California Ag Network

Tag: plant pathology lab at UC Davis

  • $1.7 million Grant to Unlock Barley’s Genetic Superpowers

    Barley is important for more than beer. A UC Riverside geneticist has won $1.7 million to study how one of the world’s staple foods might survive climate change.

    The National Science Foundation CAREER Award to Daniel Koenig, an assistant professor in the Department of Botany and Plant Sciences, will reveal details about genetic adaptations barley has made in the past to enable its survival over thousands of years. These details will also help steer its future as weather becomes more extreme.

    In addition to alcoholic beverages, barley is used as a major crop for feeding both animals and humans. It ranks fourth among cereals in terms of total world production. After it was domesticated as a crop over 10,000 years ago, it spread rapidly to environments as different as hot, dry Egypt and cold, wet Minnesota.

    Koenig, who studies plant evolution, wonders how the plant has been able to successfully adapt to these wildly different places.

    “Though we have the tools to compare the DNA of plants collected in different countries, our challenge is understanding which genes evolved in response to weather and which evolved over time in response to other pressures, like diseases,” Koenig said.

    Since only one generation of a plant can be grown per year, the process of observing adaptation real-time is lengthy. To speed up progress, Koenig’s lab is making use of an experiment started in the 1920s. Breeders took barley varieties collected from all over the world and have grown them over the last century in Davis, Calif., and Bozeman, Mont.

    “We can analyze the genes of these varieties, watch as they continue to adapt, and identify the genes that might be responsible for their survival,” Koenig said.

    The NSF CAREER Award is a competitive grant for promising new faculty to help them improve their integration of research and teaching. In this case, Koenig is going to use the award to train undergraduates to compare genes from the beginning of the 1920s experiment with those from today.

    Students will learn to use both traditional molecular biology and newer, computational techniques for this project. The process of identifying survival genes in barley can also be repeated for other crops, helping to ensure the future of other foods as well.

    Growing up in the Central Valley surrounded by agriculture, and attending graduate school at UC Davis, Koenig is excited to expose a new generation of students to food science.

    “This grant will provide an opportunity for students, especially those who grew up in urban environments, to learn about agriculture and give them the basis for possible careers in agricultural science,” Koenig said. — By Jules Bernstein, UC Riverside

  • Fusarium Wilt in Garbanzos

    A little over a month ago, I visited some contiguous garbanzo bean fields in southern San Joaquin County, at the request of the grower. The grower observed that plants were yellowing and dying (Fig. 1) and wondered what might be causing the problem. The grower did not figure that he would be able to do anything about the problem in this year’s crop, but he was thinking ahead for future cropping. He doesn’t have reliable water at this site, so his cropping options (i.e. rotation options) are limited. He would consider growing garbanzos in these fields again next year unless diagnostics revealed a disease problem.

    My observations of the field were that there were patches of several nearby plants with symptoms, but across the three contiguous fields, the patches were widespread. I suspected a vascular disease because of what appeared to be a progression of the disease from yellowing to necrosis to eventually plant death. I submitted samples to the plant pathology lab at UC Davis, and they diagnosed Fusarium oxysporum f. sp. ciceris, which is the Fusarium wilt pathogen for garbanzos. Fusarium wilt (also called Fusarium yellows) has the external symptoms previously described, but in addition to these symptoms, splitting the stems may reveal reddish-brown streaking in the vascular system at the center of the stem (i.e. xylem). The roots won’t show discoloration with Fusarium wilt like they will with Fusarium root rot. Fusarium wilt should not be confused with yellowing caused from virus, which will exhibit discoloration in the phloem. Fusarium wilt can reduce yield by reducing seed quantity and size.

    In general, cultural practices are the only ways to manage this disease. Luckily, the Fusarium wilt pathogens are crop-specific, so this pathogen will only infect garbanzos. The pathogen, however, can survive for a long time in the soil (upwards of 6 years or more) because it can survive under wide temperature and pH ranges. Therefore, crop rotation is an important management practice. Crop rotation will help to slow the proliferation of the disease, but it generally won’t eliminate it. Growers should plant certified disease-free seed. They should not save seed for planting because Fusarium wilt (and Ascochyta blight) can live externally on the seed. Growers should also consider planting UC-27, which has disease resistance and is adapted to the Central Valley. Disease management may also include cleaning soil from equipment when moving from an infected field to a non-infected field. In some studies, soil solarizaton has been shown to reduce Fusarium wilt in subsequent garbanzo crops, but to my knowledge, there hasn’t been any work on soil solarization in California garbanzos.

    Garbanzo beans are an important crop worldwide for human and animal nutrition. In California, they are grown during the winter months, like small grains, and provide growers with another crop choice that can be winter rain-fed. Because they are a legume, they can fix atmospheric nitrogen to fulfil some of their nitrogen needs. Garbanzos also are more tolerant of soil salinity than common beans and limas. In California, we annually grow approximately 10,000 acres of garbanzos. California garbanzos are generally a high-quality product grown for the canning industry. More information on garbanzo production in California can be found in the UC production manual.