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ARS Home » Southeast Area » Fort Pierce, Florida » U.S. Horticultural Research Laboratory » Subtropical Insects and Horticulture Research » Research » Publications at this Location » Publication #344656
Title: Influence of propagation method on root architecture and other traits of young citrus rootstock plants

Author
item ALBRECHT, UTE - Mid Florida Research & Education Center
item BORDAS, MIREIA - Keyplex
item LAMB, BETH - Keyplex
item MEYERING, BO - Mid Florida Research & Education Center
item Bowman, Kim

Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/8/2017
Publication Date: 11/1/2017
Citation: Albrecht, U., Bordas, M., Lamb, B., Meyering, B., Bowman, K.D. 2017. Influence of propagation method on root architecture and other traits of young citrus rootstock plants. HortScience. 52(11):1569-1576. https://doi.org/10.21273/HORTSCI12320-17.
DOI: https://doi.org/10.21273/HORTSCI12320-17

Interpretive Summary: There are generally inadequate supplies of seed for the newest citrus rootstocks to satisfy the growing demand for propagation material to be used in commercial citrus nurseries. Consequently, rootstock propagation, which is traditionally by seed, now often makes use of alternative methods such as cuttings and tissue culture. There are concerns that these alternative methods of propagation might result in an inferior root system and tree, as compared with trees propagated on seedling rootstocks. This study examined the root architecture and growth of plants generated by the seed, cuttings, and micropropagation during the first few months, to determine whether there were any important differences. The study found that rootstock plants propagated by cuttings or micropropagation generally had a larger root system with more primary roots, more first order lateral roots, and larger specific root length, as compared with plants of the same rootstock clone propagated by seed. Generally, more and longer roots on plants will be associated with better uptake of water and nutrients, so the study suggests that plants propagated by cuttings or micropropagation may have an advantage over seedlings in this area.

Technical Abstract: Citrus rootstock propagation, which is traditionally by seed, now often makes use of alternative methods such as cuttings and tissue culture because of inadequate supplies of seed for the best new rootstocks. Propagation via cuttings and tissue culture will generate a root system that is largely composed of adventitious or lateral roots, compared with seed propagation which will generally include the formation of a well-defined taproot. In this study, we compared root architecture and growth of 7 different rootstock plants, generated from seed, stem cuttings or tissue culture, during the first months of growth in the greenhouse. The percent root mass of plants generated from cuttings ranged from 11% to 16%, and from 16-29% and 21-30% for micropropagated plants and seedlings, respectively. Plants propagated via cuttings had the largest number of primary roots (7-10), followed by tissue-culture-propagated plants which developed an average of 2-6 primary roots. As expected, plants grown from seed mostly developed a single and well-defined taproot during the first months. The total number of 1st order lateral roots was highest in the plants propagated as cuttings (108-185) compared with 53-103 and 43-78 for tissue-culture propagated plants and seedlings, respectively. Similarly, specific root length was highest in plants derived from cuttings (21-43 m/g) and lowest in plants grown from seed (7-20 m/g). It is suggested that the larger number and length of roots on rootstock plants propagated via vegetative methods may be better suited for resource acquisition as compared with seed propagated plants.