Population dynamics of Meloidogyne incognita on cucumber grafted onto the Cucurbita hybrid RS841 or ungrafted and yield losses under protected cultivation

The influence of the squash hybrid RS841 rootstock (Cucurbita maxima x C. moschata) on population dynamics of Meloidogyne incognita and yield of cucumber cv. Dasher II was assessed during 2013 and 2014 in a plastic greenhouse. In addition, the relationship between ecophysiological parameters (plant water status, gas exchange, and leaf reflectance) and Pi and cucumber yield were also estimated in 2013. Nematode densities were determined at the beginning (Pi) and at the end (Pf) of each crop, and the relationship between these parameters was used to estimate the maximum multiplication rate (a), the maximum population density (M) and the equilibrium density (E) per grafted and ungrafted cucumber and cropping season. Moreover, the relationship between the multiplication rate (Pf/Pi) and Pi was compared between grafted and ungrafted cucumber per cropping season. Finally, the relative yield of grafted or ungrafted cucumber was plotted against Pi to determine the tolerance limit (T) and the minimum relative yield (m) by the Seinhorst damage function model. Values of a, M and E in grafted cucumber were higher than in ungrafted one irrespective of the cropping season. These results were supported by comparing the relationship between Pf/Pi and Pi between grafted and ungrafted cucumber. The relationship between Pi and yield fitted the Seinhorst damage function. The values of T and m did not differ between grafted and ungrafted each year. Predawn water potential, net photosynthetic rate, and leaf chlorophyll index decreased with increasing Pi. In addition, relative yield was related to variation in net photosynthetic rate and the leaf chlorophyll index. Under the conditions of this study, RS841 rootstock was neither resistant nor tolerant to M. incognita.Postprint (published version

Collision-free inverse kinematics of a 7 link cucumber picking robot

The paper presents results of research on inverse kinematics algorithms to be used in a functional model of a cucumber harvesting robot consisting of a redundant manipulator with one prismatic and six rotational joints (P6R). Within a first generic approach, the inverse kinematics problem was reformulated as a non-linear programming problem and solved with a generic algorithm. Solutions were easily obtained, but the considerable calculation time needed to solve the problem prevented on line implementation. To circumvent this problem, a second, less generic approach was developed consisting of a mixed numerical-analytic solution of the inverse kinematics problem exploiting the particular structure of the P6R manipulator. This approach facilitated rapid and robust calculation of the inverse kinematics of the cucumber harvester. During the early stages of the cucumber harvesting project, this inverse kinematics algorithm was used to off-line evaluate the ability of the robot to harvest cucumbers using 3D-information of a cucumber crop obtained in a real greenhouse. Thereafter, the algorithm was employed successfully in a functional model of the cucumber harvester to determine if cucumbers were hanging within the reachable workspace of the robot and to determine a collision-free harvest posture to be used for motion control of the manipulator during harvesting

Collision-free inverse kinematics of the redundant seven-link manipulator used in a cucumber picking robot

The paper presents results of research on an inverse kinematics algorithm that has been used in a functional model of a cucumber-harvesting robot consisting of a redundant P6R manipulator. Within a first generic approach, the inverse kinematics problem was reformulated as a non-linear programming problem and solved with a Genetic Algorithm (GA). Although solutions were easily obtained, the considerable calculation time needed to solve the problem prevented on-line implementation. To circumvent this problem, a second, less generic, approach was developed which consisted of a mixed numerical-analytic solution of the inverse kinematics problem exploiting the particular structure of the P6R manipulator. Using the latter approach, calculation time was considerably reduced. During the early stages of the cucumber-harvesting project, this inverse kinematics algorithm was used off-line to evaluate the ability of the robot to harvest cucumbers using 3D-information obtained from a cucumber crop in a real greenhouse. Thereafter, the algorithm was employed successfully in a functional model of the cucumber harvester to determine if cucumbers were hanging within the reachable workspace of the robot and to determine a collision-free harvest posture to be used for motion control of the manipulator during harvesting. The inverse kinematics algorithm is presented and demonstrated with some illustrative examples of cucumber harvesting, both off-line during the design phase as well as on-line during a field test

Molecular cytogenetic mapping of Cucumis sativus and C. melo using highly repetitive DNA sequences

