CREA Journals (Consiglio per la ricerca in agricoltura e l’analisi dell’economia agraria)
Not a member yet
791 research outputs found
Sort by
Characterization of a major quantitative trait locus on chromosome five for hundred-kernel weight of maize (Zea mays L)
Get PDFKernel weight is one of the most important components of grain yield and is controlled by quantitative trait loci (QTLs) derived from natural variations in maize. However, the molecular roles of QTLs in the regulation of kernel weight have not been fully elucidated. In this study, by using homozygous chromosome single segment substitu-
tion lines Z22(SSSL-Z22) as base material, two F
populations derived from a cross between elite maize inbred
line Zheng58 and SSSL-Z22, were employed to map QTLs of kernel weight traits in two years at the same location. Out of four traits, 3 QTLs were detected in one of the two environments whereas 2 detected in both environments. Two major QTLs, qhkw5-3 for hundred-kernel weight and qkw5-3 for kernel width, were consistently detected in similar chromosome segment in different years. qhkw5-3 was mapped to Bin 5.06 flanked by the SSR markers SYM033 and SYM108 with a genetic interval of 8.8 cM, which made kernel size smaller. qkw5-3 was identified between SYM024 and SYM129 with a genetic interval of 13.9 cM. These results will help to promote the fine map- ping and cloning of the target gene and further develop linked markers to be used in marker-assisted breeding
Identification of QTL and candidate genes for Pb accumulation in maize at maturity stage
Get PDFPb stress.which were located on chromosome 2 and 6 respectively. The two genes were dramatically up-regulated during led to the identification of two Pb-responsive genes from those QTLs, GRMZM2G137161 and GRMZM2G132995, in different tissues, including roots, stems, leaves, and kernels. Furthermore, RNA-seq data and qRT-PCR analysis correlated with stems. A total of 20 QTLs at logarithm of odds (LOD) ratio ≥3 were detected for Pb concentration tissues of maize were roots > leaves > stems > kernels. The Pb concentration of kernels was higher significantly stems and leaves ( P < 0.01). The present study has demonstrated that the trend of Pb concentration in different tissues and all the DH lines (P < 0.01). Pb concentration of kernels displayed significant positive relationships with leaves, and kernels were measured. There was a wide distribution of Pb concentration among the mentioned four ). Pb concentrations in roots, stems, -1 solution (500 mg kg2)3filled up with soil which was stressed with a Pb(NOidentified using 207 IBM10 DH at maturity stage. The IBM10 DH and parents were planted in pots which were important insights for protecting the environment. Quantitative trait loci (QTL) for Pb accumulation in maize were L) may provide Zea maysthe genetic basis for the underlying mechanism of tolerance for lead responses in maize (Lead (Pb) has become one of the most abundant heavy metal pollutants of the environment. Understandin
Characterization of paired Cas9 nickases induced mutations in maize mesophyll protoplasts
Get PDFTargeted genome modifications are important for both fundamental and applied research. The CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats / CRISPR-associated protein 9) technology has been successfully used in various plant species with high efficiency. Approaches with paired Cas9 nickase enhance the specificity of the CRISPR/Cas9 system by using guide RNA pairs to create two staggered single strand breaks on complementary DNA strands. Here we used maize mesophyll protoplasts as a transient test system and demon- strated the mutagenic potential of Cas9 nickases. Although we found activity for all the three different guide RNA pairs tested, their efficiency varied considerably. Characterization of the modification events revealed a high ratio of large deletions as well as insertions of donor DNA fragments. By the use of the maternally expressed in embryo
1 gene (mee1) as model target sequence, we could demonstrate that transcriptionally inactive and methylated genomic loci are practical targets of Cas9 nickase. The high specificity of Cas9 nickase approaches might provide advantage for genome modifications of certain loci in the complex and highly repetitive maize genome
Socio-ecological considerations on the persistence of Mexican heirloom maize
Get PDFThe vulnerability of 59 Mexican landraces of maize was assessed in relation to five socio-ecological factors, namely, social and economic marginalization, association with indigenous peoples, high biodiversity regions, environmental suitability for cultivation, and climate change effects. The most marginalized states had the highest number of landraces, 80% of which were found in predominantly or substantially indigenous municipalities. While only one third of 152 regions of high biodiversity had collection records, 47 landraces had at least one collection record in these regions. Eleven races can be cultivated in at least 10% of the Mexican territory, while 13 can occupy less than 1% under current environmental conditions. Given a projected temperature increase of 0.5 ºC and a
5% reduction in annual precipitation, 66% of the landraces could disappear during the current decade. A normalized Vulnerability Index was constructed (can have values from 0.00 for non-threatened landraces to 1.00 for the most vulnerable) that averaged 0.76 ± 0.02 for the 59 landraces. The most vulnerable third of the landraces were threatened by being from a region of low marginalization combined with a limited potential distribution both under current conditions and under the climate change scenario considered
Developing insect resistance with fusion gene transformation of chitinase and scorpion toxin gene in maize (Zea mays L)
Get PDFTransgenic plants with introduced pest-resistant genes provide an efficient alternative insect control. A binary insect-resistant gene combination, containing an insect-specific chitinase gene (chi) and a scorpion insect toxin gene (Bmk), was introduced into a maize cultivar via pollen-mediated transformation. Thirty-eight putative trans- genic plantlets with kanamycin-resistance were obtained. Transgenic statuses of plants were confirmed by South- ern blot analysis. Bioassay by inoculation of Asian corn borer (Ostrinia furnacalis Guenée; ACB) larvae indicated that the degree of ACB resistance varied among the transgenic plants. The highest average calibrated mortality of larvae was approximately 67%. The genetic analysis of T1 progeny confirmed that the inheritance of introduced genes followed the Mendelian’s rules
Genetic diversity and heterotic grouping of the core set of southern African and temperate maize (Zea mays L) Inbred lines using SNP markers
