Late-season Cultivars Research Articles

Postharvest Quality of ‘Keepsake’ Apple Fruit

Storage information regarding ‘Keepsake’ apple fruit is lacking. The objective of this research was to investigate the postharvest characteristics of ‘Keepsake’ apple (Malus ×domestica Borkh.), which is a parent of ‘Honeycrisp’. Apples were obtained from three orchards in Minnesota in 2022 and 2023, assessed for quality, and stored at 0 to 1 °C or 4 to 5 °C in air. Fruit were tested for firmness, soluble solids content (SSC), and titratable acidity (TA) for up to 6 months in storage. At harvest, fruit from different orchards differed in ground color, firmness, SSC, and titratable acidity. The starch pattern index did not differ among the orchards within a year, but it was greater during the 2023 harvest than during the 2022 harvest. Fruit firmness decreased less rapidly at 0 to 1 °C than at 4 to 5 °C. Changes in SSC with storage varied by orchard, storage temperature, and year. In 2022 to 2023, SSC changes were highly variable, remained the same during storage for fruit from one orchard, increased and then decreased for fruit from another orchard, increased after 1 month of storage, and then remained unchanged thereafter for fruit from the third orchard. In 2023 to 2024, SSC was generally unchanged during storage at 0 to 1 °C, and it increased slightly over time during storage at 4 to 5 °C. Titratable acidity decreased during storage, but there was no difference between storage temperatures. These findings demonstrate the difficulty determining when to harvest ‘Keepsake’ fruit because neither starch pattern index nor ground color is a reliable indicator of ripeness. Growers must rely on experience and fruit redness to determine when to harvest this late-season cultivar. To prolong fruit firmness, growers should store ‘Keepsake’ fruit at 0 to 1 °C rather than at 4 to 5 °C.

Performance of Mango Gerplasm in Patuakhali Condition

A study was conducted for four consecutive years from 2014 to 2917 at the Regional Horticultural Research Station (RHRS), Bangladesh Agricultural Research Institute (BARI), Lebukhali, Patuakhali. Six mango varieties, viz. BARI Aam-1, BARI Aam-2, BARI Aam-3, BARI Aam-4, BARI Aam-5, BARI Aam-8 developed by BARI and six popular cultivars Khirshapat, Langra, Mallika, Gopalbhog, Fazli and Pahutan were evaluation for their performance. The germplasm were planted in 2010. All the cultivars bloomed in 1st to 3rd week of February. Harvesting time ranged from 2nd week of May to 1st week of July and Gopalbhog and BARI Aam-4 were earlier while Fazli was late season cultivar. In the last year of study (2017), maximum number of fruits per plant was recorded 259 in BARI Aam-3 and minimum 11 in BARI Aam-1. Individual maximum fruit weight was 663.09g in BARI Aam-4 in 2016. Average, individual fruit weight ranged from 553.92 to 183.13g where Fazli was the maximum followed by 465.94g in BARI Aam-4. Minimum individual fruit weight was measured in BARI Aam-3. Total Soluble Solids percent (TSS%) ranged from 16.83 to 21 66% and BARI Aam-3 was maximum and BARI Aam- 2 was minimum. Number of fruits per plant, individual fruit and sweetness (TSS%) of variety/and cultivar fluctuated in different year although the trend of results in the succeeding years was consistent.
 Bangladesh J. Agril. Res. 46(1): 13-22, March 2021

Transcriptional profiling of the terpenoid biosynthesis pathway and in vitro tests reveal putative roles of linalool and farnesal in nectarine resistance against brown rot

