Late-Season drought tolerance in maize and sorghum
 The ability of a plant to postpone senescence under late-season drought is commonly defined as 'stay-green'. Stay-green is correlated with enhanced crop productivity, grain quality, and lodging resistance in many crops. Retention of green leaf tissue is known as visual stay-green, whereas functional stay-green is defined by maintenance of photosynthetically active tissue. The goal of our research is to characterize the expression and genetic architecture of stay-green in maize and sorghum. This knowledge will be applied to improving drought tolerance of these and other crops through marker-assisted selection and potentially transgenic approaches.
Maize exhibits substantial genetic variation for stay-green. Joint linkage mapping has been used to identify multiple QTL for stay-green across several linkage groups with sources of stay-green alleles coming from diverse genetic backgrounds. Comparisons between maize and sorghum for map positions of stay-green QTL indicate that two of the major loci occur in syntenous regions. Identification and integration of stay-green genes into commercial programs provides the opportunity to sustainably enhance the productivity of maize and sorghum in drought environments.
Heat tolerant maize for Asia 
Climate change is forcing changes in agriculture and food production. Increasing temperatures are one of the prominent problems associated with climate change. Heat stress in maize can influence the overall health and production of the crop with yield losses realized through premature senescence of vegetative and reproductive structures. The Heat Tolerant Maize for Asia (HTMA) project is a Global Development Alliance to increase our understanding of heat stress tolerance in maize with partners including CIMMYT, Purdue University, and Pioneer Hi-Bred was well as partners in the National Agricultural Research Systems (NARS) and seed companies from South Asia through the support of USAID. The partners are collaborating in research to understand heat stress tolerance at the physiological and genetic level and to create superior maize hybrids that thrive under these conditions.
Developing a functional gene discovery platform for sorghum improvement
Tremendous gaps remain in our understanding of the valuable traits contained in sorghum genetic resources. Advances in genomics, targeted mutagenesis, reverse genetics and whole-genome DNA sequencing can enable efficient gene discovery and germplasm mining for crop improvement. With support of the BMGF, we are developing genetic and genomic resources that can be used to leverage the phenotypic variation in sorghum. By developing tools in the genome-sequenced variety BTx623 and elite germplasm adapted for Africa, this project accelerates the ability of sorghum researchers to translate knowledge into practical applications in sorghum improvement.
Using this resource, African breeding programs will identify candidate genes impacting traits of value to them, easily survey alleles of those genes in sequence-indexed collections of EMS mutants and diversity panels of local and globally important lines and landraces. The best alleles for improving their target trait can then be crossed into locally adapted breeding stocks. In addition, African laboratories and breeding programs will be trained in the informatics tools needed to use rapidly expanding and available genomics databases to enable more rapid and more effective sorghum breeding.
Automated Sorghum Phenotyping and Trait Development Platform
 Bottlenecks in our ability to collect accurate,
high-resolution, phenotypic data on energy crops such as sorghum limit how
efficiently we can combine this information with genomic data to identify, and
as necessary modify, the genes and alleles needed to produce superior strains
for cultivation. More specifically, enabling the capacity to use sensing data
from ground-based mobile and airborne platforms for automated phenotyping would
greatly advance plant breeding to maximize energy potential for transportation
fuel. Our interdisciplinary team at Purdue University, with support from our
industrial partner, IBM Research, and a consultant, Scott Chapman, from the
Commonwealth Scientific and Industrial Research Organisation (CSIRO),
Australia's national science agency, are developing an automated,
high-throughput system, called the Automated Sorghum Phenotyping and Trait
Development Platform, which is designed to help end users quantify variations
in sorghum field performance and agricultural productivity and detect associations
in the sorghum genome. We will develop this disruptive technology system based
on airborne and ground-based mobile sensor systems whose accuracy in collecting
relevant phenotypic data will be confirmed during development by ground referenced
measurements obtained by our phenotyping teams using in situ and near proximal
sensors as well as biomass harvester yield data.
Modifying dhurrin metabolism in sorghum
 A genetic mutant of sorghum that does not accumulate dhurrin was reported by Blomstedt et al. (2012). This mutant was described as a P414L mutation in CYP79A1 but the mutant was reported to grow more slowly than wild-type plants. We have conducted forward genetic screens of a chemically mutagenized sorghum population and identified several new genetic variants that disrupt dhurrin metabolism. Whole genome resequencing experiments demonstrated that one of these variants harbored a C493Y mutation in CYP79A1 that disrupts dhurrin biosynthesis. Plants with this mutation do not exhibit a slow-growth phenotype. This mutation may provide a new genetic resource for eliminating dhurrin production in sorghum to improve feed, forage, and bioenergy feedstock value.
Use of seed treatment and acetolactate synthase herbicide tolerance traits for managing witchweed (Striga spp.) infestations in sorghum
Weed management is one of the most important considerations impacting sorghum production today. In Africa, witchweed (Striga spp.) infestations are a growing menace for cereal crop producers across the continent. One new and very promising Striga management technology involves use of herbicide tolerance traits for managing this weed. Low-dose imazapyr or metsulfuron seed coatings applied to herbicide tolerant varieties have been shown to be highly effective in controlling Striga infestation in field and greenhouse trials. Locally-adapted varieties that couple host-plant resistance to Striga with herbicide seed treatments are being developed to identify the combination of traits that maximizes the efficacy of control.
