13,430 research outputs found

    Current status of the cryopreservation of embryogenic material of woody species

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    Cryopreservation, or the storage at liquid nitrogen temperatures (-196°C), of embryogenic cells or somatic embryos allows their long-term conservation without loss of their embryogenic capacity. During the last decade, protocols for cryopreservation of embryogenic material of woody species have been increasing in number and importance. However, despite the large experimental evidence proved in thousands of embryogenic lines, the application for the large-scale conservation of embryogenic material in cryobanks is still limited. Cryopreservation facilitates the management of embryogenic lines, reducing costs and time spent on their maintenance, thus limiting the risk of the appearance of somaclonal variation or contamination. Somatic embryogenesis in combination with cryopreservation is especially useful to preserve the juvenility of lines while the corresponding clones are being field-tested. Hence, when tree performance has been evaluated, selected varieties can be propagated from the cryostock. The traditional method of slow cooling or techniques based on vitrification are mostly applied procedures. For example, slow cooling methods are widely applied to conserve embryogenic lines of conifers. Desiccation based procedures, although simpler, have been applied in a smaller number of species. Genetic stability of the cryopreserved material is supported by multiloci PCR-derived markers in most of the assayed species, whereas DNA methylation status assays showed that cryopreservation might induce some changes that were also observed after prolonged subculture of the embryogenic lines. This article reviews the cryopreservation of embryogenic cultures in conifers, fruit species, deciduous forest species and palms, including a description of the different cryopreservation procedures and the analysis of their genetic stability after storage in liquid nitrogen

    RECURRENT SELECTION FOR GENERAL AND SPECIFIC COMBINING ABILITY IN MAIZE

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    This study was aimed to identify efficiency  of recurrent  selection program to improve maize population. This program was applied to var. Buhooth 106 with var. 5012  Using RGCA  with the inbred Zm7 for the production of RSCA. The recurrent selection program was implemented for four consecutive seasons (2020 - 2021) at the Fields Station of the College of Agriculture - University of Anbar. In the spring season 2020, 100 top crosses  were obtained from both varieties and progeny.  During the fall season 2020, an experiment was carried out to compare the top crosses of each variety RGCA and RSCA using a 10 × 10 partially balanced lattice design.. Six genotypes from each genetic population as well as Buhooth 106 and 5012 and Zm7 inbreds). The genotype-S1-2 RSCA achieved the lowest female flowering period for females 61.50 days, the highest number of rows per ear 17.80 rows, and the highest grain yield 177.82 g. The genotype-S1-3 RSCA achieved the highest leaf area 0.593 m2 and the highest number of kernels per row 43.11 kernel. The broad sense heritability of the traits of the number of rows and the number of kernels in the row and the yield of the plant reached 53.23%, 73.85% and 41.94%, respectively, and high genetic advance for kernels per row and grain yield of 4.79 and 15.52 respectively

    THE GENETIC DIVERSITY OF MAIZE INBRED LINES GROWN IN IRAQ USING SIMPLE SEQUENCE RECURRENT (SSR) MARKERS

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    This study was conducted to determine the genetic variability among maize inbred lines grown in Iraq by using Simple Sequence Recurrent (SSR) markers. For estimating the genetic relationships, 10 SSR primers were used with 10 maize inbred lines. Two hundred and sixteen alleles (bands) with a range of 13 to 41 were identified for the SSR loci. Polymorphism information content (PIC) of the 10 SSR loci ranged from 0.60% to 100%. Primers ‘umc1566’, ‘umc1542’, and ‘umc2189’ showed the maximum PIC value; by contrast, ‘umc2225’showed the lowest PIC value. The 10 maize inbreds were clustered based on the matrix of genetic similarity using the UPGMA algorithm. Cluster analysis placed the inbreds lines in three clusters based on SSR data. The studied inbreds lines divided to groups and subgroups with cluster analysis that revealed agreement with their geographical origin. The results indicated that SSR marker has a high degree of polymorphism that allows efficient identification of maize genotypes, and this could be used in determining their heterotic groups

    Genetic Diversity and Population Structure of Haloxylon Aphyllum in Iran by ISSR Markers

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    Haloxylon aphyllum is a significant species adapted to salinity conditions and plays an important role in stabilising soil, providing forage, and serving as a source of firewood for residents. In this study, the genetic diversity of four populations of H. aphyllum in Iran was examined using four primers to assess genetic diversity, which produced a total of 41 bands. The AMOVA test showed that the studied populations differed in their genetic content. Specifically, 46% of genetic variability occurred within populations, while 54% arose between populations, indicating a high degree of genetic variation among H. aphyllum populations. The Mantel test presented a significant correlation between genetic distance and geographic distance. Additionally, the STRUCTURE analysis presented comprehensive information on the genetic structure of the studied H. aphyllum populations. The presence of genetic diversity and heterozygosity among H. aphyllum populations suggests local adaptation among populations, which may be due to the heterogeneity of environmental factors such as soil moisture and nutrients that create genetic heterogeneity