The most devastating fungal disease of peaches and nectarines is brown rot, caused by Monilinia spp. Among the many plant responses against biotic stress, plant terpenoids play essential protective functions, including antioxidant activities and inhibition of pathogen growth. Herein, we aimed to characterize the expression of terpenoid biosynthetic genes in fruit tissues that presented different susceptibility to brown rot. For that, we performed artificial inoculations with Monilinia laxa at two developmental stages (immature and mature fruit) of two nectarine cultivars (‘Venus’ –mid-early season cultivar - and ‘Albared’ –late season cultivar-) and in vitro tests of the key compounds observed in the transcriptional results. All fruit were susceptible to M. laxa except for immature ‘Venus’ nectarines. In response to the pathogen, the mevalonic acid (MVA) pathway of the ‘Venus’ cultivar was highly induced in both stages rather than the methylerythritol phosphate (MEP) pathway, being the expression of some MEP-related biosynthetic genes [e.g., PROTEIN FARNESYLTRANSFERASE (PpPFT), and 3S-LINALOOL SYNTHASE (PpLIS)] different between stages. In ‘Albared’, both stages presented similar responses to M. laxa for both pathways. Comparisons between cultivars showed that HYDROXYMETHYLGLUTARYL-CoA REDUCTASE (PpHMGR1) expression levels were common in susceptible tissues. Within all the terpenoid biosynthetic pathway, linalool- and farnesal-related pathways stood out for being upregulated only in resistant tissues, which suggest their role in mediating the resistance to M. laxa. The in vitro antifungal activity of linalool and farnesol (precursor of farnesal) revealed fungicidal and fungistatic activities against M. laxa, respectively, depending on the concentration tested. Understanding the different responses between resistant and susceptible tissues could be further considered for breeding or developing new strategies to control brown rot in stone fruit.

Impact of fruit bagging and postharvest storage conditions on quality and decay of organic nectarines

ABSTRACT Abiotic factors such as light influence the physicochemical properties of fruit and may alter the response of the fruit to the environment. The aim of this study was to investigate the effect of two postharvest storage conditions on the overall quality and natural fungal disease incidence (fruit decay) of organic nectarines. Experiments were conducted with four organically grown nectarine cultivars (two early-mid season and two late-season) that were unbagged or bagged during preharvest. After harvest, they were stored for 7–9 days in darkness or under a treatment with lighting. Quality parameters (weight, diameter, firmness, soluble solids content, titratable acidity, and single index of absorbance difference), ethylene production, and fruit decay (% incidence of decay) were evaluated. Preharvest bagging reduced fruit decay in the late-season cultivars, for which storage under darkness reduced fungal decay (up to 100%) more than storage under lighting treatment (47% reduction). Bagging altered the initial fruit quality, but values were within official recommendations. Storage conditions reduced differences attributed to bagging, especially under storage with lighting. This work highlighted the importance of modulating the light, both in the field by fruit bagging and during postharvest, to reduce fruit decay and improve fruit quality. These results may serve as a tool for both farmers and postharvest chain managers.

Changes in quality characteristics of fresh blueberries: Combined effect of cultivar and storage conditions

The influences of two storage conditions (regular atmosphere-RA and modified-atmosphere packaging-MAP) and different storage time on fruit textural parameters, chemical composition, and total quality index (TQI) of two blueberry cultivars were investigated. Freshly harvested fruit of mid and late season cultivars (‘Bluecrop’ and ‘Liberty’, respectively) were placed in plastic punnets, packed into low-density polyethylene bags of 25 µm thickness with two perforations of 3 mm and stored at 2 °C and 90% relative humidity for 30 days, either in RA or in MAP. Changes in gas composition inside the package and fruit quality characteristics were analyzed at 10-day intervals during storage: 0, 10, 20, and 30 days. ‘Liberty’ was dominant over ‘Bluecrop’ in terms of hardness (428 g and 296 g, respectively), as well as individual and total sugars (100 and 76 g·kg–1, respectively), organic acids (19 and 12 g·kg–1, respectively) and most subclasses of phenolic compounds (anthocyanins, flavonols, and hydroxycinnamic acids). In addition, a novel mathematical index of TQI was introduced to compare all evaluated parameters in order to obtain a quantitative single score, as an indicator of overall fruit quality. ‘Liberty’ had the better TQI score in RA, whereas ‘Bluecrop’ behaved better in MAP. Accordingly, for longer storage of blueberry fruit MAP should not be assumed to be uniformly helpful, since the effect of storage duration in the specific type of atmosphere substantially depends on the proper cultivar selection.

