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Backcrossing between Sikitita and its male parent Arbequina, offers the possibility to check the suitability of different self-incompatibility models proposed for olive. To determine Sikitita’s response to self- and cross-pollination treatments, including pollination with its father Arbequina, we compared the parameters following pollen–pistil interaction, the resulting initial and final fruit set, and the paternity of the seeds produced under different crosses. The results showed that Sikitita behaves as a self-incompatible cultivar due to the inhibition of pollen tube growth in the pistil of self-pollinated flowers. This incompatibility reaction led to a significant reduction of self-fertilization and fruit set. Seed paternity analyses confirmed the self-incompatibility response of Sikitita. A similar incompatibility response was observed in Sikitita flowers when hand-pollinated with pollen of Arbequina and Koroneiki. On the contrary, cross-pollination with Arbosana gave excellent results, with analyses showing that pollen of Arbosana is largely preferred by Sikitita to father its seeds more than the pollen of other cultivars presented in the orchard. The backcross failure of Sikitita with Arbequina pollen suggests that the self-incompatibility system in olives is not of the gametophytic type. In contrast, pollination tests fit features of previously reported sporophytic self-incompatibility systems. However, some amendments are proposed, among them the incompatibility groups for Sikitita and Koroneiki.

Trendy high-density olive fields are often monovarietal orchards, mostly using the cultivar Arbequina. However, Arbequina shows a strong self-incompatibility response, and its yields depend on wind cross-pollination, which is not always available. With the aim of finding suitable self-compatible cultivars that can replace Arbequina, we evaluated pollen–pistil interaction, fruit set and seed paternity in Arbosana under different pollination treatments: self-pollination, open-pollination and three cross-pollination treatments: × Arbequina, × Sikitita and × Koroneiki. All these cultivars are low-vigor cultivars suitable for high-density orchards, making them potential pollinizers for Arbosana. The results show that Arbosana is also self-incompatible with a strong reduction in fruit set due to a lower fertilization level caused by a strong inhibition of pollen tube growth in self-pollinated flowers. Seed-paternity analyses confirmed the self-incompatibility response of Arbosana and suggest that some fruit obtained in bagged shoots under self-pollination were, in fact, a product of cross-fertilization. In conclusion, we recommend against the use of Arbosana in large monovarietal orchards. On the contrary, good results were obtained under cross-pollination with Sikitita, Arbequina and Koroneiki pollen, allowing us to recommend them as pollinizers for Arbosana in appropriate pollination designs. This is the first time Arbosana self-incompatibility has been reported.

Abstract The cultivation of papaya under greenhouse has become recently a profitable alternative for horticultural crops in different regions of the world, among them South East Spain. The objective of this work was to determine the sample size to evaluate fruit quality features in mature fruits of ‘BH-65’ papaya cultivated under greenhouse in Almería (Spain). With this aim, fruits were harvested at stage 2 in July 2013, and at the end of the production cycle in March 2014. On each occasion and when fruits reached maturation phenological stage 5, 26 fruits were evaluated for physical characteristics (weight, length, diameter, cavity width), total soluble solids content, and color attributes of skin and pulp. The optimal sample size was calculated using a deterministic method. The physical parameters and the skin and pulp color attributes of fruits of ‘BH-65’ papaya cultivar present different experimental accuracy among themselves and between harvest seasons, requiring different sample sizes. Higher sample size is required for evaluating fruit weight. 25 fruits were necessary at harvest performed in July, but only 7 fruits in March, considering an error of 15% around the average.