Get PDFThe establishment of heterotic groups and heterotic patterns is crucial to a successful maize hybrid breeding programme. Molecular markers can be used for differentiating maize into heterotic groups which can be used for maximum exploitation of heterosis. A core set of 45 maize inbred lines was selected from 96 maize inbred lines that were obtained from major breeding programmes in Zambia, Zimbabwe, CIMMYT, IITA, and USA. The 45 in- bred lines were assessed for their genetic diversity and assigned to different heterotic groups using 129SNPs. The genetic distance ranged from 0.03 to 0.99, with the highest distance observed between inbred lines B73 and Mo17 and the least between L3233 and N3. The inbred lines were clustered into four groups which corresponded to the N, SC, BSS, and Lancaster heterotic groups. The genetic divergence among temperate inbred lines was larger than that among tropical inbred lines. Temperate inbred lines with potential to improve the heterotic response of the N and SC heterotic groups were identified. The study has shown that including temperate inbred pairs from established and well-known heterotic groups is recommended for effective molecular characterisation of Southern African maize inbred lines. It is recommended that the genetic distance based grouping should be verified by combining ability studies
Nutrient, fatty acid and mineral composition of selected white food-grade sorghum hybrids grown in a Mediterranean area of Southern Italy
Get PDFThe nutrient composition, fatty acid content and mineral content of six white food-grade sorghum hybrids selected in either Argentina or Bolivia, and grown in a Mediterranean area of Southern Italy were studied. The six hybrids were analyzed for various attributes including moisture, protein, carbohydrate, dietary fiber, fat contents, fatty acid composition, and mineral content. Slight variations in both protein and in fiber contents were observed among hybrids. Linoleic, oleic and palmitic were the most abundant fatty acids in all samples with noticeable difference in their percentage content between both hybrids from Argentina and Bolivia. Slight variations in the content of the elements were found among the six white sorghum hybrids examined, and K, Fe, and Sb were, respectively, the most abundant macro-element, micro-element and trace element in all analyzed hybrids. These results are discussed in the context of the importance of the white food-grade sorghum in human nutrition, and of the opportunity to select the best varieties from the point of view of nutritional content
Accuracy and simultaneous selection gains for grain yield and earliness in tropical maize lines
Get PDFWinter maize is sown between January and March in Brazil. Although this maize is sown in unfavorable weather conditions, many farmers are successful, and winter maize has become an important crop. The sowing of early hybrids is a strategy to reduce the effects of stress on yield; however, low yields may result from earliness. Thus, the objectives in this study were to investigate tropical maize lines for the possibility of simultaneous selection for yield and earliness and to compare the differences among the simultaneous selection methods. Therefore,
64 lines were evaluated in two locations for grain yield, days to female flowering and grain moisture at harvest. The genotypic values for these traits were predicted using Restricted Maximum Likelihood/Best Linear Unbiased Predictor (REML/BLUP) single-trait (univariate) and multi-trait (multivariate) methods. Using three simultaneous selection methods (i.e., Additive index, Mulamba-Mock index and Independent culling levels) with two methods of prediction for genotypic values (single-trait and multi-trait), six simultaneous selection scenarios were considered and then compared for selection gains and accuracy. Because of the low correlation between these traits, the pre- dictions of genotypic values were similar for single-trait and multi-trait methods. Thus, single-trait analysis should be prioritized because of its practicality. The Additive index obtained the highest selection gain for grain yield and simultaneously achieved good gains for days to female flowering and grain moisture at harvest. Therefore, the Additive index, using the single-trait prediction method, is the best simultaneous selection method for yield and earliness in tropical maize lines
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 resis- tance, 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
Performance of no-till maize under drip-fertigation in a double cropping system in semi arid Telangana state of India
Get PDFAvailability of water for Agriculture is becoming increasingly difficult, besides the cost of power for applying it. Improving the water and nitrogen use efficiency has become imperative in present day’s Agriculture. Drip irrigation and fertigation provides the efficient use of limited water with increased water and nutrient use efficiency, respec- tively. A field experiment was conducted during post rainy season of two consecutive years (2011 and 2012), in sandy loam soils of Warangal, Telangana State, India to study the response of no-till maize (Zea mays L) after aerobic rice (Oryza sativa L) to drip irrigation and nitrogen fertigation under semi-arid environment. The experiment was laid out in split plot design with four replications. Three irrigation schedules viz. drip irrigation at 75% Pan Evaporation (PE); 100% PE and 125% PE were taken as main plots and three nitrogen levels through fertigation viz. 120, 160, and 200 kg ha-1 as sub plots. The growth parameters (plant height, LAI, drymatter accumulation), root volume and dry weight, yield attributes (cobs plant-1, kernels cob-1, kernel weight cob-1) kernel yield, stover yield and nitrogen uptake of no till maize increased with increase in water input from 75% PE to 100% PE irrigation schedule in drip irrigation but could not reach the level of significance at 125% PE. Tasseling and silking was hastened in 125% PE schedule. Increase in the level of N application through fertigation from 120 to 160 kg N ha-1 resulted in the increase of all the growth parameters, yield attributes, kernel yield, stover yield and nitrogen uptake. Barrenness and test weight were unaffected by either the irrigation schedules or nitrogen levels. The economic indicators (gross returns, net returns and net benefit: cost ratio) were higher with the irrigation schedule of 125% PE and nitrogen dose of 200 kg N ha-1 applied through fertigation. Increased water input from 75 to 125% PE resulted in decreased water use efficiency but enhanced nitrogen use efficiency while the reverse trend was found with respect to N levels under fertigation