Widespread diseases caused by fungus can have devastating effects on sorghum production. Diseases that affect sorghum occurs in numerous locations around the world and is especially prevalent in Niger and Senegal. Smallholder farmers in Africa often experience limited access to inputs and fungicide treatment options, leaving them especially vulnerable to these harsh diseases.
Marker assisted selection for diseases that affect sorghum growth identifies and creates disease-resistant, locally adapted, sorghum cultivars. This allows breeders the advantage of marker assisted selection to greatly speed the development of sorghum cultivars with resistance to new races of the pathogens. Local farmers unions, sorghum growers, and smallholder farms benefit from the ability to grow disease-resistant cultivars.
Clint Magill Louis Prom
Adamou Haougui Coumba Fall
Mame Penda Sarr Diawara
USDA - Agricultural Research Service
Texas A&M University
Kansas State University
Niger - Institut National de la Recherche Agronomique du Niger (INRAN), Université de Tillabéri
Senegal - Centre d’Etudes Régional pour l’Amélioration de l’Adaptation à la Sécheresse (CERAAS), Institut Sénégalais de Recherches Agricoles (ISRA)
Research collaboration between Texas A&M, INRAN, and ISRA has extended to include researchers at nearby Universities in Niger and Senegal will result in the identification or creation of disease-resistant, locally adapted, sorghum cultivars that maintain properties preferred by farmers and consumers alike. Target diseases are anthracnose and long smut in Niger and anthracnose and grain mold in Senegal. The cultivar creation aspect is derived from the ability to track resistance genes or quantitative trait loci (QTLs) with DNA-based tags that can be economically scored, in-country, through the development of allele-specific PCR primers at Texas A&M University.
Marker tagging uses Genome Wide Association studies to identify Single Nucleotide Polymorphisms (SNPs) is derived from sources of genetic resistance identified in each country. F2 or later generation DNA samples from resistant and susceptible progeny of segregating crosses will identify markers associated with disease response. This technology enables breeders to take advantage of marker assisted selection to greatly speed the development of cultivars with resistance to new races of the pathogens that are certain to occur over time. Publications in scientific journals inform other scientists interested in sorghum pathology and genomics while demonstrations and interactions with local farmers unions, including sorghum growers, showcase the value of growing disease-resistant cultivars.
Results of the extensive disease survey in Senegal are complete and published, which included information on temperatures, rainfall, and soil type at each of the 206 geo-referenced sites visited. In both Niger and Senegal, hot spots for specific diseases identified were used to test local or US cultivars for disease response. In Senegal, samples of C. sublineola (anthracnose) and long smut were collected and have been purified for eventual DNA-based diversity study. In Niger and Senegal, seed from cultivars in the surveyed fields were collected and sent to Dr. Louis Prom for growth; first in quarantine and subsequently for disease response versus Texas anthracnose isolates.
Niger and Senegal have advanced at least two crosses between local adapted cultivars and SC748-5, which is anthracnose-resistant in Texas as the first step in enhancing disease resistance using gene tagging. Projects were organized and delegated for participants at INRAN and the Université de Tillabéri; including training for conducting 'field days' when COVID-19 control permitted. The response of Senegalese cultivars available in the US germplasm collection were surveyed for response to anthracnose and single nucleotide polymorphism associated with disease response were identified.
Seed collected from cultivars in Niger and Senegal were grown in Dr. Louis Prom's quarantine greenhouse and new seed collected for use in disease testing versus Texas isolates of pathogens. Only head smut tests, which require a full life cycle, have been started. Leaf samples for DNA extraction were also collected and most were acceptable for sequencing, but some were degraded so new plants have been grown to also include those cultivars. All samples need to be sequenced in the same reaction to avoid excessive costs.
Institut National de la Recherche Agronomique du Niger (INRAN)
Institut Sénégalais de Recherches Agricoles du Senegal (ISRA)