Chromosomes often serve as one of the most important molecular aspects of studying the evolution of species. Indeed, most of the crucial mutations that led to differentiation of species during the evolution have occurred at the chromosomal level. Furthermore, the analysis of pachytene chromosomes appears to be an invaluable tool for the study of evolution due to its effectiveness in chromosome identification and precise physical gene mapping. By applying fluorescence in situ hybridization of 45S rDNA and CsCent1 probes to cucumber pachytene chromosomes, here, we demonstrate that cucumber chromosomes 1 and 2 may have evolved from fusions of ancestral karyotype with chromosome number n= 12. This conclusion is further supported by the centromeric sequence similarity between cucumber and melon, which suggests that these sequences evolved from a common ancestor. It may be after or during speciation that these sequences were specifically amplified, after which they diverged and specific sequence variants were homogenized. Additionally, a structural change on the centromeric region of cucumber chromosome 4 was revealed by fiber-FISH using the mitochondrial-related repetitive sequences, BAC-E38 and CsCent1. These showed the former sequences being integrated into the latter in multiple regions. The data presented here are useful resources for comparative genomics and cytogenetics of Cucumis and, in particular, the ongoing genome sequencing project of cucumbe

Export of Cucumber and Gherkin from India: Performance, Destinations, Competitiveness and Determinants

The performance, competitiveness, major destinations and determinants of cucumber and gherkin export from India have been studied. Export performance ratio has been used to estimate the competitiveness, and log linear type of demand function has been used to determine the export determinants. It has been observed that India has made tremendous progress in the export of cucumber and gherkin products during the past 15 years (1990-2005). The export has increased by about 128.5- times with an impressive annual compound growth rate of 37.46 per cent, as against only 4.38 per cent in the world market. The major export destinations for cucumber and gherkin have been identified as France, USA, Russia, Belgium and Spain. An increasing and high value of revealed comparative advantage (RCA) and a positive and increasing value for revealed symmetric comparative advantage (RSCA) have indicated high potential in their export, particularly for the provisionally-preserved and prepared/preserved products. One per cent increase in volume of international trade in cucumber and gherkin may increase the demand from India by 5.96 per cent. This indicates that India is highly competitive in export of cucumber and gherkin and has ample scope to further increase its export. The study has also revealed that exchange rate is a more dominant determinant of export from India than price of commodity.International Relations/Trade,

The Differences Between Products Of Gene Expression In Male, Female And Hermaphrodite Cucumber Floral Buds (Cucumis Sativus L.)

Cucumber is a species in which sex expression has been extensively studied. Sexual differentiation is controlled by genotypic and environmental factors. The main genes responsible for sex determination have been described but the mechanism of their action remains unexplained. In this study we attempted to find cDNA clones which can be connected with sex differentiation and flower development in cucumber. 
Two pairs of nearly isogenic lines: GY-3 (gynoecious – FFMMGG) and HGY-3 (hermaphrodite - FFmmGG), B10 (monoecious - ffMMGG) and 2gg (gynoecious - FFMMgg) were used to search for differences in gene expression in young (1 – 2mm) cucumber floral buds.
In order to obtain differentially expressed cDNA clones the differential screening and the differential subtraction chain (DSC) methods were used. Altogether above 900 cDNA clones were isolated and part of them were randomly chosen and sequenced (tab. 1 and 2). 
To observe the expression patterns of isolated cDNA clones in developing flowers at different developmental stages, we performed in situ RT-PCR. Here we present the results for two cDNA clones designed as 216GY3 and 35GY3.The expression of 35 Gy3 clone, similar to hypotehetical protein from A. Thaliana, was localised in the stamen primordium and petals of floral buds, whereas there was no expression in male and hermaphrodite floral buds. The 216 Gy3 cDNA clone similar to chaperonine 60 beta chain precursor was strongly expressed in the pistil primordium in the male buds, whereas in female and hermaphrodite buds the oserved signals was very weak.

SUMMARY & CONCLUSIONS
The most of isolated and identified clones are involved in same part of a light or hormone signaling cascade and they may participate in the “cascade of sex expression” in cucumber. 
Signals of expression of clone 35GY3 were observed only in female cucumber flower buds and were the strongest in a site where as it seems only the development of stamens should be inhibited. 
The accumulation of large amounts of the transcripts of 216 GY3 clone in primordia of male flower pistils which will thus not develop is interesting.
 

