CREA Journals (Consiglio per la ricerca in agricoltura e l’analisi dell’economia agraria)
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PRELIMINARY RESULTS ON THE SPATIO-TEMPORAL VARIABILITYOF GLYCASPIS BRIMBLECOMBEI(HEMIPTERA PSYLLIDAE) POPULATIONSFROM A THREE-YEAR MONITORING PROGRAM IN SARDINIA (ITALY)
Get PDFThe red gum lerp psyllid Glycaspis brimblecombeiis an invasive insect species worldwide. Prolonged attacksby this psyllid may cause both direct and indirect damages to Eucalyptustrees, such as plant weakening, developmentalreductions and phylloptosis, resulting in death within 2-3 years. After the first report in Campania (Italy) in 2010 onEucalyptus camaldulensis trees, it quickly spread to all surrounding central-southern regions of Italy. In Sardinia, G.brimblecombeiwas first recorded in 2011, and is currently found throughout the island. From 2013 to 2015 amonitoring program was carried out in 11 locations throughout Sardinia in order to estimate the density pattern of bothits adults and preimaginal stages, as well as the general population trend of G. brimblecombeiover the years. Ananalysis of G. brimblecombei population abundance showed an almost stable level of infestation over the years, and aseasonal pattern with a population peak in the summer. However, an earlier peak of population abundance was detectedin 2015 compared to the previous years. A spatial heterogeneity of the level of infestation was observed throughout theisland, highlighting the potential effects of environmental conditions in regulating the populations of both G.brimblecombeiand its natural enemies
INSECT PESTS OF EUCALYPTUSPLANTATIONS IN SARDINIA (ITALY)
Get PDFIn Sardinia (Italy), Eucalyptusplantations cover approximately 23,000 hectares, above all in the southern part ofthe island. There is a complex of phytophagous insect pests that is threatening the health status of Eucalyptustrees. Themost recent invasions include the sap-suckers, Glycaspis brimblecombei, Blastopsylla occidentalis, and the bronze bug,Thaumastocoris peregrinus. Other pest species have also been reported, including the gall wasps, Ophelimus maskelliand Leptocybe invasa, the longhorn beetles, Phoracantha semipunctataand P. recurva, and the weevils, Gonipterusscutellatusand Polydrusus(= Metallites) parallelus. Defoliation caused by the gypsy moth, Lymantria dispar, have alsobeen frequently observed in various Eucalyptus-planted areas of Sardinia
Topcrosses in the selection of testers and inbred lines S3 for the yield and bromatological quality of silage maize.
Get PDFThe study aiming to evaluate the combining ability of maize partially inbred lines (S3) in crosses with testers ofnarrow genetic base aiming at the selection of the inbred lines, testers and topcross hybrids. Three simple latticetrials with 81 treatments were carried out in the 2014/2015 and 2015/2016 growing seasons. For each growingseason, trials were used to evaluate the topcross hybrids obtained in combination with the testers AG8088,DKB330 (single-cross hybrids) and 9.H33.3 (line). The hybrid AG8088 and line 9.H3.33 were the best testers forgrain yield. The line 9.H3.33 was the best tester for the traits related to yield and quality of silage maize. Theinbred lines that stood out for their combining abilities and capacity of generating great topcross hybrids with thetesters (i.e., 201-23.2, 201-59.1, 201-80.2, 201-81.5, 203-195.3, 201-100.4, 201-145.4, 201-169.3, 202-155, 202-159, 203-23, 203- 31, 203-32, 203-38, 203-75, 203-98, 203-111, 203-135, 203-139, 203-150, 203-188, 203-235,and 203-237) should be maintained in the UEM silage maize breeding program. Progenies 201-59.01, 201-100.4,203-135, 203-150, 203-235 and 203-254 were selected as tester lines of progenies derived from selfing of thetesters AG8088 and DKB330 to improve the silage maize quality. The topcross hybrids 201-95.3 x 9.H3.33, 203-71x 9.H3.33, 203-72 x 9.H3.33, 203-88 x 9.H3.33, 203-139 x 9.H3.33, and 203-150 x 9.H3.33 were selected for goodperformance for agronomic and bromatological silage maize traits. These hybrids are indicated for evaluationsin more environments, with a view to recommending commercial cultivars for grain and silage production in thefuture
QTL analysis for yield-related traits under different water regimes in maize
Get PDFDrought is one of the most essential factors influencing maize yield. Improving maize varieties with drought tolerance by using marker-assisted or genomic selection requires more understanding of the genetic basis of yield-related traits under different water regimes. In the present study, 213 F2:3 families of the cross of H082183 (drought-tolerant) × Lv28 (drought susceptible) were phenotyped with five yield-related traits under four well-watered and six drought environments for two years. Quantitative trait loci analysis identified 133 significant QTLs (94 QTLs for ear traits and 39 QTLs for kernel traits) based on single environment analysis. The joint-environment analysis detected 25 QTLs under well-watered environments (eight QTLs for ear length, eight for ear diameter, one for ear weight, two for kernel weight per ear, and six for 100-kernel weight), and nine QTLs under water-stressed environments (two QTLs for ear length, three for ear diameter, one for ear weight, one for kernel weight, and two for 100-kernel weight). Among these joint-environment QTLs, one common QTL (qEL5) was stably identified at both of the water regimes. Meanwhile, two main-effect QTLs were detected in the well-watered environments, i.e. qEL10 for ear length and qHKW2 for 100-kernel weight. Also, qED8, qEW8, and qKW8 were found to be located in the same interval of Chr. 8. Similarly, qEL4s and qKW4s were found to be located in the same interval under water-stressed environments. These genomic regions could be candidate targets for further fine mapping and marker-assisted breeding in maize
