854 research outputs found

    Participatory Barley Variety Selection and Farmers’ Selection Criteria in the Bale Highlands of Southeastern Ethiopia

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    The aim of the study was to identify farmers’ selection criteria, preferences and generate baseline information on the importance of participatory  barley breeding in Southeastern part of Ethiopia. The experiment was  conducted in non-replicated plots at each location on plot size of 16m2 in 2007 Bona and on 25m2 in 2008 Ganna and Bona cropping seasons. Yield data was taken in kg plot-1 and converted in to t ha-1 .Selection criteria was set together with farmers; and ranked by farmers and breeders. Farmers and breeders made visual score of each plot on 1-5 scale beside variety selection. Some farmers were supported by the staff in case of datarecording problem. The result showed that grain yield, disease resistance, effective tillers, early maturity and kernel size (plumpness) were among the most important selection criteria commonly used farmers. While, breeders preferred high yielding variety with insect and disease resistant and early maturing types. And farmers were able to identify the higher yielding barley varieties as breeders. Varieties such as Guta, Dinsho, Biftu and Abdane were selected as the best varieties preferred by most of the local farmers across locations except at Hora Soba (Upper Dinsho) site. Shage, Dimtu varieties and 27th IBON 73/99 (semi-dwarf advanced line) were preferred by the Hora Soba local farmers. Thus, attention should be given to seed multiplication and dissemination of barley varieties which have been highly preferred by the local farmers. It is important to consider farmers preferences in crop improvement to improve the adoption of  agricultural technologies which ultimately have significant contribution in production and productivity

    Genotype assessment of grape regenerants from floral explants

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    A molecular typing of regenerant vines based on co-dominant simple sequence repeat (SSR) markers was applied for checking recombination events during somatic embryogenesis from floral explants. Twenty-one samples of somatic embryos and plantlets from embryogenic callus of both anthers and ovaries of the V. vinifera cv. Chardonnay, the rootstock Kober 125 AA, and the accession V. rupestris du Lot were randomly chosen from a number of regenerant lines. The genotype at polymorphic VVS2, VVMD5, VVMD7, VVMD27, VrZAG62 and VrZAG79 loci was produced and compared with reference patterns. No recombination events were detected in the cells involved in the somatic embryogenesis induction of all the checked samples, since all of them generated the same SSR profile of the grape variety from which explants were isolated.

    Genetic characterization and relationships of traditional grape cultivars from Serbia

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    Reference genetic profiles were generated for 12 traditional grapevine cultivars of Serbia through a genotyping approach that included the "core set" of 9 SSR markers for genetic identification and further 13 common microsatellites for strengthening genetic relationship analysis. Consistent matching with SSR markers of grapevines cultivated in neighbouring countries or maintained in European germplasm collections was found for most of the genotypes, suggesting possible synonyms and revealing that 'Muskat Krokan' corresponds to 'Muscat fleur d’Oranger' and two 'Tamjanika' cultivars are identical to 'Moscato Giallo' and 'Moscato Rosa'. When compared with germplasm representing the classical eco-geographic grouping of grapevine cultivars, Serbian non-Muscat genotypes clustered within the Convar pontica subconvar balcanica taxon thus supporting their indigenous origin.

    RAPD markers in wild and cultivated Vitis vinifera

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    Some Vitis vinifera cultivars and V. vinifera ssp. silvestris individuals have been subjected to the RAPD analysis in order to estimate the genetic diversity existing within this germplasm. 44 decamer primers of arbitrary sequence have been used for PCR and reproducible band profiles have been obtained. The distribution of the individualized polymorphic DNA markers has not turned out to be different in a remarkable way between cultivated and wild grapevines but this RAPD approach provides for some characteristics useful to analyze genetic relationships even within the Vitis vinifera species

    Leaf monoterpene emission limits photosynthetic downregulation under heat stress in field-grown grapevine

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    Rising temperature is among the most remarkably stressful phenomena induced by global climate changes with negative impacts on crop productivity and quality. It has been previously shown that volatiles belonging to the isoprenoid family can confer protection against abiotic stresses. In this work, two Vitis vinifera cv. ‘Chardonnay’ clones (SMA130 and INRA809) differing due to a mutation (S272P) of the DXS gene encoding for 1-deoxy-D-xylulose-5-phosphate (the first dedicated enzyme of the 2C-methyl-D-erythritol-4-phosphate (MEP) pathway) and involved in the regulation of isoprenoids biosynthesis were investigated in field trials and laboratory experiments. Leaf monoterpene emission, chlorophyll fluorescence and gas-exchange measurements were assessed over three seasons at different phenological stages and either carried out in in vivo or controlled conditions under contrasting temperatures. A significant (p < 0.001) increase in leaf monoterpene emission was observed in INRA809 when plants were experiencing high temperatures and over two experiments, while no differences were recorded for SMA130. Significant variation was observed for the rate of leaf CO2 assimilation under heat stress, with INRA809 maintaining higher photosynthetic rates and stomatal conductance values than SMA130 (p = 0.003) when leaf temperature increased above 30 °C. At the same time, the maximum photochemical quantum yield of PSII (Fv/Fm) was affected by heat stress in the non-emitting clone (SMA130), while the INRA809 showed a significant resilience of PSII under elevated temperature conditions. Consistent data were recorded between field seasons and temperature treatments in controlled environment conditions, suggesting a strong influence of monoterpene emission on heat tolerance under high temperatures. This work provides further insights on the photoprotective role of isoprenoids in heat-stressed Vitis vinifera, and additional studies should focus on unraveling the mechanisms underlying heat tolerance on the monoterpene-emitter grapevine clone

