An Automatic Device for The Control of Day Length

The effects of cover crops and NPK fertilizers (in factorial combination) on the growth, crop yield and leaf-nutrient composition of young Cox’s Orange Pippin and Worcester Pearmain apple trees have been studied over a period of six years. The covers used were : (a) wild white clover, S. 184,-(b) perennial rye-grass (Lolium perenne, S.23), (c) timothy grass (Phleum pratense, S.50), and (d) natural sward as it developed (mainly Poa annua and Agrostis stolonifera).

The major effects were due to cover crops. Nitrogenous fertilizer had significant effects in combination with timothy and rye-grass, but phosphatic and potassic fertilizers had no significant effects on tree growth or crop yield.

Clover and natural sward covers had the least deleterious effect on tree growth and gave the highest yield of fruit. Timothy and rye-grass severely restricted tree growth and crop yield. This was due largely to competition for nitrogen, which was clearly reflected in a reduced nitrogen concentration in the leaves of the trees.

Optimum growth, crop yield and fruit colour in Cox were associated with a nitrogen concentration of 2 . 0-2 . 2% in dry matter of leaf samples taken in August from the mid-third region of extension shoots.

There is evidence from the composition of the leaves of the trees to suggest that clover made available additional nitrogen and phosphate.

There was a positive relationship between the total nitrogen concentration of the tracheal (xylem) sap of shoots at the green-cluster stage and the leaf-nitrogen status in the previous August.

It is suggested that the best method of establishing a permanent cover in orchards, with the least adverse effect on tree growth and nitrogen status, is to sow wild white clover and to allow the slow establishment of indigenous grasses by frequent mowing.     

Subsurface drip irrigation scheduling for cucumber (Cucumis sativus L.) grown in solar greenhouse based on 20 cm standard pan evaporation in Northeast China

The experiment was conducted in a solar greenhouse to determine the optimum irrigation frequency and quantity for cucumber under subsurface drip irrigation based on evaporation from a 20 cm diameter pan (E_p) placed above the crop canopy. Two irrigation intervals (I1: 4-day and I2: 8-day) and three plant-pan coefficients (K_cp1: 0.6; K_cp2: 0.8 and K_cp3: 1.0) were compared. Crop evapotranspiration (ET) and fruits yield increased with the increasing of irrigation water. The K_cp3 treatments had the highest yield, while K_cp2 had the highest irrigation water use efficiency (IWUE) and water use efficiency (WUE) values in both irrigation intervals. The yields of K_cp2 treatments decreased only 4.87% and 5.93% in both intervals though total irrigation water decreased 14.3% compared to K_cp3 treatment. Irrigation water amount significantly (P < 0.01) and positively affected the fruit number and fruit water content, whereas significantly and negatively affected the soluble sugar (SS), Vitamin C (Vc) and free amino acid (FAA) content in fruits. In conclusion, I2K_cp2 (0.8E_p with 8-day interval) was the optimum irrigation schedule for cumber plants grown in solar greenhouse under subsurface drip irrigation in arid and semi-arid areas that are in lack of water resources.     

The Irrigation of Early Summer Cauliflower in Relation to Stage of Growth,Plant Spacing and Nitrogen Level

A group of small farms near Ibadan provided data on the annual yields of 2,480 cocoa trees for 18 years. These were entered on punch cards.

The correlation coefficient r (p, i, q) was calculated for the mean yields of units for an earlier period of p years and a later period of q years separated by an interval of i years. The units taken were single trees, one-thirtieth-acre plots and whole farms.

For all units r (1, i, 1) tends to decrease as i increases; but for single trees when i = 0 (and to a lesser extent when i = 2 and 4) it lies below the fitted curve for odd values of i. This is evidence of biennial bearing.

