Full Bloom Date Research Articles

Retrieval of cherry flowering phenology on Flickr and YouTube: a case study along the Tarumi railway, Gifu, Japan

To further develop the accuracy of monitoring cherry flowering dates, we require phenological records from multiple points in multiple years at the catchment scale, as well as conventional in situ phenological observations, phenological data published on the Internet, and analysis using statistics of Internet search engines. We tried to detect the dates of cherry flowering phenology along the Tarumi railway, Gifu Prefecture, Japan, by using Flickr, an image hosting service, and YouTube, an online video sharing and social media platform. We detected full bloom of Cerasus ×yedoensis and Cerasus jamasakura mainly at cherry blossom viewing spots (around some train stations) on Flickr and at both viewing spots and multiple points in the landscape along the railway on YouTube. Despite local climatological differences along the railway, the detected full blooming dates corresponded not only with each other, but also with the full bloom period of Neodani Usuzumi-zakura (Cerasus itosakura), a famous tree with long-term detailed records. We could not detect the date and location in many photographs on Flickr or in any videos on YouTube. However, the usefulness of both platforms is supported by the facts that we can evaluate the year-to-year variability of full bloom dates, especially at cherry blossom viewing spots, and detect flowering phenology even in a non-photogenic landscape. By applying our method to other railways, we expect to collect multi-year records of plant phenology dates at multiple points that cannot be collected by older methods.

Model Evaluation for Predicting the Full Bloom Date of Apples Based on Air Temperature Variations in South Korea’s Major Production Regions

Model Evaluation for Predicting the Full Bloom Date of Apples Based on Air Temperature Variations in South Korea’s Major Production Regions

Monitoring of cherry flowering phenology with Google Trends.

Google Trends (GT) is an online tool designed for searching for changes over time. We assessed its use for evaluating changes in the timing of cherry flowering phenology, which is of intense interest to Japanese people. We examined the relationship between time-series of relative search volume (RSV: relative change in search requests over time obtained from the GT access engine) and cherry flowering information published on websites (as ground truth) in relation to three famous ancient cherry trees. The time-series of RSV showed an annual bell-shaped seasonal variability, and the dates of the maximum RSV tended to correspond to the dates of full bloom. Our results suggest that GT allows monitoring of multiple famous cherry flowering sites where we cannot obtain long-term flowering data to evaluate the spatiotemporal variability of cherry flowering phenology.

Reconstruction of April temperatures in Kyoto, Japan, since the fifteenth century using the floral phenology of herbaceous peony and rabbit-ear iris.

We reconstructed April mean temperatures in Kyoto since the fifteenth century by investigating historical documents such as diaries and chronicles and compiling phenological data series of the full bloom date for herbaceous peony. In order to fill gaps in phenological data series, we used the full bloom date of rabbit-ear iris, an herbaceous plant that flowers at about the same time of the year as an herbaceous peony. We obtained floral phenological data covering a total of 278years. Calibration using modern temperature data showed herbaceous peony phenology to be the preferred data source for April temperature estimation. Variations in the reconstructed April temperatures in Kyoto were synchronous with changes in the solar cycle. In particular, April temperatures were about 2℃ lower than at present around the ends of the Spoerer and Maunder grand solar minima, from 1550 to 1590 and from 1690 to 1730, respectively. In addition, the reconstructed April temperatures suggested a time lag in the climate response to solar activity changes that was about 10years longer than the previously estimated lags in the responses of wintertime and March temperatures. However, further research is needed to accurately quantify this time lag.

