Marker-assisted selection to introgress rice QTLs controlling root traits into an Indian upland rice variety
Marker-assisted selection to introgress rice QTLs controlling root traits into an Indian upland rice variety
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DOI：
10.1007/s00122-005-0110-4
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发表时间：
2006-01-01
影响因子：
5.4
通讯作者：
Witcombe, JR
中科院分区：
文献类型：
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作者：
Steele, KA;Price, AH;Witcombe, JR
进行了一项标记辅助回交（MABC）育种计划，以改善印度高地品种卡林加III的根系形态性状，从而提高其耐旱性。这个品种，在MABC的轮回亲本，以前没有被用于数量性状位点（QTL）定位。供体亲本为菲律宾高地粳稻品种Azucena。不同染色体上的五个片段被定位为渐渗;四个片段携带用于改善根形态性状（根长和根厚）的QTL，第五个片段携带用于香气的隐性QTL。在非目标区域对轮回亲本等位基因进行一些选择。我们描述了在三个回交（BC）世代和两个BC 3系之间的进一步杂交中进行的选择，以金字塔（堆叠）所有五个目标片段。在8个世代中获得了具有4个根系QTL的Pyraectin，在6年内完成了对总共323个品系的3，000个标记测定。在印度班加罗尔的5个田间试验中，对22个近等基因系（NIL）的根系性状进行了评价。9号染色体上的目标片段（RM 242-RM 201）在灌溉和干旱胁迫处理下均显著增加根长，证实来自Azucena的该根长QTL在新的遗传背景中起作用。在其他四个目标上没有发现对根长的显著影响。RM 248位点的Azucena等位基因（7号染色体上的目标根QTL下方）延迟开花。选择在这个位点的经常性亲本等位基因产生早花近等基因系，适合在印度东部的高地环境。
A marker-assisted back-crossing (MABC) breeding programme was conducted to improve the root morphological traits, and thereby drought tolerance, of the Indian upland rice variety, Kalinga III. This variety, the recurrent parent in the MABC, had not previously been used for quantitative trait locus (QTL) mapping. The donor parent was Azucena, an upland japonica variety from Philippines. Five segments on different chromosomes were targeted for introgression; four segments carried QTLs for improved root morphological traits (root length and thickness) and the fifth carried a recessive QTL for aroma. Some selection was made at non-target regions for recurrent parent alleles. We describe the selection made in three backcross (BC) generations and two further crosses between BC3 lines to pyramid (stack) all five target segments. Pyramids with four root QTLs were obtained in eight generations, completed in 6 years using 3,000 marker assays in a total of 323 lines. Twenty-two near-isogenic lines (NILs) were evaluated for root traits in five field experiments in Bangalore, India. The target segment on chromosome 9 (RM242-RM201) significantly increased root length under both irrigated and drought stress treatments, confirming that this root length QTL from Azucena functions in a novel genetic background. No significant effects on root length were found at the other four targets. Azucena alleles at the locus RM248 (below the target root QTL on chromosome 7) delayed flowering. Selection for the recurrent parent allele at this locus produced early-flowering NILs that were suited for upland environments in eastern India.