For plots and whole farms r was calculated for every combination of p = 1 or 2, q = 1, 2, 4 or 8, and i up to the maximum possible for each (p, q) combination for all possible years. The values obtained indicate that:

(a) One year’s pre-recording lessens the error variance of the first experimental year on average in the ratio of 0-5 : 1.

(b) The decrease is less for subsequent experimental years, the ratio being about 0-9 : 1 for an 8-year interval.

(c) The error variance of the mean yields over periods immediately following one or two years’ pre-recording is, after adjustment for pre-recording, mainly independent of the length of the period.

(d) Gain in accuracy from two years’ pre-recording is greater than from one, the difference generally more than justifying the cost of the extra year’s recording. But the extra pre-recording which delays the start of an experiment for a further year is not likely to be worth while.     

Development of SCAR markers to differentiate between mume (Prunus mume Sieb. et Zucc.) and apricot (P. armeniaca L.)

Summary

Mume (Prunus mume Sieb. et Zucc.) and apricot (P. armeniaca L.) are similar in fruit and tree morphology, and exhibit high cross- and graft-compatibility with each other. It is therefore difficult to differentiate mume and apricot cultivars on the basis of morphological and phenotypical characteristics. Molecular markers were developed to differentiate nine mume from ten apricot cultivars. Four dominant, random amplified polymorphic DNA (RAPD) markers that can discriminate between mume and apricot cultivars (designated OPA15₆₂₈, OPO10₅₅₀, OPO20₂₅₉, and OPU03₄₁₅) were identified from 21 decamer primers. Two RAPD markers (OPO10₅₅₀ and OPU03₄₁₅) were developed into dominant sequence-characterised amplified region (SCAR) markers (SCO10 and SCU03). These SCAR markers could differentiate between all mume and apricot cultivars.     

Monitoring the genetic fidelity of micropropagated plantlets of Spondias mangifera Willd. using RAPD marker assays

Summary

Random amplified polymorphic DNA (RAPD) markers were used to screen for clonal fidelity in in vitro-propagated plantlets of Spondias mangifera produced through direct organogenesis. One micropropagated plantlet was selected at random after each sub-cultural passage (six sub-cultures), along with the donor plant, for RAPD marker analysis. Twenty-five RAPD primers were used to study genetic similarities or dissimilarities with the mother plant as well as among the regenerated plants. Individual primers showed that the same pattern of RAPD markers was shared by all in vitro-propagated plantlets and the mother plant. No variation was observed among the micropropagated progenies. Thus, in vitro-regenerated plantlets of S. mangifera were clonally uniform and genetically stable.     

Characteristics of phosphorus uptake kinetics of poinsettia and marigold

In a previous experiment it has been found that maximum uptake rate (I_max), Michaelis constant (K_m), and minimum nutrient concentration (C_min) as plant physiological characteristics may be important for phosphorus (P) uptake in peat-substrate. Thus, variation of P uptake parameters was evaluated with a series of depletion studies for poinsettia (Euphorbia pulcherrima) and marigold (Tagetes patula) under fluctuating climatic conditions and different developmental stages.     

In vitro propagation of olive (Olea europea sativa L.) ‘Kalamon’

A micropropagation method is described for olive (Olea europea sativa L.) ‘Kalamon’ using single-node explants collected from shoots produced from olive ovules grown in a growth chamber. Shoot proliferation was obtained on OM modified medium supplemented with 0.5 mg r¹ cystine, 10 mg I^-1 pantothenic acid calcium, 0.5 mg I^-' gibberel- lic acid (GA₃), 0.1 mg T¹ indole-3-acetic acid (IAA) and 10 mg I^-1 zeatin riboside, or 7.5 mg I^-1 benzyladenine (BA), or 10 mg I^-1 N⁶-2-isopentenyladenine (2ip). Explants were rooted on a medium similar to that for shoot development, but without cytokinins and with a-naphthaleneacetic acid (a-NAA), and indole-3-butyric acid (IBA) at 1, 2 and 3 mg I^-1 for both auxins. a-NAA at all concentrations was more effective than IBA. Shoot proliferation and rooting were improved by the addition to the nutrient media of 20 mg I^-1 and 50 mg I^-1 crude extract from olive ovules, respectively. Rooted explants were transferred to pots containing equal volumes of peat and vermiculite; about half survived.     

