确定的下限。仅当多态性标记的剩余数量较低时，亲本自交系之间的多态性程度才会影响鉴别能力。此外，还针对（1）确定确定给定鉴别能力所需的标记数量以及（2）EDV鉴定程序提出了建议。
