CREA Journals (Consiglio per la ricerca in agricoltura e l’analisi dell’economia agraria)
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Genetic diversity in Algerian maize (Zea mays L) landraces using SSR markers
Get PDFIn the Sahara, maize (Zea mays L) has been adapted to extreme environmental conditions during the last five centuries; therefore, this germplasm has a potential value as source of tolerance to stress. No previous report of the genetic diversity of Saharan maize has been published so far. The objective of this study was to determine the genetic diversity of a collection of Saharan maize. Fifteen accessions representing the geographic diversity of Algeria were characterized with 18 SSR. Most loci (93%) were polymorphic; the total amount of alleles was 87 and the average of alleles per locus was 5.8. The total genetic diversity (He) was 0.57, being 69% intra-accessions and 31% inter-accession. Eight of the alleles were accession-specific and belonged to six populations. Genetic distance among the 15 accessions resulted in the definition of three main clusters related to the geographic origin. Maize germplasm from the Algerian Sahara can be classified at least in three groups and the most variable acces¬sions are in the southern oasis. Some accessions were highly variable and can be sources of favorable alleles for breeding for tolerance to extreme stress conditions
Combined approaches provide an anatomical and transcriptomic fingerprint of maize cell wall digestibility
Get PDFUnderstanding cell wall biosynthesis and degradation in grasses has become a major aim in plant biology. Although independent previous reports have focused on specific features that dictate cell wall digestibility, cytological, biochemical, and gene regulation parameters have never been integrated within the same study. Herein, we applied a combination of state-of-the-art technologies and different scales of observation on two maize lines that are characterized by highly contrasted forage digestibility. Comparative image analysis of internode sections allow to get an anatomical fingerprint associated with high digestibility: a thin peripheral rind of lignified parenchyma, small numerous vascular bundles, and low proportion of PeriVascular Sclerenchyma (PVS). This cell type patterning led to enhanced digestibility when internode sections were treated with Celluclast, a commercially cell wall degrading enzyme. At a lower scale of observation, Laser Capture Microdissection (LCM) followed by thioacidolysis of PVS revealed a higher proportion of Syringyl (S) unit lignins in the low digestible line while the high digestible line was p-Hydroxyphenyl (H)-rich. Moreover, cytological observation of internodes of the two lines point out that this difference in composition is associated with a delayed lignification of PVS. At the same time, comparative transcriptomics on internodes indicated differential expression of several genes encoding enzymes along the phenylpropanoid pathway and known cell wall-associated Transcription Factors (TFs). Together, these results give an integrative view of different factors which could aim in designing a maize silage ideotype and provide a novel set of potential regulatory genes controlling lignification in maize
Development and characterization of a coloured sweet corn line as a new functional food
Get PDFThe standard sugary sweet corn (Zea mays saccharata Sturt.) is a maize variety grown for the fresh, frozen and canned markets, traditionally appreciated. Its kernels are characterized by the presence of some antioxidant substances suggested to be beneficial for cancer prevention. For this reason an interesting challenge for breeders is the development of sweet corn genotypes with naturally high antioxidant levels, starting from flavonoids. In fact important sources of antioxidants in maize are anthocyanins, considered as nutraceuticals because they have been proven to lower the risk of many chronic diseases. In this paper we report the development of a new coloured sugary line and the results of some analyses concerning flavonoid content before and after two different cooking treatments are discussed. Attention was mainly focused on the anthocyanins, the molecules suggested as being responsible for the nutraceutical properties of the new coloured sugary line. The results show that the presence of the anthocyanins also pushes up the flavonol and the phenolic acid amounts and gives the new coloured sugary line a higher scavenging power compared to the uncoloured control. The mild cooking seems not to significantly change the metabolites analyzed in the coloured kernels, while the stronger treatment seems to drastically decrease the amounts of pigments, without changing the structure of the leftover molecules. All these findings suggest that the new colored sugary line can be considered a new functional food, able to introduce healthy compounds into the diet of many people
Evaluation of genetic variation and relationships among tropical sweet corn inbred lines using agronomic traits
Get PDFGenetic variability and relationship of 13 tropical sweet corn inbred lines derived from different source popula¬tions were investigated using agronomic traits during three consecutive years. Non-significant effects of years and years-by-lines indicated the stability of performance of the inbred lines per se over years. Contrastively, the effects of inbred lines were significant for all traits measured, indicating great genetic variability in their perfor¬mance. Among the inbred lines, TSN-S8, TSK-S8, BAK-S8, MAN-S8, MMIN-S8 and TSG-S8 were found to be high yielding, with high husked fresh ear yield, dehusked fresh ear yield and number of ears per hectare, while DFS-S8 and TFZ-S8 were found to be superior for ear characteristics including husked ear length, dehusked ear length, number of kernel rows per ear and TSS. The high heritability estimates obtained from husked and dehusked fresh ear yields in this study indicate that the inbred lines have become homozygous at almost all the loci after eight generations of selfing. Husked fresh ear yield was phenotypically and genetically correlated with dehusked fresh ear yield, number of ears per hectare, husked and dehusked ear weights, dehusked ear length, husked and dehusked ear diameter, number of kernels per row and number of kernel rows per ear, indicating direct positive contribution of these traits to husked fresh ear yield. Visualizing the relationship among the inbred lines using singular value decomposition biplot analysis revealed that the inbred lines could be assigned into three distinct groups. This indicates a strong indication of the potential of the inbred lines for their utilisation towards production of new hybrid varieties by crossing the inbred lines from different groups. It can be concluded that the inbred lines studied varied substantially in many aspects, and these differences could be exploited for specific purposes in breeding programs