    Mortgaged futures:fractured livelihoods and youth debts during COVID-19

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    The social and economic impacts of COVID-19 have been devastating for many, and collectively young people generally fared worse than older adults, with the impact amongst young people also being highly uneven. Most studies on this topic focus on Global North contexts, with experiences in the Global South being less well understood. Focusing on young people in Nepal and Indonesia who were especially exposed to the fallout from the pandemic (in part due to their occupations), this paper analyzes over 1400 weekly diary entries from 100 respondents written across four months in the first half of 2021. Participants recall increasingly precarious individual and family situations due to pandemic-related livelihood upheavals and insufficient access to social protection. Amongst diverse ‘coping strategies’, many turned to debt to smooth fluctuating incomes–leading to both financial and social obligations and forcing sometimes life-altering decisions such as leaving education and moving into risky work. Spiralling indebtedness may have consequences for livelihoods across young people’s life-courses; with futures mortgaged to survive precarity at the peak of the Delta wave of COVID-19. Looking ahead, policy makers should reconfigure disaster responses and social protection with a youth-lens to ensure a robust, fair and sustainable recovery from future crises, mitigating inter-generational scarring effects.</p

    Effect of Spirulina platensis extract on growth potential of in vitro culture pear

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    Pears are among the most economically important fruits in the world that are grown in all temperate zones. ‘Le-Cont’ rootstock pear is one of the gene sources used to improve fruit productivity, rootstock resistance, and tolerance to biotic and abiotic stresses. Traditional propagation of pear. Pear is time-consuming and limited by a short growing season and hard winter conditions. Therefore, in vitro propagation is a suitable alternative method. Murashige and Skoog medium (MS) and spirulina platensis extract at 5,10 and 20 % supplemented with different concentrations (0.25, 0.5 and 1.0 mg/l) of 6-benzyladenine (BA) and kinetin (Kin), individually or in combination with them. Treatments were used for in vitro shoot proliferation. Nodal segments were used as explants. MS medium augmented was 3mg/l 6-benzyladenine (BA) plus 20 % Spirulina platensis extraction then used for shootlets proliferation of micro-shoots. A combination of 3 mg/l BA and 20 % Spirulina platensis as a growth media resulted in a significant improvement in shoot proliferation. This combination produced the highest number of shoots (2.8 per explant) and leaves (6.3 per explant) similar with those containing MS media plus 20% extraction (2.9 per explant) and leaves (6.8 per explant). The longest shoots (2.97 cm) were obtained in each previous treatment. However, these shoots were similar with those produced from classical multiplication by MS according to ISSR analysis which scored 89.1 % of mono morphism percentage and 10.1 % polymorphism. The ISSR analysis shows the highest similarity index percentage for P5-P9 0.986301

    PELATIHAN ANALISIS MOLEKULER PADA HEWAN DENGAN MARKA RAPD UNTUK MENINGKATKAN KOMPETENSI GURU BIOLOGI SMA/MA KABUPATEN BANYUMAS

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    Penguasaan materi pembelajaran menjadi salah satu modal bagi seorang guru, karena &nbsp;sangat mendukung kompetensinya. Salah satu materi pembelajaran biologi di SMA adalah tentang Biosistematika Hewan, yang diantaranya mengajarkan tentang keragaman genetik. Pemahaman topik tersebut perlu didukung dengan pemahaman dan keterampilan pendidik dalam melakukan analisis molekuler. Tetapi kemampuan tersebut masih belum dikuasai oleh seluruh guru biologi yang tergabung dalam MGMP Biologi di Kabupaten Banyumas,&nbsp; sehingga atas permintaan kelompok tersebut akan dilakukan pelatihan, agar tugas pokok dan fungsinya tercapai. Pelatihan analisis molekuler dengan marka RAPD untuk MGMP Biologi di Kabupaten Banyumas &nbsp;ini bertujuan untuk&nbsp; meningkatkan&nbsp; kompetensi&nbsp; guru SMA&nbsp; dalam&nbsp; bidang biologi molekuler, guna mendukung pelaksanaan penelitian yang dilakukan oleh guru serta pembelajaran Biosistematik. Metode yang diterapkan adalah partisipatif, yang meliputi persiapan, pelaksanaan pelatihan dan evaluasi kegiatan. Hasilnya menunjukkan bahwa kegiatan dapat berjalan dengan baik dan lancar. Peserta pelatihan sangat antusias selama mengikuti penyampaian materi maupun praktik di laboratorium. Selain itu, juga meningkat pengetahuan dan keterampilannya dalam melakukan karakterisasi molekuler pada ikan. Berkat terselenggaranya pelatihan ini, telah ditandatangani Perjanjian Kerjasama antara Fakultas Biologi dengan MGMP Biologi Kabupaten BanyumasMastery of learning material is one of the assets for a teacher because it supports his competence. One of the biology learning materials in high school is Animal Biosystematics, which includes teaching about genetic diversity. Understanding this topic needs to be supported by educators' understanding and skills in carrying out molecular analysis. However, this ability is still not mastered by all biology teachers who are members of the Biology MGMP in Banyumas Regency, so at the request of this group training will be carried out, so that their main tasks and functions are achieved. Molecular analysis training with RAPD marking for MGMP Biology in Banyumas Regency aims to increase the competency of high school teachers in the field of molecular biology, to support the implementation of research carried out by teachers and Biosystematics learning. The method applied is participatory, which includes preparation, implementation of training, and evaluation of activities. The results show that activities can run well and smoothly. The training participants were very enthusiastic during the delivery of material and practical work in the laboratory. Apart from that, knowledge and skills in carrying out molecular characterization of fish also increase. Thanks to the implementation of this training, a Cooperation Agreement has been signed between the Biology Faculty and the Banyumas Regency Biology MGMP &nbsp

