Development of New Selection Tools and Crop Varieties for Sustainable Agriculture

View the project final report

Commodities

• Vegetables: beans

Practices

• Crop Production: crop improvement and selection, plant breeding and genetics
• Education and Training: demonstration, display, mentoring, on-farm/ranch research, technical assistance

Sustainably managed agroecosystems are profoundly different than those that are managed conventionally. Unfortunately, most crop varieties are bred to perform well under conventional systems, and sustainable farmers most often grow varieties that are not optimally suited to their conditions. Evidence suggests that most of the difference in yield between conventional and organic farms, for example, is simply due to the fact that the varieties have been selected based on performance in a conventional, rather than sustainable environment.

Beginning in 2013, we surveyed organic farmers in California to identify their most pressing needs. One major concern for these growers is weed control. With limited use of herbicides, sustainable farmers need access to crop varieties with alternative canopy structures that allow for mechanical weed control and reduce hand-weeding costs. It is also vital for crop canopies to grow rapidly early in the season to outcompete weeds. Finally, sustainable growers need crops that are sensitive to abiotic pressure, such as heat stress, in a rapidly changing climate. To date, selection for these characteristics has been slow, expensive, and imprecise, but improvement of these traits is crucial for sustainable agriculture.

In the last three years, we have developed inexpensive, cutting-edge imagery acquisition and processing methods that facilitate the selection of varieties with an optimal canopy structure and vigorous growth rate. These have been disseminated to the next generation of agricultural innovators through on-farm field day demonstrations, personalized trainings with academic and industry partners, a new course offered at UC Davis, and workshops and presentations at scientific conferences. These methods have now been employed to study rice, alfalfa, spinach, wheat/triticale, grapes, tree crops, and several species of bean. Next, we identified genetic patterns associated with vigorous growth rate across multiple populations of common bean, which will be useful for efficient marker-assisted selection of improved varieties. We then screened breeding populations using these tools, and identified patterns of improvement in our breeding populations relative to their heirloom parents. Finally, we have conducted multi-location trials of advanced-generation breeding lines that excel in terms of yield, product value, and disease resistance. These selection tools and new varieties will be tremendously valuable for sustainable farmers in the western United States.

1) Develop high-throughput phenotyping methods for stress resilience and yield that can be used by growers or breeders. Physiological characteristics such as canopy temperature and NDVI are correlated with plant health, and may be associated with faster growth rate. They are also correlated with yield and abiotic stress resistance, but methods for analyzing the data have lagged behind the ability to collect it.

2) Identify the genetic basis of vigorous early season growth. We have developed a population descended from a slow growing, bushy dry bean parent (Orca) and a fast-growing, viney parent (Black Nightfall). With genotype data, we will be able to determine the genetic cause of variation in these traits.

3) Release new varieties of dry bean that excel in early season growth rate, canopy structure, and yield under variable environmental conditions. We will use high-throughput phenotyping and marker-assisted selection to improve early season growth rate, canopy structure, and other characteristics in dry bean. These releases will primarily fall into high-value heirloom market classes, which fetch a higher price than commodity market classes.

4) Disseminate breeding tools and new crop varieties to a wider audience We will disseminate our precise and inexpensive phenotyping methods through publications targeting growers and researchers. Genetics results will be published in peer-reviewed scientific literature accessed by plant breeders. Our new varieties will be showcased at our annual on-farm field days, and will be trialed by collaborating growers that produce common bean commercially. Publications on their release will be found in a variety of formats read by scientists and sustainable growers.