Colonization of central European abandoned fields by dry grassland species depends on the species richness of the source habitats: a new approach for measuring habitat isolation

Abandoned fields are perceived as potential habitats for species of threatened semi-natural dry grasslands. However, information is lacking regarding how the spontaneous colonization of abandoned fields depends on the broader spatial context. We recorded the occurrence of 87 target species in 46 abandoned fields and 339 dry grasslands. We tested the effect of the isolation of abandoned fields from source grasslands on the number of dry grassland species occurring in abandoned fields either with or without habitat characteristics being used as covariates. The isolation of the fields was calculated using the distance and area (I _A ) or distance and species richness (I _S ) of source habitats. I _S always explained the number of grassland species in the abandoned fields better than I _A . The effect of isolation became smaller or even non-significant with the inclusion of covariates; it also changed with the method used for measuring distance (edge-to-edge or center-to-center), and it was lower when other abandoned fields were considered as additional source habitats. The different performance of the two isolation measures can be explained by the weak species–area relationship in the grasslands, indicating differences in their habitat quality. Species richness is a better proxy of habitat importance in terms of propagule source than habitat area, and the new isolation measure is therefore suitable for studying the effects of landscape structure on species richness in landscapes presenting a weak species–area relationship, such as areas exhibiting pronounced effects of land-use history. Inclusion of habitat characteristics as covariates may considerably alter conclusions regarding the effect of isolation, which might actually be overestimated when assessed separately.     

Comparative salt responses at cell and whole-plant levels of cultivated and wild tomato species and their hybrid

SUMMARY

Response to increased salinity was compared in whole plants and calli from leaf, stem and root of Lycopersicon esculentum Mill. cv. P-73, Lycopersicon pennellii (Correll) D'Arcy ac PE-47 and their interspecific hybrid. Three NaCl treatments were applied (0, 70 and 140 raM) for 28 d. In both calli and whole plants, L. pennellii was more salt-tolerant than the cultivated species and the hybrid according to the growth responses, although different degrees of salt tolerance were generally found between plants and calli. The Na⁺ and CI" accumulations with salinity were higher in L. pennellii than in L. esculentum at both levels oforganization. The interspecific hybrid showed an accumulation ability for Na⁺ and CI^" intermediate to its parents in the shoot of the whole plants and similar to L. pennellii in the callus tissues. Either no decrease or a small decrease of K⁺ concentrations with salinity were found in both whole plants and callus tissues of L. esculentum. However, K⁺ concentrations decreased in the organs and calli of L. pennellii and the hybrid with increasing salinity. Only at the whole plant level did L. pennellii have a Na7K⁺ ratio higher than L. esculentum, showing the hybrid to have values between those of its parents in the shoot.     

