22 Feb 2024
Citrus Fruit Variety

Increasing fruit size in Citrus. Thinning and stimulation of fruit growth

The importance of fruit size as a parameter of quality of citrus fruits has increased markedly in recent times. The consumer’s marked preference for large fruit causes huge differences in price between large and small fruit to the point that the income from the smaller fruit is often less than picking and hauling costs. Fruit size has become as important as yield in the determination of the profitability of citrus plantings, and an economic premium is usually obtained through the increase in fruit size even at the expense of a reduction in crop yield. This applies not only to the small fruited mandarins and hybrids but also to large fruit species such as lemons, oranges and grapefruit. To increase fruit size beyond the limits which may be obtained through the optimization of the standard cultural practices (fertilization, irrigation, pruning), several techniques have been tried such as hand thinning [80], chemical and hormone thinning [49, 77] and the hormonal  stimulation of fruit growth rate by synthetic auxins [69, 70, 71]. The earlier investigations on this subject were reviewed extensively by Coggins and Hield [12], Monselise [57] and Wilson
[78], which pointed out some drawbacks encountered with the use of these techniques in practice. Particularly, the application of synthetic auxins to increase fruit size often resulted in too erratic results to justify the use of these compounds by the growers [57].


25 Aug 2023
Citrus Fruiting

Physiology of citrus fruiting.

Citrus is the main fruit tree crop in the world and therefore has a tremendous economical, social and cultural impact in our society. In recent years, our knowledge on plant reproductive biology has increased considerably mostly because of the work developed in model plants. However, the information generated in these species cannot always be applied to citrus, predominantly because citrus is a perennial tree crop that exhibits a very peculiar and unusual reproductive biology.


28 Apr 2021
Orange Blossom

Effects of gibberellin treatment during flowering induction period on global gene expression and the transcription of flowering-control genes in Citrus buds

As we enter the flower induction stage different factor control the amount of flowering for the next season. Gibberellic acid (GA) is a strong inhibitor for the flowering genes in Citrus. The aim of the study was to determine to what length GA has got an influence. GA was applied on citrus bud and the genetics analyzed and more Leafy mRNA were transcribed in these buds.


25 Jan 2021

Fruit load restricts the flowering promotion effect of paclobutrazol in alternate bearing Citrus spp.

The floral bud inductive period, PBZ promotes flowering in Citrus; however, our results indicate that this effect is fruit-load dependent. In ‘Salustiana’ and ‘Navelina’ sweet oranges, ‘Hernandina’ Clementine mandarin, and ‘Afourer’ and ‘Moncada’ hybrids, flowering intensity significantly increased the following spring for medium-to-low fruit-load trees treated with either 1–10 g PBZ tree−1 applied to the soil or 15 g tree−1 sprayed on the canopy. PBZ significantly increased the percentage of sprouted buds and leafless floral shoots (both single-flowered shoots and inflorescences) and reduced the number of vegetative shoots.


31 Jul 2019
Citrus Improvement

Quality and Quantity Improvement of Citrus: Role of Plant Growth Regulators

Harsimrat K. Bons, H.S. Rattanpal
Department of Fruit Science, Punjab Agricultural University, Ludhiana, Punjab, India.
Nirmaljit Kaur
Department of Botany, Punjab Agricultural University, Ludhiana, India.

Citrus is one of the most important fruit tree species in the world, as the fruits are a valuable source of nutrients, vitamins and other antioxidant compounds. The citrus productivity depends on various factors, among these the plant growth regulators holds a prime position. The use of plant growth regulators has become an important component in the field of citriculture because of the wide range of potential roles they play in increasing the productivity of crop per unit area. The plant growth regulating compounds actively regulate the growth and development by regulation of the endogenous processes and there exogenous applications have been exploited for modifying the growth response.