Winter Greenhouse Research Articles

Drip Irrigation Schedule of Greenhouse Green Pepper Based on Genetic Algorithm

By drip irrigation experiment of Barrel-planted peppers in a greenhouse during autumn and winter adopting Jensen Model, the water sensitivity index and water production function of green pepper at different stages is obtained through multiple linear regression method based on test datum, and the obtained model is verified by using the measured data. Further, compiling optimization program by C#.net language, drip irrigation schedule of green pepper is optimized by the genetic algorithm with the goal of maximizing the relative production. Results show that drip irrigation water of green pepper dring its whole growth period in a greenhouse in both autumn and winter is 285 mm with the highest water production efficiency. The accuracy of the results was verified by experimental data, too.

Spatial, Vertical, and Temporal Variability of Ambient Environments in Strawberry and Tomato Greenhouses in Winter

Strawberry and Tomato Greenhouses in Winter Myong-Jin Ryu, Dong-Ki Ryu, Sun-Ok Chung*, Yun-Kun Hur, Seung-Oh Hur, Soon-Jung Hong, Je-Hoon Sung, Hak-Hun Kim Department of Biosystems Machinery Engineering, Chungnam National University, Daejeon, Korea Rural Development Administration, Gyeonggi-do, Korea Chungnam Agriculture Research & Extension Services, Chungcheongnam-do, Korea Received: November 18th, 2013; Revised: February 8th, 2014; Accepted: February 19th, 2014 Purpose: In protected crop production facilities such as greenhouse and plant factory, farmers should be present and/or visit frequently to the production site for maintaining optimum environmental conditions and better production, which is time and labor consuming. Monitoring of environmental condition is highly important for optimum control of the conditions, and the condition is not uniform within the facility. Objectives of the paper were to investigate spatial and vertical variability in ambient environmental variables and to provide useful information for sensing and control of the environments. Methods: Experiments were conducted in a strawberry-growing greenhouse (greenhouse 1) and a cherry tomato-growing greenhouse (greenhouse 2). Selected ambient environmental variables for experiment in greenhouse 1 were air temperature and humidity, and in greenhouse 2, they were air temperature, humidity, PPFD (Photosynthetic Photon Flux Density), and CO2 concentration. Results: Considerable spatial, vertical, and temporal variability of the ambient environments were observed. In greenhouse 1, overall temperature increased from 12:00 to 14:00 and increased after that, while RH increased continuously during the experiments. Differences between the maximum and minimum temperature and RH values were greater when one of the side windows were open than those when both of the windows were closed. The location and height of the maximum and minimum measurements were also different. In greenhouse 2, differences between the maximum and minimum air temperatures at noon and sunset were greater when both windows were open. The maximum PPFD were observed at a 3-m height, close to the lighting source, and CO2 concentration in the crop growing regions. Conclusions: In this study, spatial, vertical, and temporal variability of ambient crop growing conditions in greenhouses was evaluated. And also the variability was affected by operation conditions such as window opening and heating. Results of the study would provide information for optimum monitoring and control of ambient greenhouse environments.

Variability of Soil Water Content, Temperature, and Electrical Conductivity in Strawberry and Tomato Greenhouses in Winter

Variability of Soil Water Content, Temperature, and Electrical Conductivity in Strawberry and Tomato Greenhouses in Winter

Trial of Green Asparagus Out-of-Season Production for Establishing Year-Round Production in Kyushu, a Warm Area of Japan

Kyushu island, in southern Japan, is one of the main producers of green asparagus (Asparagus officinalis L.) in Japan, accommodating protected mother-fern culture in plastic greenhouses (PMC) as a conventional crop. In PMC, since few spears are produced from November to January, we attempted to produce spears during this period by prolonging the harvest of PMC to November and introducing “Fusekomi” forcing culture (FFC), in which rootstocks grown outdoors are transplanted into heated and/or thermal-retained culture beds in a plastic greenhouse in late autumn or early winter and spears are generally harvested for the following two or three months. In PMC, a combination of a foliage spray of Benzyladenine solution with thermal retention treatment in autumn prolonged the harvest period to the end of November without any significant decrease in yield the following spring. In FFC, rootstocks grown in the lowlands showed inferior spear productivity when transplanted into a greenhouse in late November, probably due to insufficient exposure to low temperature for breaking dormancy. In contrast, rootstocks grown in the highlands showed superior in productivity because they would be sufficiently exposed to low temperature for breaking dormancy by the time of transplanting. In lowlands, heating of greenhouses was unnecessary for FFC throughout the harvest period due to the mild winter climate. These results suggested that profitable year-round production of green asparagus without heating could be realized in Kyushu by combining PMC and FFC cropping types.

