Rootstock and Citrus

By Phillip Rucks, Phillip Rucks Citrus Nursery

Whether you are a professional, are thinking about it, or just want fresh citrus on the weekends, when it comes to planting a citrus tree, it is important to consider the appropriate rootstock in order to maximize your investment.

Luckily, the new Custom Query Option for the Citrus Rootstock Selection Guide was recently released online and has now been expanded to include a system to aid growers in rootstock selection. Using grower-supplied information to analyze 900 factors, the rootstock selection guide generates a ranked list for that site based on the user’s criteria.

In the report “2018-2019 Florida Citrus Production Guide: Rootstock and Scion Selection” authors Ute Albrecht, Fernando Alferez, and Mongi Zekri point out that the right rootstock and scion combination can result in higher returns without additional cost. Rootstocks affect scion vigor, yield, fruit size, and pest tolerance. However, other factors need to be considered in order to nd the best rootstock for your specific area.

The first thing a rootstock selection should be based on is soil characteristics. One should also take into consideration whether the planting site is a cold location as some rootstocks are more cold hardy than others. Choosing the right rootstock for your soil type is critical. Rootstocks performing satisfactorily on the well-drained sandy soils of the central Florida ridge may not be suitable for the wet “ flatwoods” soils of the southwest and eastern Florida production areas.

Equally important is the ability to better tolerate conditions of high pH and salinity. e second factor to take into consideration when it comes to new rootstocks is pest and disease pressure, A lot of the newer rootstock cultivars are of partially trifoliate origin, therefore inheriting some degree of tolerance to Phytophthora. Unfortunately, damage from Phytophthora is exacerbated in roots already compromised by HLB.

Although thus far no rootstock has shown to induce desired levels of tolerance to HLB, trees grown on some of the newer rootstock cultivars produce good yields under high HLB pressure and exhibit lower than average rates of fruit drop. Other factors to consider include the choice of scion, desired tree spacing, and size control, and other characteristics. Several new rootstock selections were recently released, but not much information exists on their long-term performance under different environmental conditions and different commercial management. They are available through licensed nurseries, and through FFSP – Florida Foundation Seed Producers.