Phenological shifts of buds and flowers caused by early heat recognition in citrus in Jeju, Korea

The objectives of this study were to trace the shift in bud burst and full bloom dates and provide a countermeasure for the suitable prediction of these representative phenological indices for citrus trees. The heat accumulation value was calculated by the growing degree day (GDD) model with six base temperatures (Tb) from 5 to 17.5℃ in 2.5℃ intervals, and the estimation accuracy of this value for both phenological stages was evaluated. The optimal Tb and heat requirement of Miyagawa Satsuma mandarin trees were 7.5℃ and 108.6℃·days for bud burst, respectively, and 10.0℃ and 196.2℃·days for full bloom, respectively. The data showed that bud burst and full bloom have advanced by 0.3−0.5 days per year since the 1960s, and this advancement was more drastic over the last 10 years, which reached 1.4 days per year. Moreover, the theoretical calculation of heat accumulation started on the date when fruit was harvested in the previous year, but the practical heat accumulation affecting bud burst started much later because of the negative effect associated with values below the Tb by the heat accumulation model. The start date of heat accumulation also gradually advanced in recent decades by 0.5 days per year. The dates of full bloom at specific study sites were predicted via the dates of full bloom at Jeju and Seogwipo, which are close to the northern and southern coasts and represent sites where recent meteorological data have been collected. The prediction equations had common components, and the value of the southernmost site could be used as a low variable threshold by dropping the coefficient; thus, the equation was dependent on the large variability of the northernmost site, which was represented by a higher coefficient.

Research Article Peach phenological characters: heritability, maternal effect and correlation with brown rot

Peach is a temperate fruit species that is cultivated under various edaphoclimatic conditions all over the world. In Brazil, in the early 1950s, peaches were planted only in Sao Paulo state and in the Southern states, and the harvest period was restricted to 15 days. Currently, mainly due to peach breeding programs, it is cultivated in subtropical areas and even in high altitude tropical areas, with a harvest period of over 100 days. Knowledge of genetic, phenotypic and environmental parameters that influence characters of economic importance is crucial for guiding breeding programs. The objectives of this study were to estimate the heritability of phenological characters, to evaluate their distribution within populations, to test the possible existence of maternal effect and to evaluate the relationship of these traits with brown rot incidence (Monilinia fructicola). The study was performed in Pelotas, RS, Brazil during 2015-2016 to2017-2018 seasons. Sixteen first generation (F1) progenies were evaluated, 10 of them being reciprocal crosses. All genotypes were cultivated in the same area, under the same cultural practices (without fungicide application). Full bloom was considered when more than 50% of flowers were open, and the harvest, when more than 10 fruits reached commercial maturity, the fruit development period being calculated by the difference between full bloom and harvest dates. Brown rot incidence was estimated by the percentage of fruits with symptoms. Broad-sense heritability estimates for full bloom date, harvest date, and fruit development period were high (95 to 98%), and narrow-sense heritabilities were medium to high (65 to 72%). A segregation study of these traits suggests a maternal effect on their heritability, mainly for full bloom and harvest date. The three phenological characters were significantly correlated, and only harvest date had a negative and significant correlation (-0.12) with brown rot incidence.

Modelling cherry full bloom using ‘space-for-time’ across climatically diverse growing environments

A dataset of cherry full bloom dates across the full diversity of Australian growing regions was compiled and utilised for the first time. The primary data source was from growers located across Australia's major cherry growing districts. Records were of varying length and were used to investigate the potential of using data that substitute ‘space-for-time’ in phenology assessments. Full bloom timing for three cultivars, Bing, Lapins and Van, were collated. The data showed variation in full bloom time across the sites as well as inter-annual variability within sites. This highlighted the potential benefit of a predictive model for growers to better manage the flowering period. The performance of the sequential and the chill overlap models were evaluated using this data. Both models resulted in good statistical representation of the data with RMSE of 3.2 to 5.3 days and 3.3 to 5.4 days for the training and validating data, respectively. The parameterisations of the models differed with the sequential model estimating higher chilling requirement (65–68 CP) than the chill overlap model (46–48 CP). The sequential model estimated similar heat requirements between the cultivars, with Van marginally higher (7250–8000 GDH). The chill overlap model estimated a larger difference in the minimum heat requirement with Van higher (8223 GDH) than Bing and Lapins (6262 and 6486 GDH, respectively). Collation of grower records proved to be a valuable data source which, in the absence of funded programs, could be better utilised for further research that aligns outcomes with industry needs, such as decision support around polliniser varieties, design of growing systems and use of dormancy breakers to synchronise flowering for optimal fruit set and quality.