References
  1. Malepszy S, Niemirowicz – Szczytt K., 1991. Sex determination in cucumber (Cucumis sativus L.) as a model system for molecular biology. Plant science, 80: 39-47
 2. LuoJ., Puc J.A., Slosberg E.D., Yao Y., Bruce J.N., Wright T.C., Becich M.J., Parsons R., 1999. Differential Subtraction chain, a method for identyfing differebces in genomic DNA and mRNA. Nucleic Acid research, vol, 27, No.19: e24.
 3. Urbańczyk-Wochniak, E., Filipecki, M., Przybecki, Z. A useful protocol for in situ RT-PCR on plant tissues. Cellular & Molecular Biology Letters 7 (1) (2002) 7-18. .
 4. Przybecki Z., M.E. Kowalczyk, E. Siedlecka, E. Urbanczyk-Wochniak, S. Malepszy, 2003. The isolation of cDNA clones from cucumber (Cucumis sativus L.) floral buds coming from plants differing in sex. Cell. Mol. Biol. Lett vol. 8, 421-438
 5. Przybecki Z., Kowalczyk M.E., Witkowicz J., Filipecki M., Siedlecka E. 2004. Polymorphom of sexually different cucumber (Cucumis sativus L.) NIL lines. Cell. Mol. Biol. Lett 9 (4B), 919-933.

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Preference and performance of western flower thrips

Differences in performance on, and preference for, different plant parts were studied on cucumber plants. On these plants thrips are often most abundant on the youngest plant parts. This suggests that the youngest leaves are most suitable for western flower thrips. We assessed if differences in suitability of leaves of different age could explain the distribution of thrips on cucumber plants. Evidence was obtained for a correlation between preference and performance on cucumber leaves of different age. Differences in performance on, and preference for, different host plant species were studied with selected isofemale lines. Thrips from these isofemale lines showed differences in performance on different host plant species. It was assessed whether these differences in performance were correlated with differences in preference. No clear evidence was obtained for correlations between preference and performance on different host plant specie

A Review of Recent Developments in the World Sea Cucumber Fisheries

Sea cucumbers (Holothuridae and Stichopodidae) have been harvested commercially for at least 1,000 years. The world fisheries for sea cucumbers, however, are not well documented and in general are poorly managed. Depending upon the species exploited, there are two processing procedures for the sea cucumber product. Some species are eaten raw, while most commercial species are processed into a dry product called beche-de-mer or trepang. This dry product is exported to a central market such as Hong Kong and then re-exported to the consumers. In this review, recent statistics on the world sea cucumber fisheries, collected from different services, are detailed for each major fishing area. Case studies for each fishing area are also presented. Recent major changes in the Indo-Pacific fishery include the participation of new producer countries, the shift in the species being exploited, and an increase in the Chinese market. The expansion of the largely monospecific temperate North Pacific fisheries is also described. Statistics from Hong Kong, Singapore, Taiwan, and the Food and Agriculture Organization provide valuable information on the producer and importer countries. Particular attention is paid to the reciprocal trade of beche-de-mer between Hong Kong and Singapore. An evaluation of the world sea cucumber landings and beche-de-mer production is presented. Recent developments include an expansion of the Hong Kong market due to increased demand by China, the importance of Indonesia as a major world producer, and an increase in the fisheries of Tropical Pacific nations. This increase is best documented for New Caledonia and Fiji. Ways to improve the access and the reliability of the statistics for the sea cucumber fishery are discussed, as is the potential for management of artisanal fisheries

A study of tagging methods for the sea cucumber Cucumaria frondosa in the waters off Maine

The sea cucumber fishery in waters off Maine is developing and has recently experienced great increases in landings, corresponding to expanding export markets. Between 1994 and 1996, reported landings ranged from one to three million pounds (Fig. 1). In 1999, reported landings were over eight million pounds and rose to over nine million in 2000 (Feindel1). Like other developing fisheries, we have little information about the biology and ecology of the sea cucumber off Maine, limited data on the fishery, and little knowledge about the key life history processes that characterize its population dynamics. Therefore, we have a limited understanding of the current status of the resource and the impacts the fishery may have on the stock