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Pistachio is a nut crop domesticated in the Fertile Crescent and a dioecious species with ZW sex chromosomes. We sequenced the genomes of Pistacia vera cultivar (cv.) Siirt, the female parent, and P. vera cv. Bagyolu, the male parent. Two chromosome-level reference genomes of pistachio were generated, and Z and W chromosomes were assembled. The ZW chromosomes originated from an autosome following the first inversion, which occurred approximately 8.18 Mya. Three inversion events in the W chromosome led to the formation of a 12.7-Mb (22.8% of the W chromosome) non-recombining region. These W-specific sequences contain several genes of interest that may have played a pivotal role in sex determination and contributed to the initiation and evolution of a ZW sex chromosome system in pistachio. The W-specific genes, including defA, defA-like, DYT1, two PTEN1, and two tandem duplications of six VPS13A paralogs, are strong candidates for sex determination or differentiation. Demographic history analysis of resequenced genomes suggest that cultivated pistachio underwent severe domestication bottlenecks approximately 7640 years ago, dating the domestication event close to the archeological record of pistachio domestication in Iran. We identified 390, 211, and 290 potential selective sweeps in 3 cultivar subgroups that underlie agronomic traits such as nut development and quality, grafting success, flowering time shift, and drought tolerance. These findings have improved our understanding of the genomic basis of sex determination/differentiation and horticulturally important traits and will accelerate the improvement of pistachio cultivars and rootstocks.

Understanding the basis of hybrid vigor remains a key question in crop breeding and improvement, especially for rootstock development where F1 hybrids are extensively utilized. Full-sibling UCB-1 F1 seedling rootstocks are widely planted in commercial pistachio orchards that are generated by crossing 2 highly heterozygous outbreeding parental trees of Pistacia atlantica (female) and P. integerrima (male). This results in extensive phenotypic variability, prompting costly removal of low-yielding small trees. To identify the genetic basis of this variability, we assembled chromosome-scale genome assemblies of the parental trees of UCB-1. We genotyped 960 UCB-1 trees in an experimental orchard for which we also collected multiyear phenotypes. We genotyped an additional 1,358 rootstocks in 6 commercial pistachio orchards and collected single-year tree-size data. Genome-wide single marker association tests identified loci associated with tree size and shape, sex, and precocity. In the experimental orchard, we identified multiple trait-associated loci and a strong candidate for ZZ/ZW sex chromosomes. We found significant marker associations unique to different traits and to early vs late phenotypic measures of the same trait. We detected 2 loci strongly associated with rootstock size in commercial orchards. Pseudo-testcross classification of markers demonstrated that the trait-associated alleles for each locus were segregating in the gametes of opposite parents. These 2 loci interact epistatically to generate the bimodal distribution of tree size with undesirable small trees observed by growers. We identified candidate genes within these regions. These findings provide a foundational resource for marker development and genetic selection of vigorous pistachio UCB-1 rootstock.

The production and consumption of nuts are increasing in the world due to strong economic returns and the nutritional value of their products. With the increasing role and importance given to nuts (i.e., walnuts, hazelnut, pistachio, pecan, almond) in a balanced and healthy diet and their benefits to human health, breeding of the nuts species has also been stepped up. Most recent fruit breeding programs have focused on scion genetic improvement. However, the use of locally adapted grafted rootstocks also enhanced the productivity and quality of tree fruit crops. Grafting is an ancient horticultural practice used in nut crops to manipulate scion phenotype and productivity and overcome biotic and abiotic stresses. There are complex rootstock breeding objectives and physiological and molecular aspects of rootstock-scion interactions in nut crops. In this review, we provide an overview of these, considering the mechanisms involved in nutrient and water uptake, regulation of phytohormones, and rootstock influences on the scion molecular processes, including long-distance gene silencing and trans-grafting. Understanding the mechanisms resulting from rootstock × scion × environmental interactions will contribute to developing new rootstocks with resilience in the face of climate change, but also of the multitude of diseases and pests.

Pistachio (Pistacia vera L.), is an important food source for human health. It has nutritional content rich in protein, fat, fatty acids, fiber, vitamins and minerals. Such as other nuts, pistachio oil is rich in unsaturated fatty acids. Pistachio is rich in omega fatty acids such as n-3, n-6, n-9, it is known to be beneficial in decreasing cholesterol by increasing HDL level in blood plasma. Oleic acid (C18: 1) and palmitoleic acid are the main component of unsaturated fatty acids in pistachio. It has fatty acids such as linoleic acid and alpha linoleic acid among polyunsaturated fatty acids and myristic acid, palmitic acid, stearic acid among saturated fatty acids. Gas chromatography-flame ionization detector (GC-FID) is generally used for the analysis of fatty acids in foods. The main component of unsaturated fatty acids contained in pistachio is oleic acid (C18: 1) and the variety varies between 51.6% and 81.17% according to the origin. Linoleic acid (C18:2) content, which is a polyunsaturated fatty acid, varies between 15% and 30%. Stearic acid content of saturated fatty acids varies between 0.8% and 3.5%. This review provides information about the properties and curent status of the fatty acids in pistachios.

