Location: Crop Germplasm Research
2023 Annual Report
Objectives
Objective 1: Utilize unadapted germplasm to increase genetic diversity of elite sorghum inbreds with improved agronomic performance through a collaborative effort involving public and private sector breeders.
Objective 2: Create nested association mapping resources from backcross-derived introgression populations to facilitate marker-assisted sorghum improvement.
Approach
A major challenge facing crop geneticists and breeders is how to develop strategies that combine genetic resources with the vast amount of knowledge and tools in genomics, marker-trait associations, high-throughput phenotyping platforms, genome editing, and bioinformatics to accelerate the rate of genetic gain in applied breeding programs. This project aims to utilize recent advances in high-throughput genotyping and phenotyping, knowledge of gene-to-phenotype trait relationships, whole genome profiles of genetic diversity within and between sorghum germplasm accessions, and emerging information management systems to acquire knowledge of sorghum genes and germplasm, and utilize this information to enhance the rate of genetic gain for complex traits such as grain yield through the development of new adapted breeding material. Utilizing a pre-breeding backcrossing scheme augmented with robust genomic and phenotypic tools, this project focuses on the improvement of sorghum hybrids by the introgression of desirable traits from unadapted and wild germplasm into elite sorghum inbreds, which will introduce new elite germplasm and favorable genes for complex traits, including grain yield, into sorghum breeding programs. The products of this research will include well-characterized elite sorghum inbreds with new genetic diversity and desirable traits, improved effectiveness of hybrid breeding programs through the introduction of new superior-performing diverse elite inbreds, and the development of public resources including backcross-nested association mapping (BC-NAM) populations and associated phenotypic and genotypic characterization to facilitate genomic-assisted breeding and innovative approaches for dissecting the genetic architecture of complex traits.
Progress Report
Work under this project during FY 2023 resulted in significant progress in sorghum germplasm evaluation and development, which included the registration of nested association mapping populations that contain new lines with novel genetic diversity (Objective 1, 2). The discoveries made will facilitate ongoing efforts focused on exploiting molecular technologies in developing improved sorghum hybrids for effective utilization by farmers in all temperate production areas. During the life of this project, major progress was made in utilization of unadapted sorghum germplasm to improve agronomic performance and in creating novel genetic diversity by exploiting genomics technology; the work was done in close collaboration with stakeholders and academic partners. Specific accomplishments under Objective 1 included the identification and evaluation of introgression lines with novel genetic diversity and improved agronomic performance. Achieving this goal resulted in the creation of new inbreds and favorable genes for complex traits including grain yield for use in sorghum breeding programs. Significant accomplishments under Objective 2 were made towards creating and evaluating nested association mapping resources in close collaboration with ARS and academic partners. These efforts resulted in the registration and distribution of novel populations of sorghum germplasm with detailed phenotypic observations, which is critical to exploiting new sources of genetic diversity for crop improvement. This project expired in FY 2023 and was replaced by 3091-21000-047-000D which is continuing and expanding upon the work.
Accomplishments
1. New inbreds and populations from tropical sorghums. Sorghum is an important grain crop in many areas of the U.S. and other temperate regions worldwide. However, much of the potentially valuable sorghum germplasm is tropical in origin and does not successfully flower and produce seed in temperate environments, making these sources of genetic variability unavailable to many of the world's sorghum producing areas. ARS researchers at College Station, Texas, working with academic collaborators, utilized a classical backcrossing scheme to introgress novel genetic diversity from unadapted (tropical) sorghum germplasm into new inbreds. From a large panel of unadapted germplasm, introgression lines and populations with potentially superior breeding value were selected and subsequently evaluated by sorghum researchers outside this project in work to develop higher-producing sorghum hybrids for farmers in the United States and worldwide.
Review Publications
Crozier, D., Leon, F., Fonseca, J.M., Klein, P.E., Klein, R.R., Rooney, W.L. 2023. Inbred phenotypic data and non-additive effects can enhance genomic prediction models for hybrid grain sorghum. Crop Science. Article e20927. https://doi.org/10.1002/csc2.20927.
Winans, N.D., Klein, R.R., Fonseca, J.M., Klein, P.E., Rooney, W.L. 2023. Evaluating introgression sorghum germplasm selected at the population level while exploring genomic resources as a screening method. Plants. Article e12030444. https://doi.org/10.3390/plants12030444.
Zhang, S., Wang Jie, He, W., Kan, S., Liao, X., Jordan, D., Mace, E., Tao, Y., Cruickshank, A., Klein, R.R., Yuan, D., Tembrock, L., Wu, Z. 2023. Variation in mitogenome structural conformation in wild and cultivated lineages of sorghum corresponds with domestication history and plastome evolution. BMC Plant Biology. Article e12870-023-04104-2. https://doi.org/10.1186/s12870-023-04104-2.
Kent, M.A., Fonseca, J.M., Klein, P.E., Klein, R.R., Hayes, C.M., Rooney, W.L. 2023. Use of genomic prediction to screen sorghum B-lines in hybrid test crosses. The Plant Genome. Article e20369. https://doi.org/10.1002/tpg2.20369.
