Optimized breeding strategies for multiple trait integration: I. Minimizing linkage drag in single event introgression.
Optimized breeding strategies for multiple trait integration: I. Minimizing linkage drag in single event introgression.
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DOI：
10.1007/s11032-013-9936-7
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
Mumm RH
中科院分区：
文献类型：
--
作者：
Peng T;Sun X;Mumm RH
从育种的角度来看，多性状整合（MTI）是使用回交育种将优良品种/杂种转化为增值性状（例如转基因事件）的四步过程，最终重新获得目标杂种的性能属性沿着增值性状的可靠表达。鉴于在完成的转换中恢复等同性能的总体目标，本研究侧重于MTI的第一步，单事件渐渗，探索标记辅助回交转换的目标玉米杂交种的15个转基因事件的可行性，将8个事件并入母本杂交种亲本和7个事件并入父本杂交种亲本。在平行流中进行单事件渐渗以转化用于单个事件的轮回亲本（RP），主要目的是使残留的非轮回亲本（NRP）种质最小化，特别是在与事件的染色体接近度（即连锁拖累）中。与96.66%总体RP种质回收率的限定下限（即，考虑到1，788 cM的基因组大小，NRP种质≤120 cM）保持一致，为15个单事件转化中的每一个开发了育种目标：整个基因组中<8 cM的残留NRP种质，在事件侧翼的20 cM区域中约lcM。使用计算机模拟，我们的目的是确定最佳的育种策略，单事件渐渗，以实现这一育种目标，测量效率方面的数量回交世代所需的标记数据点，跨世代的总人口规模。比较了从BC_1到BC_3、BC_4或BC_5的三阶段选择、改良两阶段选择和组合选择方案。育种目标通过涉及五代标记辅助回交的选择方案实现，其中BC 1至BC 3选择用于感兴趣的事件和在600的群体大小下的最小连锁阻力，并且BC 4和BC 5选择用于感兴趣的事件和在400的群体大小下的整个基因组中的RP种质的恢复，对于所有世代的选择强度为0.01。此外，还评价了选择供体亲本以促进转化效率和质量的策略。为给定的RP选择最佳供体亲本的两个基本标准建立：渐渗历史显示在事件侧翼的20 cM区域中连锁阻力减少到~1 cM，以及RP和潜在供体亲本之间的遗传相似性。计算机模拟表明，使用先前转化的RP作为事件供体，具有<8 cM残留NRP种质的单事件转化可以通过没有遗传相似性的BC 5、通过具有30%遗传相似性的BC 4和通过具有86%遗传相似性的BC 3来完成。这项研究表明，MTI可以产生“优质”的15事件堆叠混合转换。此外，它奠定了一个全面的方法MTI的基础，概述了一个途径，以产生适当的起始材料，进行版本测试之前的事件识别和特征修复。本文的在线版本（doi：10.1007/s11032-013-9936-7）包含补充材料，可供授权用户使用。
From a breeding standpoint, multiple trait integration (MTI) is a four-step process of converting an elite variety/hybrid for value-added traits (e.g. transgenic events) using backcross breeding, ultimately regaining the performance attributes of the target hybrid along with reliable expression of the value-added traits. In the light of the overarching goal of recovering equivalent performance in the finished conversion, this study focuses on the first step of MTI, single event introgression, exploring the feasibility of marker-aided backcross conversion of a target maize hybrid for 15 transgenic events, incorporating eight events into the female hybrid parent and seven into the male parent. Single event introgression is conducted in parallel streams to convert the recurrent parent (RP) for individual events, with the primary objective of minimizing residual non-recurrent parent (NRP) germplasm, especially in the chromosomal proximity to the event (i.e. linkage drag). In keeping with a defined lower limit of 96.66 % overall RP germplasm recovery (i.e. ≤120 cM NRP germplasm given a genome size of 1,788 cM), a breeding goal for each of the 15 single event conversions was developed: <8 cM of residual NRP germplasm across the genome with ~1 cM in the 20 cM region flanking the event. Using computer simulation, we aimed to identify optimal breeding strategies for single event introgression to achieve this breeding goal, measuring efficiency in terms of number of backcross generations required, marker data points needed, and total population size across generations. Various selection schemes classified as three-stage, modified two-stage, and combined selection conducted from BC1 through BC3, BC4, or BC5 were compared. The breeding goal was achieved with a selection scheme involving five generations of marker-aided backcrossing, with BC1 through BC3 selected for the event of interest and minimal linkage drag at population size of 600, and BC4 and BC5 selected for the event of interest and recovery of the RP germplasm across the genome at population size of 400, with selection intensity of 0.01 for all generations. In addition, strategies for choice of donor parent to facilitate conversion efficiency and quality were evaluated. Two essential criteria for choosing an optimal donor parent for a given RP were established: introgression history showing reduction of linkage drag to ~1 cM in the 20 cM region flanking the event and genetic similarity between the RP and potential donor parents. Computer simulation demonstrated that single event conversions with <8 cM residual NRP germplasm can be accomplished by BC5 with no genetic similarity, by BC4 with 30 % genetic similarity, and by BC3 with 86 % genetic similarity using previously converted RPs as event donors. This study indicates that MTI to produce a ‘quality’ 15-event-stacked hybrid conversion is achievable. Furthermore, it lays the groundwork for a comprehensive approach to MTI by outlining a pathway to produce appropriate starting materials with which to proceed with event pyramiding and trait fixation before version testing. The online version of this article (doi:10.1007/s11032-013-9936-7) contains supplementary material, which is available to authorized users.
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影响因子：
2.3
作者：
Frisch, M;Melchinger, AE
通讯作者：
Melchinger, AE
DOI：
10.1038/nbt0293-194
发表时间：
1993-02-01
期刊：
BIO-TECHNOLOGY
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作者：
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