Abstract: 【Objective】 Plant characters including plant height, ear height, etc., are important traits that can decide planting density and grain yield in field. They also have high heterosis, and used as a model to dissect the genetic basis of heterosis in studies, so identifying the heterotic loci for plant characters can provide useful information for selecting elite commercial maize hybrids.【Method】 A set of single segment substitution lines (SSSLs) population, which was constructed using the inbred line Xv178 as the receptor parent and the inbred line Zong 3 as the donor parent. The test populations were crossed with the receptor parent Xv178, and were used as the material in this study. The populations were evaluated in the field by following three replicates in randomized complete blocks carried out at Xunxian, Xinxiang and Xuchang locations in Henan province in 2014. Ten plants of each material were selected for measuring plant height, ear height, leaf number after the pollen shedding in the field. The heterotic loci for plant characters were identified through significant analysis comparing to each test hybrid and its mid-parent value by mean of t test. 【Result】 The three traits of plant characters of SSSL test population all had some heterosis, the mid-parent heterosis data of plant height were 4.74%, 3.61% and 1.09% in the Xunxian, Xinxiang and Xuchang locations, respectively, the mid-parent heterosis values of ear height were 6.06%, 7.77% and 7.51%, and leaf number had a little heterosis. A total of 9 QTL for plant height, 10 QTL for ear height, 5 QTL for leaf number were identified in the SSSL population in three environments. In the test population, 6 heterotic loci for plant height were identified, and 3 heterotic loci were detected in three environments simultaneously. For ear height, 8 heterotic loci were detected, including 1 heterotic locus identified in three locations simultaneously. There were 5 heterotic loci detected for leaf number, and 1 heterotic locus was identified in three environments simultaneously. A total of 24 QTL and 19 heterotic loci were identified for the 3 measured traits of plant character in the SSSL and its test population, 5 QTL and heterotic loci were identified in the same SSSLs. 【Conclusion】 The results revealed that the heterosis in plant height and ear height was greater than that in plant leaves number. Of the detected QTL and HL, a certain number of them were conserved across different environments. The chromosomal regions of these QTL/HL probably contain the important genes for corresponding trait. And, a few of chromosomal segments were proved to be associated with multiple traits, which indicated that these traits interact with each other during the plant development. Most of QTL/HL for plant height and ear height sowed over-dominant effects, but less over-dominant QTL/HL for plant leaf number. It implies that high heterosis is associated with high proportion of QTL/HL. Here the three tested traits are associated with each other, achieving balance among them is an important lodging-resistant breeding target. The above mentioned QTL and HL can be used by MAS (molecular assistance selection) to realize the target of elite plant architecture breeding.

Key words: maize, plant characters, single segment substitution lines, heterotic loci, mapping