Search results for "FRUIT SET"

Gibberellin reactivates and maintains ovary-wall cell division causing fruit set in parthenocarpic Citrus species

2016

[EN] Citrus is a wide genus in which most of the cultivated species and cultivars are natural parthenocarpic mutants or hybrids (i.e. orange, mandarin, tangerine, grapefruit). The autonomous increase in GA(1) ovary concentration during anthesis was suggested as being the stimulus responsible for parthenocarpy in Citrus regardless of the species. To determine the exact GA-role in parthenocarpic fruit set, the following hypothesis was tested: GA triggers and maintains cell division in ovary walls causing fruit set. Obligate and facultative parthenocarpic Citrus species were used as a model system because obligate parthenocarpic Citrus sp (i.e. Citrus unshiu) have higher GA levels and better n…

Effect of fruit-set time on the quality performance of Anona cherimola Mill. fruit in south italy

2019

Abstract The aim of this work was to analyse the differences between fruits obtained by different dates of fruit set and identify the proper fruit-set time that allows to obtain the optimum fruit quality in Annona cherimola cv Fino de Jete, planted in Southern Italy. Six fruit-set dates were selected from the first week of June to the second week of July. Fruits were sampled from October to November, when 1500 Growing Degree Days (DD) were accumulated; The DD were calculated using a base temperature of 12 °C. Fruit fresh weight (FW) and skin colour were measured. These parameters were measured also after storage, and in addition, the following parameters were measured: fruit shape (FS), pul…

Gibberellic acid in Citrus spp. flowering and fruiting: A systematic review

2019

[EN] Background In Citrus spp., gibberellic acid (GA) has been proposed to improve different processes related to crop cycle and yield. Accordingly, many studies have been published about how GA affects flowering and fruiting. Nevertheless, some such evidence is contradictory and the use of GA applications by farmers are still confusing and lack the expected results. Purpose This review aims to collate, present, analyze and synthesize the most relevant empirical evidence to answer the following questions: (i) how does gibberellic acid act on flowering and fruiting of citrus trees?; (ii) why is all this knowledge sometimes not correctly used by farmers to solve yield problems relating to flo…

Urea as a thinning agent in olive: The influence of concentration and time of application

1992

Urea was tested as chemical thinner on olive cv. Nocellara del Belice using three concentrations (2, 4 and 6%) applied at full bloom (FB), FB + 10 and FB + 20 days. Urea reduced fruit set significantly only when applied at FB + 20 days, the fruitlet stage. Final fruit set was reduced by about 50% compared with the untreated control (6% FB + 20 days). Crop load and fruit characteristics were both affected by the treatments.

Improvement in yield and fruit size and quality of the main Italian table olive cultivar 'Nocellara del Belice'

2014

Olive (Olea europaea L.) shows alternate bearing, with unreliable cropping patterns and inconsistent fruit size and quality every year. In many countries, thinning with naphthaleneacetic acid (NAA) is used to minimise alternate bearing behavior in olives. However, in Italy, growers are reluctant to employ this practice and no detailed knowledge is available for specific cultivars. We evaluated the effects of spraying NAA on various dates on the productive and vegetative characteristics of the main Italian table olive cultivar'Nocellara del Belice'. Trunk cross-sectional area, fruit set, fruit drop, fruit size, pit size, yield per tree, crop density and flesh to pit ratio were analysed. The …

NUTRITIONAL AND HORMONAL FACTORS AFFECTING FRUIT SET IN AVOCADO (Persea americana Mill.)

2017

Under favourable conditions, the avocado sets more fruits than the tree is able to bring to maturity, so that the plant adjusts, during the early stages of development, its ability to nourish them by modifying their number, that is, causing the fruit drop of those who can not maintain their growth rate. Accordingly, carbohydrate availability could be a key factor in the physiological abscission of these fruits. Since this species presents dichogamy, the abscission of fruits has also been attributed to the absence of pollination, but at the same time it has been related to failures in seed development, embryo abortion, seed coat collapse, and with the effect of an environmental stress, espec…

Two new apricot varieties

2010

Nella and Dora are apricot seedlings recently selected by R. Chiappetta in Sicily. Their vegetative, floreal, agronomic and fruit-quality characteristics were checked for three years (2003 - 2005) in Partinico (Palermo coast area), under mild winter and spring temperatures, in comparison with Tyrinthos variety. Nella and Dora have an upright tree habit and are self-compatible. Blooming started a week earlier in Nella and Tyrinthos (end of February) and concluded in the second part of March in all varieties. Fruit set was satisfactory in all cultivars. Crop was harvested from May 25th to 30th in Dora, May 24th to 30th in Nella and May 24th to 28th in Tyrinthos. Fruit weight, as a three years…

GIBBERELLINS REGULATE CELL DIVISION AND PARTHENOCARPIC FRUIT SET IN CITRUS

Fruit set and growth is regulated by hormones interaction, gibberellins (GA) being a main part of the process in Citrus. Actually, it is well known the time-course of GA content in the citrus ovary during flowering and its correlation with fruit set in both seeded and seedless species. However, GA endogenous role is uncertain. Is GA in the ovary a direct regulator or an indirect part of the hormonal stimuli that reactivates and maintains cell division triggering fruit set? While in seeded varieties GA synthesis that occurs in fertilized ovules is the primary stimulus controlling early ovary development, is there any specific tissue-dependent regulation of parthenocarpy? While initiation of …

Grapevine fruit set: Physiology of the abscission zone

2000

Effects of ethylene and of 'anti-ethylene' compounds on the floral pedicel abscission zone in grapevines were analysed via a laboratory model consisting of isolated flowers held in Petri dishes. Our model permitted precise determination of abscission and enabled us to test a range of physiologically-active compounds including ethylene precursors, and antagonists of ethylene action. For example, a precursor of ethylene, 1-aminocyclopropane-l-carboxylic acid, had the same effect as ethylene in promoting abscission. Conversely, an inhibition of ethylene action by silver thiosulfate or an inhibition of ethylene synthesis by amino-oxyacetic acid both strongly inhibited abscission zone function. …