Grafted coffee increases yield and survivability

Authors: Myers, Roxana; KAWABATA, ANDREA - University Of Hawaii; NAKAMOTO, STUART - University Of Hawaii; CHO, ALYSSA - University Of Hawaii

Submitted to: HortTechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/13/2020
Publication Date: 5/11/2020
Citation: Myers, R.Y., Kawabata, A., Nakamoto, S., Cho, A. 2020. Grafted coffee increases yield and survivability. HortTechnology. 30(3):428-432. https://doi.org/10.21273/HORTTECH04550-20.
DOI: https://doi.org/10.21273/HORTTECH04550-20

Interpretive Summary: Typica coffee, Coffea arabica, grown in Hawaii is negatively affected by Kona coffee root-knot nematode. Severe root destruction by this pest results in coffee decline causing leaf flagging, yellowing, and subsequent defoliation. Roots become necrotic, corky, and feeder roots diminish. Yields of infested coffee are significantly reduced below optimal production levels. Other coffee species exist that exhibit tolerance to root-knot nematodes and can be used as rootstocks on susceptible Typica scions. These species have more vigorous root systems that remain healthy in the presence of high nematode populations. An infested field planted in 2006 evaluated seven coffee cultivars for their potential as nematode tolerant rootstocks. In the last 3 harvest seasons, all but one of the cultivars tested had higher yields than non-grafted Typica. After 13 years, root-knot nematodes killed 81% of non-grafted Typica trees. From this trial, new rootstocks have been identified that show promise as management tools for coffee root-knot nematodes.

Technical Abstract: Kona coffee root-knot nematode (Meloidogyne konaensis) causes severe decline of ‘Kona Typica’ arabica coffee trees (Coffea arabica) in Hawaii. Defoliation and destruction of the root system results in significant yield losses and can kill the host. Grafting with other coffee species (Coffea) that exhibit tolerance to root-knot nematodes is a viable solution for mitigating damage in the field. An infested field was established in 2006 with ‘Kona Typica’ scions being grafted on seven accessions of promising rootstock and non-grafted ‘Kona Typica’ as the control. Four grafted trees of each accession were planted per plot with four repetitions. Yield data was assessed for the 2016-17, 2017-18, and 2018-19 seasons. Three liberica coffee (Coffea liberica) accessions [‘Arnoldiana’ (‘Arnoldiana’ 1 and ‘Arnoldiana’ 2), ‘Dewevrei’, ‘Fukunaga’ 1], demonstrated higher yields of coffee cherry compared to non-grafted ‘Kona Typica’ in the 2016-17 season. In the 2017-18 and 2018-19 seasons, five accessions of liberica and ‘Nemaya’ robusta coffee (Coffea canephora) exhibited higher cherry yields than ‘Kona Typica’. Plant vigor was greater in trees grafted on ‘Arnoldiana’ and ‘Fukunaga’ compared to other accessions and non-grafted ‘Kona Typica’ with taller trees, higher vertical branches, thicker trunk circumference, and overall better health. After 13 years in the field, non-grafted ‘Kona Typica’ showed the highest mortality with 81% of trees lost. Liberica rootstocks performed consistently well in the presence of kona coffee root-knot nematode with the healthiest trees, highest yields, and least mortality of the coffee species evaluated.