Star Ruby is the main grapefruit (Citrus paradisi) variety grown in Turkey; however, small fruit size is a common problem in ‘Star Ruby’ grapefruit. Fruit size is a decisive external quality parameter in citrus at the marketing of fresh citrus fruits. Fruit size can be enhanced by several techniques such as girdling and thinning. Various plant growth regulators are known to affect the growth and size of citrus fruit. The objective of the present study was to observe the effects of 2,4 dichlorophenoxypropionic acid-p (2,4-DP-P) on the fruit size, yield and quality of Star Ruby from 20-year-old trees budded on sour orange rootstock in Adana, Turkey in 2007. Four concentrations (50, 100, 150 and 300 ppm) of 2,4-DP-P were applied 8 weeks after anthesis during physiological fruit drop when the mean fruit diameter was 13-15 mm. The results indicated that the application of 2,4-DP-P increased the fruit size of Star Ruby grapefruit without reducing yield. The application had a significant effect on fruit yield except for trees treated with 50 ppm 2,4-DP-P. Compared with the control trees, applications of 2,4-DP-P increased the number of large, commercially valuable Star Ruby (>93 mm, 89-93 mm and 84-89 mm). No effects were determined on fruit internal quality parameters. Thus, the results of the present study revealed that 2,4-DP-P can be used to improve the fruit size of Star Ruby fruitlets during the June drop.

The existence of a large amount of seeds in citrus fruits results as a major impediment to customer acceptability, even if the fruits have high organoleptic properties. Irradiation, which mainly reduces seed number of varieties, is a faster way than hybridization. The use of irradiation in citrus breeding programs is now quite widespread with most programs in the major citrus producing countries actively developing new selections. The present study reports the primarily results of gamma irradiation on seed number and fruit quality of Ortanique tangor mutant population. The shoots of scion were irradiated with gamma rays from 60Co at the dose of 50 Gy (gray) in April of 2014. All the treated buds were then immediately budded onto rootstocks and the survival rate was recorded as 60.34%. In order to stabilize the mutation, mV3 plants were developed by re-budding and plants at mV3 generation were transplanted in the orchard in 2017. Within the following year, 68 mV3 plants out of 852 grown in the field bore sufficient amount of fruit and were screened in terms of 19 fruit quality characters such as seed number per fruit, fruit diameter and ripening index. Fruit diameters of mV3 population varied from 56.72 mm to 84.79 mm, and fruit weight ranged between 90.00 g and 287.60 g. The number of seeds per fruit ranged between 0.6 and 13.1 whereas seed number of non-irradiated Ortanique tangor was recorded as 10.7 in the same fruit crop year. In general, fruit characteristics such as fruit weight, fruit height and fruit diameter which describe fruit size of a big part of the population, were similar to Ortanique tangor. According to primarily results, 18 plants have been described as low seeded (≤4). In addition, a cluster analysis was performed by using Euclidean similarity coefficient and similarity index ranged between 29.29% and 93.10% regarding variables related to fruit. The stability of mutations detected is being evaluated and new commercial field trials will be established with the selected materials.

This study was established at the experimental field of Horticulture Department of Çukurova University in Adana, Turkey during 2013-2015 harvest period two consecutive years. Two plum cultivars (‘Black Diamond’, ‘Angeleno’) and Friar as pollinizer grafted on Myrobolan rootstock were used as plant material. Trees produced commercially good yield in 2014, at the fourth growing season. The aim of this study was to compare four different pruning systems (spindle, 4 leader- Quad-V, central leader and open vase) and six different planting distances (0.8-1-1.2-1.6-2- 4 m and standard inter rows 4 m) for yield (ton ha-1) on several fruit quality variables such as (fruit weight, firmness, fruit flesh/seed weight, TSS, TA). Morphological and phenological characters were observed and chilling accumulation of the study area was determined. Sufficient chilling accumulation was calculated in both years regarding fruit crop load. The best results for quality characteristics were obtained from Spindel (1.2x4 m) high density pruning system for both cultivars. Also, ‘‘Black Diamond’’ cultivar on Spindel (1.2 m) gave the highest fruit weight (110.4 g) and yield (62.27 ton ha-1).

In this study, Minneola Tangelo hybrid, a cross of grapefruit and mandarin (Duncan grapefruit x Dancy mandarin), used as interstock to Star Ruby grapefruit with different lengths. Effects of different interstock lengths on fruit yield and quality, plant development and photosynthetic parameters were investigated. According to the results, different interstock lengths significantly affected fruit yield and size. The highest fruit yield was determined in T-M20-S whereas the lowest was on T-M5-S. The highest fruit size were determined in Star Ruby fruits on T-M5-S and T-M40-S whereas the lowest on T-M20-S and T-S (control). T-M40-S and T-M20-S treatments markedly reduced stem diameter and tree canopy in comparison to other treatments and control. Usage of different interstock lengths did not significantly affected some of fruit quality traits, net photosynthetic rate, stomatal conductance, leaf transpiration rate, leaf water usage efficiency and leaf chlorophyll concentration. In regards to seasonal changes, net photosynthetic rate were higher in spring and summer seasons then winter and fall seasons.

Lipoxygenases (LOX) gene family is a type of nonheme iron-containing dioxygenases, which has a very important aspect in plant development and fruit quality. LOX gene, which is responsible for lipid oxidation, the main role for the biosynthesis pathway of unsaturated fatty acids. Although some studies have investigated the LOX gene family in several species including arabidopsis, soybean, peanut and apple, there is no information from Pistachio; and the phylogeny of this gene family in the Pistacia genus is still not determined. In this study, Arabidopsis thaliana LOX1 gene (NCBI Reference Sequence: NM_104376.3) was selected and used as a query sequence for performing a BLASTN search. Among all sequence query which was found by NCBI platform, 9 sequences were selected for further analysis. Phylogenetic tree of full-length LOX gene sequences from the Pistacia genus was constructed using the Maximum Likelihood method with MEGA software. By using phylogenic analysis, we identified variations in gene structure and revealed the phylogenetic evolutionary relationship of this gene family. Additionally, this may serve as a reference value for assessing the genetic relationships among various LOX genes in Pistacia genus species. This variations provides us the possibility the design the primer to achieve us to find the exact LOX gene in Pistacia genus and future research on the evolutionary history and transgenic research on LOX genes.