Metabolism and cold chain performance of ‘Chuhwangbae’ Asian pears as impacted by 1-MCP treatment

The ‘Chuhwangbae’ Asian pear, a late-season cultivar that has become popular in Korea, is susceptible to physiological disorders during cold storage. The objective of this study was to evaluate the effect of 1-methylcyclopropene (1-MCP) treatment on fruit quality, physiological disorders, and targeted metabolites of ‘Chuhwangbae’ Asian pear fruit during cold storage and at the post-storage ripening stage. ‘Chuhwangbae’ Asian pear fruit were treated with 1-MCP immediately following harvest, stored at 1 °C for up to 3 months, and subsequently stored at 25 °C for 14 d to ripen. Indicators of fruit quality, namely the incidence of browning disorder and the degree of water loss or “shriveling,” as well as levels of key metabolites, were repeatedly analyzed during the simulated cold chain. Fruit treated with 1-MCP lost more weight but slightly maintained firmness than did untreated fruit during the entire cold chain. Treatment with 1-MCP reduced the severity of flesh browning but enhanced the incidence and severity of shriveling during post-storage ripening after 3 months of cold storage. GABA, histidine, phenylalanine, and tyrosine levels were higher in the flesh of the 1-MCP-treated fruit than in untreated fruit. The results indicate that the overall changes in metabolite levels following 1-MCP treatment were less during cold storage than those during post-storage ripening. Therefore, postharvest 1-MCP treatment could be at least partially effective in retaining flesh firmness and reducing the severity of internal browning of ‘Chuhwangbae’ Asian pears during the entire cold chain.

Sensitivity of Northern Highbush Blueberry Cultivars to Soil Water Deficits during Various Stages of Fruit Development

In many regions, water limitations are increasing because of frequent and persistent droughts and competition for water resources. As a result, growers in these regions, including those producing blueberries, must limit irrigation during drier years. To identify the most critical periods for irrigation, we evaluated the effects of soil water deficits during various stages of fruit development on different cultivars of northern highbush blueberry (Vaccinium corymbosum L.). The study was conducted for 2 years in western Oregon and included two early season cultivars, ‘Earliblue’ and ‘Duke’, a midseason cultivar, ‘Bluecrop’, and two late-season cultivars, ‘Elliott’ and ‘Aurora’. Volumetric soil water content and stem water potentials declined within 1 to 2 weeks with no rain or irrigation in each cultivar and were lowest during the later stages of fruit development. Water deficits reduced berry weight by 10% to 15% in ‘Earliblue’ and ‘Elliott’ when irrigation was withheld in the second year during early or late stages of fruit development and by 6% to 9% in ‘Aurora’ when irrigation was withheld in either year during the final stages of fruit development. However, water deficits only reduced yield significantly in ‘Aurora’, which produced 0.8 to 0.9 kg/plant fewer fruit per year when irrigation was withheld during fruit coloring. In many cases, water deficits also reduced fruit firmness and increased the concentration of soluble solids in the berries, but they had inconsistent effects on titratable acidity and sugar-to-acid ratios. As a rule, water deficits were most detrimental during later stages of fruit development, particularly in midseason and late-season cultivars, which ripened in July and August during the warmest and driest months of the year.