Loquat prices depend on fruit size and earliness. Earliness is improved by postharvest deficit irrigation (DI), without negative effects on fruit size. An optimization of postharvest DI strategies carried out by limiting the dry period led to greater harvest date advancement, but water savings were reduced. To further improve fruit earliness and quality and increase water savings, we combined pre and postharvest DI strategies. Treatments were T1: trees not irrigated during six weeks after harvest (no preharvest DI applied); T2: trees that, in addition to postharvest DI, were not watered from the rapid fruit growth phase to harvest (nine extra weeks of DI); T3: trees that, in addition to postharvest DI, were not watered from color break to harvest (six weeks of DI plus postharvest DI); and T4: trees that in addition to postharvest DI were not watered during rapid fruit growth, but were re-irrigated at color break (2–3 weeks of DI, depending on the season). Full-irrigated trees were grown for comparison. T1 saved 18% water with respect to full-irrigation, and advanced harvesting by 16 days. T2 saved more water, had an earlier harvest and produced a higher early yield. Shorter dry periods were beneficial to a lower extent. Fruit size was significantly diminished by T2, but not by T4. A major advantage of T3 and T4 was the better performance of fruit during handling and shelf life. T2 fruits were favored by panelists for their sweetness but criticized for their smaller size.

Lack of color in the skin of red table grape varieties is a serious problem in areas of warm climate. This problem is often addressed by the application of ethylene release products such as ethephon. Strict regulation in the use of this product in EU forces European grape producers to look for suitable alternatives. With the aim to increase red skin color, we applied regulated deficit irrigation (RDI) strategies from veraison until harvest on “Flame Seedless” table grape vines cultivated under nets and under a plastic greenhouse in South East Spain, and compared yield and fruit quality with vines fully irrigated under the same net and plastic greenhouses. Our results show a modest improvement in the percentage of commercial clusters with better skin color, probably because the short duration of the deficit irrigation period only caused a slight decrease in soil water content and a mild water stress in RDI vines. Larger differences were observed under the more limiting conditions of the plastic greenhouse for light environment, especially when berry skin color was measured by CIRG (color index of red grape). More noticeable effect of RDI was noted on fruit earliness. Water savings were also remarkable. Negative effects of RDI on berry size or total soluble solid content were not perceived. Our results suggest that RDI is a suitable strategy to save irrigation water without substantial negative effects on yield and berry size. However, the effects on skin color were insufficient in the trial conditions.

To determine if water-stressed trees need more time and heat to mature their fruits, we compared chronological and thermal time from bloom to harvest among control fully-irrigated ‘Algerie’ loquat trees and trees suffering prior-to-bloom deficit irrigation (DI). Heat requirement calculation was performed using the double sine method with a lower threshold temperature of 3 °C. The results show that the greater the blooming advancement achieved by DI, the longer the period to mature the fruits. Such a pattern indicates that the longer duration for bloom-harvest period under DI is due to a displacement of the reproductive phenology to cooler dates. However, some effects of DI on heat requirements for ripening persist, indicating a slower fruit development in some, but not all, DI treatments. The differences in fruit development rate between fully-irrigated and water-stressed trees were established during the phase of rapid fruit growth. The comparison of water stress effects on sink (flower size and seed number) and source (leaf number and size, gas exchange and mineral and carbohydrate nutrition) of DI treatments seems to indicate that the amount of stored reserves in the leaves to sustain early fruit development is the most plausible reason behind the increase in thermal time between bloom and harvest in water-stressed loquats.

Abstract Papaya (Carica papaya L.) is a tropical fruit crop of rapid growth and early yielding. In recent years, papaya cultivation has extended to subtropical regions due to its commercial interest. In South East Spain, protected cultivation is, however, mandatory to ensure the optimal development of the crop. Even more, to assure profitability, the selection of plant material well adapted to the structural constrains and the climatic conditions inside greenhouses is essential. With this objective, different papaya cultivars with diverse geographical origin, characteristics and pedigree have been compared. ‘BH-65’, ‘Siluet’, ‘Sensation’, ‘Intenzza’ and ‘Red Lady’ papaya cultivars were thus grown under a plastic greenhouse in Almería, SE Spain and their growth, phenology, yield and fruit quality compared in a 21-month production cycle. The results showed that ‘Siluet’ and ‘Sensation’ papayas are well-adapted to greenhouse protected cultivation, produce high yield, and optimal fruit quality for long and short distance markets. Cultivars like ‘BH-65’ could be of interest for low-height greenhouses due to its reduced plant vigor and high fruit quality. However, ‘BH-65’ yield is low. According to the European consumer preferences, the cultivation of ‘Siluet’ and ‘Sensation’ is recommended, for the harsh conditions the greenhouse cultivation imposes in subtropics.