Crop breeding

Sesame cultivation: expansion versus temperature stress

Garnished on top of a freshly baked hamburger bun or deeply nestled within a crunchy granola bar, tiny sesame seed seldom gets enough of our attention. But it’s captured the interest of farmers in the United States, who are growing more of it in their fields over the past decade.

Sesame (Sesamum indicum) is one among the most versatile crops. Sesame seed is a reservoir of healthy fats (50% oil), protein (25% by weight). They also contain vitamins, minerals, fiber, and antioxidants. In addition to bakery and confectionery uses, sesame seed is used in making soups and salad. And let’s not forget hummus, or a sweet Middle Eastern paste ‘tahini.’

Consuming sesame seed has countless health benefits. These include lowering cholesterol levels, protecting against bacterial infections, and controlling blood sugar control. They are being investigated as cancer prevention.

Tall white tubes that have different sizes of sesame plants in them.

Researchers at Oklahoma State University are studying sesame to determine which varieties grow best under different conditions like heat and water stress. Shown: growth of sesame across six temperature treatments. Credit: Gurjinder Baath

The oil extracted from sesame seeds is a premium cooking oil. It’s often acknowledged as “the queen of oils” due to its high concentration of antioxidants. In Europe, it is even used as a substitute for olive oil.

Sesame oil is also well known for its skincare benefits and hydrating properties. It is used in making soaps, perfumes, or cosmetics.

When making sesame oil, the residue is still valuable. It is used as a high protein material ideal for poultry and livestock feed.

What is sesame like in the field?

Sesame is a broadleaf summer crop that can reach up to six feet in height. Sesame plant is very leafy, losing its leaves as it matures. It has a fairly short time-to-maturity of 120 to 150 days.

Large, (usually) white, bell-shaped flowers start appearing about 35-45 days after planting. Flowering begins on the lower stem and gradually proceeds upward as the stem elongates within a period of weeks.

Seeds are formed within capsules, often termed as pods. Most of the sesame grown across the world is harvested manually since capsules often shatter when they are dry, making them more prone to split open.

Sesame crops grow best on medium to light textured, well-drained soils. It can grow across slightly acidic to alkaline soils (pH 5-8) but cannot tolerate waterlogged or saline conditions.

flowering sesame plant in dry environment
Flowering of a sesame plant under field conditions in El Reno, Oklahoma. After flowering, the plant will produce seeds in pods. Credit: Gurjinder Baath

Why do farmers grow sesame?

Besides a good market demand for sesame seed crops, there are several reasons farmers choose to grow it:

  • Due to its short growing season, it can be easily added to various crop rotations.
  • Sesame requires lower resources and offers more return (less risk) than other crops.
  • Farm equipment that farmers already have can be used for growing sesame.
  • Sesame is known for its heat, drought, disease, and insect tolerance. It is also less susceptible to economic damage from wild hogs, deer, or birds.
  • Sesame has low water use during the drying phase that leads to more soil water storage for the subsequent crop in double-cropping systems.
  • The brittle sesame residue controls soil erosion like higher residue crops, without the need for excess residue bailing equipment.
hundreds of sesame seeds scattered on a flat surface
Sesame seeds have multiple uses. They are used alone as a food source, like Tahini. Oil can be pressed from sesame and is valued for its high level of antioxidants in both food and cosmetic ingredients. Credit: Irish Lorraine B. Pabuayon

During the last decade, the area under sesame cultivation has increased substantially due to the rising demand for sesame products and multiple benefits offered by the crop. Within US, sesame is now cultivated in the states of Kansas, Oklahoma, and Texas. Oklahoma farmers grow more than 30,000 acres.

Sesame acreage has further been expanding into several US northern and southeastern states. Apart from the United States, many African and European countries are seeing more acres planted with sesame.

What research is being done on sesame?

Non-traditional growing regions could see lower yields than the current farms. Researchers at Oklahoma State University, where I work, have been investigating the potential impacts of different air temperatures on sesame growth, yield, and physiology. We hope to define suitable regions for sesame cultivation. In addition, we will develop adaptation strategies for offsetting the impacts of future climate change.

several tall sesame plants growing flowers and seed pods with sky and clouds in background
Sesame plants have broad leaves, and they can grow to three feet. They are drought tolerant, making them a good choice for farmers in areas where water is limited. Credit: Irish Lorraine B. Pabuayon

Sesame is sensitive to air temperature. No seed capsules will form if temperatures are above 88°F. The optimal temperature for sesame seed yield is 77°F.

Future research will study the factors responsible for temperature tolerance in sesame. Genetic evaluation of sesame is necessary to identify varieties capable of maintaining reproductive development under high temperatures. This will provide a broader geographic adaptation and sustain crop yields under current and future climates.

Answered by Gurjinder Baath, Oklahoma State University

Read here about how farmers are substituting sesame crops on land used for cotton.

About us: This blog is sponsored and written by members of the American Society of Agronomy and Crop Science Society of America. Our members are researchers and trained, certified, professionals in the areas of growing our world’s food supply while protecting our environment. We work at universities, government research facilities, and private businesses across the United States and the world.

2 replies »

  1. This is an excellent article, as a Botanist it’s always good to come across academic info as it allows to put forth solutions to problems and this seed is excellent for some future conditions that will occur. Good job I look forward to the outcome

Leave a Reply to Petal Cancel reply