CREA Journals (Consiglio per la ricerca in agricoltura e l’analisi dell’economia agraria)
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Antioxidant activity in a set of sorghum landraces and breeding lines
Get PDFSorghum (Sorghum bicolor L) is becoming an increasingly important crop in the developed world especially as a cereal grain option for patients with celiac disease, being also characterized by a high level of bioactive compounds. It is a good source of phenolic compounds, including phenolic acids, flavonoids and condensed tannins, that express antioxidant capacity and potential health benefits. A group of 210 sorghum genotypes was evaluated in terms of physical parameters and resulted to be characterized by a wide range of 1000-seeds weight (6.93 - 42.67 g) and kernel colour. A sub-set of 121 samples were selected by near infrared spectroscopy for chemical analyses, and revealed a wide range of variability for total antioxidant capacity (6.89 - 172.02 mmol TE kg-1 dm-1), phenols (0.60 - 20.73 g GAE kg-1 dm-1), condensed tannins (0 - 28,362.63 μg CE g-1 dm-1) and flavonoids (0 - 8,138.22 μg CE g-1 dm-1). A high negative correlation was observed between antioxidant compounds and the colour parameters L* and b*; on the contrary, correlation of the same parameters with a* was low and positive. The results of these preliminary analyses highlighted genotypes characterized by light-coloured grains (white or yellow), large seeds, high antioxidant properties but absence of condensed tannins, all traits which make them suitable for food industry
Revealing core heterotic germplasm and characterizing of maize inbred lines using SSRs
Get PDFClear knowledge about germplasm characteristics of inbred lines is very important for breeding and genetic research in maize. In this study, a total of 100 SSR markers uniformly distributed on all chromosomes were used to classify 758 lines with broad germplasm types and to reveal the germplasm relationship of 452 introduced lines with unknown pedigree and 91 lines from different sources. Great genetic diversity was observed among these lines, with total alleles 384, alleles per locus 2 ~ 11, polymorphic information content 0.23 ~ 0.86, gene diversity
0.26 ~ 0.88, major allele frequency 0.09 ~ 0.50. All lines were divided into 10 groups G1~G10, in which all lines with unknown pedigree were included. Five typical heterotic groups were revealed. Three groups (G1, G2, and G7, totally included 695 lines, accounting for 91.69%) and two core heterotic types (G1×G2 and G7×G2) were consistently revealed according to typical lines, the genetic differences among different groups and between pairs of parental lines for 48 important commercial hybrids. Eighteen high-oil and 18 popcorn lines were distinctly classified in G7-9 and G8 groups. The namesake lines from different sources were classified into the same groups for
82 lines, while other 9 such lines were classified into different groups or subgroups. In addition, line improvement among typical groups was obviously reflected and proved to be the effective way in further maize breeding. These results were mainly consistent with inbred pedigree/heterotic groups, previous researches and breeding practice, and could provide useful gerplasm information for all lines in further maize breeding and genetic research
Morphological diversity and relationships among the IPGRI maize (Zea mays L) landraces held in IITA
Get PDFGenetic variability estimates in maize (Zea mays L) landraces is an important information for trait improvement for food and nutrition security. Genetic diversity information in the Sub-Sahara African maize landraces is lack- ing. Agromorphological trait evaluation is a practical approach for genetic diversity estimation. Our objective was to assess genetic diversity among 60 IPGRI maize landraces held in IITA, Ibadan, against a check, «Obatanpa GH». Twenty-one quantitative traits and five qualitative traits were field-evaluated in Ghana in 2011 and 2012 wet seasons in a three-replicated randomized complete block design experiment. Large phenotypic variation was identified in all traits except cob colour, principal grain colour, and number of ears per plant. A moderate within population variation based on pooled Shannon Diversity Index was 0.68 ± 0.28. Between population variation was largest in earliness, anthesis-silking interval, and grain yield. Genetic similarity of 0.11 ± 0.00 based on squared correlation coefficient confirmed a large variability among accessions. Two major clusters, I and II, were separated on the basis of maturity characteristics, anthesis-silking interval, plant and ear heights, and grain yield. The first two principal components explained 67.89 % of the total variance. Four genotypes, TZm-1125 and TZm-1117 (5.0 Mg ha-1), TZm-1119 (5.4 Mg ha-1), and TZm-1139 (6.2 Mg ha-1) competed with the check (5.8 Mg ha-1) in grain yield. The IPGRI genotypes represent a large genetic reserve awaiting exploitation for trait improvement
Validation of housekeeping genes for qPCR in maize during water deficit stress conditions at flowering time
