The Valencia orange is a high quality fruit grown in Turkey; however, small fruit size resulting in poor packouts is common in Valencia oranges. Small fruit size is the main factor limiting the marketing of Valencia oranges; thus, synthetic auxins are commonly used to enhance the size of citrus fruit. The objective of the present study was to observe the effects of 3,5,6-trichloro-2-pyridyloxyacetic acid (3,5,6-TPA) on fruit size, yield and quality of Valencia oranges from 29-year-old trees budded on sour orange rootstock in Adana, Turkey in 2006. The application of 3,5,6-TPA to the entire tree was from 8th to 11th week after anthesis during June drop (JD). Following 3,5,6-TPA treatments, different combinations were used in the experiment: T1 2 tablets per 100 litres applied just after the end of June drop (JD), T2 2 tablets per 100 litres applied 5-7 days after the end of JD, T3 3 tablets per 100 litres applied 5-7 days after the end of JD, T4 4 tablets per 100 litres applied 5-7 days after the end of JD, T5 3 tablets per 100 litres applied 10-14 days after the end of JD and control trees receiving no 3,5,6-TPA (T0).
Mitigation of Heat Stress effects by using Shade Net on Washington Navel Orange Trees grown in Al-Nubaria Region, Egypt
High temperature stress can be detrimental to plants, resulting in reduced fruit yield and increased incidences of fruit disorders. One strategy that farmers can use to maintain or increase their yields in the face of a changing climate is to adjust of farm climate by using shade net on the trees. Such, the use of shade netting on Washington navel orange planted on the sandy soil in Al-Nubaria region, Egypt were studied during two successive seasons, either using a permanent shade throughout all the season or using a moveable shade for certain period from the first of March until the end of June for every season.
Mid-long term effects of saline reclaimed water and regulated deficit irrigation on fruit quality of citrus
Non-conventional water sources and water saving techniques can become a valuable implement in semiarid regions, although its long-term effects on the citrus quality are little known. This study evaluated the effects of irrigation with two sources: transfer water (TW) and reclaimed water (RW) combined with two irrigation strategies: full irrigation (FI) and regulated deficit irrigation (RDI) on fruit quality response of mandarins and grapefruits during eight growth seasons. RESULTS: The RW irrigation in mandarin, without water restriction, determined maturity index (MI, SSC·TA-1) lower than in the TW-FI, owing to titratable acidity (TA) increased to a greater degree than soluble solid contents (SSC). Nevertheless, juice quality standards were satisfied. Besides, regardless of the irrigation treatment (FI or RDI), an increasing trend fruit weight was also detected by RW.
The effect of fruit thinning time and thinning rate on flowering, fruit yield and fruit quality of clementine trees (Citrus clementine Hort. ex Tanaka) was investigated during three successive seasons 2017/2018, 2018/2019 and 2019/2020. Data recorded only during 2018/2019 and 2019/2020 seasons. Thinning applied at three different times on 1st June, 15th June and 30th June. Fruit thinning rate were performed when the fruit diameter reached about 25-30 mm, as hand thinning by removing 0, 25 or 50% of fruit number/shoot per tree.
Regulated deficit irrigation (RDI) has been assessed in a wide number of fruit crops. However, few are the studies dealing with long-term RDI strategies. In this work, we assessed the response of ‘Clementinade Nules’ citrus trees to summer RDI treatments [RDI-1, irrigated at 50% of crop evapotranspiration (ETc)and RDI-2, irrigated at 35% ETc] during six consecutive seasons (2007–2012). Although water restrictions were applied according to reductions over ETc, threshold values of stem water potential (−1.3 to −1.5 MPain the RDI-1 treatment and −1.5 to −1.7 MPa in the RDI-2) were also considered for scheduling deficitirrigation. Results showed that the water stress imposed in the RDI-2 treatment had a noticeable impacton fresh fruit weight, reducing yield and economic return over the six years and more so during the first two years in comparison to a control treatment irrigated at 100% ETc during the whole season. The RDI-1strategy had a lower impact than the RDI-2 treatment on the fresh fruit weight and did not significantly reduce yield or the economic return over the six seasons.
Sheet-mulching Cultivation Promotes the Number of Floral Buds via Upregulation of Citrus Flowering Locus T Expression in Two Citrus Cultivars,‘Haraguchi-wase’ and ‘Harehime’
Sheet-mulching cultivation during the fruit developmental stage is often carried out to produce high-quality Satsuma mandarin (Citrus unshiu Marc.) and ‘Harehime’ ((‘Kiyomi’ × ‘Osceola’) × ‘Miyagawa-wase’) fruits because they show high Brix% by exposure to drought stress conditions. In this study, we investigated the effect of drought stress on the number of floral buds in ‘Haraguchi-wase’ Satsuma mandarins and ‘Harehime’. To clarify the relationship between drought stress and the number of floral buds, we applied four different drying treatments to the fruit trees, (i) first-half drying (drying treatment during the first-half of the fruit development stage), (ii) second-half drying (drying treatment during the second-half of the fruit development stage), (iii) all-drying (drying during the full fruit development stage), and (iv) well-watered (non-drought stress during the fruit development stage). The drying treatment was applied to the fruits at ψ max −0.7 to −1.2 MPa at an intensity comparable to proper drought stress for high-quality fruit production according to our previous studies.
Harsimrat K. Bons, H.S. Rattanpal
Department of Fruit Science, Punjab Agricultural University, Ludhiana, Punjab, India.
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.
Y. Erner, B. Artzi, E. Tagari and M. Hamou
The Volcani Center, Institute of Horticulture, Department of Fruit Trees, Israel
Potassium plays a critical role in citrus trees and it affects many phenomena, both visible and invisible. The requirement for K in trees is next to that for nitrogen and ranges from 0.5 to 2% of dry matter. Adequate yield, for the fresh fruit market can be achieved only when the level of K is in the optimum range.