Forest tree Marginal Populations in Europe - Report on the state of knowledge on forest tree marginal and peripheral populations in Europe
Get PDFMarginal/peripheral (MaP) forest populations exist at the edge of species ranges, and may contain unique genetic diversity arising from adaptation to the adverse and unusual in the regions which they inhabit. The effects of climatic and other global changes are likely to be increasingly significant, and will affect forest tree species and their marginal populations.Studying adaptive processes in MaP populations is crucial and of mutual interest for European and non-European countries to understanding the evolution of species, and for the development of forest genetic resources (FGR) conservation, management strategies, and networks to cope with global change.These populations are threatened not only by global warming, but by various other threats arising from human activities. Because of their millennia-long history of adaptation to environmental changes, FGR growing in Europe may prove invaluable for adapting the forestry sector
Marginal/peripheral populations of forest tree species and their conservation status: report for southeastern Europe
Get PDFThe Southeastern Europe, which is usually known as Balkan Peninsula, harbours a vast number of plant species among which a great number of relict and endemic ones. This region was one of the main areas in Europe where plant species found shelter in refugia and survived during the last glaciation. These refugia were the source areas for the postglacial colonization of many forest tree species. Human impact has been reported in the region since antiquity resulting in fragmentation of forests and deforestation. Marginal/peripheral (MaP) populations could be identified for most of the forest tree species occurring in the region. However, detailed information about MaP populations is restricted to few cases. Most of the MaP populations identified by FP1202 experts are not located in protected areas. Thus, approximately 27 % of the MaP populations are included in Natura 2000 sites, and only one out of the four reported populations is included in a genetic conservation unit. Many MaP populations (40%) are registered as seed stands and only 14% are included in EUFGIS database. Conservation of forest genetic resources, including MaP populations, is a component of sustainable management of forests in many countries of the region
MACROINVERTEBRATES OF ITALIAN MOUNTAIN LAKES: A REVIEW
Get PDFThe paper summarizes the state of knowledge and the evolution of the researches on benthic macroinvertebrates ofItalian mountain lakes, and identifies key aspects that need to be further explored. Mountain lakes have been investigatedsince the end of the XIX century. In the beginning, studies focused mainly on their geography, geology, geomorphologyand hydrology. Only lately, interests arise on their hydro-chemistry and biology, in relation to water acidification and, inrare cases, to eutrophication. In particular, in the 1920s, the studies dealt mainly on lake basins morphology and theirgenesis. Later, researches were driven mainly by the growing need of hydroelectric power plants, shifting the attention ontheir hydrological and geological aspects. Nonetheless, more detailed limno-biological studies began in confined areas.During the 1960s, attention was redirected to the alpine environment in terms of environmental awareness, for the creationof parks, and to analyse the alteration of water quality caused by the deposition of transported pollutants from thelowlands. This created the opportunity to combine observations on both the hydro-chemical and biological aspects, toreach a synoptic view of these environments. It is only in the mid-1990s that ISI journals came to power and, striving forhigher visibility, strongly promoted the production of papers. In this decade, the application of paleo-limnology, thecreation of a long term ecological research network, the never abandoned idea of implementing best practice managementfor freshwaters conservation purposes, and the growing attention on the global climatic change gave new impulse to thestudies on mountain lakes. Since the 2000s, biodiversity preservation, biological recovery, environmental key-drivers(mainly nitrogen increase) have become the new focus of the current research activities
Determinants of drought tolerance at seedling stage in early and extra-early maize hybrids
