Determination of Salt Tolerance of ‘Camarosa’ and ‘Chandler’ Strawberries Grown in Perlite and Perlite

ABSTRACT

The effects of salt (NaCl) applications of various concentrations (0, 500, 1000 and 2000 mg/L) for 6 months on ‘Camarosa’ and ‘Chandler’ strawberry varieties grown in perlite and perlite:zeolite (1:1) media were investigated. In order to determine the salt resistance of varieties, the tolerance index (T.I.) and tolerance ratio (T.R.) were calculated on the basis of total chlorophyll content, and leaf and root dry weight. Also, the ability of keep in balance for potassium:sodium (K:Na) ratio in the aerial part and roots of plants were considered. It was determined that the highest T.I. and T.R. values calculated on the basis of leaf and root dry weight in cv. Camarosa in both media. Concerning the evaluations calculated on the basis of total chlorophyll, the results indicated that ‘Chandler’ is more resistant in perlite medium, ‘Camarosa’ is more resistant in perlite:zeolite (1:1) medium. K:Na ratio decreased with increasing salinity in both varieties. However, it was determined that K:Na ratio is higher in cv. Chandler, i.e., 0.83 than in cv. Camarosa (0.61). As a conclusion, it was determined that ‘Camarosa’ was more resistant to salt than ‘Chandler’. In addition, regarding the salt resistant performance of plants, perlite:zeolite (1:1) medium had more effective results than perlite.     

Preharvest applications of ethephon reduce superficial scald of ‘Fuji’ and ‘Granny Smith’ apples in storage

In 1989 and 1990, preharvest applications of 2-chloroethyl phosphonic acid (ethephon) at dosages from 50–400 mg 1’1 were applied to ‘Fuji’ and ‘Granny Smith’ apples. In 1989, the greatest reduction in scald after storage on both ‘Fuji’ and ‘Granny Smith’, relative to the untreated control resulted from applying 400 mg 1^?1 ethephon five weeks before harvest and was 45% and 55% of controls, respectively. On ‘Granny Smith’ 400 mg 1^? was also effective when applied three weeks before harvest. In 1990, preharvest applications of ethephon at either 200 or 400 mg 1^?1 reduced scald in both cultivars relative to the controls. Ethephon applied six weeks before harvest had no dosage effect on scald reduction after storage. There was no consistent effect on fruit maturity at harvest from any treatment in either year, and no effect on quality of fruit out of storage.     

Growth and photosynthesis of Oncidium ‘Goldiana’

SUMMARY

The growth and photosynthesis of Oncidium ‘Goldiana’, a popular tropical orchid for cut flower production, were studied. Four main developmental stages were identified: bud stage, plantlet stage, unsheathing stage and pseudobulb stage. Pseudobulb formation occurred during the unsheathing stage which was closely followed by the formation of an inflorescence. The pseudobulb is of the heteroblastic type (arising from a single node) and lacks stomata. It is a G, shade plant based on chlorophyll a/b ratio, C0₂ compensation point, post-illumination C0₂ outburst and light response curves. The formation of new sinks such as inflorescence and axillary bud have a significant effect on the rate of photosynthesis of certain leaves. The photosynthetic rates of leaves L₂ and L₃ increased during the development of the axillary bud and inflorescence respectively. Pseudobulbs have high water content and contain chlorophyll but show no sign of gas exchange in light and dark. However, fixation of C0₂ is possible in light with partial removal of the underlying cuticle.     

Preliminary trials to examine the effects of ethephon as a thinner of ‘Gala’ and ‘Jonagold’ apples

Trials in southern Tasmania examined the thinning effects of ethephon on ‘Gala’ and ‘Jonagold’ apples. Untreated controls were compared with ethephon thinning sprays applied at full bloom at 50,100,200,400,800 and 1 600 mg I“1 to both cultivars. Thinning of both cultivars was related to the concentration of the spray and in most cases logistic models were fitted. Thinning effectiveness was largely reflected in increased fruit weight and size. The ‘Gala’ fruit was still not large enough for Australian markets. Ethephon at 200 mg I“1 effectively thinned ‘Jonagold’ and produced the required increases in fruit size and weight. ‘Jonagold’ was overthinned by the high concentrations of ethephon, but this was not reflected in increased fruit weight and size. Ethephon also reduced vegetative growth at the higher concentrations which was considered an advantage. More work is required to establish specific recommendations for either cultivar.     