New stable-dwarf sorghum varieties
 Sorghum plant height is a quantitative trait controlled by four major genes (Dw1:Dw2:Dw3:Dw4). Nearly all of the grain sorghum grown in the developed world is produced using semi-dwarf cultivars. These cultivars commonly are called "3-dwarf" sorghum since they utilize recessive dwarfing alleles at three of the four major dwarfing genes (dw1:Dw2:dw3:dw4). Karper (1932) was the first to note that the dw3 mutation produced a useful dwarf phenotype, but also noted that dw3 was unstable and frequently reverted to wild-type Dw3. These plants are tall and generally referred to as "height mutants". Farmers dislike height mutants because these off-types are unsightly in commercial grain production fields. Commercial seed producers do not like height mutants because of the effort and cost required to rogue these plants from seed production fields. These management efforts increase the "cost-of-goods" and, in some cases, seed lots must be destroyed if the frequency of off-types is too high. A novel dw3 allele (dw3-sd2) with a 6-bp deletion in the coding region of gene has been identified. This new allele is being incorporated into elite sorghum parent lines for deployment in commercial hybrids.
Professional Positions
2013 - present Scientific Director, Institute for Plant Sciences, College of Agriculture, Purdue University 2007-present Wickersham Chair of Excellence in Agricultural Research, Department of Agronomy, Purdue University 2007 - present Professor, Department of Agronomy, Purdue University 2006 - 2007 Professor, Department of Agronomy, Kansas State University 2001 - 2005 Associate Professor, Department of Agronomy, Kansas State University 1997 - 2001 Assistant Professor, Department of Agronomy, Kansas State University 1997 Post-Doctoral Fellow, Department of Agronomy, Purdue University 1994 Teaching Assistant, Department of Horticulture, Purdue University 1994 - 1996 Research Assistant, Department of Horticulture, Purdue University 1993 Teaching Assistant, Department of Horticulture, Purdue University 1993 Teaching Assistant, Department of Agronomy, Purdue University 1991 - 1993 Research Assistant, Department of Horticulture, Purdue University
Courses
AGRY 520: Principles of Plant Breeding
AGRY 285: World Crop Adaptation and Distribution
Honors and Awards
Fellow, American Society of Agronomy – 2017 Fellow, Crop Science Society of America – 2017 Nominated for David C. Pfendler Outstanding Undergraduate Counselor Award – 2017, 2018 Spotlight Educator, Agricultural Council Student Choice Award, Purdue University – 2016 Seeds for Success, Purdue University – 2009, 2013, 2014, 2016, 2017 Wickersham Chair of Excellence in Agricultural Research, Purdue University – 2007, 2015 Gamma Sigma Delta – Early Career Award, 2001 Fellow, Gamma Sigma Delta – The Honor Society of Agriculture, 1994 McKnight Doctoral Fellowship, McKnight Foundation, 1994
Recent Publications
Diatta E, Anderson JS, Hatch R, Massafaro M, Tuinstra MR, Weil C. (2019 – In review). A Modified Protocol for Rapid Determination of Protein Digestibility in Sorghum Based on Turbidity. Nature protocols.
Ma D, Carpenter N, Rehman T, Maki H, Tuinstra MR, Jin J. (2018 – In review). Greenhouse Environment Modeling and Simulation for Microclimate Control. Computers and Electronics in Agriculture.
Griebel S, Webb MM, Campanell OH, Craig BA, Weil C, Tuinstra MR. (YJCRS_2019_646_R1 – In press). The Alkali Spreading Phenotype in Sorghum bicolor and its Relationship to Starch Gelatinization. Journal of Cereal Science.
Al Khalifah N, Campbell DA, Falcon CM, Gardiner JM, Miller ND, Cinta Romay R, Walls R, Walton R, Yeh CT, Bohn M, Bubert J, Buckler ES, Ciampitti I, Flint-Garcia S, Gore MA, Graham C, Hirsch C, Holland JB, Hooker D, Kaeppler S, Knoll J, Lauter N, Lee EC, Lorenz A, Lynch NP, Moose SP, Murray SC, Nelson R, Rocheford T, Rodriguez O, Schnable JC, Scully B, Smith M, Springer N, Thomison P, Tuinstra MR, Wisser RJ, Xu W, Ertl D, Schnable P, De Leon N, Spalding EP, Edwards J, Lawrence-Dill CJ. 2018. Maize Genomes to Fields: 2014 and 2015 field season genotype, phenotype, environment, and inbred ear image datasets. BMC research notes, 11(1), p.452.
Balzan, S., Carraro, N., Salleres, B., Dal Cortivo, C., Tuinstra, M.R., Johal, G. and Varotto, S., 2018. Genetic and phenotypic characterization of a novel brachytic2 allele of maize. Plant Growth Regulation, pp.1-12.
