小麦籽粒大小和形态是决定产量的主要因素之一,挖掘籽粒大小和形态性状的关联位点,筛选相关候选基因对于提高小麦产量具有重要意义。本研究以国内外具有代表性的300份冬小麦自然群体为研究材料,对千粒重、粒长、粒宽、粒厚、籽粒长宽比...小麦籽粒大小和形态是决定产量的主要因素之一,挖掘籽粒大小和形态性状的关联位点,筛选相关候选基因对于提高小麦产量具有重要意义。本研究以国内外具有代表性的300份冬小麦自然群体为研究材料,对千粒重、粒长、粒宽、粒厚、籽粒长宽比、籽粒面积、籽粒周长、籽粒形状和籽粒饱满度等9个籽粒性状进行表型鉴定,利用小麦90 K SNP芯片进行基因型采集,通过混合线性模型(MLM+Q+K)对籽粒大小和形态性状进行全基因组关联分析。研究结果表明,小麦籽粒大小和形态性状表现出丰富的表型变异,变异系数范围3.80%~26.06%,广义遗传力在56.25%~91.98%之间。通过GWAS检测出66个与籽粒大小和形态相关的稳定关联位点(P≤0.001),分布在除3D、4D、5D外的18条染色体上,可解释3.74%~14.34%的表型变异。检测到37个与两个及以上籽粒性状关联的一因多效位点,其中3B染色体的BS00022512_51标记同时与4个籽粒性状(粒长、粒宽、粒厚和籽粒长宽比)关联,具有最大的表型贡献率(7.06%~14.34%),6D染色体的wsnp_Ex_c4480_8055475标记同时与除粒厚、籽粒形状和籽粒饱满度以外的6个籽粒性状关联,表型贡献率为3.81%~8.25%。将BS00022512_51和wsnp_Ex_c4480_8055475标记进行单倍型分析,发现位于6D染色体上的wsnp_Ex_c4480_8055475位点存在GC-Hap1、ATHap2和AC-Hap3三种单倍型,单倍型GC-Hap1为籽粒较大的高千粒重单倍型。3种单倍型的整体分布频率分别为65.58%、32.25%和2.17%,单倍型GC-Hap1在中国4个冬麦区品种(系)中被大量选育。对37个一因多效位点进行发掘,筛选到9个籽粒大小和形态性状相关的候选基因。展开更多
The Middle Mountains is one of the regions of Nepal most vulnerable to water erosion, where fragile geology, steep topography, anomalous climatic conditions, and intensive human activity have resulted in serious soil ...The Middle Mountains is one of the regions of Nepal most vulnerable to water erosion, where fragile geology, steep topography, anomalous climatic conditions, and intensive human activity have resulted in serious soil erosion and enhanced land degradation. Based on the 137 Cs tracing method, spatial variations in soil erosion, organic carbon, and total nitrogen(TN) in terraced fields lacking field banks and forestland were determined. Soil samples were collected at approximately 5 m and 20 m intervals along terraced field series and forestland transects respectively. Mean 137 Cs inventories of the four soil cores from the reference site was estimated at 574.33 ± 126.22 Bq m-2(1 Bq(i.e., one Becquerel) is equal to 1 disintegration per second(1 dps)). For each terrace, the 137 Cs inventory generally increased fromupper to lower slope positions, accompanied by a decrease in the soil erosion rate. Along the entire terraced toposequence, 137 Cs data showed that abrupt changes in soil erosion rates could occur between the lower part of the upper terrace and the upper part of the immediate terrace within a small distance. This result indicated that tillage erosion is also a dominant erosion type in the sloping farmland of this area. At the same time, we observed a fluctuant decrease in soil erosion rates for the whole terraced toposequence as well as a net deposition at the toe terrace. Although steep terraces(lacking banks and hedgerows) to some extent could act to limit soil sediment accumulation in catchments, soil erosion in the terraced field was determined to be serious. For forestland, with the exception of serious soil erosion that had taken place at the top of slopes due to concentrated flows from a country road situated above the forestland site, spatialvariation in soil erosion was similar to the "standard" water erosion model. Soil organic carbon(SOC) and TN inventories showed similar spatial patterns to the 137 Cs inventory for both toposequences investigated. However, due to the different dominant erosion processes between the two, we found similar patterns between the <0.002 mm soil particle size fraction(clay sized) and 137 Cs inventories in terraced fields, while different patterns could be found between 137 Cs inventories and the <0.002 mm soil particle size fraction in the forestland site. Such results confirm that 137 Cs can successfully trace soil erosion, SOC and soil nitrogen dynamics in steep terraced fields and forestland in the Middle Mountains of Nepal.展开更多