Agronomic traits associated with genetic gains in maize yield during three breeding eras in West Africa
Get PDFStudies on genetic gains in grain yield in maize (Zea mays L) is crucial to identify traits of potential value and the necessary modifications in breeding methodologies and strategies for increased progress in future breeding efforts. Fifty early-maturing maize cultivars developed during three breeding eras were evaluated for 2 yr in two field experiments involving 16 multiple stress (drought, Striga-infested, and low soil nitrogen) environments and 35 optimum environments to determine the changes in agronomic traits associated with the genetic gains in grain yield over three breeding eras. The average rate of increase in grain yield was 30 kg ha–1 yr-1 corresponding to 1.59% annual genetic gain across multiple stresses. Among the agronomic traits under stress, only ears per plant (0.32% year-1), ear aspect (-0.51% year-1), plant aspect (-0.24% year-1) and days to anthesis (0.11% year-1) changed significantly (
Effect of leaf area on maize productivity
Get PDFMaize (Zea mays L) leaves provide energy for growth and development. Increases in plant densities the past 75 years have contributed to increased maize grain yields. No recorded change has been observed in leaf area per plant during this period, but some change may have occurred. Plant density increases are associated with in¬creases in leaf area per-unit of land mass. Grain yield increases resulted from hybrids with improved tolerance to higher plant densities. Recently developed maize hybrids have upright leaves and smaller tassels allowing more light to penetrate the leaf canopy. Tolerance to increased plant density is directly related to intra and inter-plant shading plus changes in leaf area per plant may change leaf canopy structure. To evaluate the concept, maize leaf area affects grain yield, we developed high- and low leaf area hybrids. Objectives were to evaluate productivity of high and low leaf area maize hybrids at three high plant densities for two years. Averaged over three plant densities low leaf area hybrids produced significantly more grain than high leaf area hybrids. Low leaf area hybrids tolerated higher plant density better than high leaf area hybrids. Results indicate low leaf area hybrids are superior in several maize productivity traits
Indel and single nucleotide variations of zeins generate unique 2D-zein patterns and molecular markers useful in maize (Zea mays) genotyping
Get PDFIn this study, we investigated the inter- and intra-genomic sequence variation of alpha-zein genes and their polypeptide expression in different maize genotypes, i.e. inbreds and a set of Lombardy open pollinated varieties, by analyzing their RFLP, coding nucleotides and 2-dimensional (2D) protein fractionation profiles. An extensive analysis of coding capacity of alpha-zein sequences in various genotypes and in the B73 reference inbred allowed us to assign 2D-spots to specific zein sequences. Moreover, we found that some genes reported to contain in frame stop codons are very likely expressed. Collectively these data allowed us to constitute two barcodes respectively based on nucleotide variation and on 2-D protein patterns that identify univocally each genotype
A New aphid species (Hemiptera Aphididae) living on Centaurea from Iran
Get PDFMacrosiphoniella (Papillomyzus) iranica sp. n. (Aphididae Macrosiphini) is described from Iranian apterous viviparous females caught on Centaurea sp. and conserved in the Natural History Museum in London and in the Muséum national d’Histoire naturelle in Paris. The features of the new species are compared with those of the other 6 species of the subgenus Papillomyzus which are hosted on Centaurea and on other Cardueae, Cynareae or Anthemideae (Asteraceae) species and are distributed along a Mediterrean-Pontian-Turanian-East Palaeartic band
Increasing wood mobilization through Sustainable Forest Management in protected areas of Italy
Get PDFThe European Community has long recognized the need to further promote renewable energy. Under the overall objective to support and enhance sustainable management, the promotion of the use of forest biomass could help to mitigate climate change by substituting fossil fuel, increasing carbon stock in wood products and improve energy self-sufficiency enhancing security of supply and providing job opportunities in rural areas. To what extent Italian forests can satisfy an increased wood demand, without compromising the others Ecosystem Services (ESs) remains an open question. Our aim was to assess the potential supply of woody biomass from the network of protected areas in Italy considering the felling constraints. We estimated the theoretical annual potential increment from forest inventory data performing a correlation with the Corine Land Cover 2006 at the IV level with a 1:100,000 resolution elaborated in a GIS (Geographic Information System) environment. The average annual potential increment at national level available for felling was 4.4 m3ha-1. Within the network of protected areas (EUAP and Natura 2000), the average annual increment, available to felling, was 0.98 m3ha-1, respectively, 0.81 m3ha-1 from coppice and 1.14 m3ha-1 from non-coppice forests. Based on data obtained from this study, the availability of wood materials could be increased of almost 20 % at national level by pursuing an active management within the network of protected areas. In Italy, the actual level of resource utilization is rather low; increasing felling together with the implementation of an active management within protected areas could allow satisfying, theoretically, the Italian wood consumption
First record from Greece of the invasive red gum lerp psyllid Glycaspis brimblecombei Moore (Hemiptera Psyllidae) and its associated parasitoid Psyllaephagus bliteus Riek (Hymenoptera Encyrtidae)
Get PDFThe occurrence of the invasive pest red gum lerp psyllid Glycaspis brimblecombei Moore (Hemiptera: Psyllidae), infesting Eucalyptus camaldulensis Dehnh. (Myrtaceae), is reported for the first time from mainland Greece and the Ionian island of Corfu. This species, native to Australia, has been first reported for the Palaearctic Region in 2008, when it has been recorded from the Iberian Peninsula, subsequently spreading to other Mediterranean countries. Updated information on geographical distribution is provided. Association with its specific antagonist Psyllaephagus bliteus Riek (Hymenoptera: Encyrtidae) was also observed and level of parasitism was investigated. The spread of P. bliteus in Greece is due to an accidental introduction, probably together with its host, as already happened in New Zealand, Brazil, Spain, Italy and Morocco