Identification of quantitative trait loci under drought conditions in tropical maize .11. Flowering parameters and the anthesis-silking interval
Identification of quantitative trait loci under drought conditions in tropical maize .11. Flowering parameters and the anthesis-silking interval
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DOI：
10.1007/bf00221905
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发表时间：
1996-05-01
影响因子：
5.4
通讯作者：
GonzalezdeLeon, D
中科院分区：
文献类型：
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作者：
Ribaut, JM;Hoisington, DA;GonzalezdeLeon, D
干旱是一种重要的气候现象，仅次于土壤贫瘠，是发展中国家玉米生产第二严重的限制因素。当干旱胁迫发生在开花期之前或期间时，会观察到吐丝延迟，导致花期-吐丝间隔（ASI）长度增加和谷物产量下降。事实证明，选择热带开放授粉品种的 ASI 降低与干旱胁迫下产量的提高相关。由于有效选择耐旱性需要仔细管理实验条件，因此使用分子标记来识别负责 ASI 表达的基因组片段，最终目标是开发标记辅助选择 (MAS) 策略。对 234 个个体的 F-2 种群在 142 个位点进行了基因分型，并在几种水况下对 F-3 家族进行了田间评估，包括雄性开花 (MFLW)、雄性不育 (STER)、雌性开花 (FFLW) 和 ASI。 ASI的遗传方差随着胁迫强度的增加而增加，胁迫条件下MFLW、FFLW和ASI的广义遗传力较高，分别为86%、82%和78%。在染色体 1、2、4、5、8、9 和 10 上检测到参与干旱下 MFLW 和/或 FFLW 表达的推定性状位点 (QTL)，约占这两个性状表型变异的 48%。对于 ASI，在干旱条件下，在 1、2、5、6、8 和 10 号染色体上鉴定出 6 个假定的 QTL，合计约占表型变异的 47%。水分胁迫条件下，MFLW和FFLW表达共有4个QTL，ASI和MFLW表达共有1个QTL，ASI和FFLW表达共有4个QTL。两个性状的共同QTL数量与这两个性状之间的线性相关水平有关。发现 ASI 的分离是越界的，易受干旱影响的亲本在两个 QTL 位置上贡献了 ASI 减少（4 天）的等位基因。其他四个 QTL 上的抗性品系贡献的等位基因导致 ASI 7 天的减少。这四个 QTL 约占连锁图谱的 9%，并且多年来和胁迫水平都很稳定。有人认为，基于 ASI QTL 的 MAS 应成为提高热带玉米自交系耐旱性的有力工具。
Drought is an important climatic phenomenon which, after soil infertility, ranks as the second most severe limitation to maize production in developing countries. When drought stress occurs just before or during the flowering period, a delay in silking is observed, resulting in an increase in the length of the anthesis-silking interval (ASI) and in a decrease in grain yield. Selection for reduced ASI in tropical open-pollinated varieties has been shown to be correlated with improved yields under drought stress. Since efficient selection for drought tolerance requires carefully managed experimental conditions, molecular markers were used to identify the genomic segments responsible for the expression of ASI, with the final aim of developing marker-assisted selection (MAS) strategies. An F-2 population of 234 individuals was genotyped at 142 loci and F-3 families were evaluated in the field under several water regimes for male flowering (MFLW), male sterility (STER), female flowering (FFLW) and ASI. The genetic variance of ASI increased as a function of the stress intensity, and the broad-sense heritabilites of MFLW, FFLW and ASI were high under stress conditions, being 86%, 82% and 78%, respectively. Putative cluantitative trait loci (QTLs) involved in the expression of MFLW andlor FFLW under drought were detected on chromesomes 1, 2, 4, 5, 8, 9 and 10, accounting for around 48% of the phenotypic variance for both traits. For ASI, six putative QTLs were identified under drought on chromesomes 1, 2, 5, 6, 8 and 10, and together accounted for approximately 47% of the phenotypic variance. Under water-stress conditions, four QTLs were common for the expression of MFLW and FFLW, one for the expression of ASI and MFLW and four for the expression of ASI and FFLW. The number of common QTLs for two traits was related to the level of linear correlation between these two traits. Segregation for ASI was found to be transgressive with the drought-susceptible parent contributing alleles for reduced ASI (4 days) at two QTL positions. Alleles contributed by the resistant line at the other four QTLs were responsible for a 7-day reduction of ASI. These four QTLs represented around 9% of the linkage map, and were stable over years and stress levels. It is argued that MAS based on ASI QTLs should be a powerful tool for improving drought tolerance of tropical maize inbred lines.