The effects of sodium chloride on ornamental shrubs

The use of saline waters is an option for the irrigation of salt tolerant ornamentals as competition for high quality water increases. However, despite the importance of ornamental shrubs in Mediterranean areas, salt tolerance of such species has received little attention. The aims of our investigation were to quantify the growth response and any injury symptom of 12 widely cultivated ornamental shrubs to irrigation with saline water and to investigate any possible relation with the concentration of Na⁺ and Cl⁻ in the plants. Species were irrigated with different salinities (10, 40, and 70 mM NaCl) for a 120-day period. At the end of salt treatment, plants were sampled and dry biomass recorded; the relative growth rate (RGR) was also calculated. Root and leaf samples from each species were used to evaluate Na⁺, K⁺ and Cl⁻ concentrations. Growth rates were significantly reduced in Cotoneaster lacteus, Grevillea juniperina and Pyracantha ‘Harlequin’, which also showed the highest percentage of necrotic leaves. The increasing external NaCl lead to an increase of Na⁺ and Cl⁻ in roots and leaves of the different species, although less Na⁺ was accumulated than Cl⁻: growth reduction well correlated with the concentration of Cl⁻ and/or Na⁺ in the leaves. The most sensitive species (i.e. C. lacteus, G. juniperina and Pyracantha ‘Harlequin’) had high concentrations of Na⁺ and/or Cl⁻ in their leaves and also showed a decrease in their leaf K⁺/Na⁺ ratios. Even though other species (i.e. Bougainvillea glabra, Ceanothus thyrsiflorus, Leptospermum scoparium, Leucophyllum frutescens and Ruttya fruticosa) demonstrated a high ion concentration in their leaves, they could be considered relatively salt tolerant as there was little growth reduction and few symptoms of injury in the leaves. In some other cases (i.e. Cestrum fasciculatum, Escallonia rubra and Viburnum lucidum) the observed tolerance was related to higher ion concentration in the roots compared to the leaves, probably indicative of a limited transport to the shoots. Only in Eugenia myrtifolia was the absence of symptoms associated with a limited Na⁺ and Cl⁻ uptake from the rhizosphere.     

A Study of the Plant/Insect Relationships and Pod-Setting in the Runner Bean (Phaseolus Multiflorus)

Pod-setting in runner bean crops depends on the building up and maintenance of a sufficiently large population of efficient insect pollinators, and this appears to be affected by the early spring weather.

Runner bean flowers were visited and could be pollinated both by bumblebees (Bombus spp.) and honeybees (Apis mellifera). Visits to the front of the flower for nectar or pollen resulted in pollination, but “nectar-robbing” via a hole bitten through the underside of the flower, caused little or no pollination. During periods of intense nectar-robbing activity, pollination efficiency varied widely and depended largely upon whether or not insects were also collecting pollen from the crop.

A technique was devised for measuring the daily insect pollinating efficiency in a crop, that is, the actual daily pod-set as a percentage of the potential daily pod- set. A simple visual method for assessing the current day’s pollinating activity in the field is described, and the efficiency thus indicated compares well with results obtained from experimental pollination efficiency measurements.     

Determination of optimal harvest boundaries for ‘Ambrosia’ apple fruit using a delta-absorbance meter

In this study, a new chlorophyll measurement tool, the delta absorbance (DA) meter, was used to develop an optimal harvest maturity model for ‘Ambrosia’ apple (Malus × domestica Borkh.) fruit. Fruit from four commercial orchards in the Annapolis Valley, Nova Scotia, Canada, were sampled (25 fruit from three or four trees per location) over nine consecutive weekly harvests during the 2011 and 2012 growing seasons, and 8 weeks in the 2013 season. At each harvest, five fruit from each orchard site had their index of absorbance difference (I_AD) values, firmness, mass, titratable acidity (TA), soluble solids content (SSC), red skin colouration and internal core ethylene concentrations measured. Following approx. 3 months of storage at 3.5°C, 20 fruit from each site were removed and assessed for the incidence of disorders such as senescent breakdown, cortical browning and coreflush. Chlorophyll concentrations in the epidermis were strongly and positively related to I_AD values in the same tissue (P ≤ 0.001), confirming the assumption that chlorophyll was the basis for the DA meter I_AD signal. In addition, I_AD values declined significantly during fruit maturity and were negatively related to harvest week (P ≤ 0.001). The optimum harvest period was identified by aligning all ‘at harvest’ I_AD values, fruit quality measurements, and ‘post-storage’ disorder data with the corresponding harvest week. I_AD values associated with harvests having the highest commercial fruit quality then delineated the optimal harvest boundaries. The upper boundary I_AD value of 0.47 was defined as ‘when to begin harvest’, while the lower boundary I_AD value of 0.28 was considered to be ‘when to end harvest’ for long-term storage. The use of a DA meter and its I_AD value to define the optimal harvest boundaries may be applicable to all commercial apple cultivars, but should be developed for each cultivar and growing region.     

