Department of Plant Breeding and Genetics, Punjab Agricultural University, Ludhiana 141 004, India.
BMC Genet. 2012 Nov 27;13:104. doi: 10.1186/1471-2156-13-104.
Mustard aphid is a major pest of Brassica oilseeds. No source for aphid resistance is presently available in Brassica juncea. A wild crucifer, Brassica fruticulosa is known to be resistant to mustard aphid. An artificially synthesized amphiploid, AD-4 (B. fruticulosa × B. rapa var. brown sarson) was developed for use as a bridge species to transfer fruticulosa resistance to B. juncea. Using the selfed backcross we could select a large number of lines with resistance to mustard aphid. This paper reports cytogenetic stability of introgression lines, molecular evidence for alien introgression and their reaction to mustard aphid infestation.
Majority of introgression lines had expected euploid chromosome number(2n= 36), showed normal meiosis and high pollen grain fertility. Well-distributed and transferable simple-sequence repeats (SSR) markers for all the 18 B. juncea chromosomes helped to characterize introgression events. Average proportions of recipient and donor genome in the substitution lines were 49.72 and 35.06%, respectively. Minimum alien parent genome presence (27.29%) was observed in the introgression line, Ad3K-280 . Introgressed genotypes also varied for their resistance responses to mustard aphid infestations under artificial release conditions for two continuous seasons. Some of the test genotypes showed consistent resistant reaction.
B.juncea-fruticulosa introgression set may prove to be a very powerful breeding tool for aphid resistance related QTL/gene discovery and fine mapping of the desired genes/QTLs to facilitate marker assisted transfer of identified gene(s) for mustard aphid resistance in the background of commercial mustard genotypes.
芥菜蚜虫是油菜籽的主要害虫。在芥菜中，目前还没有蚜虫抗性的来源。野生芸薹属植物芸薹被认为对芥菜蚜虫有抗性。人工合成的双二倍体 AD-4（芸薹×芸薹褐籽变种）被开发为桥梁物种，用于将芸薹的抗性转移到芥菜中。利用自交回交，我们可以选择大量对芥菜蚜虫具有抗性的品系。本文报道了渐渗系的细胞遗传学稳定性、外源基因渗入的分子证据及其对芥菜蚜虫侵染的反应。
大多数渐渗系具有预期的整倍体染色体数（2n=36），表现出正常的减数分裂和高花粉粒育性。分布均匀且可转移的简单序列重复（SSR）标记可用于鉴定 18 条芥菜染色体，有助于鉴定渐渗事件。在替代系中，受体和供体基因组的平均比例分别为 49.72%和 35.06%。在渐渗系 Ad3K-280 中，观察到最小的外源亲本基因组存在（27.29%）。在两个连续季节的人工释放条件下，渐渗基因型对芥菜蚜虫的抗性反应也不同。一些测试基因型表现出一致的抗性反应。
芥菜-芸薹渐渗系可能成为一个非常强大的育种工具，用于发现与蚜虫抗性相关的 QTL/基因，并对所需基因/QTL 进行精细定位，以促进在商业芥菜基因型背景下识别基因（s）的标记辅助转移，用于芥菜蚜虫抗性。
