Morphological and yield characteristics of 'Washington' navel orange and 'Tahiti' lime trees produced with buds from "floral" versus "vegetative" mother shoots

Authors: LOVATT, CAROL - University Of California - Cooperative Extension Service; Krueger, Robert

Submitted to: Acta Horticulturae
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/31/2013
Publication Date: 2/1/2015
Publication URL: http://handle.nal.usda.gov/10113/60759
Citation: Lovatt, C.J., Krueger, R. 2015. Morphological and yield characteristics of 'Washington' Navel Orange and 'Tahiti' Lime trees produced with buds from "floral" versus "vegetative" mother shoots. Acta Horticulture Proceedings. 1065:1831-1837.

Interpretive Summary: Citrus trees produce both “floral” shoots and “vegetative” shoots. “Floral” shoots produce more inflorescences and fewer daughter vegetative shoots from similar numbers of nodes than do “vegetative” shoots. Portions of a citrus tree canopy that are composed predominantly of floral shoots produce a larger proportion of the tree’s total yield than do portions that are composed predominantly of vegetative shoots. We hypothesized that trees propagated from buds taken from floral shoots would retain the internal physiological status of a floral mother shoot to produce more floral daughter shoots than trees propagated from buds taken from vegetative mother shoots and thus be more productive. This hypothesis was tested on ‘Tahiti’ lime and ‘Washington navel’ trees at the University of California, Riverside. At age 3 years, ‘Tahiti’ lime trees propagated from buds from floral mother shoots produced 28% more fruit than trees propagated from vegetative mother shoot buds. Similarly, 3-yr-old ‘Washington’ navel orange trees produced with buds from floral mother shoots yielded 26% more fruit than trees produced with buds from vegetative mother shoots. For ‘Washington’ navel trees propagated with buds from floral mother shoot, 4-year cumulative and 4-year average yield as number of fruit per tree was significantly greater than trees propagated with buds from vegetative mother shoots; the same relationship was true for ‘Tahiti’ lime, but the results were not significant at the 5% confidence level.

Technical Abstract: Citrus cultivars bear “floral” shoots that produce more inflorescences than vegetative shoots (411 inflorescences, 11 vegetative shoots). Each cultivar also bears “vegetative” shoots that produce fewer inflorescences (208) and more vegetative shoots (202) than floral shoots on a similar number of nodes. Canopy sections in which floral shoots develop contribute a greater percent of tree total yield than those dominated by vegetative shoots. We hypothesized that trees propagated from buds taken from floral shoots would retain the internal physiological status of a floral mother shoot to produce more floral daughter shoots than trees propagated from buds taken from vegetative mother shoots and thus be more productive. Buds from the two types of mother shoots collected from ‘Tahiti’ lime and ‘Washington’ navel orange were budded on ‘Carrizo’ citrange rootstocks. Forty trees were established in a field at UC-Riverside. At age 3 years, ‘Tahiti’ lime trees propagated from buds from floral mother shoots produced 28% more fruit than trees propagated from vegetative mother shoot buds. Similarly, 3-yr-old ‘Washington’ navel orange trees produced with buds from floral mother shoots yielded 26% more fruit than trees produced with buds from vegetative mother shoots. For ‘Washington’ navel orange trees propagated with buds from floral mother shoot, 4-year cumulative and 4-year average yield as number of fruit per tree was significantly greater than trees propagated with buds from vegetative mother shoots; the same relationship was true for ‘Tahiti’ lime, but the results were not significant at the 5% confidence level.