Evaluation Of Utilization Potential Formajormaize Inbred Lines Of Improved Huangzao4

Inbred line is important for maize breeding and successful selection of elite hybrid. HuangZao4 improved lines are potential for yield under high density environment being of their excellent plant architecture. To dissect the relationship of yield traits and combined ability for HuangZao4 improved lines would help solving the wandering condition of unit yield in China.10 lines selected from excellent American hybrids and 5 HuangZao4 improved lines were used in NCII incomplete diallel cross experiment with two environments and four replications. The major results are as follows:1) Increase of plant height above the ear was an efficient way to decrease the ear height for plant architecture breeding. Ear length was the prime factor influencing hybrid yield, accompanied by coherent plant height effect on yield. Plant height was significantly correlated with all traits tested except ear height and ear diameter. Additionally, it was negative to the number of tassel and row number per ear. 100-kernel weight decreased when ear height and trefoil angel bar increased, but was enhanced by the increase of ear length. The row number per ear which was negative to ear diameter could be improved by the increase of trefoil angel bar and the number of tassel, however, it reduced with the enlarge of ear length2) Lx9801 had great potential for plant architecture breeding, because it had the highest general combined ability (GCA) of ear length, ear diameter, kernel number per row, 100-kernel weight, and ear weight, along with the lowest GCA of ear height, trefoil angel bar, and number of tassel. Xun928 and Xun926 had the highest GCA for kernel number of row and row number per ear among the five paternal lines, respectively. However, their oddly high GCA of plant height should be improved before extensive practice. Although the moderate GCA, K17 and Chang7-2 were still worthy for breeding as paternal line for the lowest ear height and highest number of tassel, respectively. The highest GCA of line F6 and F3 for ear length and kernel number of row, F8 for ear length, F2 and F7 for ear diameter and row number per ear, and the lowest GCA of line F7 for ear height, would be the favorable characteristics in maize breeding practice.3) Xun928 which had the oddly high special combined ability (SCA) could be used to produce prominent hybrid with certain yield trait, followed by combination of F2×Chang7-2. Total combined ability (TCA) was more useful than GCA and SCA to evaluate the potential of inbred lines, because TCA had consistent effect with plot yield level. Lines crossed with Xun928 could yield high TCA for plant height and tassel length, and low TCA of trefoil angel bar and number of tassel. F7×Xun926 and F2×Xun928 also produced relatively high TCA for certain trait of the ear. High TCA of kernel number of row and ear weight was observed in F6×Chang7-2 and F2×Chang7-2. K17 could reduce the ear height and trefoil angel bar, which exhibited outstandingly in F1×K17.4) It was possible to produce elite hybrid with. K17 for its relatively high special combined ability variance (SCAV). The high SCAV of Xun926 for ear length, ear diameter, and 100-kernel weight could also be used in breeding practice. Lx9801 was the wonderful parental line with the high GCA and total special combined ability variance (TCAV). However, trefoil angel bar and the number of tassel should be improved for its utilization. Line F2, F3, and F5 could be exploited with their SCA, because they had high SCAV for yield traits. F6, F7 and F8 were relatively perfect parental lines for their high GCA and SCAV.5) Additive effect was major for yield traits. It was suitable to select the traits of tassel length, number of tassel, and row number per ear in early generation, because they had high broad and narrow heritability more than 50%. However, the relatively low broad and narrow heritability of less than 30% was observed for kernel number of row and trefoil angel bar which were prone to be influenced by the environment. Selection for these traits should be delayed to a relatively high generation.