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以优良杂交种豫玉22两亲本Z3和87-1为基础构建一套F8家系的重组自交系群体为研究材料,在正常供氮和低氮两种氮水平下进行田间试验,利用复合区间作图法对玉米穗长、穗行数、行粒数、百粒重和单穗粒数进行QTL定位分析。两种氮水平下共定位到24个玉米穗部性状的QTL位点,其中正常供氮条件下定位到13个QTL,低氮水平下定位到11个QTL,集中分布在第1(8个QTL)、第5(6个QTL)和第8(5个QTL)染色体上。两种氮水平下共位或紧密连锁的QTL位点较少,表明玉米穗部性状在低氮水平下的遗传机制发生很大改变。研究发现,第1染色体umc1122/bnlg1556位点是一个控制低氮水平下玉米单穗粒数的主效QTL,单个QTL可解释19.7%的表型变异,该位点还同时影响低氮水平下玉米穗长、穗行数和百粒重的表型。与前人定位结果比较发现,该位点所在的染色体区域是一个产量及氮效率相关性状的QTL富集区,对此位点附近进行相关分子标记辅助选择,可能会在玉米氮高效分子育种上有所突破。
A group of recombinant inbred lines of F8 pedigree was constructed based on the excellent hybrid Yuyu 22 parents Z3 and 87-1. The field experiments were conducted under the two nitrogen levels of normal and low nitrogen. Mapping the QTLs for ear length, number of rows per ear, number of rows, 100-kernel weight, Under the two nitrogen levels, QTL loci were mapped to 24 ear traits of maize, of which 13 QTLs were mapped under normal nitrogen supply, 11 QTLs were mapped at low nitrogen levels, and concentrated on the first (8 QTLs) ), 5th (6th QTL) and 8th (5th QTL) chromosomes. There were fewer QTLs co-located or closely linked under the two nitrogen levels, indicating that the genetic mechanism of ear traits under low nitrogen levels changed greatly. The results showed that the locus umc1122 / bnlg1556 on chromosome 1 was a major QTL controlling the grain number per spike of maize at a low nitrogen level. A single QTL explained 19.7% of the phenotypic variation, which also affected both maize Spike length, number of ears and 100-weight phenotype. Compared with the previous results, it was found that the locus of the locus was a QTL-rich region for yield and nitrogen efficiency-related traits. The molecular marker-assisted selection near this locus may be useful in molecular breeding of high molecular nitrogen of maize A breakthrough.