Selection of New Late-Season Mandarin Cultivars Based on Sensory Changes and Consumer Acceptance after Fruit Cold Storage

Late-season mandarins are normally cold-stored to prolong the commercial season. Thus, it is necessary to investigate poststorage consumer acceptance to predict the potential success of new late-season mandarin varieties on the market. The aim of the present work was to evaluate consumer response to three new late-season cultivars preselected in the IVIA breeding programme (Omet, Matiz and Tri-703) after different cold storage periods. The three new cultivars were compared to commercial cultivars Orri, Nadorcott and Ortanique, all of which are widely available in stores. A multidisciplinary approach was used to determine the main changes during storage at 1 °C for up to one month: (1) analysis of physico-chemical parameters; (2) description of the sensory profile by semitrained assessors by the Free Choice Profile technique; (3) evaluation of consumer acceptability and purchase intention. Our results showed that the sensory changes that fruit underwent during storage depended on the variety; these changes allowed us to understand why consumer preferences varied during storage. Of the three new cultivars, two (Omet and Tri-703) showed the greatest potential for success. However, while Tri-703 can be stored for one month, Omet should not be stored longer than 15 days due to its susceptibility to manifest skin damage during storage. Of the commercial cultivars, internal Orri quality was keenly appreciated by consumers, while Ortanique was considered the most attractive variety. The multidisciplinary approach followed in this study proved to be a potent tool for selecting varieties that should be implemented in selection processes of breeding programmes.

Wintering Index and Yield Traits for Early, Mid, and Late Season Strawberry for Colder Climates

ABSTRACT In temperate climatic regions where severe winter conditions persist, the winter hardiness and fruit yield of strawberry cultivars vary greatly in perennial production systems. A 4-year study was carried out to investigate the wintering ability of different June-bearing strawberry cultivars in the cold semi-arid continental climate of Manitoba between 2015 and 2018. The wintering index and yield traits of early, mid, and late season strawberry cultivars were evaluated. Six different cultivars tested in each year. ‘Wendy,’ ‘Kent’, and ‘Cabot’ were common in each year. Mid-season cultivar ‘Kent’ and ‘Mira’ yielded significantly (p< .05) higher with greater wintering index compared to early and late season cultivars within each trial and across 4 years. Low winter temperatures with less snow on grounds establish pronounced effect on early season cultivars wintering index. A significant variation for temperatures was recorded for the months within and between years.

Elastic sowing dates with low seeding rate for grain yield maintenance in mechanized large-scale double-cropped rice production

Elastic sowing dates (ESDs) are correlated with rice grain yield. ESD is the easiest factor for farmers to manipulate in mechanized large-scale farming. In this study, field experiments were conducted over a 2-year period to determine the effects of different sowing dates on growth duration, effective accumulated temperature, and yield attributes in two early- and late-season machine-transplanted rice cultivars. In early rice (ER), a delay in the sowing date led to decreased grain yield and shorter growth duration. In late rice (LR), delayed sowing led to significantly lower grain yield and prolonged growth duration. In LR, significantly positive correlations were detected between effective accumulated temperature in the post-heading stage and both filling ratio and yield. Reproductive redundancy increased markedly in LR, by 7.72% over a 5-day interval. We determined that the ESDs for LR were 10 days later than the control, and that of ER was recommend early sowing rather than late sowing. These findings suggest a new strategy to meet the demands of mechanized large-scale rice farming: the development of thermal sensitive high-yield long-duration ER cultivars and high-yield short-duration LR cultivars.

Using sap flow data to assess variations in water use and water status of apple orchards of varying age groups in the Western Cape Province of South Africa

