At the University of Delaware Carvel Research and Education Center in Georgetown, Borel Global Fellow Mary Starford Matovolwa planted 150 accessions of Amaranthus cruentus to study the plant's tolerance to drought and cold in an effort to improve global food security.

Cultivating versatility

Article by Molly Schafer Photos by Michele Walfred October 07, 2025

Borel Global Fellow Mary Starford Matovolwa researches drought-tolerant amaranth

Amaranth may be an ancient grain, but it has a lot to offer the modern world. Not only is this flowering plant packed with nutrients, but it can be made into a gluten-free flour and performs well with organic farming methods.

University of Delaware Borel Global Fellow Mary Starford Matovolwa is working to improve amaranth tolerance to cold and drought. She hopes her research will improve global food security.

“Amaranth is a nutritious crop with complete protein, meaning it has all nine essential amino acids,” Matovolwa said. “We can eat the leaves in salad or cook them like spinach. The seeds can be popped like popcorn or ground into flour for baking.”

The Amaranthus genus includes more than 50 species, several of which are cultivated for food. Others have ornamental value, and some are considered weeds. Matovolwa is focusing her research on Amaranthus cruentus.

“The plant itself comes in beautiful colors from green to deep purple,” Matovolwa said. “The seeds vary in color, including brown, black and cream, and they have many versatile uses.”

Amaranthus cruentus is topped with deeply colored grain heads, which can produce thousands of seeds. The seeds can be popped like popcorn or ground into gluten-free flour.

Matovolwa came to UD’s College of Agriculture and Natural Resources (CANR) through the Borel Global Fellows Program, which was established with generous support from Marcia and Jim Borel. The program supports students from Sub-Saharan Africa pursuing a Master of Science degree at CANR and seeks to increase food security, improve agricultural development and conserve natural resources in Africa.

Matovolwa completed her undergraduate degree at Sokoine University of Agriculture in Tanzania, then spent seven years as a research assistant for plant breeding at the World Vegetable Center.

“I did plant breeding to improve traditional vegetables, the ones which have been mostly forgotten,” said Matovolwa of her work with amaranth and African eggplant. “I was looking to improve those varieties because they’re nutritious and can be alternative crops during climate change.”

Matovolwa noticed that although the varieties she helped create were more nutritious, farmers didn’t favor them because they were not high-yielding crops. Matovolwa knew she could help, but first, she needed to expand her knowledge base and grow her skills. To gain the necessary experience, Matovolwa decided to pursue an M.S. in Plant and Soil Science.

“I was looking for a program that could help me gain the knowledge I needed, at a university with advanced technology,” Matovolwa said. “UD was the best place for me.”

The Borel Global Fellows Program is unique in that it blends the educational experience at UD with an applied research experience in the student’s home country.

“The program was looking for leaders, young agricultural scientists,” Matovolwa said. “They offer you an education so you can help your country, and that is exactly what I wanted to do.”

Matovolwa used a high tunnel to control the amount of water a section of plants received. Other sections relied on rain or irrigation.

Tanzania has both a dry season and a rainy season. The effects of climate change on these well-established weather patterns have made farming difficult, with severe droughts resulting in crop failures.

“Farmers in Tanzania depend on rain,” Matovolwa said. “Most don’t have the advanced irrigation systems I see here in the U.S. Without rain, crops can’t be cultivated, there won’t be enough food, and farmers will not have income. I want to help farmers by finding a variety that can sustain drought and produce a higher yield.”

Testing tolerance

Matovolwa believes a solution can be found by breeding plants tolerant of cold and drought. Her own tolerance to cold was put to the test during her first winter in the U.S. The experience was shocking for Matovolwa, who is used to the warmer temperatures of Eastern Africa. Luckily, she spent her time in the Fischer Greenhouse Lab, growing several generations of A. cruentus to collect seeds for her research.

When spring arrived, Matovolwa planted a diverse group of 150 A. cruentus accessions obtained from the United States Department of Agriculture (USDA) Germplasm Resources Information Network (GRIN) gene bank at the UD Carvel Research and Education Center in Georgetown. By July, Matovolwa’s research plot was bursting with tall amaranth plants. The dark pink or green grain head or panicle atop the plants produces thousands of tiny seeds. The plants are part of Matolvolwa’s drought tolerance trial and are subjected to various growing conditions.

“I collected data on amaranth performance under normal conditions in a well-irrigated field, drought-stressed conditions in the high tunnel, and rainfed and cold conditions in the germination chamber,” Matovolwa said.

She is conducting a genome-wide association study (GWAS), a research approach used to identify genomic variants statistically associated with a particular trait, in this case, cold and drought tolerance.

Matovolwa’s irrigated field of Amaranthus cruentus at UD’s Carvel Research and Education Center. The plants can grow up to six feet tall.

“I then combined these observations with SNP data from genotyping at the University of Wisconsin Biotechnology Center,” Matovolwa said. “I can find markers linked to these traits by using GWAS. Breeding programs may use these markers as tools to speed up the development of amaranth varieties with higher yields and more stress tolerance.”

She is also testing a few theories about how the plant's leaves may affect its tolerance to drought. Do more narrow-shaped leaves conserve water while broader leaves allow a larger quantity of water to evaporate? Does a fuller leaf canopy provide significantly more shade to dry ground?

Matovolwa works closely with her advisor, Emmalea Ernest, UD Cooperative Extension fruit and vegetable specialist.

“Amaranth is a resilient crop, but extreme weather can still damage yield and reduce production during certain times of the year,” Ernest said. “Mary’s project addresses the two main climate stressors that constrain amaranth production in Tanzania. She is also developing a genotyped diversity panel, which can be used to explore the genetic basis for many other traits in the future.”

Ernest and Matovolwa presented their research at the UD Carvel Research and Education Center in Georgetown during the annual Agronomic, Fruit and Vegetable Crops, and Poultry Tours in August.

Matovolwa and Emmalea Ernest, UD Cooperative Extension fruit and vegetable specialist, presented their amaranth research during UD’s 2025 Agronomic Field Crop Tours.

“This crop has great potential for global food security, especially as climate change makes summers hotter and winters colder,” Matovolwa said. “I want people to know the benefits of this crop because it’s easy to grow. You can grow it organically without using fertilizers, and it has strong resistance to pests.”

This upcoming winter in CANR’s Fisher Greenhouse, Matovolwa will conduct a cold trial by testing amaranth plants at both normal and low growing temperatures. After completing her UD coursework, she will return to Tanzania.

“I want to expand this work by focusing on leaf yield, since leafy amaranth is widely consumed and important for nutrition,” Matovolwa said. “I will test how drought, rainfed and well-irrigated environments affect leaf yield.”

Matovolwa also plans to share her findings with the World Vegetable Center to strengthen their amaranth breeding program. A vital component of the Borel Fellowship is for fellows to return to their native countries to promote and improve wealth and health for farmers.

“Mary is passionate about helping people to improve their health by making highly nutritious crops more productive and reliable,” Ernest said. “She is interested in all aspects of addressing food insecurity challenges — from plant breeding, to crop management recommendations, to developing easy-to-prepare recipes.”

Learn more about the Borel Global Fellows program. Applications close Nov. 1, 2025.