Molecular and Genetic Characterization of Newly Released CIMMYT Inbred Maize Lines

Tropical germplasm has accumulated a large number of genes adapted to a variety of adversities. In this study, we assessed the genetic diversity and population structure of 109 inbred maize lines newly released from the International Maize and Wheat Improvement Center (CIMMYT) in the last few years. The results indicated the following: (1) linkage disequilibrium (LD) analysis showed that tropical maize germplasms had a faster rate of LD decay, suggesting higher recombination rates and genetic diversity; (2) both the phylogenetic tree and structure analysis supported the classification of the material into three subgroups; (3) the results of the principal component analysis were consistent with the population structure analysis, further verifying the reliability of subgroup delineation; (4) the genetic distances between the tropical germplasms from groups 2 and 3 and the elite temperate inbred lines were relatively close, which is suitable for temperate germplasms improvement. The results can help us select suitable tropical germplasms and speed up the process of inbred line development and maize improvement.