Girdling of early season ‘Mayfire’ nectarine trees

The effect of four times of limb girdling on fruit and tree response was examined on ‘Mayfire’ nectarine (Prunus persica (L.) Batsch). Girdling prior to Stage II of fruit growth reduced the lag phase associated with Stage II, and caused peak fruit growth rates to occur earlier in the season than on later girdled or ungirdled trees. Optimum response was obtained by girdling prior to Stage II, when fruit seed length was approximately 10 mm. Girdling at this time increased fruit weight by 22.5% and more than doubled the percentage of fruit in the largest three size categories. Maturity, measured as soluble solids concentration, was increased by 42%. Shoot extension growth was reduced only by early girdling. Leaf weight per unit area was increased, and leaf nutrient concentrations were decreased by all girdling treatments. Leaf conductance to water vapour (g,) was not affected when measured 8 days prior to and 78 days after harvest. Fifteen days after harvest, g, was decreased in all girdling treatments.     

Effects of Flower-forcing Agents on the Metabolic Hormones Differentiation of Guzmamia ‘ Denise'

以观赏凤梨“丹尼斯”为试材,研究了不同催花剂处理对观赏凤梨“丹尼斯”内源激素含量的影响.结果表明:不同催花剂处理后,“丹尼斯”凤梨植株体内的IAA含量呈下降趋势,ZRs含量呈增加趋势.说明催花剂能抑制内源IAA的产生,促进内源ZRs的产生.以乙炔气体饱和溶液处理效果最明显.     

The effect of defoliation on bulb production of tulip cultivar ‘Apeldoorn’

The distribution of dry matter between the different bulblets of tulip is not markedly influenced by either changes in leaf area or the position of the leaf. On the contrary, total bulb yield is strongly affected.A reduction factor, S_c, for incomplete soil coverage, when the leaf area index (LAI) is less than 4, normally used for evaluation of planting density effects, can also be used for the effects of defoliation on dry matter increase. This LAI-dependent factor shows a distinctly asymptotic pathway closely resembling

$\text{S}{}_{\mathrm{c}}\text{=}\text{P}{}_{\mathrm{act}}\text{P}{}_{\mathrm{pot}}\text{=1?e}{}^{\mathrm{?k1LAI}}$

where k ～ 0.6 and in which P_act is the actual measured dry weight increase and $\text{P}\text{?}{}_{\mathrm{<mtext>pot</mtext>}}$ the potential net dry weight increase for a closed canopy.     

The effect of rootstock on yield and quality of ‘Mutsu’ apples

Summary

Yield and fruit quality parameters were studied during three years in a rootstock trial with ‘Mutsu’ apple. M.9 provided the highest total yield per tree as well as the highest quantity of intermediate and yellow fruit as compared with J.9, M.26 and B.9. Within similar colour categories, significant differences among rootstocks were also recorded for fruit starch degradation pattern (SDP), firmness, titratable acidity (TA), and soluble solids concentrations (SSC). Generally, the lowest SDP and highest fruit firmness was found in fruits from trees on rootstocks M.26 and B.9. The highest TA was found in fruits from trees on rootstocks M.26 and J.9 and the highest SSC in fruits from trees on rootstocks J.9 and B.9. However, considerable variations among years were also recorded. Correlation coefficients between rootstock and several yield and quality parameters revealed high correlation to SSC for green fruit and TA for medium and yellow fruit and some correlation to yield and number of fruits per tree.     

Fate of photosynthates from spur leaves of ‘Nijisseiki’ pear during the period of rapid fruitgrowth

Summary

Spurs of ‘Nijisseiki’ pear (Pyrus pyriflora Nakai) were allowed to assimilate _10033;CO₂ at 87.d after anthesis (DAA) and at 108 DAA during the period of rapid fruit growth. Then the spurs were sampled periodically until fruit harvest time to trace the time course and amount of movement of assimilates from spur leaves to individual organs in the spur. The amount of _10033;C absorbed by fruit within 3.d after labelling was constant until harvest, regardless of the labelling date. However, the total amount of _10033;C in the spur decreased continually until harvest.Of the total amount of _10033;C recovered in the spur labelled at 87 DAA, by harvest, 43.2% of 13C was found in the fruit flesh (cortex of receptacle), 5% in the core (pith of receptacle 1 pericarp 1 seeds), 5.6% in spur stem, 5.4% in the source leaves, and 40.8% was respired and exported from the spur. Of total amount of initial _10033;C labelled at 108 DAA, at harvest, the proportion of _10033;C translocated to flesh, core, stem, respired, and remaining in leaves was 61%, 6.1%, 3.0%, 24% and 5.4%, respectively. Photosynthates fixed by the spur early in the rapid growth stage of the fruit contribute more to the formation of starch and structural materials and less to solublecarbohydrates in fruit than do those fixed later.     