Addo-Quaye, C., Tuinstra, M., Carraro, N., Weil, C. and Dilkes, B.P., 2018. Whole genome sequence accuracy is improved by replication in a population of mutagenized sorghum. G3: Genes, Genomes, Genetics, pp.g3-300301.
Larsson S, Peiffer JA, Edwards JW, Ersoz ES, Flint-Garcia SA, Holland JB, McMullen MD, Tuinstra MR, Romay C, Buckler ES. 2017. Genetic analysis of lodging in diverse maize hybrids. bioRxiv 185769.
Bouchet, S., Olatoye, M.O., Marla, S.R., Perumal, R., Tesso, T., Yu, J., Tuinstra, M. and Morris, G.P., 2017. Increased power to dissect adaptive traits in global sorghum diversity using a nested association mapping population. Genetics, 206(2), pp.573-585.
Pontieri, P., Troisi, J., Bagnasco, A., Boffa, A., Motto, M., Del Giudice, F., Tuinstra, M.R., Chessa, A.L., Pizzolante, G., Romano, R. and Alifano, P., 2016. Yield potential and adaptability of selected food-grade sorghum hybrids to Mediterranean conditions. International Journal of Current Research in Biosciences and Plant Biology. Int. J. Curr. Res. Biosci. Plant Biol, 3(10), pp.118-127.
Chen, K., Camberato, J.J., Tuinstra, M.R., Kumudini, S.V., Tollenaar, M. and Vyn, T.J., 2016. Genetic improvement in density and nitrogen stress tolerance traits over 38 years of commercial maize hybrid release. Field Crops Research, 196, pp.438-451.
Pontieri, P., Del Giudice, F., Dimitrov, M.D., Pesheva, M.G., Venkov, P.V., Di Maro, A., Pacifico, S., Gadgil, P., Herald, T.J., Tuinstra, M.R. and Pizzolante, G., 2016. Measurement of biological antioxidant activity of seven food-grade sorghum hybrids grown in a Mediterranean environment. Australian Journal of Crop Science, 10(7), p.904.
Sukumaran, S., Li, X., Li, X., Zhu, C., Bai, G., Perumal, R., Tuinstra, M.R., Prasad, P.V., Mitchell, S.E., Tesso, T.T. and Yu, J., 2016. QTL mapping for grain yield, flowering time, and stay-green traits in sorghum with genotyping-by-sequencing markers. Crop Science, 56(4), pp.1429-1442.
Massafaro, M., Thompson, A., Tuinstra, M., Dilkes, B. and Weil, C.F., 2016. Mapping the Increased Protein Digestibility Trait in the High-Lysine Sorghum Mutant P721Q. Crop Science, 56(5), pp.2647-2651.
Elias, A.A., Robbins, K.R., Doerge, R.W. and Tuinstra, M.R., 2016. Half a century of studying genotype × environment interactions in plant breeding experiments. Crop Science, 56(5), pp.2090-2105.
Pontieri P, Troisi J, Di Fiore R, Di Maro R, Bean SR, Tuinstra MR, Roemer E, Boffa A, Del Guidice A, Pizzolante G, Alifano P, Del Giudice L. 2014. Mineral contents in grains of seven food-grade sorghum hybrids grown in a Mediterranean environment. Australian Journal of Crop Science 8(11): 1550-1559.
Kaufman RC, Herald TJ, Bean SR, Wilson JD, Tuinstra MR. 2013. Variability in tannin content, chemistry and activity in a diverse group of tannin containing sorghum cultivars. Journal of the Science of Food and Agriculture 93: 1233-1241.
Sukumaran S, Xiang W, Bean SR, Pedersen JF, Tuinstra MR, Tesso TT, Hamblin MT, Yu J. 2012. Association mapping for grain quality in a diverse Sorghum collection. Plant Genome 5: 126-135. doi: 10.3835/plantgenome2012.07.0016.
Barrero Farfan ID, Johal G, Tuinstra MR. 2012. A stable dw3 allele in sorghum and a molecular marker to facilitate selection. Crop Science 52: 2063-2069. doi:10.2135/cropsci2011.12.0631.
Wu Y, Xianran L, Xiang W, Zhu C, Lin Z, Wu Y, Li J, Pandravada S, Ridder DD, Bai G, Wang M, Trick H, Bean S, Tuinstra MR, Tesso T, Yu J. 2012. Presence of tannins in sorghum grains is conditioned by different natural alleles of Tan1. Proceedings of the National Academy of Sciences. 109: 10281–10286. doi: 10.1073/pnas.1201700109.
Lin Z, Li X, Wang ML, Bai G, Li J, Clemente TE, Trick HN, Tuinstra MR, Tesso TT, White F, Yu J. 2012. Parallel domestication of SHATTERING1 gene in crops. Nature Genetics 44: 720-724. doi:10.1038/ng.2281.
Kershner KS, Al-Khatib K, Krothapalli K, Tuinstra MR. 2012. Genetic resistance to acetyl-coenzyme A carboxylase-inhibiting herbicides in grain sorghum. Crop Science 52: 64-73.
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