A simpler way to predict flowering and full bloom dates of cherry blossoms by self-organizing maps

Knowledge of flowering and leaf flush phenology is important for a deep understanding of the responses of ecosystem functions, ecosystem services, and biodiversity to climate change. Process-based phenology models, which account statistically for chilling accumulation for endodormancy release and thermal accumulation after endodormancy release, can predict flowering and leaf flush dates, but they are difficult to develop for poorly studied species. A simpler approach is needed. We propose a model of the blooming phenology of Yoshino cherry trees (Cerasus ×yedoensis) based on bidirectional self-organizing maps (SOM). SOM, a data mining approach, is a tool for categorizing patterns in n-dimensional observation data by forming a two-dimensional lattice. The bi-directional SOM was applied to the data of daily mean temperature, using flowering (or full blooming) dates as teacher signals. We inputted daily mean air temperatures during the thermal accumulation period (mainly from February to just before flowering) into multiple input vectors and obtained flowering or full bloom dates into an output vector. The mean absolute errors between predicted and observed dates at 42 locations in Japan ranged from 2.8 to about 4.5 days for flowering and full bloom. The bidirectional SOM approach had a slightly higher error than the process-based phenology model approach, but it has an advantage in predicting flowering and leaf flush dates of poorly studied species under future warming conditions.

Genotype, environment and their interaction effects on olive tree flowering phenology and flower quality

Flowering is one of the most critical processes in the reproductive phenology in fruit trees including olive. Under Mediterranean climate, olive flowering period normally occurs from early to late spring. Therefore, flowering time could be affected by environmental conditions such as water availability and temperature, thus influencing flower quality as well. Previous works have demonstrated the effect of genotype and environment on olive flowering, but those factors have never been compared in a single study nor their interaction evaluated. In the present work, we used a multi-environment trial established in four different agro-climatic conditions of Andalucia, Southern Spain, to test the genetic and environmental influences on flowering timing (flowering period, full bloom period, and full bloom date) and flower quality (flower number, perfect flower number and perfect flower percentage). Most of the variability found for flowering phenology parameters was due to environmental influence. On the contrary, for flowering quality parameters, most of the variability was of a genetic nature. In all cases, the genotype-environment interaction was significant. In this sense, the genotype by environment effects biplot model used to analyse the interaction showed that most of the genotypes evaluated have low stability for most of the parameters evaluated, except ‘Picual’ for flowering phenology parameters and ‘Koroneiki’ for quality. This emphasize the benefits of multi-environment trials on olive in order to select the best genotypes adapted to different environments and as a tool to face the future variability of environmental conditions caused by the climate-warming scenario. In conclusion, multi-environment trials allowed to efficiently quantify the effects of genetic and environmental factors and of their interaction on flowering phenology and on flower quality in olive.

Climate warming enhances flower formation, earliness of blooming and fruit size in plum (Prunus domestica L.) in the cool Nordic environment

The predicted and ongoing climate warming is expected to affect many aspects of plant development. We analysed data from a 31-year series of observations (1985–2016) on spring phenology and flowering and fruiting performance of three plum cultivars in an experimental orchard at Ås in southeast Norway (59° 40′N; 10° 50′E). Regression analyses revealed a trend of increasing March and April temperature during the study period that was highly significantly (P < 0.001) negatively correlated with the date of full bloom (FB). On average for all cultivars, blooming was advanced by 10 days over the study period. August and September temperature, which also increased significantly during the study period, was closely positively correlated with the amount of flowering in the subsequent spring and also interacted with early spring temperature in advancing blooming time. Investigation of the time of floral initiation in two of the studied plum cultivars revealed that the transition to reproductive development took place in early to mid-August. This finding strongly suggests that the close positive correlation between August-September temperature and the amount of flowering in plum observed in this and other studies, is causally linked to a specific physiological effect of elevated temperature on the flower bud formation process.Increasing March and April temperatures during the last 30 years has advanced blooming and spring phenology in plum and the resulting extension of the growing season has led to increasing fruit size at harvest. We conclude that so far, the ongoing climate warming appears to have been positive for plum production in the cool Nordic environment. However, an increasing risk of frost associated with earlier blooming will represent a potential negative effect of continued warming.