Get PDFPlant stress studies are increasingly being based on gene expression. The analysis of gene expression requires sensitive, precise, and replicable measurements for specific mRNA sequences. Real-time RT-PCR is nowadays the most sensitive method for the detection of low abundance mRNA. A stable reference gene is mandatory to obtain reliable quantitative real-time PCR (qPCR) analysis results. Real-time RT-PCR is referred with one or several internal control genes, which should not fluctuate during treatments. In this study, we have chosen eight genes as candidates of possible reference genes for maize (Zea mays L) during water deficit stress at flowering time: a-tubulin, 3`phosphate glyceraldehyde dehydrogenase (GAPDH), 18S ribosomal subunit, protein 13S ribosomal, actin, zein, invertase, and starch synthase IIB. The eight reference genes candidates were tested on maize plants around flowering time, under three different conditions: before water deficit (BWD), under water deficit (WD) and after water deficit (AWD). Results from the three experimental conditions indicated that protein 13S ribosomal gene was the most stable among all the reference genes tested. This result suggests that protein 13S ribosomal gene can be used as internal control (housekeeping) for qPCR analysis in maize plants under water deficit stress during flowering time
A simple, fast and accurate screening method to estimate maize (Zea mays L.) tolerance to drought at early stages
Get PDFThere is a great need for the selection of plants with higher drought tolerance, so that fast and effective techniques to identify variations in drought tolerance are mandatory for screening large numbers of genotypes. This work presents a protocol for easy and reliable assessment of responses of maize genotypes to water stress conditions imposed during early stages of development. Three experiments using 11 commercial maize hybrids under four levels of water stress were carried out: (1) germination, (2) seedling growth, and (3) early growth bioassays. Constant and uniform water stress was imposed using solutions of polyethylene glycol 6000 (PEG 6000). Plant material was evaluated for several morphological, physiological and biochemical traits and monitored for photosynthetic efficiency. Principal component analysis (PCA) of these joint experiments revealed that germination percentage, early root development and stomatal conductance were the most useful traits for discriminating maize hybrids according to their tolerance to water stress. A subsequent greenhouse assay performed with two hybrids with contrasting responses under soil drying conditions validated the previous results. According to our results, the key of drought tolerance was a rapid response of stomatal conductance, which allowed a longer survival to stress even under severe desiccation. This work provides the researcher with a simple and reliable screening method that could be implemented as a decision support tool in the selection of the most suitable genotypes for cultivation in areas where water availability is a problem, as well as for the selection of tolerant genotypes to early drought in breeding programs
Variability and mechanisms of drought tolerance in maize populations from Honduras
Get PDFMaize breeding for drought tolerance requires searching mechanisms and sources of drought tolerance. We assessed drought tolerance at juvenile stages of development in a collection of open-pollinated maize populations from a dry area of Honduras. Eighteen Honduran populations were evaluated for the response of morphological, physiological and photosynthetic traits to increasing levels of water stress during germination, seedling and early growth. Water stress was imposed by using solutions of polyethylene glycol6000. The population Natual Olote Gordo faced drought by increasing root elongation; the population Langueño was able to maintain natural photosynthetic traits under drought conditions at a reasonable level; Capulin was drought tolerant at germination and early growth, and Maicito Montecristo maintained root biomass at seedling and early growth stages. At early growth, Castaño Sur, Maicito Montecristo, Negrito, Sangre de Cristo, and Tuy showed diminished conductance while there was no significantreduction in Langueño. Considering photosynthetic performance, the response to drought can be classifiedas resistance (Langueño) or tolerance (Capulín). Therefore, diverse mechanisms of drought adaptation are displayed by these populations depending on the feature measured and the stage of development. Different adaptive traits to drought at early stages of development could be combined by crossing the appropriate populations
Marginal/peripheral populations of forest tree species and their conservation status: report for Baltic region
Get PDFThe Baltic region includes in this report Fennoscandia (Norway, Sweden, Finland, Denmark), the Baltic states (Estonia, Latvia, Lithuania) and Poland. This region is fairly heterogeneous as regards forest history, forest policy, forest economy as well as climate and conditions for forest growth. The climate of the Baltic region is cool, but still drastically modified by the Gulfstream which skirts the western coast of Scandinavia, giving rise to much warmer summers and milder winters than expected based on the latitude. The warming associated with climate change is expected to be particularly pronounced in winter and at high latitudes. In coastal areas precipitation may increase notably. With elevated temperature, the frequency of both spring frost and drought events is predicted to increase in continental parts. The vegetation and forest types are heterogeneous. Fennoscandia has a large proportion of boreal vegetation where coniferous forests dominate and many broadleaves common in Central Europe are rare and scattered. In the Baltic region