Storability of ‘Conference’ Pear Under Various Controlled Atmospheres

In two consecutive experimental seasons it was investigated the storage capacity of ‘Conference’ pear (Pyrus communis, L.) under regular air (RA) and various controlled atmosphere (CA) conditions during six months at 0?°C (±0.3). The occurrence flesh browning (FB), core browning (CB) and cavity formation (CF) was evaluated at each 2?months storage intervals and the ripening quality traits analyzed immediately at the end of storage period and after 7 days of shelf-life in air at 20?°C. The storage conditions were: RA; 0.5?kPa O₂?+?0.5?kPa CO₂; 1.5?kPa O₂?+?1.5?kPa CO₂, 2.0?kPa O₂?+?1.0?kPa CO₂; 3.0?kPa O₂?+?6.0?kPa CO₂ and 0.5?kPa O₂?+?6.0?kPa CO₂. After six months, ‘Conference’ pear was very susceptible to FB, CB and CF under CA-storage. The damages started to develop at the second month of storage, increasing continuously until end of storage period. At storage end, pear fruits kept under 0.5?kPa O₂?+?6.0?kPa CO₂ showed a dramatic high occurrence of FB, CB and CF with a severity index of 50.6, 45.3 and 27.1, respectively. The lowest incidences of FB, CB and CF were scored in fruits kept at 2.0?kPa O₂?+?1.0?kPa CO₂ with severity indexes of 1.1, 1.1 and 1.0, respectively. Flesh firmness, skin color, titratable acidity and total soluble solids were satisfactory under 2.0?kPa O₂?+?1.0?kPa CO₂. In conclusion, ‘Conference’ pear cannot be stored under O₂ partial pressure lower than 2.0?kPa and CO₂ higher than 0.5?kPa.     

Resolving the Parentage of the Apple Cultivar ‘Meran’

In the mid-1970s, a new apple variety named ‘Meran’ was discovered in South Tyrol (northern Italy), which harbours the largest continuous apple growing area in Europe. The cultivar was registered for varietal protection and patented in several countries, and was declared to be a cross of the varieties ‘Golden Delicious’ and ‘Morgenduft’ (synonym ‘Rome Beauty’). The parentage of ‘Meran’ has, however, been questioned, and the present study aimed to assess the descent of this cultivar by the combined use of molecular genetic and bioinformatic tools. Five accessions of ‘Meran’ were collected from three different European germplasm collections and analysed at 14 variable microsatellite DNA loci. Subsequently, computer software was used to allocate the most likely parent pair from a set of cultivars representative for the apple growing area of South Tyrol in 1975. The molecular genetic data clearly excluded ‘Morgenduft’ as a gene donor to ‘Meran’ and provided strong evidence that ‘Meran’ is a cross of the cultivars ‘Golden Delicious’ and ‘Jonathan’, confirming previous assumptions based on morphological traits of the tree and fruit.     

Effects of 22S, 23S-Homobrassinolide and Gibberellic Acid on Occurrence of Physiological Disorders and Fruit Quality of ‘Summit’ and ‘Regina’ Sweet Cherries

Plant growth regulators play a vital role in fruit growth and development. However, effects of compounds belonging to the group of brassinosteroids have not been fully investigated in sweet cherries. One relatively new and one commonly applied growth regulator, 22S, 23S-Homobrassinolide and GA₃, respectively, were tested on ‘Summit’ and ‘Regina’ sweet cherries to determine the effects on fruit quality and physiological disorders. The substances were applied with a handgun sprayer at full bloom and at the beginning of fruit development (shuck split) for a 2-year period. GA₃ was applied at the concentrations of 25, 50, 100 mgL^?1 and 22S, 23S-Homobrassinolide at 0.05, 0.1, 0.5 mgL^?1. A combined application of 100 mgL^?1 GA₃ + 0.1 mgL^?1 22S, 23S-Homobrassinolide was also applied. Effects of GA₃ and 22S, 23S-Homobrassinolide on fruit weight and size were evident for the concentrations applied and between the seasons for both of the cultivars. Combination of the both growth regulators and 100 mgL^?1 GA₃ alone produced longer fruits compared to the control trees in ‘Regina’. The 22S, 23S-Homobrassinolide applications increased the firmness of the flesh slightly, but not to a great degree, compared to the GA₃ applications alone. The brightness of the red color was better with GA₃ applications in ‘Summit’ and ‘Regina’. Brassinosteroid caused the fruits to have comparably dull red color. Total soluble solid contents of the cultivars were influenced by the substances and the year of the application. Stem resistance to separation from the fruit was under the influence of both treatments and seasons. In general, 22S, 23S-Homobrassinolide provided better stem resistance than the GA₃ applications. There were no effects of the substances on the development of physiological disorders.     