No accurate quantitative information currently exists on how water use of apple (Malus domestica) orchards varies from planting to full-bearing age, leading to poor irrigation and water allocation decision making. This study sought to address this knowledge gap by investigating how the water use and tree water status vary with canopy cover, cultivar, and climatic conditions in 12 orchards growing in prime apple-producing regions in South Africa. The orchards were planted to the Golden Delicious/Golden Delicious Reinders cultivars which are widely planted in South Africa and the Cripps’ Pink/Cripps’ Red/Rosy Glow which are high-value late-season cultivars. The performance of two transpiration reduction coefficients, one based on sap flow (Ksf) and the other based on soil water depletion (Ks) (FAO approach) were evaluated against the midday stem water potential (MSWP) in all the orchards. While canopy cover had a clear effect on the whole-tree sap flow rates, there were no significant differences in the transpiration per unit leaf area among the cultivars. The daily average sap flux density under unstressed conditions was highest (~284 cm3∙cm-2) in the medium canopy cover orchards (30–44% fractional cover), followed by the mature orchards (~226 cm3∙cm-2), and was lowest in the young orchards (~137 cm3∙cm-2). Canopy cover rather than growing season length had a greater effect on seasonal total water use. Peak daily orchard transpiration ranged from 1.7 mm for young Golden Delicious Reinders trees to 5.0 mm in mature Golden Delicious trees that were maintained with large canopies to reduce sunburn damage to the fruit. For the red cultivars, the peak daily transpiration ranged from 2.0 to 3.9 mm, and the mature trees were maintained with less dense canopies to facilitate the development of the red fruit colour. The less dense canopies on the red cultivars had water-saving benefits since the seasonal total transpiration was lower relative to the Golden Delicious cultivar. The sap flow derived stress coefficient was strongly correlated to the MSWP (R2 ~ 0.60–0.97) in all the orchards while Ks was not able to detect plant stress due to over-irrigation.

Using sap flow data to assess variations in water use and water status of apple orchards of varying age groups in the Western Cape Province of South Africa

No accurate quantitative information currently exists on how water use of apple (Malus domestica) orchards varies from planting to full-bearing age, leading to poor irrigation and water allocation decision making. This study sought to address this knowledge gap by investigating how the water use and tree water status vary with canopy cover, cultivar, and climatic conditions in 12 orchards growing in prime apple-producing regions in South Africa. The orchards were planted to the Golden Delicious/Golden Delicious Reinders cultivars which are widely planted in South Africa and the Cripps’ Pink/Cripps’ Red/Rosy Glow which are high-value late-season cultivars. The performance of two transpiration reduction coefficients, one based on sap flow (Ksf) and the other based on soil water depletion (Ks) (FAO approach) were evaluated against the midday stem water potential (MSWP) in all the orchards. While canopy cover had a clear effect on the whole-tree sap flow rates, there were no significant differences in the transpiration per unit leaf area among the cultivars. The daily average sap flux density under unstressed conditions was highest (~284 cm3∙cm-2) in the medium canopy cover orchards (30–44% fractional cover), followed by the mature orchards (~226 cm3∙cm-2), and was lowest in the young orchards (~137 cm3∙cm-2). Canopy cover rather than growing season length had a greater effect on seasonal total water use. Peak daily orchard transpiration ranged from 1.7 mm for young Golden Delicious Reinders trees to 5.0 mm in mature Golden Delicious trees that were maintained with large canopies to reduce sunburn damage to the fruit. For the red cultivars, the peak daily transpiration ranged from 2.0 to 3.9 mm, and the mature trees were maintained with less dense canopies to facilitate the development of the red fruit colour. The less dense canopies on the red cultivars had water-saving benefits since the seasonal total transpiration was lower relative to the Golden Delicious cultivar. The sap flow derived stress coefficient was strongly correlated to the MSWP (R2 ~ 0.60–0.97) in all the orchards while Ks was not able to detect plant stress due to over-irrigation.

