Preliminary Phenotypic and SNP-Based Molecular Characterization of Maize (&i&Zea mays&/i& L.)-Mexicana (&i&Zea mays&/i& SSP. &i&Mexicana&/i&) Introgression Lines under Inbred Background of 48-2

摘要

Wild relatives possess potential genetic diversity for maize ( Zea mays L.) improvement. Characterization of maize- mexicana introgression lines (ILs) is of great value to diversify the genetic base and improve the maize germplasm. Four maize- mexicana IL generations, i.e. BC1, BC2, BC3, and RIL, were constructed under the elite inbred background of 48-2, elite inbred line that is widely used in maize breeding in Southwestern China, and were phenotyped in different years and genotyped with 56110 SNPs. The results indicated that 48-2 had higher phenotypic performances than all the characterized ILs on most of the agronomic traits. Compared with other ILs, BC2 individuals exhibited more similar performance to 48-2 on most traits and possessed the highest kernel ratio (66.5%). Population structure and principal component analysis indicated that BC3 individuals gathered closer to 48-2 and exhibited the lowest mexicana -introgression frequency (0.50%), while BC2 (29.06%) and RIL (18.52%) showed higher introgression frequency. The high level of genetic diversity observed in the maize- mexicana ILs demonstrated that Z . mays ssp. mexicana can serve as a potential source for the enrichment of maize germplasm.