CREA Journals (Consiglio per la ricerca in agricoltura e l’analisi dell’economia agraria)
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First record of the invasive Siphonatrophia cupressi (Swain) (Aphididae Aphidini Aphidina) in the Iberian peninsula.
Get PDFSiphonatrophia cupressi Swain, 1918 has been caught for first time in the Iberian Peninsula in the Arboretum and Botanical Garden of Lleida. Small colonies with apterous and alate individuals were recorded on Cupressus macrocarpa Hartw. The aphid was mainly associated to the as native parasitoid Lysiphlebus testaceipes Cresson, which enhances the role of this parasitoid in potentially preventing outbreaks of the new immigrant aphid species
Molecular diagnosis of Bursaphelenchus xylophilus (Steiner & Buhrer) Nickle (Nematoda Aphelenchida Parasitaphelenchidae) in presence of polyphenols and other inhibitory compounds.
Get PDFThe pine wood nematode Bursaphelenchus xylophilus (Aphelenchida Parasitaphelenchidae) infects conifers, in particular pines, causing pine wilt disease. This nematode is considered a quarantine organism according to the EPPO and AQISQ guidelines. For this reason, several procedures for an affordable diagnostic test have been developed based on LAMP technique. In this work we shown how this technique behaved in presence of compounds that exert an inhibitory effect on DNA polymerases, a common problem that could be found in DNA preparations obtained from samples included in plant matrixes LAMP technique was found able to detect presence of its specific DNA target in almost all cases studied but we found that the addiction of polyphenolic compounds present in some woody matrixes to DNA preparations could affect significantly on the sensibility of diagnostic test, while resinous material had a lesser influence on amplification
Potential impact of Entomophaga maimaiga Humber, Shimazu, and Soper (Entomophthorales Entomophthoraceae) on the lepidopteran fauna inhabiting cork forests in Sardinia (Italy).
Get PDFPeriodic outbreaks of forest defoliators like the gypsy moth cause severe impact to the forest ecosystem, which is normally counterbalanced by the action of their natural enemies, including predators, parasitoids, and entomopathogens. Among the latter, the host-specific fungus Entomophaga maimaiga can be very effective under favourable conditions. Whilst its close evolutionary relationship with gypsy moth, this entomopathogen has never been detected in certain forest areas where L. dispar is a common pest. The results of three years laboratory assays with two different strains of E. maimaiga from Bulgaria and Croatia against Lepidopteran species inhabiting cork oak forests in Sardinia are reported. Significant toxicity and virulence against gypsy moth larvae exposed to soil contaminated with resting spores of the fungus was detected for both strains, even if the strain from Bulgaria was significantly more effective. Significant lethal effects were observed also on M. neustria larvae, but a successful development and reproduction of the fungus within insect cadavers was detected only in the gypsy moth. No significant effects were observed on other Lepidopteran species. Given a proper choice of candidate strains, the introduction of E. maimaiga in Sardinia, to manage the disruptive action of the gypsy moth would be desirable
Pathogenic and molecular characterization of Fusarium moniliforme Sheld, the incitant of Fusarium maize stalk rot in the Punjab State of India
Get PDFFifty six isolates of Fusarium moniliforme collected from different maize cultivars grown in various regions of Pun- jab were characterized for their pathogenic variation and molecular diversity. Based on the multivariate cluster analysis of pathogenicity data, seven clusters were formed, each representing a specific disease reaction to a par- ticular maize hybrid/inbred line used in this study. The isolate Fm 10 was found the most virulent with an average disease index (ADI) of 66.6% whereas, Fm 45 was found least virulent with ADI of 42.5%. The sub-mountaneous undulating region of Punjab represented maximum percentile of least virulent isolates, however, undulating plain region of Hoshiarpur and Shaheed Bhagat Singh Nagar district of the State represented the most virulent zone of F. moniliforme isolates. Genetic diversity in the Punjab populations of F. moniliforme was studied using twenty random amplified polymorphic DNA (RAPD) markers, out of which 18 showed amplification with a total of 220 amplified fragments. Primer OPT-12 was found to be highly polymorphic with PIC value of 0.913 while OPT-9 was least polymorphic. The size of amplified DNA fragments ranged from 0.1-2.0 kb. Dendrogram based on molecular data generated by 18 RAPD primers showed six clusters with similarity percentage ranging from 36 to 96% and one independent lineage with 26% similarity coefficient. No correlation was obtained between the genetic diversity and pathogenic variation; however the latter was influenced by agro-climatic zones of north-western India. This was the first attempt to study the genetic diversity of F. moniliforme causing Fusarium stalk rot of maize in Punjab
Genetic diversity analysis of elite maize inbred lines of diverse sources using SSR markers
Get PDFGenetically diverse and complementary elite inbred lines are fundamental for hybrid maize breeding or for stra- tegic conservation. The objectives of this study were to determine the genetic diversity present among 79 elite maize inbred lines collected from five different sources using 30 SSR markers and to identify unique genotypes for breeding. The mean numbers of observed and effective alleles were 4.7 and 2.4 per marker, respectively. The polymorphic information content (PIC) of the 30 SSR markers ranged from 0.01 to 0.92, with a mean of 0.51. Six markers: phi 031, phi 308707, phi 96100, phi 114, phi 299852 and phi 063 revealed the highest PIC values greater than 0.70 suggesting the potential of these loci for genetic diversity analysis. The mean value of total gene diversity was 0.51 which partitioned 72% among inbred lines, 26% within inbred lines and 7% was attributed to variation between the five sources. Cluster analysis allocated the inbred lines into three main genetic groups. The principal coordinate analysis explained 67% of the total genetic variation detected among inbred lines and separated them into two main clusters. The study identified elite maize inbred lines such as TL2012-2, TL2012-14, TL2012-20, TL2012-31, TL2012-54 and TL2012-55 from Cluster I; TL2012-6, TL2012-35, TL2012-53 and TL2012-75 from cluster II; TL2012-12, TL2012-27, TL2012-29 and TL2012-58 from cluster III with marked genetic differences for hybrid breeding to exploit heterosis