Get PDFAdequate knowledge of response of genotypes to stress and identification of important adaptive traits under stress conditions facilitate rapid progress in a breeding program. The objectives of this study were to evaluate the response of early and extra-early maturing maize hybrids to drought stress imposed at seedling with a view to identifying tolerant hybrids for further breeding studies and identify adaptive traits that could be used as selection criteria for tolerant maize genotypes at this growth stage. This study was conducted in the screenhouse in the Faculty of Agriculture, Obafemi Awolowo University, Ile-Ife, Nigeria. Five seedlings each of 15 hybrids each from early- and extra-early-maturity groups were raised in pots and the pots were arranged in a randomized complete block design with three replicates. The experiment was adequately watered for the first seven days and thereafter watering stopped. The plants were observed for 42 days and data were recorded on emergence and other seed- ling traits. Data collected were subjected to analysis of variance, principal component analysis and correlation analysis. Results showed significant difference between maturity groups for root length and significant difference among genotypes within maturity were obtained for total number of leaf shed, moisture content of root, fresh shoot weight, total fresh biomass and seedling aspect, indicating there was wide variability in the response of the genotypes from the different maturity groups for tolerance to drought at seedling stage. Principal component analysis also identified these traits as the primary traits contributing to diversity among the hybrids under induced drought at seedling stage. Results of correlation analysis showed differential association among traits of early and those of extra-early maize, indicating that mechanism of tolerance to drought in the two maize maturity groups are different. It was concluded that early and extra-early maize hybrids responded differently under drought stress imposed at seedling stage and that seedling stage total number of leaf shed, moisture content of root, fresh shoot biomass, and total fresh biomass were important drought adaptive traits and the traits should be included in computing base index for selecting drought tolerant maize at seedling stage
The Critical period for weed control in spring maize in North-West India
Get PDFSpring maize is becoming popular in Punjab state owing to its higher yield potential and is a new introduction. A field experiment was conducted at Punjab Agricultural University, Ludhiana with 12 treatments viz. crop kept weedy for 20, 30, 40, 50, 60 DAS, crop kept weed free for 20, 30, 40, 50, 60 DAS, weed free throughout and weedy check. The weed density showed a linear progression as the weedy interval was increased from 30 to 40 days, 40 to 50 days and 50 to 60 days. The results showed that yield attributes and grain yield declined with the increased duration of crop- weed interference period and increased with long weed free durations. Significant reduction in grain yield was recorded with increased weed infestation from 30 to 60 DAS, however, the differences observed between 20 and 30 days weedy were statistically at par. This suggested the tolerance of weed interference up to 30 days in spring maize. The 60 days weed free treatment resulted in grain yield statistically same with that of weed free throughout but significantly better from all other weed free duration treatments. This marked the end of critical period of crop-weed competition in spring maize. A significant negative linear correlation was observed for weed biomass and grain yield. The critical period of crop-weed competition in spring maize started at 30 DAS and ended at 60DAS. This period needs immediate attention for the adoption of weed control measure
Measurement of cell membrane thermo-stability and leaf temperature for heat tolerance in maize (Zea mays L): Genotypic variability and inheritance pattern
Get PDFThe rise in ambient temperature is intimidating sustainability of maize productions worldwide. To overcome heat stress effects, identification of potential genotypes and knowledge of inheritance pattern is necessary for developing thermo-tolerant cultivars. This investigation, consisted of four experiments, was conducted for assess- ing genetic variation followed by developing and evaluating breeding material in non-stressed and heat-stressed environments. The first experiment concerning reproductive stage heat tolerance comprised one hundred maize inbred lines, was conducted at mean day/night temperatures of 33°C/19°C (field) and 40°C/23°C (plastic tunnel), respectively. Variance analysis of absolute and relative data for leaf temperature and cell membrane thermo- stability revealed statistically significant (P ≤ 0.01) genotypic variations. In second and third experiments, one heat tolerant (ZL-11271) and one susceptible (R-2304-2) lines were selected and crossed in a generation mean fashion to develop non-segregating (P , P , F ) and segregating (BC , BC , F ) plant populations. The fourth experiment
involved appraisal of six basic generations in a factorial randomized complete block design replicated thrice with
mean day/night temperatures of 33°C/20°C and 39°C/24°C. Data on leaf temperature and cell membrane thermo- stability recorded at reproductive phase were analyzed in a nested block design which suggested involvement of digenic epistatic interactions in controlling inheritance of both these traits. Generation variance analysis, however, revealed predominance of additive genes supported by higher estimates [> 60%] of broad sense and narrow sense heritability (F
and F ). Future progress in plummeting leaf temperature and cell membrane thermo-stability of plant material is achievable through hybridization and rigorous selections in succeeding generations