scholarly journals Leafy Influorescences: Key to Improve Fruit Set and Yield of the 'Shamouti' and 'Washington' Navel Orange Varieties

1985 ◽  
Author(s):  
Yair Erner ◽  
Carol J. Lovatt ◽  
Charles W. Coggins, Jr.
Keyword(s):  
Fruit Set ◽  
Navel Orange ◽  
Washington Navel

Response of orchard 'Washington Navel' orange, Citrus sinensis (L.) Osbeck, to saline irrigation water. II. Flowering, fruit set and fruit growth

1989 ◽  
Vol 40 (2) ◽  
pp. 371 ◽  
Author(s):  
H Howie ◽  
J Lloyd
Keyword(s):  
Leaf Area ◽  
Citrus Sinensis ◽  
Fruit Set ◽  
High Salinity ◽  
Starch Content ◽  
Fruit Growth ◽  
Leaf Abscission ◽  
Navel Orange ◽  
Washington Navel ◽  
Floral Differentiation

Flowering, fruit set and fruit growth of 'Washington Navel' orange fruit was monitored on 24-year-old Citrus sinensis trees on Sweet orange rootstocks that had been irrigated with either 5 or 20 mol m-3 NaCl for 5 years preceding measurements.Trees irrigated with high salinity water had reduced flowering intensities and lower rates of fruit set. This resulted in final fruit numbers for trees irrigated with 20 mol m-3 being 38% those of trees irrigated with 5 mol m-3 NaCl. Final fruit numbers were quantitatively related to canopy leaf area for both salinity treatments.Despite little difference between trees in terms of leaf area/fruit number ratio, slower rates of fruit growth were initially observed on high salinity trees. This effect was not apparent during the latter stages of fruit development. Consequently, fruit on trees irrigated with 20 mol m-3 NaCl grew to the same size as fruit on trees irrigated with 5 mol m-3 NaCl, but achieved this size at a later date. Measurements of Brix/acid ratios showed that fruit on high salinity trees reached maturity standards 25 days after fruit on low salinity trees.Unimpaired growth of fruit on high salinity trees during summer and autumn occurred, despite appreciable leaf abscission, suggesting that reserve carbohydrate was utilized for growth during this period. Twigs on high salinity trees had much reduced starch content at the time of floral differentiation in winter. Twig starch content and extent of floral differentiation varied in a similar way when examined as a function of leaf abscission. This suggests that reduced flowering and fruit set in salinized citrus trees is due to low levels of reserve starch, most of which has been utilized to support fruit growth in the absence of carbohydrate production during summer and autumn.

scholarly journals Effect of Urea, Some Micronutrients, and Growth Regulator Foliar Sprays on the Yield, Fruit Quality, and Some Vegetative Characters of Washington Navel Orange Trees: Fruit Pedicel Pectin Content, Flowering Aspects, and Fruit Set, and Dropping Percentages

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 880B-880
Author(s):  
Ahmed M. Akl ◽  
Abdel-Fattah M. Eid ◽  
Mohamed Y. Hegab
Keyword(s):  
Growth Regulators ◽  
Fruit Quality ◽  
Growth Regulator ◽  
Fruit Set ◽  
Navel Orange ◽  
Fruit Drop ◽  
Pectin Content ◽  
Washington Navel ◽  
Vegetative Characters ◽  
Orange Trees

This part of the investigation studied the effect of foliar spraying with urea (0.5%); a mixture of Zn (0.4%), Mn (0.3%), Fe (0.5%), and Cu (0.3%) in sulphates (from 23% Zn, 28% Mn, 19% Fe, and 30% Cu, respectively); and two growth regulators (GA3 at 25 ppm and α-NAA at 10 ppm); as well as number and date of sprays on fruit pedicel pectin content, some flowering aspects, and fruit set and drop percentages. Applying urea, micronutrients, or both significantly increased pectin content in the pedicels of the attached and dropped fruit. The treatment including urea plus micronutrients resulted in the highest values for pectin in fruit stem. Either GA3 or NAA significantly raised pectin content over that of the water-sprayed control. However, NAA was more effective in increasing pectin content in fruit pedicel. The overall treatment including urea and micronutrients with GA3 or NAA was the most effective in producing the highest percentage of leafy inflorescence in 1991–92 and 1992–93 seasons. Any nutrition treatment was significantly effective in increasing fruit set and reducing fruit drop compared with the water-sprayed control; however, the treatment including all sprayed nutrients was the most effective. Application of GA3 or NAA significantly increased fruit set percentage and reduced June and preharvest fruit drop; however, NAA was more effective in reducing fruit drop than GA3.

