SORGHUM TRAIT DEVELOPMENT PIPELINE FOR IMPROVED FOOD AND FEED VALUE Sorghum is poised to play a key role in expanding agricultural development and food security in countries around the world. New marketing opportunities for sorghum include use in high‐quality food and beverage products, feed for poultry and egg production, and use of grain and potentially biomass in the biofuels industry. Success in meeting these demands hinges, in part, on the successful transfer of genetic, genomic, and agricultural technologies that have been developed for the crop. This proposal seeks funding to support research that leverages new genetic technologies to enhance the value and performance of sorghum in farmer‐accepted varieties adapted in Niger and Senegal in West Africa. Panicle diversity of sorghum OBJECTIVES This project will leverage the development of a Functional Gene Discovery Platform for Sorghum Improvement that is being developed with support from the Bill and Melinda Gates Foundation in Ghana and Burkina Faso. With funding from the SMIL, we will leverage this platform investment to develop a Sorghum Trait Development Pipeline. We will identify and characterize genes that define traits important in sorghum crop improvement, at the same time bringing its use geographically into Niger and Senegal. We will utilize the approximately 69,000 EMS‐induced mutations represented in our subpopulation of 600 lines to engineer new traits for sorghum crop improvement, especially relating to kernel and forage quality. 1 RESEARCH STRATEGY 1. Identify genes and alleles that can be used to improve grain quality and feed value of sorghum. This project will use a forward‐reverse genetics platform to develop new traits for sorghum crop improvement in West Africa. The forward genetics strategy involves analyses of our 12,000 EMS‐
mutagenized sorghum lines or the 600 sequence‐indexed EMS sorghum mutants for novel mutant phenotypes. Seeds of the mutants were produced at Purdue in 2013 and are available for phenotype analyses. Low‐cost, phenotypic screens will be used to identify mutants for: a.
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improved protein digestibility reduced phytic acid content to improve iron bioavailability in sorghum grain modified starch composition designer starches with altered gelatinization temperatures Screening for phytic acid content Reverse genetic strategies to develop new traits for sorghum crop improvement in West Africa will use the sorghum genome sequence as a tool to identify and characterize variations in genes related to the expression of end‐use traits. We have developed a gene discovery pipeline that uses a population of 600 DNA sequence indexed mutants that represent more than 69,000 novel protein changing alleles representing most genes in the sorghum genome (Figure 1). Seeds of the EMS sorghum mutants were increased in field nurseries at Purdue in 2013 and are available for use in phenotyping and plant breeding studies. 2 8
6.97 X 10 bp in the sorghum reference genome
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1.1 x 10 SNPs
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2.1 X 10 SNPs in coding sequences
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8.89 X 10 bp coding sequence
577 GA SNPs in coding sequences
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1.8 X 10 curated coding sequence
Single GA mutation in Dhurinnase2
Chr8: 13,746,113
Figure 1. Next Generation Sequencing Single Nucleotide Polymorphism narrowing to causative mutation. The lines are representative of base pairs (bp) of the genome. The coding sequence represents ∼13% of the whole genome. Steps for SNP filtering are as follows: (1) SNPs within the coding sequences, (2) G‐to‐A as well as complementary C‐to‐T SNPs in coding sequence, and (3) SNPs within the candidate gene list (Adapted from Krothapalli et al., 2013). A major goal of this project is to get NARS breeding programs to apply this technology to their own research as needed. We are proposing an exchange of material and personnel that place this population of sorghum mutants at multiple sites in sub‐Saharan Africa with differing climates and soils, allowing local breeders to use their expertise to identify traits useful to their programs. Seed of these lines will then be provided freely for introduction of valuable alleles into locally adapted germplasm. Once the mutant population and/or specific mutants are transferred to the NARS in Niger and Senegal, we intend to initiate collaborations with the food science and nutrition researchers at each location to develop experiments that test impacts of these mutations in food‐ and feed‐value. Therefore, in addition to the gene targets identified above, we are working with our NARS partners to identify additional genetic targets for crop improvement. 3 During the project inception meeting in West Africa in 2014, the NARS programs requested assistance: a. INRAN requested assistance in developing locally‐adapted, high‐quality forage and dual purpose grain sorghum cultivars, especially brown midrib (bmr) sorghum cultivars. b. CERAAS from SENEGAL requested assistance in developing locally‐adapted sorghum cultivars with improved protein digestibility as described above. Screening for protein digestibility content 2. Develop locally adapted sorghum varieties and hybrids having improved grain quality and feed value. This objective focuses on development of locally‐adapted, guinea and non‐guinea sorghum varieties and hybrids having improved food‐ and feed‐quality characteristics for use in Niger and Senegal. Engagement of on‐site breeding programs is an essential part of this proposal. Varieties and germplasms with improved food quality have been developed in different parts of Africa; however, farmers often are reluctant to grow introduced varieties because of poor local adaptation characteristics. Key West African collaborators and implementation sites are Aissata Mamadou (intaaoudi@yahoo.fr), M. Soumana Souley (nsoumana@yahoo.com), and M Moustapha Moussa, (moustimou@yahoo.fr), INRAN, NIGER; N'Diaga CISSE, CERAAS (ncisse@refer.sn) and Dr. Ababacar NDOYE, ITA (dgita@ita.sn), SENEGAL. Some progress has been made in use of mutants and exotic germplasm to produce locally adapted varieties with improved grain quality. The NARS programs in Mali and Niger have been particularly successful in cultivar development with the release of interracial guinea sorghum varieties such as Grinka, developed by IER, and release of the caudatum sorghum varieties 90SN7 and SEPON82 by INRAN. These accomplishments serve as an example, and we propose to further extend germplasm resources and technical support to sorghum breeding efforts in the region. The elite food‐sorghum varieties from the region will provide excellent starting materials for development of improved food‐
grade guinea and non‐guinea sorghum varieties. 4 Locally adapted guinea sorghum The Purdue PIs will work with the sorghum breeders and food technologists in NARS in Niger and Senegal to initiate breeding programs to incorporate new sorghum traits into locally adapted varieties. To jumpstart this effort, the PIs from Purdue have obtained a number of elite food‐and feed‐quality sorghums from West Africa that can serve as recurrent parents for trait introgression (see below). The Purdue PIs will initiate crosses to introgress traits we identify in BTx623 into the West African sorghum varieties. Crosses and plant breeding populations segregating for key target traits will be sent to NARS collaborators for selection. The Purdue PIs will visit collaborating host‐country programs each year to assess progress in current research, identify additional landraces that should be targeted for improvement, and to develop future research goals. Development of hybrid cultivars with improved food‐ and feed‐quality characteristics was also identified as an important regional research goal. Although hybrid seed production and distribution remains a significant challenge, efforts to harness heterosis in locally adapted cultivars promises to be the single most impactful technology for enhancing food production in the West Africa region. The PIs will work with host‐country collaborators to enhance seed and pollinator parent lines to produce hybrids with local‐adaptation. These hybrids will be evaluated for performance and adaptation by our on‐site collaborators. NARS in Niger and Senegal use farmer participatory methods for variety selection and improvement through evaluation in on‐farm trials. The PI will collaborate with these programs to evaluate acceptance and promote production of new varieties using this system. Similar efforts will be pursued in other host‐countries as appropriate. 5