Determination of genetic loci in the control network of grapevine flowering

The study of grapevine phenological traits such as flowering and ripening time has become increasingly important in the past few years. With regard to climate change, cultivars with delayed flowering and ripening characteristics may be more advantageous in viticulture. However, genetic markers for these traits applicable for marker-assisted breeding are sparse. Even though homologs of genes that control flowering time have already been identified and characterized in model plants, our overall knowledge about which genetic factors are involved in the complex control of flowering time in Vitis remains very limited. A mapping population consisting of 150 F1 individuals derived from the cross of the early-flowering genotype 'Calardis Musque' and late-flowering cultivar 'Villard Blanc' was used for quantitative trait locus (QTL) detection of the flowering-time trait. For this purpose, vines were phenotyped in 11 seasons for the date of full bloom. QTL analysis led to the identification of several genomic regions, and epistatic effects between the identified loci were observed. The QTLs could be verified in a large extended population of 'Calardis Musque' × 'Villard Blanc'.

Phenology, flowering and fruit-set performance of six recent pear cultivars of Nordic origin

ABSTRACT Flowering performance and phenology of six new pear cultivars of Nordic origin were examined during a 12 year period. The seasonal timing of shoot growth and flower initiation were monitored in three years. The morphological floral stages of the flower bud formation process were examined for the cultivar ‘Celina’. Seven floral stages were identified and described. The date of full bloom varied between years as a function of the currently accumulated heat sum in early spring. Still, the earliness ranking of the cultivars was consistent across years for both flower initiation and blooming. The cultivars ‘Anna’ and ‘Ingeborg’ consistently initiated floral primordia 2–3 weeks earlier than ‘Celina’, ‘Clara Frijs’, ‘Fritjof’ and ‘Kristina’, and this was accompanied with 4–5 days earlier blooming in the following spring. The early flower initiation cultivars ‘Anna’ and ‘Ingeborg’ also had richer flowering than the late-blooming cultivars. ‘Fritjof’ was identified as a suitable pollinator for ‘Celina’ in the Nordic climate. Comparison of the flowering phenology of pear and apple cultivars showed that while the pears, on average, flowered a week ahead of the apples, they initiated flower primordia almost two weeks later, thus rendering the intervening period approximately three weeks longer in pear than in apple.

Phenotypic, Biochemical and Molecular Characterization of New Egyptian Mango Genotypes

The first step towards improving mango production was started by the selection of eleven genotypes because of their superior horticultural characteristics and fruit quality parameters, from Suez Canal University orchard through 2016 to 2018 seasons. All studied mango genotypes (G) differed in dates of full bloom, maturity stage, bearing habit, floral malformation and fruit characteristics. All genotypes had commercially acceptable qualities and produced relatively high yield ranged from 298.7 - 394 Kg/tree. Generally, genotype No. 9 recorded the highest value (96.6%) in the general evaluation according to yield, Biennial bearing and fruit quality, followed by genotypes No. 7 and No. 5 which scored 94.0 and 91.8%, respectively. In general, these three genotypes possessed most of the desired commercial attributes of international standard. In addition, further understanding of the structure of genetic diversity was done using nine SSR markers based on their scorability, repeatability and capability to differentiate among studied genotypes. Also, analyze of DNA fingerprinting data to create molecular IDs was done to get an idea for the conservation and protection of studied genotypes. The nine SSR loci produced a total of 32 alleles with 97% polymorphism and observed alleles per locus diversified from 1 to 8 alleles with an average of 3.6 without zero alleles. The observed heterozygosity (Ho) within the loci ranged from 0.0 to 0.55 with an average value of 0.23, heterozygosity level within the genotypes varied from 0.11 to 0.44. The polymorphic information content (PIC) values ranged from 0.0 to 0.86 with an average value of 0.49, whereas the mean of discriminating power (DP) for all loci was 0.51. Regarding the probability of matching fingerprints, none of the genotypes were different or similar at all loci with any of the rest genotypes and this value ranged from low to medium with an average of 0.48. The similarity degree ranged from 0.18 to 0.90 with an average of 0.53, indicating that the genetic differences were moderate among mango genotypes under study. Whereas, seven of these genotypes produced 11 unique bands maybe accompanying to number of novel functional alleles, which can be used in mango improvement.