Sensitivity and effectiveness and of landscape metric scalograms in determining the characteristic scale of a hierarchically structured landscape

Landscape metric scalograms (the response curves of landscape metrics to changing grain size) have been used to illustrate the scale effects of metrics for real landscapes. However, whether they detect the characteristic scale of hierarchically structured landscapes remains uncertain. To address this question, the scalograms of 26 class-level metrics were systematically examined for a simple random landscape, seven hierarchical neutral landscapes, and the real landscape of the Xilin River Basin of Inner Mongolia, China. The results show that when the fraction of the focal patch type (P) is below a critical value (P _c), most metric scalograms are sensitive to change in single-scale and lower-level hierarchical structure and insensitive to change in higher-level hierarchical structure. The scalograms of only a few metrics measuring spatial aggregation and connectedness are sensitive to change in intermediate-level hierarchical structure. Most metric scalograms explicitly identify the characteristic scale of a single-scale landscape and fine or intermediate characteristic scales of a multi-scale landscape for both simulated and real landscapes. When P exceeds P _c, only some metrics detect scale and change in structure. The scalograms of total class area and Euclidean nearest-neighbor distance cannot detect scale or change in structure in either case. Landscape metric scalograms are useful for addressing scale issues, including illustrating the scale effects of spatial patterns, detecting multi-scale patterns, and developing possible scaling relations.

     

Race-specific genetics of resistance to black rot disease [Xanthomonas campestris pv. campestris (Xcc) (Pammel) Dowson] and the development of three random amplified polymorphic DNA markers in cauliflower

Summary

In order to understand the genetics of resistance to black rot disease caused by Xanthomonas campestris pv. campestris (Xcc) (Pammel) Dowson in cauliflower (Brassica oleracea var. botrytis L.) and to identify random amplified polymorphic DNA (RAPD) markers that segregate with the resistance genes, susceptible (‘Pusa Himjyoti’, female parent) and resistant (‘BR-161’, pollen parent) plants were crossed. Six generations of plants (30 P₁, 30 P₂,30 F₁, 120 F₂, 90 B₁, and 90 B₂) were evaluated for the presence or absence of black rot disease in a randomised block design with three replications. The pattern of segregation of resistance was tested by the χ² test at the 5% level of significance. All F₁ progeny plants were resistant, and the segregation of resistant and susceptible plants in the F₂ and two backcross generations (B₁ and B₂) showed that a single dominant gene caused resistance to the black rot pathogen in ‘BR-161’. Three polymorphic RAPD markers (OPO-04₈₃₃, OPAW-20₂₅₃₈, and OPG-25₆₂₅) were found by bulk segregant analysis, which produced unique amplicons 833 bp, 2,538 bp, and 625 bp in length, respectively. These markers were associated in coupling phase to the resistance allele. Best fit ratios of 3:1 (resistant:susceptible) in the F₂ plants with the three RAPD markers, suggested that the markers were linked to the single gene controlling black rot resistance. These markers will be useful to identify more closely-linked markers and to develop black rot-resistant hybrid cauliflower varieties.     

Characterisation of novel simple sequence repeat (SSR) markers for melon (Cucumis melo L.) and their use for genotype identification