    KASP-IEva: an intelligent typing evaluation model for KASP primers

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    KASP marker technology has been used in molecular marker-assisted breeding because of its high efficiency and flexibility, and an intelligent evaluation model of KASP marker primer typing results is essential to improve the efficiency of marker development on a large scale. To this end, this paper proposes a gene population delineation method based on NTC identification module and data distribution judgment module to improve the accuracy of K-Means clustering, and introduces a decision tree to construct the KASP-IEva primer typing evaluation model. The model firstly designs the NTC identification module and data distribution judgment module to extract four types of data, grouping and categorizing to achieve the improvement of the distinguishability of amplification product signals; secondly, the K-Means algorithm is used to aggregate and classify the data, to visualize the five aggregated clusters and to obtain the morphology location eigenvalues; lastly, the evaluation criteria for the typing effect level are constructed, and the logical decision tree is used to make conditional discrimination on the eigenvalues in order to realize the score prediction. The performance of the model was tested by the KASP marker typing test results of 2519 groups of cotton varieties, and the following conclusions were obtained: the model is able to visualize the aggregation and classification effects of the amplification products of NTC, pure genotypes, heterozygous genotypes, and untyped genotypes, enabling rapid and accurate KASP marker typing evaluation. Comparing and analyzing the model evaluation results with the expert evaluation results, the average accuracy rate of the four grades evaluated by the model was 87%, and the overall evaluation results showed an uneven distribution of the grades with significant differential characteristics. When evaluating 2519 KASP fractal maps, the expert evaluation consumes 15 hours, and the model evaluation only uses 8min27.45s, which makes the model intelligent evaluation significantly better than the expert evaluation from the perspective of time. The establishment of the model will further enhance the application of KASP markers in molecular marker-assisted breeding and provide technical support for the large-scale screening and identification of excellent genotypes

    Image_1_Genetic variation of Amaranthus retroflexus L. and Chenopodium album L. (Amaranthaceae) suggests multiple independent introductions into Iran.jpeg

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    Amaranthus retroflexus L. and Chenopodium album L. (Amaranthaceae) are weedy plants that cause severe ecological and economic damage. In this study, we collected DNA from three different countries and assessed genetic diversity using inter-simple sequence repeat (ISSR) markers. Our analysis shows both weed species have low genetic diversity within a population and high genetic diversity among populations, as well as a low value of gene flow among the populations. UPGMA clustering and principal coordinate analysis indicate four distinct groups for A. retroflexus L. and C. album L. exist. We detected significant isolation-by-distance for A. retroflexus L. and no significant correlation for C.album L. These conclusions are based data from 13 ISSR primers where the average percentage of polymorphism produced was 98.46% for A. retroflexus L. and 74.81% for C. album L.These data suggest that each population was independently introduced to the location from which it was sampled and these noxious weeds come armed with considerable genetic variability giving them the opportunity to manifest myriad traits that could be used to avoid management practices. Our results, albeit not definitive about this issue, do not support the native status of C. album L. in Iran.</p

    Marker Assisted Selection in Groundnut

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    Groundnut (Arachis hypogaea L.) is an important oilseed crop worldwide. Objective of this review is to highlight molecular breeding approach such as marker assisted selection on groundnut improvement with future perspectives. The review analyzed application of marker assisted selection including simple sequence repeats, random amplified polymorphism DNAs, single nucleotide polymorphism, amplified fragment length polymorphism and inter simple sequence repeats on groundnut improvement. Among the molecular markers, random amplified polymorphic DNA is a rapid method for developing genetic maps and to determine DNA fragments to characterize peanut cultivars. DArTseq is used for SNP discovery and genotyping, which enables considerable discovery of SNPs in a wide variety of non-model organisms and provides measures of genetic divergence. Polymorphism screening performed using these newly developed SSRs will greatly increase the density of SSR markers in the peanut genetic map in the future
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