Search for sweet cherry (Prunus avium L.) cultivars suitable for warm climate in the southwestern region of Japan

The cool climate of the northern part of Japan’s main island, Honsyu is suitable for the cultivation of sweet cherry (Prunus avium L.). In recent years, the warm southwestern region of Japan has also been proposed as a candidate region for cherry cultivation; cherry fruit set has, however, previously been reported to be significantly inhibited under warm climate conditions before flowering. We aimed to identify a suitable cherry cultivar for cultivation in the warm southwestern region by examining five cherry cultivars: ‘Summit’, ‘Benitemari’, ‘Kokanishiki’, ‘Benisyuho’, and ‘Saori’. Trees were grown in 2013 and 2014 in Matsue city, Shimane prefecture, Japan, (35°28’N; 133°03’E) with an annual mean temperature of 14.9°C, annual means of maximum and minimum temperature of 19.9 and 11.6°C, respectively (2013) and annual precipitation of 1787.2 mm. The data showed that the full bloom dates were around mid-April. These cultivars could all cross-pollinate one another. The fruit set of the cultivars was over 10% but that of ‘Summit’ was only 5.7% in 2013. Harvesting time was overlapping in June (June 1-20 in ‘Kokanishiki’ and ‘Benisyuho’, June 1-30 in ‘Benitemari’, June 4-16 in ‘Summit’, and June 6-20 in ‘Saori’). Harvesting time in Shimane prefecture could be two weeks earlier than those in the Yamagata prefecture, primary cherry producing prefecture in Japan. The soluble solid content of ‘Kokanishiki’ and ‘Benisyuho’ cherries was over 20 °Brix, and ‘Kokanishiki’ softened more rapidly. With juice extraction ratios of between 30 and 40%, the fruits of all cultivars were juicy. We recommend ‘Benisyuho’ which possessed the highest quality as being the most suitable cultivar for cultivation in the warm southwest region of Japan; the other three cultivars, excluding ‘Summit’, were also suitable for cultivation in this area.

Van Bölgesi'nde Yetiştirilen Erik (Prunus domestica L.) Genotiplerinin Agro Morfolojik Özellikleri

This study was conducted in the years 2010 and 2011 to determine plum genotypes naturally grown in Van region and to identify biological diversity in the region. Phenological, pomological and morphological properties of available plum genotypes were assessed and a total of 45 genotypes were monitored for two years. Among the investigated genotypes, 10 were selected as promising plum genotypes. Budburst dates of promising genotypes varied between 5-26 April, initiation of flowering dates varied between 30 April - 14 May; full-bloom dates varied between 03-17 May; end of flowering dates varied between 11-24 May; and harvest dates varied between 01 August-10 September. Fruit weights of promising genotypes varied between 8.66-25.59 g; fruit widths between 22.29-31.22 mm; fruit lengths between 22.98-35.86 mm; fruit heights between 23.16-33.32 mm; seed weights between 0.59-1.45 g; seed widths between 9.56-19.23 mm; seed lengths between 11.91-20.97 mm; fruit volumes between 12.00-32.00 cm³; fruit densities between 0.80-1.53 g cm-3 fruit flesh/seed ratios between 11.50-23.09%; fruit juice titratable acidity values between 0.89-2.62%; pH values between 3.75-4.08; total soluble solids contents (TSSC) between Brix° 10.5-15.5; vitamin C contents between 9.84-29.80 mg 100g-1, tree canopy heights between 2.30-6.00 m; and canopy widths between 2.30-7.40 m.