Summary

The objectives of this study were to provide a set of useful simple sequence repeat (SSR) markers, to characterise them, and to demonstrate their ability to detect polymorphisms across diverse genotypes of melon. A total of 183 SSR markers were developed in melon from libraries enriched for (CA)_n, (CT)_n, (AAG)_n, and (ATG)_n repeats. The efficiency of marker development was highest in the CT library. The efficiencies of the CA, AAG, and ATG libraries were similar, and approx. 60% of that of the CT library. Dinucleotide motifs were observed more frequently than trinucleotide motifs. Approx. 50% of CA/TG motifs and approx. 30% of CT/AG motifs exhibited a repeat number greater than ten, while most other motifs showed a repeat number of less than ten. Fifty primer pairs were selected at random and used to evaluate polymorphisms among 19 melon accessions representing seven varieties. All 50 markers were amplified successfully in the majority of accessions, and 42 markers were polymorphic among the 19 melon accessions. All polymorphic markers could detect variation between at least two accessions belonging to the same variety, with polymorphic information content values ranging from 0.10 - 0.96. The SSR markers developed were variable and transferable and will be valuable molecular tools in melon breeding programmes.     

Chilling-induced changes in the apoplastic solution of tomato pericarp

Summary

Low-temperature storage of chilling-sensitive commodities affects membrane function and is likely to induce changes in the apoplastic environment. Mature-green tomato (Solanum lycopersicum L.) fruit were stored at 5°C for 14 d, then transferred to 15°C for an additional 6 d. Low-temperature storage induced acidification and a slight increase in the osmolality of pressure-extracted tomato apoplastic fluid. The apoplastic levels of cations such as K⁺, Ca²⁺, and Mg²⁺ remained constant during low-temperature storage, but decreased upon transfer of fruit to 15°C following low-temperature storage. These changes in apoplastic cations paralleled the changes observed in electrolyte leakage. Apoplastic pH and mineral concentrations were altered in chill-injured fruit, but the small changes observed in osmolality provide evidence against severe membrane dysfunction in chill-injured fruit.     

The Lorenz curve: a suitable framework to define satisfactory indices of landscape composition

Context

Patch diversity, evenness and dominance are important metrics of landscape composition. They have been traditionally measured using indices based on Shannon’s information entropy (H) and Simpson’s concentration statistic (λ).

Objectives

The main objectives of this study are: (1) to show that the Lorenz curve is an appropriate framework to understand and measure patch dominance, evenness and diversity; (2) to show that Lorenz-compatible indices have better mathematical behavior than H-based and λ-based indices.

Methods

Thirteen different hypothetical landscapes were created to assess landscape composition with the Lorenz curve and to compare the mathematical behavior of Lorenz-compatible indices with that of H-based and λ-based indices.

Results

The Lorenz curve is a suitable framework to understand and measure patch dominance, evenness and diversity due to four relevant equivalences: (1) patch dominance?=?the separation of the Lorenz curve from the 45-degree line of perfect patch evenness; (2) patch evenness?=?1 ? patch dominance; (3) patch diversity (eliminated by patch dominance)?=?patch richness?×?patch dominance; (4) patch diversity (preserved by patch evenness)?=?patch richness?×?patch evenness. Accordingly, patch diversity/patch richness?=?1???patch dominance and land-cover concentration?=?1/patch diversity.

Conclusions

Lorenz-compatible indices have better mathematical behavior than H-based and λ-based indices, exhibiting greater coherence and objectivity when measuring patch dominance, evenness and diversity.

     

Assessment of genetic variation among thornless blackberries (Rubus spp.) using random amplified polymorphic DNA

Summary

To assess genetic relatedness in thornless blackberry (Rubus spp.), 11 different blackberry cultivars were screened using random amplified polymorphic DNA (RAPD) markers. The blackberries selected represented four different thornless backgrounds. Genetic similarity was estimated using 140 random primers, and the cluster analysis conducted using the RAPD data grouped the cultivars into three distinct clades. Ninety-eight primers produced 113 cultivar-specific RAPD fragments capable of identifying each cultivar. In addition, reproducible polymorphism using two primers was observed within the ‘Evergreen’ (R. laciniatus) clade that consisted of the pure thornless blackberry ‘Everthornless’, the chimeral ‘Thornless Evergreen’, and their thorny progenitor ‘Evergreen’. All three plants are believed to be identical, except for a single mutational event that caused the phenotypic change from thorny to thornless. The R. laciniatus RAPD marker data provide information that may eventually be useful to identify the gene(s) responsible for thornlessness in that species.     

