Evaluation of Coffea arabica cultivars for resistance to Meloidogyne konaensis

Authors: Myers, Roxana; Mello, Cathy; NAGAI, CHIFUMI - Hawaii Agriculture Research Center; SIPES, BRENT - University Of Hawaii; Matsumoto Brower, Tracie

Submitted to: Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/26/2023
Publication Date: 5/31/2023
Citation: Myers, R.Y., Mello, C.L., Nagai, C., Sipes, B.S., Matsumoto Brower, T.K. 2023. Evaluation of Coffea arabica cultivars for resistance to Meloidogyne konaensis. Agriculture. 13(6). Article 1168. https://doi.org/10.3390/agriculture13061168.
DOI: https://doi.org/10.3390/agriculture13061168

Interpretive Summary: Coffee is the 2nd highest valued crop in the State of Hawaii and is recognized for its superior cupping quality. In advancing the coffee breeding program, attention needs to be focused on maintaining that reputation while providing growers with cultivars that have resistance to damaging pests and diseases. Utilizing host plant resistance as a management strategy helps mitigate damage without changes to grower practices or harm to the environment. Root-knot nematodes are pervasive in the Kona and Ka'u coffee growing regions and extremely damaging to the root systems of coffee plants. In this study, we evaluated semi-wild Ethiopian Coffea arabica cultivars and found them to be highly resistant to the Kona coffee root-knot nematode. With the recent introduction of coffee leaf rust to the islands, there is great interest in replanting with rust resistant coffee cultivars. We examined two of these cultivars to understand their vulnerability to the local root-knot nematode species and found both cultivars to be susceptible and intolerant of nematode infestation. Using the nematode resistant Ethiopian Arabica and cultivars resistant to coffee leaf rust as parents in the breeding program could lead to new cultivars for the Hawaii coffee industry that provide resistance to both root-knot nematodes and coffee leaf rust.

Technical Abstract: Coffee is an important agricultural crop for the State of Hawaii. Developing new coffee cultivars with resistance to damaging pests and diseases is crucial for improving production and maintaining the profitability of the industry. With the recent discovery of Hemileia vastatrix, coffee leaf rust (CLR), to Hawaii there is a strong interest in replanting with CLR-resistant germplasm. However, when selecting an appropriate cultivar for replanting, susceptibility to other pathogens, such as plant-parasitic nematodes, should be taken into consideration. Meloidogyne konaensis, the Kona coffee root-knot nematode, causes severe destruction of the root system, reducing the yield and causing the mortality of susceptible Coffea arabica cv. Typica trees. Fortunately, resistance to root-knot nematodes has been found in some C. arabica germplasm. In this study, accessions of wild Ethiopian C. arabica and two CLR-resistant C. arabica cultivars, Tupi-HI and Obata, were evaluated for resistance to M. konaensis in a greenhouse bioassay. All Ethiopian accessions retained high levels of resistance, resulting in reproductive factors (Rfs) lower than 1.0, and low root-rot ratings. Tupi-HI was highly susceptible to M. konanensis, with an Rf value of 7.12, whereas Obata was slightly susceptible, with an Rf value of 2.33. Both cultivars had high root-rot ratings, suggesting intolerance to the nematode. Hybridizing Ethiopian C. arabica with Tupi-HI or Obata may result in new elite cultivars, resistant to both H. vastatrix and M. konaensis.