Improvement of fruit quality and storage potential of ‘Braeburn’ apple through deficit irrigation

Summary

We explored the potential of deficit irrigation (DI) applied at different times during the growing season for improving fruit quality and storage potential of ‘Braeburn’ apple growing in a commercial orchard. Because DI often reduces fruit size, effects of fruit size on fruit quality were also examined. The irrigation treatments were: commercially irrigated control (C), early deficit irrigation (EDI) applied from 63 to 118 d after full bloom (DAFB), and late decifit irrigation (LDI) applied from 118 DAFB to final harvest on 201 DAFB. Both EDI and LDI improved fruit quality in terms of increases in: dry-matter concentration (DMC) at harvest, flesh firmness, total soluble solids, and total soluble sugars both at harvest and after storage. The DI fruit had less weight loss during storage than did C fruit. Deficit irrigation affected the concentrations of a few individual aroma volatiles but not total volatile concentration. Incidence of physiological disorders was not affected by irrigation treatments. Mean fruit weight was lower in DI than in C but the difference was not significant. Among the quality attributes studied, only firmness and DMC were affected by fruit size with their values being higher in smaller fruit.     

Application timing and concentration of abscisic acid affect the quality of ‘Redglobe’ grapes

Summary

The plant hormone abscisic acid (ABA), the concentration of which increases in grape berry skins at the onset of maturation (veraison), appears to be involved in the regulation of anthocyanin accumulation. Preliminary tests suggested that exogenous applications of ABA could improve grape berry colour, but its high cost precluded the development of commercial applications. Recently, a lower-cost ABA production method was developed, which led to the evaluation of different concentrations of ABA, applied at or around veraison, on the quality of ‘Redglobe’ grapes. In two of three years of tests, several ABA treatments enhanced the anthocyanin content of grape skins. ABA, applied at approx. 300 mg l^–1 at veraison, may be required to reliably increase pigmentation, and improve the colour of ‘Redglobe’ grapes. Although the total anthocyanin content was increased by ABA treatment, anthocyanin composition was not affected. Applications of ABA had few effects on fruit size or composition, although they did cause fruit softening, which is undesirable. A secondary objective of this study was to determine how the anthocyanin content of berry skins affected berry colour characteristics. Strong curvilinear relationships between anthocyanin content and lightness and hue showed that these colour characteristics were saturated by anthocyanin contents over 0.02 mg cm^–2 of skin. These data suggest that colour measurements may be needed to evaluate the effect of cultural practices on colour in table grapes.     

Modelling the effects of timing and rates of application of benzyladenine as a secondary thinner of ‘Fuji’ apple after ethephon

A trial on ‘Fuji’ apples at the Grove Research Station in southern Tasmania during the 1991/92 season studied the thinning effect and interactions between ethephon and benzyladenine (BA) when BA was applied as a secondary thinner after a full bloom (FB) application of ethephon. The spray treatments were a factorial combination of eight application times of BA (11,13,15,17,19, 21, 23 or 25 days after full bloom (AFB)) with ten concentrations (20,40,60,80,100,120,140,160,180 or 200 mg I“1). An unsprayed control and an ethephon control were included. Target thinning results were achieved 19- 23 d AFB with concentrations of 140-160 mg I“1. A corollary of this successful thinning was an increase in fruit weight and size. Return bloom was improved significantly where thinning was successful. There was no effect on fruit firmness, soluble solids or lateral branching. Drawbacks were an increase in the incidence of russet and a reduction in pip number at the optimum thinning times and concentrations.     

Effects of 1-MCP Treatment on Quality and Physiology of ‘ Whangkeunbae' Pear During Cold Storage

以“黄金梨”果实为试材,研究了1-MCP处理对冷藏“黄金梨”果实品质及生理的影响.结果表明:500 nL/L l-MCP处理能有效延缓“黄金梨”果实贮藏期间硬度下降以及可溶性固形物的增加,抑制呼吸强度、多酚氧化酶和过氧化物酶活性的变化,减轻“黄金梨”货架期间果实褐变的发生.     