Role of grafting in cucurbitaceous crop s-A review

Due to limited availability of arable land and high market demand for off-season vegetables, cucurbits (plants in the family Cucurbitaceae) are continuously cultivated under unfavorable conditions in some countries. These conditions include environments that are too cold, wet, or dry, or are cool low-light winter greenhouses. Successive cropping can increase salinity, the incidence of cucurbit pests, and soil borne diseases like fusarium wilt caused by Fusarium spp. These conditions cause various physiological and pathological disorders leading to severe crop loss. Chemical pest control is expensive, not always effective, and can harm the environment. Grafting can overcome many of these problems. Some seed companies now offer watermelon transplants grafted on to squash or bottle gourd rootstocks, and some transplant facilities offer grafting services.

Farmer innovation diffusion via network building: a case of winter greenhouse diffusion in China

Abstract Farmer innovation diffusion (FID) in the developing world is not simply the adoption of an innovation made by farmers, but a process of communication and cooperation between farmers, governments, and other stakeholders. While increasing attention has been paid to farmer innovation, little is known about how farmers’ innovations are successfully diffused. To fill this gap, this paper aims to address the following questions: What conditions are necessary for farmers to participate in FID? How is a collaborative network built up between farmers and stakeholders for this purpose? And what roles can government play? The above questions are addressed through analysis of the diffusion of winter greenhouse technology in China. A framework for analyzing a FID system is developed, and the conclusion is drawn that building mutual trust and collaborative networks is crucial for the success of FID. Furthermore, this network building can be broken down into various levels with different scales, speeds and consequences for FID: informal networks among farmers themselves, farmer-led networks, and government-facilitated networks. The success of government intervention depends upon building and enhancing the collaborative networks in which farmer leadership is crucial.

사체의 유기장소별 부패진행에 따른 발생 파리류 비교

Because insect visitors was different depending on decomposition stage, dipterans occurred on chicken carcasses depending on postmortem intervals were compared by abandoned sites and decomposition from a serial study on arthropod occurrence from carcasses as forensic indicator. Species occurrence and decomposition of carcasses were different depending on abandoned sites (forest hill, open field, stream, greenhouse and roof), seasons (spring, summer, fall and winter), and situation (burying and non-burying). Development of carcass decomposition was faster at all sites in summer, carcass in greenhouse in winter, and unburied carcasses. Although visiting time of blow flies (Calliphoridae) (Phaenicia sericata, Lucilia illustris, Lucilia sp., Chrysomyia pinguis, and Chrysomyia megacephala) was different depending on abandoned season, their adults were generally collected from carcasses within 2 days. However, there were no visited flies at fresh stage of buried carcasses. The flesh flies (Sarcophagidae) were collected from all sites and seasons, and much faster from unburied carcasses than buried carcasses. Those were collected earlier from carcasses in greenhouse than other sites and occurrence was also shorter. In greenhouse, occurrence time of flesh flies were different depending on season; spring and summer - from fresh to active decay stage, fall - fresh to active decay stage, and winter - advanced decay to remains stage. Calliphora lata, Tricerotopyga calliphoroides, and Aldrichana grahami were dominant species and occurrences were different from other flies. These flies were active mainly from fresh to active stage. Larvae of sarcophagid flies were occurred earlier than those of calliphorid flies on buried carcasses.

Effects of different light intensities on chlorophyll fluorescence characteristics and yield in lettuce