Growth and yield performance of late-season plum cultivars in the Belgrade area

Growth and yield performance of late-season plum cultivars in the Belgrade area

Introducing Different Cherry Cultivars to Inner and Crossover Areas

This study was carried out to evaluate quality, yield and phenology of some sweet cherry cultivars with different maturation periods in Isparta-Egirdir conditions. The study was carried out between 2000 and 2011, on Veysel, Précoce Bernard, Star, Venus, Mechlain Haimer, Summit, Techlovan, Fercer Arcina, Sylvia, Noire de Meched, Oktavia, Belge, 0900 Ziraat, Kordia, and Ferbolus. Venus, Bernard, Techlovan and Star cultivars were identified as the earliest blooming. Oktavia, Belge, Kordia and 0900 Ziraat cultivars were found to be the latest blooming cultivars. Generally; Veysel, Bernard and Star come to harvest maturity first. Venus, Mechlain Haimer, Summit, Techlovan, Fercer Arcina, Sylvia were found to be middle season cultivars, while N. De Meched, Oktavia, Belge, 0900 Ziraat, Kordia and Ferbolus were found to be the latest. Veysel early cherry cultivar were determined to be the most productive one, while late cultivar N. De Meched and mid-season cultivar Techlovan were also found to be very efficient. In terms of fruit sizes; early sweet cherry cultivar P. Bernard, mid-season cultivar Summit and late season cultivar 0900 Ziraat gave the biggest fruits.

Performance of late season litchi cultivars grown in Jharkhand Province of India

The narrow genetic diversity and short market availability of litchi (Litchi chinesis Sonn.) are the main constrains for its cultivation more profitable in Indian sub-continent. Late season litchi cultivars in subtropical and tropical India are prone to fruit cracking and diseases susceptibility. Seven promising selections and four late season commercial cultivars viz; CHES-1, CHES-2, CHES -3, CHL-5. CHL-7, Lal Bombaiya, Late Bedana, Purbi, Selection -3-7, Selection 8-1 and Swarna Roopa were evaluated during 2014-15 at ICAR-RCER Ranchi, based on physico-chemical characters, cracking habit and diseases susceptibility. The results revealed that the cultivars Purbi, Lal Bombaiya and Late Bedana were cracking resistant. The maximum fruit weight was found in the cultivars Lal Bombaiya (22.0 g ) being comparable with Late Bedana (21.2 g) and CHES-2 (21.0 g). The cultivars Lal Bombaiya and CHES –2 had the highest aril weight of 19.44 g and 17.66 g, respectably. The maximum TSS of 22.2 0B was found in CHES-1 both in Jharkhand and Bihar. Late Bedana cultivar had high sugar acid ratio (73.52) with pomegranate flavor and popular for local market. Litchi fruit borer mainly attacked Lal Bombaiya and CHES-2 at early stage whereas the cultivars Purbi and Swarna Roopa were affected (3-6% bunch) by litchi stink bug (Tessaratoma javanica) at late harvest season. From the present study, it was concluded that CHES-1, Lal Bombaiya, Purbi and Late Bedana were promising late season cultivars for commercial cultivation with effective management of litchi fruit borer and stink bug.

Harvest index of apple and kiwifruit – how high can we go by optimising plant architecture and canopy management?

Efficiency of plant function is measured using harvest index (HI), the fraction of annual fruit dry mass yield divided by the total annual dry mass of tree. HI describes the proportion of total annual biomass allocated into harvestable sinks. The HI of mature apple trees on dwarfing rootstocks is ~60-70%, higher than HI estimates of ~40% for kiwifruit vines. In a recent physiological study using tall spindle ‘Scilate’ (EnvyTM) apple planted intensively on M.9, a mature tree fruit yield of 105 kg tree(-1) fresh weight (175 t ha(-1) at 1667 trees ha(-1)) was achieved in the 9th year from planting. Average fruit dry matter content at harvest was 16.2%, suggesting a calculated annual dry weight fruit yield of 17 kg tree(-1) (28.3 t ha(-1)) in the 9th year. This mature tree yield was produced from minimal tree structure compared with traditionally-managed trees; the main axis and branches were slender in girth, and the mean dry weight of winter prunings following harvest in the 9th year was 0.62 kg tree(-1). Hence, high fruit yields were associated with little investment in standing tree structure and prunings, implying a very high tree physiological efficiency (HI). The HI of these ‘Scilate’ trees on M.9 in the 9th year was estimated to be 0.81. We speculate that HI of late season cultivars on M.9 could reach 0.85 with further optimisation of canopy management and tree architecture using artificial spur extinction. Exploiting vine architecture and optimising canopy management of kiwifruit may similarly improve yield and fruit quality by increasing vine HI. Preliminary results on whole vine behaviour (flowering, yield and vigour) in response to canopy architectural modification using spur pruning to reduce pruning intensity of ‘Zesy002’ (SunGold®) kiwifruit indicated that spur pruning did not modify yield but reduced vine dry weight of winter prunings by 50% after a single growing cycle. Ongoing work will compare vines managed by spur pruning and replacement cane pruning to quantify budbreak, flowering, yield and fruit quality responses over successive growing cycles.

