LIBRO-CONGRESO-CITRUS

S11
compare ‘Valencia’ trees on (1) ‘Rangpur’ lime, on (2) ‘Swingle’ citrumelo, or (3) as inarched using these
two rootstocks. Inarched trees had the same size as those on ‘Rangpur’ alone and both types were larger
than trees on ‘Swingle’ alone in the first 5-7 years of the orchards. Inarched trees had similar yields as those
on ‘Rangpur’ lime alone and both types yielded more than trees on ‘Swingle’ alone. In addition, inarched
trees had fruit quality intermediary between that of fruit from trees on ‘Rangpur’ and that of fruit from
trees on ‘Swingle’ alone.
S11O04
Morphological and yield characteristics of ‘Washington’ navel orange and ‘Tahiti’ lime trees
produced with buds from floral versus vegetative mother shoots
Lovatt C.J. 1 , and Krueger R.R. 2
1University of California-Riverside (UCR), Department of Botany and Plant Sciences, USA; and 2USDA-ARS National Clonal Germplasm
Repository (USDA-ARS), USA. carol.lovatt@ucr.edu
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 shoot yielded 26% more fruit than trees produced with buds from vegetative mother
shoots. At the end of June drop, 4-yr-old ‘Washington’ navel orange trees propagated from floral mother
shoot buds retained 35% more fruit than trees propagated with vegetative shoot buds, but the reverse was
true for ‘Tahiti’ lime.
S11O05
Effect of different pruning severities on incidence of creasing and fruit quality in sweet orange
Hussain Z., Singh Z., and Mandel R.
Horticulture Research Laboratory, (HRL), Department of Environment and Agriculture, School of Science, Faculty of Science and
Engineering, GPO Box U1987, Perth, 6845, WA, Australia. zachoundi@yahoo.com
Creasing (albedo breakdown) is a physiological disorder with cracks in the internal white tissue (albedo)
causing puffiness of orange peel. It causes considerable economic losses to citrus growers in Australia and
other parts of the world. We investigated the effects of pruning severities on incidence of creasing and fruit
quality in ‘Washington’ navel, ‘Lane Late’ and ‘Navelina’ sweet oranges. Pruning treatments including control
(no pruning), light pruning (25% branches) and severe pruning (50% branches) were applied after fruit harvest
on 20th September, 2010 at Gingin, Western Australia. The experiment was laid down following a split plot
design, with four replications and single tree as an experimental unit. Thirty five ripe fruits per tree were
harvested randomly around the tree canopy to determine the incidence of creasing and fruit quality. Results
showed that both pruning treatments have reduced percentage of creased fruit and creasing index in all
three cultivars as compared to control. Severe pruning was more effective in reducing creasing in all cultivars
than light pruning. The effects of pruning on soluble solids and acid ratio, ascorbic acid, total antioxidants,
individual sugars and organic acids in the juice will also be presented and discussed. In conclusion, severe
pruning was more effective in reducing the incidence of creasing and enhancing the fruit quality in sweet
oranges.
178 - VALENCIA CONFERENCE CENTER, 18th-23rd NOVEMBER 2012