文摘小麦籽粒大小和形态是决定产量的主要因素之一,挖掘籽粒大小和形态性状的关联位点,筛选相关候选基因对于提高小麦产量具有重要意义。本研究以国内外具有代表性的300份冬小麦自然群体为研究材料,对千粒重、粒长、粒宽、粒厚、籽粒长宽比、籽粒面积、籽粒周长、籽粒形状和籽粒饱满度等9个籽粒性状进行表型鉴定,利用小麦90 K SNP芯片进行基因型采集,通过混合线性模型(MLM+Q+K)对籽粒大小和形态性状进行全基因组关联分析。研究结果表明,小麦籽粒大小和形态性状表现出丰富的表型变异,变异系数范围3.80%~26.06%,广义遗传力在56.25%~91.98%之间。通过GWAS检测出66个与籽粒大小和形态相关的稳定关联位点(P≤0.001),分布在除3D、4D、5D外的18条染色体上,可解释3.74%~14.34%的表型变异。检测到37个与两个及以上籽粒性状关联的一因多效位点,其中3B染色体的BS00022512_51标记同时与4个籽粒性状(粒长、粒宽、粒厚和籽粒长宽比)关联,具有最大的表型贡献率(7.06%~14.34%),6D染色体的wsnp_Ex_c4480_8055475标记同时与除粒厚、籽粒形状和籽粒饱满度以外的6个籽粒性状关联,表型贡献率为3.81%~8.25%。将BS00022512_51和wsnp_Ex_c4480_8055475标记进行单倍型分析,发现位于6D染色体上的wsnp_Ex_c4480_8055475位点存在GC-Hap1、ATHap2和AC-Hap3三种单倍型,单倍型GC-Hap1为籽粒较大的高千粒重单倍型。3种单倍型的整体分布频率分别为65.58%、32.25%和2.17%,单倍型GC-Hap1在中国4个冬麦区品种(系)中被大量选育。对37个一因多效位点进行发掘,筛选到9个籽粒大小和形态性状相关的候选基因。
基金Financial support for this study was provided by the Aid project on Science and Technology for developing countries from Ministry of Science and Technology of China(2013)the National Natural Science Foundation of China(No.41401313)
文摘The Middle Mountains is one of the regions of Nepal most vulnerable to water erosion, where fragile geology, steep topography, anomalous climatic conditions, and intensive human activity have resulted in serious soil erosion and enhanced land degradation. Based on the 137 Cs tracing method, spatial variations in soil erosion, organic carbon, and total nitrogen(TN) in terraced fields lacking field banks and forestland were determined. Soil samples were collected at approximately 5 m and 20 m intervals along terraced field series and forestland transects respectively. Mean 137 Cs inventories of the four soil cores from the reference site was estimated at 574.33 ± 126.22 Bq m-2(1 Bq(i.e., one Becquerel) is equal to 1 disintegration per second(1 dps)). For each terrace, the 137 Cs inventory generally increased fromupper to lower slope positions, accompanied by a decrease in the soil erosion rate. Along the entire terraced toposequence, 137 Cs data showed that abrupt changes in soil erosion rates could occur between the lower part of the upper terrace and the upper part of the immediate terrace within a small distance. This result indicated that tillage erosion is also a dominant erosion type in the sloping farmland of this area. At the same time, we observed a fluctuant decrease in soil erosion rates for the whole terraced toposequence as well as a net deposition at the toe terrace. Although steep terraces(lacking banks and hedgerows) to some extent could act to limit soil sediment accumulation in catchments, soil erosion in the terraced field was determined to be serious. For forestland, with the exception of serious soil erosion that had taken place at the top of slopes due to concentrated flows from a country road situated above the forestland site, spatialvariation in soil erosion was similar to the "standard" water erosion model. Soil organic carbon(SOC) and TN inventories showed similar spatial patterns to the 137 Cs inventory for both toposequences investigated. However, due to the different dominant erosion processes between the two, we found similar patterns between the <0.002 mm soil particle size fraction(clay sized) and 137 Cs inventories in terraced fields, while different patterns could be found between 137 Cs inventories and the <0.002 mm soil particle size fraction in the forestland site. Such results confirm that 137 Cs can successfully trace soil erosion, SOC and soil nitrogen dynamics in steep terraced fields and forestland in the Middle Mountains of Nepal.