the most distinct marginal populations are those at the northern fringe of their distribution. The distribution ranges are limited by a combination of different factors such as low winter temperatures, short growing season either for growth or for seed maturation, soil types and human influence. Fragmentation may limit gene flow between stands, and some populations also show slight inbreeding. The countries in the region have protected jointly 4,9 M ha in the main MCPFE categories. The northern part of the region seems to put more weight on nature conservation through no intervention whereas the southern part emphasizes conservation through active management. The countries of the Baltic region have uploaded altogether 1'172 in situ genetic conservation units in the European Information System on Forest Genetic Resources (EUFGIS)
Screening and analysis of soda saline-alkali stress induced up- regulated genes in sugar sorghum
Get PDFSoil salinization severely constrains the growth of crops, which ultimately leads to reduced yields. Because Sorghum dochna (common name sugar sorghum) has the advantageous properties of excellent salt stress resistance, high biomass, and tremendous flexibility for utilization as food, livestock feed, and industrial products, this species holds great potential to be further developed as a primary alternative crop. To elucidate the molecular mechanism that governs sugar sorghum’s adaptation to high salinity environments, we constructed a suppression subtractive hybridization (SSH) cDNA library from sugar sorghum transcripts that contains the soda saline-alkali induced up-regulated genes from the resistant variety M-81E. The SSH cDNA library was screened by using the colony hybridization method, and the ESTs obtained were sequenced and analyzed. A total of 200 EST clones were identified, representing 127 unigenes (6 contigs and 121 singlets). A Blast analysis showed that 48 ESTs (46.6%) have annotated functions in GenBank, 55 ESTs (53.4%) have unknown functions (or encode hypothetical proteins), and 24 ESTs (18.9%) have no blast hits. The majority of the hypothetical ESTs from the cDNA library displayed very high sequence similarity with their homologs found through GenBank. A clustering analysis of the ESTs with known functions indicated that a wide variety of genes were induced during the salt stress treatment. These genes were found to function in photosynthesis, material and energy metabolism (carbohydrates, lipids, amino acids, co-enzymes, ions, etc.), synthesis or maintenance of constituents of the cell wall and cell membrane, signal transduction, transcriptional regulation, and as water channels. This indicates that sugar sorghum tolerance to soda saline-alkali stress results from the coordinated functions of many genes
Investigating the unusually high cell wall digestibility of the old INRA early flint F4 maize inbred line
Get PDFThe old INRA flint early line F4, which belongs to the northern flint group, is typified by its high cell wall digest- ibility which reaches values as high as those observed in several brown-midrib bm3 mutant lines. The F4 line thus appeared as a model that could contribute to the understanding of genetic mechanisms involved in variation of secondary wall traits. Different strategies and results were thus gathered including especially cell wall biochemical and digestibility investigations, expression approaches, QTL investigations, and colocalizations between QTLs and candidate genes. Lignin content was lower in F4 than in other lines, with a tendency to lower p-coumarate content. The Syringyl/Guaiacyl lignin unit ratio was similar in F4 as in other lines, but this ratio was nearly not reduced in F4bm3, conversely to what is observed in bm3 mutants. In comparison with the INRA F2 control line, expressions of three PAL genes including the ZmPAL, of the ZmF5H1 and the ZmCOMT genes were significantly reduced in F4 lignifying ear internodes at early silking stage. In the F7025 x F4 RIL progeny, seven QTLs were shown with favorable alleles (increasing cell wall digestibility) originating from F4. Two strong QTLs were located in bins 1.03 and 2.03 colocalizing with the ZmMYB019 and ZmSWN6 transcription factors, respectively. Orthologs of ZmMYB019 have been shown to be involved in lignin biosynthesis, and the PpMYB8 ortholog was shown to regu- late PAL gene expression in maritime pine. The ZmSWN6 NAC transcription factor is an upstream master regulator of the secondary wall biosynthetic programs. At the other QTL positions, colocalizations were also shown with other secondary wall related ZmMYB, but also with BAHD genes involved in arabinoxylan feruloylation, and with the position of the bm6 mutation. Three QTL positions were shown with favorable alleles originating from F7025, which colocalized with ZmMYB and ZmNAC transcriptions factors. As a tentative conclusion, the F4 unusually high cell wall digestibility is likely greatly related to the altered working of at least two major transcription factors regulating cell wall biosynthesis and assembly
Materiale eterogeneo per agricoltura biologica – Grani antichi – Progetto Elaborabio
No full textThe genetic improvement of cereals for organic farming: heterogeneous materialHeritage wheatsThe registration of new varieties of sunflower Helianthus annuus The soybean seed reproduction in Italy (2010-2016)New seed rape varieties registered in the Italian Variety CatalogueElaborabio: trend analysis of biological seeds databas