Gall Rust Disease Incidence and Severity in a Falcata (Falcataria moluccana (Miq.) Barneby & J.W.Grimes) Plantation Grown from Select Mother Trees in Mindanao, Philippines

It remains unknown whether there are available gall rust resistant seed sources of Falcata (Falcataria moluccana (Miq.) Barneby & J.W.Grimes) in the country or elsewhere. This study was conducted to obtain baseline data for future progeny selection of gall rust resistant clones of Falcata in the region. The objectives were to determine whether there are available seed sources or mother trees in the region that are resistant to gall rust, and whether gall rust infection has negative effects on the growth of Falcata. The trial (with 130 mother trees as treatments and four replications) was assessed in November 2020- or five-years following establishment in 2015. Mean percent incidence (15.0 ± 5.0% to 80.0 ± 14.1%) and severity (3.75 ± 1.25%) to 35.0 ± 16.95%) of gall rust varied significantly among treatments indicative of genetic diversity among mother trees. The incidence ranged from ‘occasional’ to ‘widespread’ while severity ranged from ‘low’ to ‘high’ with mother trees 99 (Mutia, Zamboanga del Norte) and 106 (Magsaysay, Baliangao, Misamis Occidental) emerged as the most resistant of all. Height and diameter were positively related to gall rust incidence and treatments only, although none of the mother trees with resistant traits had superior growth. There was however indication of growth and disease tolerance tradeoff where trees with higher gall rust incidence tend to grow bigger perhaps to compensate for any negative impacts from gall rust infection.