The Planar Cordon – new planting systems concepts to improve light utilisation and physiological function to increase apple orchard yield potential

Contemporary high density apple orchards, although very productive in historical terms, are yield-limited at 100-120 t ha(-1) because their maximum fractional utilisation of sunlight is only circa 60% of total seasonally-available radiation. Previous research in New Zealand proposed a theoretical potential productivity of 169 t ha(-1) for late-season cultivars if orchard light interception of 90% could be achieved. A major constraint to improving light interception by planting systems is the allocation of space between rows. Any increase in light utilisation will require closer rows and/or inclined canopies. New planting systems to increase light interception by reducing inter-row distances, whilst achieving adequate within-canopy irradiance for high quality fruit, are being studied in New Zealand. Rows spaced at 1.5 to 2 m apart require new tree forms with narrow planar canopies for both eco-physiological and practical reasons. Tree architecture comprises two opposing, not-quite horizontal cordon leaders along the row, each subtending five vertical non-branched fruiting stems, 30 cm apart, to create narrow planar trees, 3 m long, less than 0.5 m wide, and with an anticipated height of 3-3.5 m. Four cultivars in a first prototype, planted at 1667 (2 m inter-row) and 2222 (1.5 m inter-row) trees ha(-1) yielded from 9 to 29 t ha-1 in their second year. Fractional light interception of 2- and 3-year-old plantings characterised young-tree planar cordon canopy row spacing effects, in comparison with a same-aged 1.5×3.5 m tall spindle system. Productivity traits from 3-year-old systems planted at 1.5 and 2 m row spacing and between vertical and narrow vee planar canopy variants of two-year-old planting systems indicate productivity gains over the three-dimensional tall spindle canopy configuration. In additional to light interception, these results also indicate that growth processes regulating the allocation fate of annual growth resources are important factors determining the productivity potential of apple orchards. Evidence for plasticity of resource partitioning into fruit development in response to different manipulations of tree architecture are drawn from our studies of new planar cordon systems and with conventional tall spindle planting systems.

Genetic diversity assessed by genotyping by sequencing (GBS) and for phenological traits in blueberry cultivars.

Blueberry is a small fruit crop which includes a complex group of different Vaccinium species of various ploidy levels. Commercial blueberries have been grown in Europe most recently, so there is not much information available about their adaptation into new regions. In this work we investigated adaptation to the environmental conditions of northern Spain, in terms of flowering and ripening seasons, of a set of 70 blueberry cultivars including several of the most important cultivated American species (V. corymbosum, V. virgatum, V. macrocarpon and V. uliginosum) in order to identify which types are best-suited in this geographical area of Europe. Most materials showed high chilling requirements for flowering under local conditions, while materials with low-chilling requirements showed problems in the maturation process of the flowers. Most cultivars were early or mid-season while a relative lack of late-season cultivars was observed. GBS was used for the analysis of genetic diversity in this sample of 70 cultivars. A total of 5255 SNP markers were obtained and a cluster analysis revealed three main groups associated with the ploidy level of the species. A Principal Component Analysis revealed a grouping of the V. corymbosum cultivars according to their chilling requirements. A total of 29 SNPs were identified as being highly informative for diversity analysis and potentially useful for cultivar identification and for breeding purposes. The results obtained from this research should contribute to the expansion of this crop, as well as providing data about genetic diversity useful for the preservation of genetic resources or for future breeding programs.