Urbanization predicts infection risk by a protozoan parasite in non-migratory populations of monarch butterflies from the southern coastal U.S. and Hawaii

Context

Urbanization can affect the density of hosts, altering patterns of infection risk in wildlife. Most studies examining associations between urbanization and host-parasite interactions have focused on vertebrate wildlife that carry zoonotic pathogens, and less is known about responses of other host taxa, including insects.

Objectives

Here we ask whether urban development predicts infection by a protozoan, Ophyrocystis elektroscirrha, in three populations of monarchs (Danaus plexippus): migratory monarchs in northeastern U.S., non-migratory monarchs in southeastern coastal U.S., and non-migratory monarchs in Hawaii.

Methods

We used impervious surface and developed land cover classes from the National Land Cover Database to derive proportional measures of urban development and an index of land cover aggregation at two spatial scales. Parasite data were from previous field sampling (Hawaii) and a citizen science project focused on monarch infection in North America.

Results

Proportional measures of urban development predicted greater infection prevalence for non-migratory monarchs sampled in the southern coastal U.S. and Hawaii, but not in the northern U.S. Aggregations of low intensity development, dominated by single-family housing, predicted greater infection prevalence in monarchs from the northern and southern coastal U.S. populations, but predicted lower infection prevalence in Hawaii.

Conclusions

Because natural habitats have been reduced by land-use change, plantings for monarchs in residential areas and urban gardens has become popular among the public. Mechanisms that underlie higher infection prevalence in urban landscapes remain unknown. Further monitoring and experimental studies are needed to inform strategies for habitat management to lower infection risk for monarchs.

     

Determining the S-genotypes of several sweet cherry cultivars based on PCR-RFLP analysis

Summary

Based on the cDNA sequences encoding sweet cherry self-incompatibility associated ribonucleases (S-RNases), a PCR-based S-allele typing system for sweet cherry cultivars has been recently developed. Using this technique, we determined S-genotypes of the three newly released Japanese cvs Kouka-Nishiki, Beni-Sayaka and Beni-Shuho and one British cv Merton Glory that was classified as a Universal Donor, which is able to be used as a pollen donor for all cultivars in pollen incompatibility groups I to XIII. Furthermore, we also determined the partial sequences of the S-RNase genes of ‘Rainier’ (S¹S⁴)‘ and ‘Sato-Nishiki (S³S⁶)’,which leads to the development of a more reliable S-allele identification method of PCR-RFLP for sweet cherry cultivars. Total DNA isolated from leaves of the four cultivars along with those from ten cultivars with known S-genotypes were PCR amplified with two sets of primers that were designed from DNA sequences encoding the signal peptide (Pru-T2) and two conserved domains (Pru-C2 and Pru-C4R) of sweet cherry S-RNases. By comparing the size of PCR products on agarose gel, the 5-genotypes of ‘Kouka-Nishiki’, ‘Beni-Sayaka’, ‘Beni-Shuho’ and ‘Merton Glory’ were suggested to be S¹S³, S¹S⁶, S⁴S⁶, and S⁴S⁶, respectively. Two of these three S-genotypes (S¹S⁶ and S⁴S⁶) were found for the first time. DNA sequencing of PCR products from S-alleles of ‘Rainier’ and ‘Sato-Nishiki’ revealed that Ban II, Nru I, Apa LI and Ava I sites, respectively, were unique in the S¹-, S³-, S⁴- and S⁶- sequences flanked by Pru-T2 and Pru-C4R primers. RFLP analysis of the PCR products using these enzymes confirmed that S¹-, S³-, S⁴- and S⁶-alleles of the four cultivars contained the respective restriction enzyme recognition sites.