The worldwide demand for Romaine lettuce (Lactuca sativa L.) is increasing. Regulation measures of supplementary or shading light are often used in the production of lettuce in some regions. However, inconsistent results on light saturation point of lettuce from previous studies did not facilitate the regulation of light intensity. In the present study, the effects of different light intensities on chlorophyll fluorescence characteristics and yield in lettuce were investigated. The results show that in the 100 and 800μmolm−2s−1 treatments, the values of qP, ΦPSII, and ETR were low, resulting in low light use efficiency and plant yield in lettuce. In the 200, 400, and 600μmolm−2s−1 treatments, the values of qP, ΦPSII, and ETR were high, resulting in high light use efficiency and plant yield in lettuce. Light-use efficiency in the 200μmolm−2s−1 treatment was the highest, whereas plant yield in the 600μmolm−2s−1 treatment was the highest. No significant difference in plant yield was observed between the 400 and 600μmolm−2s−1 treatment. In addition, judging by the values of Fv/Fm, the lettuce samples were under rather serious stress in the 800μmolm−2s−1 treatment, whereas they were under mild stress in the 600μmolm−2s−1 treatment. Based on these results, an optimal regulation strategy of light intensity that can maximize economic benefits for lettuce growers in some regions of the world is proposed. That is the range of 400–600μmolm−2s−1 is a recommendable light intensity for production of certain types of lettuce, and light intensity of 400μmolm−2s−1 can be an optimal value of supplementary light for winter greenhouse production of certain types of lettuce in higher latitudes, while light intensity of 600μmolm−2s−1 can be an optimal value of shading light for late spring and early autumn production of certain types of lettuce in lower latitudes.

The biomass and total lipid content and composition of twelve species of marine diatoms cultured under various environments

Twelve species of purified marine diatoms were cultured in summer and in winter greenhouses and in an incubator. Subsequently, their biomasses were estimated, and their fatty acid components and contents were analysed using gas chromatography. Among the investigated diatoms, the biomasses ranged from (1.18±0.059)×106 to (2.51±0.0126)×107cells/mL. The total lipid content (dry weight) ranged from 30.2±1.59% to 45.1±2.39%, and each diatom included from 12 to 19 different types of fatty acids from a total of 22 different kinds of fatty acids found. The diatoms cultured at varied temperatures (17–32°C) and light intensities (122–655μmolphotonsm−2s−1) showed different trends of accumulation of PUFA and SFA.

Characteristics of Heating Load for Greenhouses in Mid Winter of Hokkaido

Characteristics of Heating Load for Greenhouses in Mid Winter of Hokkaido

Energy inputs and crop yield relationships in greenhouse winter crop tomato production

In this study, energy use patterns and the relationship between energy inputs and yield for single crop (winter) greenhouse tomato production were examined in Antalya province, one of the most important greenhouse centres in Turkey. Data were collected using face-to-face surveys from 85 farms producing winter greenhouse tomatoes. The results indicated that the bulk of energy was consumed in fertilizer (38.22%), electricity (27.09%), manure (17.33%) and diesel-oil (13.65%). Average yield and energy consumption were calculated as 57,905.1 kg/ha and 61,434.5 MJ/ha, respectively. Results also determined an output–input ratio of 0.8 and a respective energy productivity and specific energy of 1.061 MJ/t and 0.94 kg/MJ. In addition, the Cobb Douglas production function was applied to test the relationship among different forms of energy consumption. The findings suggested that single crop tomato producers must optimize their use of indirect energy resources. Single crop producers applied an excess use of chemicals, resulting in an inverse effect on yield as well as imposing risks to natural resources and human health. This research suggested an expansion in energy use training opportunities to greenhouse farmers in the region.

Effects of air and soil temperatures on the chemical composition of fruit and agronomic performance in strawberry (Fragaria ananassa Duch.)

SummaryThe effects of different air and soil temperatures on the levels of bioactive components in strawberry fruit (cv. Elsanta) were studied under Winter greenhouse conditions, as were agronomic parameters such as fruit yield, fruit size, and leaf area. The following three temperature Treatments were applied: A, cool (day/night: 16°C/12°C); B, warm (day/night: 22°C/16°C); and C, warm with soil heating to 26°C during the day. Increasing the air temperature in the greenhouse, or the soil temperature, decreased the average fruit weight. Fruit quality attributes such as dry matter and soluble solids contents, and titratable acidity, were not significantly influenced by the different treatments. Strawberries grown in the cool environment (Treatment A) had a lower anti-oxidant capacity, in terms of their total phenolics (TP) content, trolox equivalent anti-oxidant capacity (TEAC), and oxygen radical absorbance capacity (ORAC), than strawberries produced in the warmer environment (Treatment B). This was due to lower concentrations of total monomeric anthocyanins, total pro-anthocyanidins, total ellagitannins, and kaempferol 3-glucoside-malonate. On the other hand, ascorbic acid concentrations in fruit grown in the cooler environment were higher compared to fruit grown in the warmer environment. An increase in soil temperature in the warmer environment (Treatment C) did not result in any additional accumulation of anthocyanins, or any other phenolics in the fruit, except for p-coumaroyl glucose. However, the concentrations of pro-anthocyanidins were even lower in fruit grown with heated soil. These results showed that air and soil temperatures have a significant influence on the phenolics composition of strawberries.