Effect of Postharvest Chemical Treatments, Heat Curing, and Refrigerated Storage on Marketability of Short-day Onions

Vidalia onions (Allium cepa) are very susceptible to infection from pathogens and diseases compared with other types of onions. Botrytis neck rot (BNR) (Botrytis allii) is the most common and destructive storage disease, whereas sour skin (Pseudomonas cepacia) can cause significant bacterial losses, particularly, for late season cultivars. The objective of this study was to assess the effects of different fungicide and bactericide drenches on marketability of Vidalia onions using the cultivar Savannah Sweet grown, harvested, and graded for high-quality onions. Six different fungicide treatments were evaluated, including fludioxonil at two different rates, fluopyram and pyrimethanil in combination, and pyraclostrobin and boscalid in combination with a water-only and an untreated entry. In addition, four different bactericide treatments were evaluated, including copper hydroxide and copper sulfate pentahydrate with a water-only and untreated control. Treatments were applied by drenching the onion bags with 1 gal of solution at the desired concentration. Onions treated with fungicide were inoculated with the pathogen that causes BNR, whereas the bactericide treatments were inoculated with the pathogen that causes sour skin by placing a single inoculated bulb into each bag. Half of the bags were heat-cured for 48 hours and all of the onions were stored immediately under refrigerated conditions at 34 to 36 °F for 2 or 4 months. Bactericide treatments were not heat-cured the second year of the study. Onions were evaluated after 1 and 14 days of shelf life. For both years, all the fungicide applications were effective with more marketable onions compared with the controls. Fludioxonil, fluopyram/pyrimethanil, and boscalid/pyraclostrobin had the highest percentage of marketable onions compared with the water or untreated controls. Fluopyram/pyrimethanil and boscalid/pyraclostrobin fungicides had significantly higher percentage of marketable onions than the controls but were similar to the low rate of fludioxonil. Bactericide applications were not effective in reducing losses when compared with the controls.

Genetic variability in selected date palm (Phoenix dactylifera L.) cultivars of United Arab Emirates using ISSR and DAMD markers.

Nine (9) different date palm (Phoenix dactylifera L.) cultivars from UAE, which differ in their flower timings were selected to determine the polymorphism and genetic relationship between these cultivars. Hereditary differences and interrelationships were assessed utilizing inter-simple sequence repeat (ISSR) and directed amplification of minisatellite DNA region (DAMD) primers. Analysis on eight DAMD and five ISSR markers produced total of 113 amplicon including 99 polymorphic and 14 monomorphic alleles with a polymorphic percentage of 85.45. The average polymorphic information content for the two-marker system was almost similar (DAMD, 0.445 and ISSR, 0.459). UPGMA based clustering of DAMD and ISSR revealed that mid-season cultivars, Mkh (Khlas) and MB (Barhee) grouped together to form a subcluster in both the marker systems. The genetic similarity analysis followed by clustering of the cumulative data from the DAMD and ISSR resulted in two major clusters with two early-season cultivars (ENg and Ekn), two mid-season cultivars (MKh and MB) and one late-season cultivar (Lkhs) in cluster 1, cluster 2 includes two late-season cultivars, one early-season cultivar and one mid-season cultivar. The cluster analysis of both DAMD and ISSR marker revealed that, the patterns of variation between some of the tested cultivars were similar in both DNA marker systems. Hence, the present study signifies the applicability of DAMD and ISSR marker system in detecting genetic diversity of date palm cultivars flowering at different seasons. This may facilitate the conservation and improvement of date palm cultivars in the future.