Over the centuries, strawberry fruit quality has greatly improved through various selection studies. The discovery of genes and genomic positions related to traits such as fruit quality and resistance to diseases and pests has been accelerated by new biotechnological methods. The objectives of this study are (i) to construct single nucleotide polymorphism (SNP) Fana array-based high-throughput genetic linkage groups for the 'Fortuna × Rubygem' F1 population, and (ii) to detect quantitative trait loci (QTL) regions associated with Botrytis cinerea resistance in leaf and fruit traits of strawberry. A total of 945 and 984 SNPs were mapped in the 'Fortuna' maternal and the 'Rubygem' paternal maps, respectively. The lengths of the linkage groups (LGs) and the average length of 'Fortuna' were calculated to be 1814 cM and 55.0 cM, respectively. The total length of 'Rubygem' was determined to be 2170 cM, with an average length of 65.7 cM. The average marker densities for the'Fortuna' and 'Rubygem' linkages per cM were recorded as 0.58 and 0.53 markers, respectively. The 'Fortuna' female produced a mean of 28.64 markers per LG, while the 'Rubygem' male linkage groups had approximately 30 markers per LG. Five significant QTLs associated with resistance to B. cinerea in the leaves were identified in both parents. QTLs associated with resistance in strawberry fruits were found within a total of three LGs in different positions. The compressive genetic linkage maps developed in 'Fortuna × Rubygem' population can be used in genetic and QTL studies for important agronomical traits. The identified QTLs associated with Botrytis cinerea resistance may be preferred for use in future strawberry breeding programs to carry out markerassisted selection. [ABSTRACT FROM AUTHOR]

Alternate bearing is a common challenge in horticultural plants, leading to irregular yield in successive years. The potential role of phenolic compounds in regulating this phenomenon, however, is not well understood. This study aimed to investigate the potential role of phenolic compounds in alternate bearing in pistachio trees by analysing samples from different parts of the "Uzun" cultivar over two consecutive years. Seven phenolic compounds (gallic acid, p-coumaric acid, caffeic acid, ferulic acid, chlorogenic acid, catechin, and quercetin) were analysed using high-performance liquid chromatography at 10-day intervals. Significant variations were observed in the levels of certain phenolic compounds between "ON" and "OFF" years, suggesting a potential role for these compounds in alternate bearing. Ferulic acid exhibited a significant decrease in leaves and shoots, indicating its translocation to the nuts, leading to a sharp decline during the nut lignification process. A negative and significant correlation between ferulic and caffeic acid levels was observed in the "ON" and "OFF" years, which may be linked to the alternate bearing and kernel development process in pistachio. These findings provide valuable insights into the role of phenolic compounds in regulating alternate bearing in pistachio trees and could inform future strategies for enhancing pistachio yields and quality. [ABSTRACT FROM AUTHOR]

Alternate bearing is a significant economic problem that affects fruit producers, consumers and the economy of a country. Concentrations of cytokinin (CK)-like compounds in different tissues of pistachio trees (Pistacia vera ‘Uzun’) were measured to elucidate the relationship between endogenous CKs and flower bud abscission (alternate bearing). Identification and quantification of CK-like compounds of the Z, DHZ and iP types from different physiological stages and tissues were performed using high-performance liquid chromatography–electrospray ionisation–tandem mass spectrometry (HPLCESI-MS/MS) techniques. Five to seven different CK-like compounds were detected, respectively. Isopentenyl adenine riboside (iPR) and trans-zeatin-O-glucoside (t-ZOG) were the main isoprenoid CKs, as the dominant conjugates in all the analysed organs of pistachio trees. The leaves and shoots of ‘On’-year trees had significantly higher CK contents than those of ‘Off’-year trees on all the sampling dates. Interestingly, the relatively high CK activity was recorded before flower bud abscission in the fractions corresponding to iPR and t-ZOG, while this activity dropped considerably during the flower bud abscission period (55 DAFB). Consequently, the strong negative correlation between CK concentration and bud abscission could be the first indication of the role of CK-like compounds in this unique phenomenon in the ‘Uzun’ pistachio cultivar. It was concluded that CKs could have an important role in the alternate bearing in pistachio.