Genetic variability within accessions of the B73 maize inbred line
Get PDFThe maize inbred line B73 has been extensively studied at the molecular level. Researchers now have access to the genome sequence of B73 as well as to databases of biallelic and multiallelic markers where functional poly- morphisms between B73 and a public inbred line population can be compared to relate genotypes to phenotypes. This indicates the importance to determine the genetic fidelity of the germplasm during preservation and propa- gation processes, in particular, when seeds of reference inbred lines such as B73 are maintained. The aim of this study was to assess the genetic uniformity among three different sources of the B73 inbred line by means of 75
Simple Sequence Repeats (SSRs). The three B73 sources showed homozygosis; however, some accessions dif- fered greatly from the expected locus size predicted at the reference B73 genomic sequence. A particular haplo- type was prevalent in the USDA accession PI550473. The error rate of the allele size determination was estimated. The genotyping technique used in this work allowed the separation of alleles of ± 2 bp range difference within the same electrophoresis run, whereas allele size estimations between experiments, within the laboratory, differed in
± 4 bp range difference. Besides experimental errors in genotyping, the putative cause of differences among ac- cessions could be attributed to seed contamination and genetic drift. The B73 accessions evaluated in our work can be shared among laboratories to precise genotyping and phenotyping of maize inbred lines
Genetic contribution to maize yield gain among different locations in China
Get PDFMaize (Zea mays L) yields have increased as the result of new hybrids and improved agronomic practices. Climatic factors markedly influenced maize growth and grain yield. The objectives of this study were to i) analyze changes in maize yield with genotype and agronomic-management improvement in different locations, and ii) assess the contributions of genotype, agronomic management, and genotype × agronomic management to maize yield gain between locations. Maize yield respectively increased 8.81 t ha-1 in Changji, 7.14 t ha-1 in Gongzhuling, and 7.98 t ha-1 in Xinxiang, from the 1950s to 2010s. In the three different growing sites, the contributions to yield gain were estimated 41.72 - 62.74% for genotype, 23.1 - 34.74% for agronomic improvement, and 10.6 - 29.89% for the combined effects of genotype × agronomic management. The contribution of genotype to yield gain was highest in Xinxiang at > 60%. The relative yield gain ratios of the three locations were Xinxiang > Gongzhuling > Changji considering genotype and cultivation improvement since the 1950s. The high contribution of genotype and relative yield gain ratio in Xinxiang may have resulted from Xinxiang having the lowest basic yield in the 1950s, and new hybrids having enhanced adaptability in the area. It suggested that breeding for improved adaptation to different environments is required in order to continue increasing maize yield in China
Evaluating testcross performance and genetic divergence of lines derived from reciprocal tropical maize composites
Get PDFThe development of hybrids with enhanced expression of heterosis depends on the genetic background of the source population and the effectiveness of a breeding scheme used to identify and use divergent inbred lines with good combining ability. The present study was conducted to examine the potential of improved tropical reciprocal
composites as sources of inbred lines for developing productive hybrids. Thirty-six S
lines derived from the third
RRS cycle of each composite were crossed in pairs to form 36 testcrosses, which were evaluated along with com- monly grown commercial hybrids in Nigeria across nine test environments. Results showed consistent ranking of testcrosses for grain yield and other traits across the diverse test environments. The best 22 testcrosses produced
21% to 51% more grain yields than the highest yielding commercial hybrid. Several testcrosses combined high grain yields with other desirable agronomic traits. The SSR and SNP markers used in the present study detected a
broad range of genetic diversity among the 72 S
lines, which was structured along the two composites. The two
markers portrayed similar trends in determining genetic distance estimates and detecting composite-specific al-
leles in the S
lines. These results highlight the potential of improved reciprocal composites as sources of new and
divergent parents for developing productive hybrids and as sources of novel alleles for broadening and diversifying the genetic base of adapted germplasm to sustain genetic gain in productivity of hybrids in WCA
Volume function for the tree farming English oak plantations of the Valdarno (Tuscany, Italy)
Get PDFIn the past centuries a notable reduction of lowland forests in Italy was detected as a result of the spreading of intensive agriculture and deforestation activities. According to the national forest inventory (INFC 2005) the English oak (Quercus robur L.) is mainly a scattered species and is distributed across 146,000 hectares of mixed forests. However this species has often been used in many national programs to recreate new woodlands in the lowlands as well as tree farming plantations. In the '80s, during the restoration program of the Santa Barbara mining area in the Municipality of Cavriglia (Valdarno, Tuscany), about 172 hectares of tree farming plantations were created with English oak. Due to the lack of a specific volume equation for Italian plantations a sampling campaign was carried out. The volume of 299 sample trees was measured using the Heyer formula and a volume equation was studied as a polynomial function of DBH and total height of trees. The final equation demonstrated to be quite robust with a RMSE of 0.0176 m3 corresponding to a relative RMSE of 10%
First report of Gonipterus scutellatus complex (Coleoptera Curculionidae) in Sicily (Italy).
Get PDFDuring August 2015, the weevil Gonipterus scutellatus complex (Coleoptera Curculionidae), a pest of Eucalyptus spp., was found for the first time in Sicily. According to our surveys, Eucalyptus globulus was the only infested tree species