Development of alternate cut-flower rose greenhouse temperature set-points based on calorimetric plant tissue evaluation

Energy utilization for heating is one of the most expensive greenhouse climate control operations. The temperature set-point is determined by many interrelated environmental, physiological, and economic factors but is fundamentally driven by the required growth rate of the plant or crop for quality and profitability. Temperatures are maintained to maximize production and affect timing of harvest of greenhouse-grown crops. In general, winter greenhouse environments for most cut-flower roses are heated to a target temperature of 16–18 °C. For rose, such temperature targets are based on grower experience along with horticultural research and should be considered a compromise across all factors. In the current research we studied the concept of “potential growth rate” (PGR), based on a thermodynamic growth model and how PGR relates to the typical temperature recommendation (TTR) for set-points for greenhouse heating and cooling in commercial horticultural production. PGR of specific growing organs (leaves, shoot tips, roots, etc) can be deduced using calorespirometric measurements in relation to various environmental factors such as temperature effect on biomass production. This research consisted of two facets: (1) determination of cultivar-specific alternate TTRs based on calorimetric PGR measurement and then (2) testing these TTRs in greenhouse rose flower production. The results of this study suggested that TTRs for the cultivar ‘Kardinal’ can be lowered at the time of bud emergence, when this cultivar can tolerate a lower temperature. Also, since the cultivar ‘Milva’ can tolerate lower temperature at time of leaflet unfolding, the current TTR can be adjusted to reflect this. We investigated a set of alternate TTRs by growing rose plants on movable carts and shifting them to various pre-determined night temperature conditions. During the relevant growing stages, half of the plants were given a cold night temperature (14 °C) treatment, while control plants were left in the normal greenhouse temperature (18 °C). This procedure was repeated for three flushes of flowering rose shoots. Flower shoots were counted and weighed (fresh and dry); shoot length was measured several times per week. It was found that the predictions were valid and (with one exception) no significant effect on the number of flowers, their quality or biomass was caused by this procedure. The implication of this work is that heating cost can be reduced for some rose cultivars by allowing night temperatures to be lower than the typical recommendations for those cultivars that show high metabolic activity at such cooler conditions.

Response of Bedding Plants to Saline Water Irrigation

Bedding plants are extensively used in urban landscapes. As high-quality water supply becomes limited in many parts of the world, the use of recycled water with high salt levels for landscape irrigation is being encouraged. Therefore, information on salt tolerance of bedding plants is of increasing importance. Two experiments were conducted, one in a 25% light exclusion shadehouse in summer (Expt. 1) and the other in a greenhouse in winter (Expt. 2). Plants were irrigated with saline solution at electrical conductivities of 0.8, 2.8, 4.0, 5.1, or 7.4 dS·m−1 created by adding NaCl, MgSO4, and CaCl2 to tap water to simulate the composition of local reclaimed water. In Expt. 1, shoot dry weight (DW) at the end of the experiments was reduced in all species at 7.4 dS·m−1 compared with the control (0.8 dS·m−1). The magnitude of reduction varied with species and cultivars. The salinity thresholds of irrigation water in which growth reduction occurred were 4.0 dS·m−1 for angelonia (Angelonia angustifolia) cultivars and ornamental pepper (Capsicum annuum) ‘Calico’ and 4.0 to 5.1 dS·m−1 for helenium (Helenium amarum), licorice plant (Helichrysum petiolatum), and plumbago (Plumbago auriculata). Shoot DW and growth index of ornamental pepper ‘Black Pearl’ and vinca (Catharanthus roseus) ‘Rose’ decreased linearly as salinity increased. All plants survived in Expt. 1 regardless of treatment, except for ornamental pepper ‘Purple Flash’. No visual injuries were observed in Expt. 1 regardless of treatment. Leaf sodium (Na) and chlorine (Cl) concentrations varied with species and treatments. Ornamental pepper ‘Black Pearl’ had the highest leaf Cl concentrations at higher salinities compared with other species and cultivars. Leaf Na concentrations in licorice plant and plumbago were in the range of 10 to 30 g·kg−1 DW, higher than those in other species. In Expt. 2, shoot DW was reduced by salinity treatments in ornamental pepper ‘Black Pearl’, plumbago, and angelonia but not in other species. The three ornamental peppers, ‘Black Pearl’, ‘Calico’, and ‘Purple Flash’, exhibited slight foliar injuries on some plants in Expt. 2 as a result of high salinity in the root zone in the highest salinity treatment. Ornamental pepper ‘Black Pearl’ was most sensitive to salinity stress. In general, the bedding plants tested in this study are moderately tolerant to salt stress and may be irrigated with saline water up to 4.0 dS·m−1 with little reduction in aesthetical appearance.