Response of secondary bloom of ‘Bartlett’ pear (Pyrus communis L.) to pruning

Summary

Type V secondary bloom of pear (Pyrus communis L.) is associated with pruning and is frequently infected by fire blight (Southwick et al., 2000). The goal of this research was to determine which pruning practices would most likely be associated with subsequent Type V secondary bloom. Pruning date, shoot age, type of pruning cut and shoot orientation were varied and effect on Type V secondary bloom assessed. In both 1998 and 1999, dormant pruning was more likely to result in Type Vs than summer pruning or pruning one month after harvest. Pruning one week after harvest in 1998 was as likely to lead to Type Vs as dormant pruning, but was less likely in 1999. The likelihood that Type Vs would occur was lowest from 49 to 89.d from full bloom (DFB) and at 175 DFB in 1998. The lowest likelihood of Type Vs in 1999 was found on shoots pruned at 83 or 185 DFB. The likelihood for Type Vs rose with increasing shoot age from one to four years, but there was no difference between three- and four-year old shoots. In 1998, stub cuts (severe heading) were more likely to have Type Vs than head cuts when pruning two year old shoots, but not for one year old shoots. In 1999, type of pruning cut had an inconsistent effect on the likelihood for Type Vs and was not the same for each shoot age. NAA applied to summer pruned shoots completely prevented Type Vs from occurring and almost completely stopped Type Vs when applied to dormant pruning cuts. Summer pruning from 50 to 90 DFB or pruning one month after harvest and the application of NAA to pruning wounds may be strategies for reducing the occurrence of Type V secondary bloom.     

Effect of agar,galactomannan and indole-butyric acid on in vitro rooting of the pear cultivar ‘Durondeau’ and apple rootstock cultivar ‘Marubakaido’

Summary

The influence of partial substitution of agar by galactomannans in culture media supplemented with different concentrations of indole-3-butyric acid (IBA) was studied on in vitro rooting of pear (Pyrus communis L.) cultivar ‘Durondeau’ and apple rootstock (Malus prunifolia Borkh.) cultivar ‘Marubakaido’. The galactomannans applied were obtained from Cassia fastuosa (cassia) and Cyamopsis tetragonolobus (guar gum) seeds. The results obtained with mixtures of agar and galactomannan (3 g l^–1 each) were compared with those from media solidified with a standard concentration of agar (6 g l^–1). The rooting of pear shoots was enhanced significantly in the presence of a mixture of agar plus cassia galactomannan compared to medium solidified with agar only. The modified media promoted a higher number of roots than the control, and increased the percentage of rooted shoots. A maximum of 84.8% rooting was obtained on half-strength MS medium (¹?2MS) supplemented with 0.49 µM IBA and solidified with a blend of agar plus cassia galactomannan. For the apple rootstock, only the number of roots per shoot was influenced significantly by the addition of galactomannan to the rooting medium. The highest number of roots per shoot was 16.67 on ¹?2MS medium gelled with a mixture of agar plus guar galactomannan supplemented with 4.90 µM IBA. The behaviour of the agar-galactomannan gel and the possibility of reduced costs when compared with systems containing only agar, suggest new biological and commercial applications for galactomannans.     

Effects of Fertigation on Pigment Pattern and Fruit Quality of cv. ‘Gala’ Apples

Fruit pigmentation in ripening cv. ‘Gala, Schniga’ apples was monitored under the influence of fertigation weekly during 21 July–31 August 2009, i.e. 34 days before and 7 days after the optimal harvest date in Slovenia. The soil was a heavy loam clay with high humus content (2.8 %) and high acidity (low pH 4.9). The spectral indices NDVI (Normalized Difference Vegetation Index) and NAI (Normalized Anthocyanin Index) were obtained by a PA 1101 on attached fruit on the transition between the ground and blush colour of the fruit surface. NAI increased slowly from 0.25 to 0.6 two weeks prior to optimum maturity. NDVI values fell from 0.9 to 0.2 before and during ripening, with significant changes starting ca. 3 weeks before and during the week after the optimum harvest date. Fertigation delayed fruit ripening viz harvest date by ca. 4 days. Fertigation delayed changes in the intensity of the fruit’s epidermal pigments, expressed as NDVI for 1 week and NAI for 4 weeks, respectively, but had no significant effect on fruit colour or NDVI and NAI values at the optimal harvest date. At this time, those fruits from the fertigated trees were firmer with a lower starch index compared with the un-fertigated control. Statistically, highly significant correlations were found (p?≤?0.01) (r?=?0.35 to r?=?0.91, R²?=?0.11–0.83) between all the studied spectral and standard parameters i.e. fruit fresh firmness, soluble solids content and starch index.