New alfalfa varieties aim for better field establishment

By Andi Anderson

Stand establishment is a critical phase in alfalfa production. However, this stage can be challenged by poor soil drainage, seedling diseases, weed pressure, and autotoxicity. These issues can lead to failed stands, causing economic losses due to wasted seeds, inputs, and labor.

Researchers at Cornell University are developing new alfalfa varieties that can establish more reliably and produce vigorous seedlings capable of competing with weeds and thriving in their seeding year.

Since 2021, a lab funded by USDA's Hatch program has been selecting alfalfa populations based on traits like large seed size, deep planting emergence, root characteristics, and field vigor. Two rounds of trait selections have already been completed, with ongoing efforts to determine the most effective approach for improving alfalfa plant vigor.

Farmers often plant alfalfa in mixtures with forage grasses or small grain nurse crops to manage weeds and improve stands in varying field conditions.

This practice is especially common in New York and the Northeast, where poor soil drainage and winter weather fluctuations are frequent challenges. Approximately 84% of alfalfa acreage is planted in mixtures.

Traditional alfalfa breeding and variety testing typically focus on the performance of alfalfa alone. Given the significance of grass-alfalfa mixtures and nurse crops in certain regions, it is crucial for breeders to develop varieties that can thrive alongside grass companions.

In another experiment, Cornell’s lab is evaluating different alfalfa cultivars and breeding populations planted with common grasses like triticale, meadow fescue-tall fescue mix, and orchardgrass-timothy mix. The surviving plants from these trials will be selected to develop new alfalfa varieties adapted to mixed stands.

Autotoxicity is another challenge for alfalfa growers. It occurs when established alfalfa plants produce compounds that are toxic to new alfalfa seedlings, leading to poor germination and low stand productivity.

Michigan State University, under the leadership of Kim Cassida and funded by USDA’s National Institute of Food and Agriculture, is researching the causes of autotoxicity and ways to manage it. Their goal is to identify the toxic compounds and develop a rapid soil test to determine the safety of replanting alfalfa.

Cornell’s role in this project is to create new alfalfa varieties that either produce fewer autotoxic compounds or are less affected by these compounds when present in the soil.

These combined efforts aim to reduce the risks associated with alfalfa establishment and support farmers in successfully growing this valuable forage crop.

Photo Credit: gettyimages-goodlifestudio