Quantitative trait loci for leaf length in perennial ryegrass (Lolium perenneL.)

AbstractLeaf length is an important trait for forage grasses. Molecular marker development offers the opportunity to identify Quantitative Trait Loci (QTLs) and to begin to dissect the genetic regulation of complex traits. The objective of this study was to look for QTLs for leaf length and related traits (plant height, lamina and sheath lengths, leaf elongation rate and leaf elongation duration) in the progeny of a cross between two genotypes ofLolium perenneL. with contrasting leaf length. Measurements were performed in a plant nursery in autumn and spring, and in a heated greenhouse in winter. A high level of variability and heritability was observed for all traits. Lamina lengths at different dates were moderately but significantly correlated. For all traits, QTLs were found and explained between 0·08 and 0·44 of phenotypic variance. Although different leaf length QTLs were found at different dates, linkage groups two, four and seven were particularly important.

Wood formation in Abies balsamea seedlings subjected to artificial defoliation

We determined the cambial sensitivity and quantified the anatomical differences in xylem of Abies balsamea (L.) Mill. seedlings subjected to artificial defoliation to simulate spruce budworm feeding. Defoliation was performed by removing two-thirds of needles of all current-year shoots for up to four consecutive growth cycles to account for inter- and intra-annual xylem formation. In Experiment 1, xylem development was studied from May to October 2005 in seedlings defoliated at the end of June. In Experiment 2, anatomical features of the xylem were measured along the tree rings formed in 2005 and 2006 during the four cycles of growth and defoliation. Control and defoliated seedlings showed similar patterns of cambial activity and timing of xylem differentiation, although fewer enlarging cells were observed in August to September in defoliated seedlings. Tree-ring widths were similar in control and defoliated seedlings, with thinner rings produced in the greenhouse in winter. No effect of defoliation on cell lumen area was observed, and effects on radial cell diameter and wall thickness were found only occasionally. The results indicate that the A. balsamea seedlings produced all the resources required to maintain stem growth during the four cycles of defoliation.

Cucurbit Grafting

Due to limited availability of arable land and high market demand for off-season vegetables, cucurbits (plants in the family Cucurbitaceae) are continuously cultivated under unfavorable conditions in some countries. These conditions include environments that are too cold, wet, or dry, or are cool low-light winter greenhouses. Successive cropping can increase salinity, the incidence of cucurbit pests, and soilborne diseases like fusarium wilt caused by Fusarium spp. These conditions cause various physiological and pathological disorders leading to severe crop loss. Chemical pest control is expensive, not always effective, and can harm the environment. Grafting can overcome many of these problems. In fact, in many parts of the world, grafting is a routine technique in continuous cropping systems. It was first commonly used in Japan during the late 1920s by grafting watermelon [Citrullus lanatus (Thunb.) Matsum. and Nakai] onto pumpkin [Cucurbita moschata Duchesne ex. Poir] rootstocks. Soon after, watermelons were grafted onto bottle gourd [Lagenaria siceraria (Molina) Standl.] rootstocks. This practice helped control declining yield due to soilborne diseases. China produces more than half the world's watermelons and cucumbers (Cucumis sativus L.), and approximately 20% of these are grafted. Use of rootstocks can enhance plant vigor through vigorous attainment of soil nutrients, avoidance of soil pathogens and tolerance of low soil temperatures, salinity, and wet-soil conditions. The type of rootstock affects cucurbit plant growth, yield, and fruit quality. Cucurbit grafting is rare in the United States, but with continued loss of quality disease-free farmland along with the phase-out of methyl bromide, the U.S. cucurbit industry sees grafting as an attractive option. Some seed companies now offer watermelon transplants grafted onto squash or bottle gourd rootstocks, and some transplant facilities offer grafting services. There have been thorough analyses of cucurbit grafting in other countries, but the literature in English is limited. This review summarizes the state of the cucurbit grafting industry on a global level, translating work published in many languages.

