| In this experiment,an African germplasm was used as material and a batch of selected lines were obtained by continuous self-crossing for 3 generations.Combined with the main heterosis utilization pattern in the southwest mountainous ecological zone:temperate germplasm×tropical germplasm,52 germplasm selection lines were used as paternal par-ents and 3 test species（CA345,7854,1718）were designed using NCII genetic mating 156combinations were prepared for field identification in three different environments,Anyue,Chongzhou,and Zigong,Sichuan.The combining ability,heritability,heterosis and silage quality of these selection lines were analyzed to provide a theoretical basis for their effec-tive use.The main results are as follows:1.The GCA effect analysis of main agronomic characters showed that there were 8lines with better comprehensive characters:S1-32-2,S1-45-1,S1-51-2,S2-32-2,S2-40-2,S2-48-2,S2-51-2,S3-67-2.The GCA effect values of per plant yield,ear length,ear rows and row grains were all positive.Among them,the GCA effect values of plant height（-4.43）and ear height（-11.69）of S2-40-2 are all negative,and the main grain traits are positive,indicating that the material can be used in the selection of dwarf corn,but it will grow bar-ren ear tip.S2-48-2 has outstanding performance,only the grain index（-0.87）and volume weight（-0.79）have negative GCA effect values,the per plant yield（10.02）ranks second,and the GCA effect values of other major yield traits are all as a positive effect,it has the potential to be an excellent high-yielding breeding parent.2.The results of heritability estimation showed that the order of general heritability and narrow heritability was not the same,among which the general heritability and narrow heritability of nine characters,ear rows,grain index,ear length,per plant yield,row grains,plant height,ear diameter,ear height,and kernel depth,were all greater than 50%,which was suitable for selection in the early generation.The general heritability of 100-kernel weight is more than 50%,but the narrow heritability is less than 50%,it should be selected in the early and late generations.The broad sense heritability and narrow sense heritability of barren ear tip and volume weight were less than 50%,which were not suitable for early generation selection.3.The results of yield heterosis analysis showed that there were 49 combinations whose yield was higher than that of the control,39 with a control advantage between 0 and10%,and 10 with more than 10%.The 10 combinations were composed of CA345 and S1-51-2,S1-32-2,S1-45-1,S2-40-2,S2-7-1,S3-7-1,S1-48-2,S1-35-1,S2-67-2,S3-67-2,indicating these combinations had strong control heterosis of yield per plant and strong heterosis with Reid group represented by CA345.4、After two rounds of mixed parental control selection,the basic population AC0improved its own ear length and ear rows traits to some extent,but with the increase of plant height,ear height and barren ear tip,the other seven traits such as ear rows and ear diameter were not improved,but their mean values changed little.5、The indexes of samples were determined by NIRSDA1650,and compared with the control Yuqing 386.combined with the quality index of silage corn in China,70 combina-tions of NDF,ADF and TS,such as S1-32-2×1718,S1-40-2×7854,S1-40-2×CA345,were better than the control and the difference of protein content was between-2.53 and 0.04,indicating that most of the combinations had better quality.It has the value of silage utili-zation. |