    Patterns of genetic diversity and linkage disequilibrium in a highly structured Hordeum vulgare association-mapping population for the Mediterranean basin

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    Population structure and genome-wide linkage disequilibrium (LD) were investigated in 192 Hordeum vulgare accessions providing a comprehensive coverage of past and present barley breeding in the Mediterranean basin, using 50 nuclear microsatellite and 1,130 DArT® markers. Both clustering and principal coordinate analyses clearly sub-divided the sample into five distinct groups centred on key ancestors and regions of origin of the germplasm. For given genetic distances, large variation in LD values was observed, ranging from closely linked markers completely at equilibrium to marker pairs at 50 cM separation still showing significant LD. Mean LD values across the whole population sample decayed below r 2 of 0.15 after 3.2 cM. By assaying 1,130 genome-wide DArT® markers, we demonstrated that, after accounting for population substructure, current genome coverage of 1 marker per 1.5 cM except for chromosome 4H with 1 marker per 3.62 cM is sufficient for whole genome association scans. We show, by identifying associations with powdery mildew that map in genomic regions known to have resistance loci, that associations can be detected in strongly stratified samples provided population structure is effectively controlled in the analysis. The population we describe is, therefore, shown to be a valuable resource, which can be used in basic and applied research in barle

    In vitro screening of interspecific hybrids (Malus spp.) for resistance to apple proliferation

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    A breeding programme was set up six years ago in Trentino as part of the Project “Scopazzi del Melo - Apple Proliferation” (SMAP) in order to obtain AP resistant apple rootstocks.Twenty-six hybrids generated from the crossings (Malus sieboldii, second generation, x Malus domestica) were micropropagated and studied in standardised conditions. An in vitro screening system for AP resistance previously set for the parents of the crosses was adopted and modified. Specific symptoms of the disease, as well as height and basal proliferation of the shoot and size of the leaves, were recorded in vitro at 3 months post-inoculation. At the same time, phytoplasma concentration was determined in the whole shoot by quantitative RT-PCR. An in vitro disease index taking into account all the above-mentioned parameters was developed.Each healthy genotype was graft-inoculated in triplicate with two different phytoplasma strains after plant rooting and acclimatisation. Phenotype and phytoplasma titre were evaluated in the roots the year after infection.Preliminary results indicated that the resistance trait segregates in the progenies. The resistant genotypes had lower phytoplasma concentrations than the susceptible controls, did not show AP-specific symptoms and their growth was not affected by infection. By comparing the resistant behaviour of the same genotypes, the in vitro screening allows for a quick selection of genotypes that are worth evaluating in the field for agronomic traits.Keywords: Apple Proliferation, Malus sieboldii, resistance screening, quantitative real-time PCR, disease inde

    Genetic relationships among local Vitis vinifera cultivars from Campania (Italy)

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    A total of 114 accessions putatively corresponding to 69 local grape cultivars from Campania (Southern Italy) were analysed with 8 microsatellite markers (VVS2, VVMD5, VVMD7, VVMD25, VVMD27, VVMD31, VrZAG62 and VrZAG79) in order to evaluate their genetic diversity and relationships. According to their unique genotype at SSR loci finally 56 varieties were found. Interesting cases of synonymy, i.e. Greco di Tufo and Asprinio, Palummina and Piedirosso, and homonymy were disclosed. Pairwise genetic distances were calculated between all cultivars. Clustering of cultivars did not reflect their current distribution and this suggests that grape cultivars of Campania might have been introduced from various and distinct geographic areas

    Ampelometric evaluation of wild grape (Vitis vinifera L. ssp. sylvestris (C.C. Gmel.) Hegi) accessions in the germplasm collection of FEM-IASMA, Italy

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    In this paper, 45 wild grapevine accessions collected during two consecutive years were compared for 36 ampelometric traits using digital image analysis. The sample set contained male and female individuals from different geographic regions: Germany, North Italy, Central Italy, South Italy, Sardinia and Turkey. The leaf morphological data from the collected samples suggest that geographic origin, gender and vintage could have an effect on ampelometric traits in this species

    The parentage of 'Sangiovese', the most important Italian wine grape

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    A previous microsatellite study pointed out a possible parent-offspring relationship between 'Sangiovese', the most widespread red grape cultivar in Italy, and 'Ciliegiolo', an ancient Tuscan variety. Testing 'Sangiovese' as a parent of 'Ciliegiolo', we searched for the putative other parent in our extensive, private and standardized database, but we did not find any candidate. Testing 'Ciliegiolo' as a parent of 'Sangiovese', we found four candidate cultivars. After the analysis of 50 microsatellites, only one stood the paternity test and we established with a strong statistical support that 'Sangiovese' is a progeny of 'Ciliegiolo' and 'Calabrese di Montenuovo', an obscure grapevine from Campania, Italy. This cultivar does not have a registered name and is supposed to have been introduced from Calabria. Among 180 additional local grape cultivars from Calabria, Campania or Tuscany, we did not find any matching variety. As a consequence, we propose to adopt the name 'Calabrese di Montenuovo' for this grape cultivar. In addition, we found relatives of 'Sangiovese' and 'Calabrese di Montenuovo' in Calabria, thus strongly suggesting a Calabrian origin for 'Calabrese di Montenuovo' and indicating that 'Sangiovese' has ancestors and/or progenies in Tuscany and in Southern Italy.
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