The development of cuttings of the Washington navel orange to the stage of fruit set. III. The fruiting cutting

1961 ◽  
Vol 12 (6) ◽  
pp. 1081 ◽  
Author(s):  
CT Gates ◽  
D Bouma ◽  
H Groenewegen
Keyword(s):  
Fruit Set ◽  
Dominant Role ◽  
Field Studies ◽  
Nutrient Supply ◽  
Navel Orange ◽  
Developmental Studies ◽  
Cycle Growth ◽  
Washington Navel ◽  
Npk Fertilization

Studies of the effect of NPK fertilization on fruiting cuttings of the Washington Navel orange are described and are considered in relation to previous developmental studies. Fruiting occurred on the second cycle growth flush. The growth of the plant as a whole was affected by nutrient supply. Where fruit was developed, its development was at the expense of the rest of the plant, and especially of the parts nearest to it. In this regard, the dominant role of the fruit with respect to the vegetative parts, differed from the somewhat uniform pattern of response between the vegetative parts that was previously observed for a differential in phosphorus supply. The importance of adequate nutrition in early stages of fruit development is apparent, and the value of the technique in field studies is noted.

Competition and fruit set in the Washington navel orange

1984 ◽  
Vol 62 (3) ◽  
pp. 297-302 ◽  
Author(s):  
J. L. Guardiola ◽  
F. Garcia-Mari ◽  
M. Agusti
Keyword(s):  
Fruit Set ◽  
Navel Orange ◽  
Washington Navel

scholarly journals Effect of Urea, Some Micronutrients, and Growth-regulator Foliar Sprays on the Yield, Fruit Quality, and Some Vegetative Characteristics of `Washington' Navel Orange Trees—Vegetative Growth and Mineral Leaf Content

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 774D-774
Author(s):  
Ahmed M. Akl ◽  
Abdel-Fattah M. Eid ◽  
Mohamed Y. Hegab
Keyword(s):  
Growth Regulators ◽  
Growth Regulator ◽  
Fruit Set ◽  
Shoot Length ◽  
Navel Orange ◽  
Pronounced Increase ◽  
Leaf Analysis ◽  
Washington Navel ◽  
Macro And Micronutrients ◽  
Orange Trees

This investigation was carried out during the experimental seasons of 1991–92 and 1992–93 on 25-year-old `Washington' navel orange trees grown in an orchard at Beni Suef (≈120 km south of Cairo). This part of the investigation studied the effect of foliar spraying urea (0.5%), a mixture of Zn (0.4%), Mn (0.3%), Fe (0.5%), and Cu (0.3%) in sulfates from 23% Zn, 28% Mn, 19% Fe, and 30% Cu, respectively, and two growth regulators (GA3 at 25 ppm and α-NAA at 10 ppm) on some vegetative aspects and leaf content of some macro- and micronutrients. The investigation also included the effect of number and date of spraying (one spray 3 weeks before flowering, one spray 4 weeks after fruit set, and two sprays at the two dates) on the studied traits. The results showed that the overall treatments included two sprays of urea, micronutrients (Zn, Mn, Fe, and Cu) and NAA at 10 ppm achieved the highest values for average leaf area and shoot diameter in both seasons. The treatment on shoot length was more effective when GA3 replaced NAA. Leaf analysis showed that the application of any of the nutrients was responsible for a pronounced increase in leaf content of that element, but reduced the contents of others. Growth regulator treatments lowered leaf content of the determined elements. However, all other treatments in this study reduced leaf content of P and K.

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