高氮和低氮条件下玉米穗位叶持绿性状的QTL定位

李东亚; 王祎; 汤继华; 许恒; 谭金芳; 韩燕来

doi:10.11674/zwyf.18080

高氮和低氮条件下玉米穗位叶持绿性状的QTL定位

QTL mapping for ear leaf stay-green in maize under high and low N conditions

摘要

摘要:
目的玉米叶片持绿性与籽粒产量、品质性状密切相关，本研究利用单片段代换系群体，对高氮和低氮条件下的玉米穗位叶持绿性状进行了QTL定位，旨在为持绿相关基因的精细定位以及克隆相关主效QTL奠定基础。
方法以氮效率差异显著的两个亲本许178和综3构建的172个玉米单片段代换系为研究材料，采用完全随机区组设计，在高氮 (N 240 kg/hm²) 和低氮 (N 75 kg/hm²) 条件下，进行了两年大田试验。以吐丝后第10天穗位叶的SPAD值作为玉米持绿性的表型值，根据代换系与亲本许178表型值的T-test结果，利用该群体的SSR遗传图谱，在P < 0.01条件下定位持绿性状的QTL。
结果在基因组范围内，两个氮水平下共定位53个穗位叶持绿QTL (贡献率为–2.45%～–22.65%)。上述QTL在玉米的10条染色体上均有分布，其中以第1染色体上检测到的数量最多 (14个)，第7染色体上检测到的数量最少 (1个)。高氮条件下检测的QTL为29个，6个在两年试验条件下被重复检测，分别为qhnSG1d、qhnSG2a、qhnSG3a、qhnSG4a、qhnSG8b和qhnSG10c，其中qhnSG8b和qhnSG10c为高氮特异QTL，两年内QTL的贡献率分别为–4.47%、–9.17%、–9.46%和–5.05%；低氮条件下检测的QTL为16个，2个QTL在两年大田环境被重复检测，分别为qlnSG1f和qlnSG2b。其中qlnSG1f为低氮特异QTL，两年内QTL贡献率分别为–9.70%和–10.85%。
结论通过对玉米穗位叶持绿性状分析，将高氮特异持绿染色体片段定位到umc1077～umc2350区段内，低氮特异染色体片段定位到umc1013～umc2047区段内。

Abstract:
Objectives Stay-green of maize leaves is closely associated with the grain yield and quality. In this study, QTLs for ear leaf stay-green in maize were identified by using single segment substitution lines (SSSLs) to provide theoretical support for the fine mapping and cloning of major QTLs.
Methods Two years field experiments with a randomized complete block design were conducted, and a total of 172 maize SSSLs from a cross between a N-efficient inbred line Xu178 and a N-inefficient inbred line Zong3 were used as test materials. Nitrogen levels of 240 kg/hm² (high) and 75 kg/hm² (low) were applied for each material. The SPAD values of 10 days-old ear leaves after silking were measured to evaluate their stay-green feature. The T-test method was used to analysis the phenotype differences between SSSL and Xu178, and the QTLs for stay-green were mapped in the SSR genetic linkage map at P < 0.01.
Results In the genome range, 53 QTLs for ear leaf stay-green were detected under the two nitrogen levels and effectively resulted in contribution rates of –2.45% to –22.65%. These QTLs were unevenly distributed in all the 10 chromosomes of maize, up to 14 QTLs were detected in chromosome 1, while only one QTL was detected in chromosome 7. Under high nitrogen condition, a total of 29 QTLs were detected, and in which six QTLs including qhnSG1d, qhnSG2a, qhnSG3a, qhnSG4a, qhnSG8b and qhnSG10c were detected simultaneously under the two-year experimental condition. Here, qhnSG8b and qhnSG10c represented QTLs with high N-specific characteristics, and effective contribution rates were –4.47%, –9.17%, –9.46% and –5.05% in two years, respectively. Under low nitrogen condition, a total of 16 QTLs were detected, and 2 QTLs of which, qlnSG1f and qlnSG2b, were detected repeatedly under the two-year experimental conditions. qlnSG1f was a low N-specific QTL, and made effective contribution rates of –9.70% and –10.85% in two years, respectively.
Conclusions The high N-specific stay-green QTL is localized in the segment of umc1077−umc2350 and the low N-specific stay-green QTL is localized in the segment of umc1013−umc2047.

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