Comparison between two methods of estimation of chilling and heat requirements for flowering in almond

A precise determination of thermic requirements (chilling and heat) for breaking dormancy is quite difficult under field conditions. However, quantification under laboratory conditions should be considered with caution and it is costly and time consuming when analyzing a large number of genotypes. For this reason, statistical models based on the analysis of historical blooming dates have been developed to fit the responses of tree species to local weather conditions. Chilling and heat requirements for breaking dormancy and flowering were studied in five local almond cultivars with a widespread time of full bloom (‘Pizzuta d’Avola’, the earliest, ‘Tribuzio’, ‘Tuono’, ‘Cristomorto’ and ‘Rana Gentile’, the latest) in Apulia region (southern Italy). The chilling portions (CP), determined by dynamic model, and the growing degree hours by Richardson model (GDH) were used to determine chilling and heat accumulations, respectively. Using both full bloom dates and temperatures of previous seasons for nine years, two methods for estimating thermic requirements were compared: the Ashcroft method (AM), and a new version (Ashcroft method modified, AMM) that takes into account in a higher extent the GDH accumulation in comparison with AM, and allows selecting the optimal requirements when alternative choices are possible. The two methods generally underestimated the blooming date, but with a difference from the real one within 5 days for most of the cases studied. AMM resulted more effective than the original method in Apulian semi-arid conditions. The estimation of thermic requirements using temperature data and full bloom dates seemed to be useful, easy and not too expensive to be implemented for a wide number of cultivars.

Promising Strawberry Tree Genotypes from North Anatolia, Turkey

Anatolia is one of the primary centers of origin of strawberry tree (Arbutus unedo L.). Pomological and morphological characteristics of strawberry tree genotypes, naturally growing in natural flora of Northern Anatolia, were investigated in this study in 2008 and 2009. In 2008, 48 genotypes were identified and subjected to physico-chemical analyses (fruit weight, fruit length and width, soluble solids content, titratable acidity), phenological observations (initial-bloom and full-bloom dates) and sensory analyses (fruit taste, stoniness, juiciness, appearance and roughness). Based on weighted-ranked scores for different attributes, 24 genotypes were selected as promising ones and analyses were continued on these genotypes in 2009. Fruit weights of genotypes varied between 2.28 g (28G32) and 11.00 g (28G41); fruit widths between 16.51 mm (28G32)–28.05 mm (28G41); fruit lengths between 13.06 mm (28G26) and 22.03 mm (28G41); soluble solids contents between 24% (28G28, 28G40) and 31% (28G30) and titratable acidity between 0.77% (28G30) and 1.19% (28G41). Initial-bloom dates varied between 5th of October (28G36, 28G45 and 28G46) and 10th of November (28G16 and 28G26) and full-bloom dates varied between 15th of November (28G02, 28G31, 28G36, 28G47) and 15th of December (28G02, 28G44, 28G45). These 24 genotypes were selected as promising genotypes potentially to be used in breeding studies on strawberry tree fruits.

Evaluation of three modelling approaches for almond blooming in Mediterranean climate conditions

Abstract Chilling and heat requirements for breaking dormancy and flowering were studied in seven almond cultivars in Southern Italy. Chilling portions (CP), computed through the Dynamic model, and growing degree hours (GDH) were used to determine chill and heat accumulation, respectively. Then, using full bloom dates and temperature data from nine seasons (2003/2004-2007/2008 and 2009/2010-2012/2013), three sequential methods for the estimation of thermal requirements were compared: 1) the Ashcroft Method (AM), where chilling and heat requirements were selected considering the lowest variability of the GDH at several intervals of CP, and two variations: 2) modified Ashcroft Method (AMm) that took into consideration the lowest variability in both CP and GDH, and 3) reverse Ashcroft Method (AMr) opposite to AM. All methods were effective in predicting full bloom dates; however the modified Ashcroft method was the most accurate under Mediterranean conditions and allowed to classify almond cultivars for their thermal requirements. The results from AMm, showed chilling requirements ranging between 24–62 CP and heat requirements between 3263 and 6699 GDH, respectively.

