Location: Crop Germplasm Research
Project Number: 3091-22000-039-000-D
Project Type: In-House Appropriated
Start Date: Mar 4, 2022
End Date: Jun 6, 2022
Objective:
Objective 1. Evaluate national and international sorghum germplasm resources, and determine the inheritance and allelic relationships of host plant resistance to anthracnose, grain mold, head smut, and downy mildew diseases.
Subobjective 1.A: Identify new sources of resistance to anthracnose within converted and exotic sorghum.
Subobjective 1.B: Characterize the inheritance of host-plant resistance for populations derived from crosses between anthracnose resistant sources and the susceptible line PI609251.
Subobjective 1.C: Identify sources of resistance to grain mold fungi.
Subobjective 1.D: Identify sources of resistance in the Sorghum Association Panel to pathotypes P5 and P6 of Sporisorium reilianum.
Subobjective 1.E: Determine the genetic inheritance of host-plant resistance for populations derived from the bi-parental crosses between head smut resistant sources and BTx643.
Subobjective 1.F: Identify sources of resistance to the new Peronosclerospora sorghi pathotype (SDM P6) and identify chromosomal regions associated with differences in sorghum downy mildew response.
Objective 2. Determine the population structure of diverse anthracnose (Colletotrichum sublineolum) and head smut (Sporisorium reilianum) isolates and phenotypic expression patterns of virulence on host differentials.
Subobjective 2.A: Monitor changing populations of C. sublineola and determine the virulence pattern of diversified new isolates based on a set of sorghum differentials.
Subobjective 2.B: Identify pathotypes of S. reilianum among head smut isolates collected from different sorghum growing regions in the US and Puerto Rico.
Approach:
Sorghum productivity in the US is hampered by several biotic stresses, most notably plant pathogens causing anthracnose, grain mold, head smut, and downy mildew. These diseases cause significant yield and quality losses. Currently, the available information on host-plant resistance to the new pathotypes of head smut and downy mildew pathogens and inheritance patterns of some of the resistant sources are limited. The focus of this project will be to mitigate the impact of these diseases by evaluating diverse sorghum germplasm in multiple locations and greenhouses to identify resistance sources and the allelic relationship of host plant resistance to diverse pathotypes of Colletotrichum sublineola, Sporisorium reilianum, and the oomycete Peronosclerospora sorghi. The goal will be to select accessions with resistance to anthracnose, grain mold, new pathotypes of head smut, and downy mildew in order to provide breeders with new sorghum lines that will help to broaden the genetic base with resistance background for hybrid development. To achieve this goal, populations of sorghum will be generated to determine the inheritance and allelic relationship of host-plant resistance. Also, emerging pathotypes of these diseases will be monitored by collecting isolates from different sorghum growing regions and determine their virulence patterns on sets of sorghum differentials. Genome-wide association study (GWAS) to identify single-nucleotide polymorphic loci from a publicly available genotype by sequencing the dataset for the Sorghum Association Panel also will be utilized with TASSEL association mapping software to identify chromosomal locations associated with differences in downy mildew response. Finally, results generated from this research will be a significant advancement in sorghum disease research in that it will provide to sorghum breeders and other researchers critical new germplasm that will be foundational in developing new, disease-resistant sorghum varieties for productive use in the US and abroad.
