Early Response of ‘Mexican’ Lime, ‘Fina’ Clementine Mandarin, and ‘Campbell’ Valencia Orange on Selected Rootstocks Grown under Fertigation Practices in an Oxisol in Puerto Rico

In Puerto Rico, Huanglongbing (HLB), detected in 2009, continues to produce losses in orchards across the island. Efforts to produce clean propagation materials and select different combinations of scions and rootstocks to mitigate the disease have been a priority. In 2016, an experiment was established in Isabela in Coto clay series soils at 120 m to assess ‘Mexican’ lime, ‘Fina’ clementine mandarin, and ‘Campbell’ Valencia orange grafted in ‘Swingle’ citrumelo, ‘HRS 812’, and ‘HRS 897’. Tree growth parameters, tree fruit production, HLB incidences, and tree mortality were evaluated under a fertigation system. Higher fruit production was obtained with ‘Fina’ clementine mandarin and ‘Campbell’ Valencia orange when grafted in ‘HRS 812’ followed by ‘HRS 897’. ‘Mexican’ lime had higher fruit production when grafted in ‘HRS 897’. On the basis of total fruit production and HLB incidence, ‘HRS 812’ was outstanding, yielding fruits with higher values even though they were infected with HLB. Moreover, ‘HRS 897’ rootstock was demonstrated to be a potential rootstock for the Puerto Rico conditions.