Evaluation of Flower, Fruit, and Juice Characteristics of a Multinational Collection of Cider Apple Cultivars Grown in the U.S. Pacific Northwest

Little information exists on the bloom and fruit characteristics of cider apple (Malus ×domestica) cultivars grown in the United States for the juice and alcoholic beverage markets. In this study, a total of 17 cider apple cultivars, including 4 American, 9 English, and 4 French, plus 1 Danish standard dessert apple cultivar (Red Gravenstein, Worthen strain) commonly used for cider, all grown in northwest Washington, were evaluated from 2000 to 2015 for commercially relevant traits. Trees were rated each year and the cultivars were categorized accordingly by relative bloom time, bloom habit, and productivity. The mean full bloom (FB) date of the 18 apple cultivars evaluated ranged from 25 Apr. to 25 May, with 6 cultivars categorized as early season bloomers, 9 as midseason, and 3 as late season. The mean bloom density (BD) rating (measured on a scale of 1–5) for all cultivars was (mean ± sd) 3.8 ± 0.6 (moderate bloom), with the bloom habit of 1 cultivar categorized as biennial, 11 as consistent, and 6 as strongly consistent. The mean productivity rating (measured on a scale of 1–5) for all cultivars was 2.9 ± 0.6 (light fruiting), with the productivity of 4 cultivars categorized as biennial, 10 as consistent, and 4 as strongly consistent. The mean fruit diameter of the 18 apple cultivars was 2.7 ± 0.4 inches (medium sized), with the fruit size of 2 cultivars categorized as small-fruited, 15 as medium-fruited, and 1 as large-fruited. For the 18 cultivars, the mean tannin and titratable acidity (TA) were 0.20% ± 0.14% and 0.54% ± 0.28%, respectively, and using the English cider apple classification system of juice type, 4 of the cultivars were classified as bittersweet, 1 as bittersharp, 3 as sweet, and 10 as sharp. Three of the cultivars had tannin content lower than what was historically recorded at the Long Ashton Research Station (LARS) in Bristol, England, for those same cultivars. The mean specific gravity (SG) of the 18 cultivars was 1.052 ± 0.007, the average predicted alcohol by volume (ABV) was 6.9% ± 0.9%, and the mean pH was 3.68 ± 0.39. Classification of three cultivars in northwest Washington, based on juice characteristics, differed from their historical classification in England, likely because of differences in climate and management. Only cultivars Golden Russet (sharp), Grimes Golden (sharp), and Yarlington Mill (sweet, but borderline bittersweet) were strongly consistent in productivity, but none produced high levels of tannin, whereas only cultivars Bramtot (bittersweet), Chisel Jersey (bittersweet), and Breakwell Seedling (bittersharp) were consistent in productivity and produced high levels of tannin.

Flowering and heat requirements of four olive cultivars grown in the south of Tunisia

Olive phenology is a sensitive indicator of climate change and especially the climatic warming of areas where olives are grown. Flowering occurs after being exposed to chilling and subsequent accumulation. The Mediterranean region is characterized by a changeable climate, especially in spring when temperature varies quickly from year to year. In this context, a study was carried out on local ('Meski' and 'Chemlali') and foreign ('Picholine' and 'Koroneiki') olive cultivars grown in southern Tunisia to calculate the heat requirements for flowering during the period 2008-2012. The aim of the present work is to compare flowering full bloom dates for the different cultivars and to calculate the heat requirement until flowering. Heat units were expressed in growing degree day (GDD). For the GDD accumulation, the results indicated a large inter-annual variation. The GDD began being recorded when the calculations of chilling accumulation were stopped. There were differences in flowering dates among cultivars. During the springs of 2008, 2009 and 2010, 'Chemlali' began blooming on 16 April, just after accumulation of 173.85, 100.7 and 160.65 GDD after the end of chilling respectively. 'Koroneiki' was in full bloom on 12 April in 2010-2011 after accumulation of 133.33 GDD. For the year 2011-2012, 'Meski' entered to bloom on 12 April after accumulation of 182.56 GDD while the other cultivars entered into bloom after receiving heat requirements ranging between 169.45 and 267.6 GDD.