Genetic, Evolution, and Utilization of Crop Germplasm in Crop Improvement

Crop germplasm is essential for breeders as it forms the foundation for modern plant improvement. Normally, crop germplasm shows strong diversity due to its wide genetic background. The genetic background formation of crop germplasm closely correlates with evolution under different environments including temperature, light, water, and other factors; and associated natural selection pressures. Besides evolution, propagation both by active and passive methods also importantly contributed to this issue. The seeds of crop germplasm can be distributed by air and water flow and insect transportation. When they travel a long way, especially entering different ecological areas, many traits will be changed and then fixed to be adaptive to the new environment after a long time. Both wild and cultivated germplasm are also collected by the breeder to enrich genetic diversity in the breeding program and evaluate altered genetic backgrounds formed by the recombination of genetic materials.

Although germplasm is fundamental to breeders and studies on germplasm are performed continuously, some questions should be addressed regarding further germplasm utilization. The first question is what are the genetic differences among germplasms and what are the mechanisms of its formation? It is much easier to distinguish phenotype than to identify its causal genotype. Therefore, using genotype information to understand genetic variation and its structure in different ecological areas is of importance. The second concern is how the germplasm is adaptive to different environments, resulting in genetic background diversity. As plant populations moved to new environments, there should be some adaptive genetic and/or epigenetic changes to improve fitness in the new environment. As a result, new germplasm differs from its progenitors both in phenotype and genotype. The third one is how researchers and breeders effectively use germplasm, from chromosomal to gene levels. As the nature of germplasm utilization is to exchange and recombine parts of the genetic information, it is meaningful to explore mechanisms and genetic technology for the effective utilization of germplasm.

This Research Topic mainly concerns the following scope:

• genetic variation and structure of crop germplasm and control of important traits;

• molecular evidence of the evolution of crop germplasm;

• response to different environments of germplasm and impact on the genetic diversity among germplasm accessions;

• germplasm utilization through genetic and molecular manipulation;