In this review, we address the interaction between abscisic acid (ABA) and gibberellins (GAs) in regulating non-climacteric fruit development and maturation at the molecular level. We review the interplay of both plant growth regulators in regulating these processes in several fruit of economic importance such as grape berries, strawberry, and citrus, and show how understanding this interaction has resulted in useful agronomic management techniques. We then relate the interplay of both hormones with ethylene and other endogenous factors, such as sugar signaling. We finally review the growing knowledge related to abscisic acid, gibberellins, and the genus Citrus. We illustrate why this woody genus can be considered as an emerging model plant for understanding hormonal circuits in regulating different processes, as most of the finest work on this matter in recent years has been performed by using different Citrus species.

No abstract

Studies on rootstocks and scions are of major importance for citrus crop production. The goal of this study was to evaluate vegetative growth, yield performance, and fruit quality of ‘Navelina’ sweet orange trees grafted on five different rootstocks in Northern Parana state, Brazil. The experimental design was completely randomized blocks, with six replications, two plants per plot, and five treatments: ‘Rangpur’ lime; ‘Cleopatra’ mandarin, ‘Sunki’ mandarin; ‘Swingle’ citrumelo; and ‘Fepagro C-13’ citrange. Tree vegetative growth, yield performance, and fruit physical-chemical characteristics were analyzed. ‘Sunki’ mandarin provided the largest canopy volume for ‘Navelina’ sweet orange trees, whereas ‘Swingle’ citrumelo, ‘Fepagro C-13’ citrange, and ‘Rangpur’ lime provided a smaller volume for tree canopy. Compared to Rangpur lime, ‘Swingle’ citrumelo provided higher accumulated yield and production efficiency for ‘Navelina’ sweet orange trees. All rootstocks induced good physical and chemical quality to ‘Navelina’ sweet orange fruits.

No abstract

Over the past decade the desert rose received fame in the flower market due to its striking and sculptural forms; however, the commercial production of these species is quite recent and little is known about its crop management, including substrates recommendation. The objectives of this study were to investigate the effect of different substrates on desert rose seed germination and production of its seedlings. Experiment I: freshly harvested seeds of desert rose were sown in different substrates e.g. sand, coconut fiber, semi-composted pine bark, sand + coconut fiber, semi-composted pine bark + sand and coconut fiber + semicomposted pine bark. These substrates were evaluated to study the emergence percentage of seeds, initial growth of seedlings and seedling emergence speed index (ESI). Experiment II: desert rose from the experiment I were transferred to plastic pots filled with the same substrates as in experiment I. The pH and electrical conductivity (EC) of the substrates were noted every 30 days while the growth parameters of seedlings were recorded after 240 days. Results from experiment I showed higher germination rate and seedling growth in substrates containing semi-composted pine bark. Similarly, in experiment II, better quality seedlings were observed in substrates containing semi-composted pine bark. Thus, for desert rose seed germination and seedling growth, it is recommended to use substrates containing semi-composted pine bark.

The nursery plants supply is one of the most important factors that limites blueberries production in some areas, due to some propagation difficulties observed on this species. In this way, this study aimed to evaluate substrates and IBA application methods on 'Powderblue' blueberries (Vaccinium ashei) minicuttings rooting, as well as to verify the rooting development in different periods. The study was divided in two experiments. The first one aimed to evaluate 'Powderblue' blueberry minicuttings rooting in three substrates (pine bark, carbonized rice husk and vermiculite) in response to two indolebutyric acid (IBA) application methods: 50% alcohol solution and talc. The second experiment aimed to evaluate 'Powderblue' blueberry minicuttings rooting using the best substrate recorded in the first trial (pine bark) and two IBA application methods associated to three periods of rooting access, in order to obtain the ideal rooting period and root development. In the first experiment the rooting percentage presented significant difference among the substrates; the higher percentage of rooted minicuttings occurred in pine bark substrate (68%). Regarding the methods used to IBA application, the talc method was more efficient to promote minicuttings rooting. In the second experiment, it was observed an increase in cutting rooting percentage from 55 to 84%, according to the evaluated seasons; however, the IBA application method did not influence the rooting percentage. Therefore, to produce 'Powderblue' blueberry plants from minicuttings it is recommended to use pine bark as substrate and talc as method to IBA application, transplanting the nurseries at 110 days after planting.

Adenium obesum, also known as desert rose, has recently become popular in Brazil, due to its exuberance and sculptural shape. However, the production of the species in commercial scale has been facing challenges regarding propagation of hybrids by in vitro cultivation techniques, potting medium composition, irrigation and fertilization management, disease and pest control. Unlike other species sold as potted plants, there are no commercial production protocols established for Adenium, mainly due to the scarcity of technical information about this species. Thus, this technical article aimed to provide information related to the Adenium growth, in view of its commercial scale production. In addition, aspects related to floral morphology, pollination and seed production of the species, as well as, vegetative propagation strategies were discussed.

This study aimed to determine carbohydrates and organic acids in fruit from ‘Salustiana’ orange tree [Citrus sinensis (L.) Osb.] grafted onto different rootstocks using the HPLC technique, as well as to evaluate their physicochemical properties. As rootstocks, we tested ‘Rangpur’ lime, ‘Cleopatra’ mandarin, ‘Sunki’ mandarin, ‘Swingle’ citrumelo, and ‘C-13’ citrange. Fully mature fruit was first characterized according to their physicochemical parameters as fruit mass, longitudinal and equatorial diameters, peel color, juice yield, soluble solids, titratable acidity, and ratio. Then, freshly squeezed juice was used to determine and to quantify organic acids and carbohydrates by the HPLC system. All analyses were performed in triplicate complete randomized with five treatments (rootstocks). Fruit from all evaluated rootstocks presented adequate physicochemical attributes, meeting the quality standards of the citrus industry. ‘C-13’ citrange induced in a production of large-sized fruit whereas ‘Rangpur’ lime promoted higher soluble solids content in its juice. Significant differences were not observed between the treatments with regards to organic acids and carbohydrates concentrations. Citric and ascorbic acids were identified and quantified in the juice samples. The sugars identified were sucrose, glucose, and fructose. Organic acids and carbohydrates concentrations are consistent with those reported in the literature for citrus juice, providing information about nutrition and quality of ‘Salustiana’ sweet orange produced onto different rootstocks.