Basis for the new challenges of growing broccoli for health in hydroponics

AbstractBACKGROUND: Variations in the contents of phytochemicals with biological activity in broccoli could originate as a result of genetic and environmental factors. An understanding of the effects of growth conditions on the bioactive compounds in broccoli is essential for improving its quality and nutritive value. Using salinity (40 mmol L−1 NaCl), and foliar sprayed compounds (methionine, tryptophan and chitosan) as different stress conditions, broccoli developed in soilless culture in the greenhouse was analysed for biologically active phytochemicals (glucosinolates, caffeoyl‐quinic, ferulic and sinapic derivatives and vitamin C).RESULTS: The application of elicitors during head formation could be beneficial for the enrichment in phytochemicals in broccoli. Management practices for increasing a given phytochemical (e.g., glucoraphanin or glucobrassicin) may be related to a decreased level of natural antioxidants (hydroxycinnamic acids). Growing broccoli hydroponically in the greenhouse in winter (Mediterranean climate) needs the supporting treatment of abiotic stress during development (i.e., NaCl, elicitors).CONCLUSION: The use of hydroponic growth conditions for broccoli and the application of stress factors (elicitors) at head induction and during development may serve the purpose of enhancing its nutritional quality to deliver a health‐promoting food. Copyright © 2008 Society of Chemical Industry

TYLCV detection in Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) B and Q biotypes, and leaf curl symptom of tomato and other crops in winter greenhouses in Shizuoka Pref., Japan

We investigated whitefly species and their biotypes, PCR-positive individuals of Tomato yellow leaf curl virus (TYLCV), and leaf curl symptoms by collecting whitefly adults and observing the leaves of various crops in winter greenhouses in Shizuoka Pref., Japan. From January to February 2006, 48 collection sites and 5 kinds of crops were investigated. Leaf curl symptom was observed in 23 out of 36 tomato greenhouses. The whitefly in tomato greenhouses were collected from 23 Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) B biotype populations and 12 Trialeurodes vaporariorum (Hemiptera: Aleyrodidae) populations. The B. tabaci Q biotype was detected in only 2 separate poinsettia greenhouses. From strawberry and melon greenhouses, only Trialeurodes sp. and B. tabaci B biotype, respectively, were collected. TYLCV was detected in 13 out of 30 B. tabaci B biotype populations and in 6 out of 6 T. vaporariorum populations collected from tomato, poinsettia, and melon greenhouses, irrespective of the presence of leaf curl symptom. TYLCV was not detected in any B. tabaci Q biotype individuals.

Does fruit number per plant, or fruit-set order affect seed yield and quality in cucumber?

SummaryTwo experiments, one in a greenhouse in Winter and the other in the field during the following Summer, were conducted to study the effects of fruit number per plant, and position in the fruit-set order, on the seed yield of individual fruit. The genetic material used was ‘Poinsett 76’, an old American cultivar used for fresh consumption. The two experiments differed not only in season and location, but also in cultural practices. In the Winter, the plants were trailed and hand-pollinated, whereas in the Summer the plants lay on the beds and were naturally bee-pollinated. The number of fruit per plant did not significantly affect individual fruit weight or seed yield components in either experiment. In contrast, fruit-set order position affected the seed yield components in the field, but not in the greenhouse. In the field experiment, both seed number per fruit and mean seed weight decreased with increasing fruit-set order position. The number of seeds per fruit in ‘Poinsett 76’ cucumber, a cultivar with a strong tendency to parthenocarpic fruit-set, varied, and was affected by cultural conditions. The number of fully-developed seeds per fruit was often low, far below its full potential. In the present study, this was expressed in high mean percentages of empty seeds: 58% and 55% in Winter and Summer, respectively. Neither the number of fruit per plant, nor the fruit-set order position affected the germination percentages at fruit harvest, or after up-to-7 years in storage. In all germination tests, Summer- and Winter-produced seeds achieved germination percentages of 80–95% and > 95%, respectively. On the other hand, the speed of germination was decreased by storage, and was slower in seeds extracted from immature fruit than in those from fully mature fruit.