CREA Journals (Consiglio per la ricerca in agricoltura e l’analisi dell’economia agraria)
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Comparison of dynamic changes of endogenous hormones between calli derived from mature and immature embryos of maize
Get PDFMature and immature embryos of maize inbred lines 87-1 and 137 were used as explants to induce callus on
improved N6 medium. The contents of endogenous hormones abscisic acid (ABA), indoleacetic acid (IAA), gibberellic
acid (GA3) and cytokinins (ZR) of immature, mature embryos and their corresponding calli were detected
by method of enzyme-linked immunosorbant assay (ELISA). At the beginning of culture, IAA and GA3 levels decreased
rapidly and reached their lowest levels at day 7, indicating that large amounts of IAA and GA3 are needed
for germination. Levels of IAA and GA3 were highest at the beginning of embryonic callus formation from immature
embryos, suggesting high levels of IAA and GA3 were beneficial to induction of embryonic callus from immature
embryos (CIME). The IAA, GA3 and ABA contents and ration of IAA to ABA (IAA/ABA), GA3 to ABA (GA3/ABA) in
callus of mature embryos (CME) were higher than those of CIME after the 14th day from culture initiation and the
changes of ratios IAA/ABA and GA3/ABA increased rapidly in CME while they remained low in CIME during the
whole experimental period. This inferred that high levels of IAA, GA3 or ABA and large increases in IAA/ABA and
GA3/ABA might hinder the induction and maintenance of embryonic calli from mature embryos
Development and characterization of a core set of SSR markers for fingerprinting analysis of Chinese maize varieties
Get PDFA core set of 60 SSRs was selected and modified using 231 Chinese and USA maize (Zea mays L.) inbred lines
from more than 2000 SSRs for DNA fingerprinting analysis. All 60 SSR markers met the following criteria: (1) amplification
of a single locus; (2) distinct amplification products; (3) adequate intervals between adjacent alleles; (4)
suitable PCR fragment size; (5) reasonable discrimination power (DP); and (6) even distribution across the maize
genome. Furthermore, the 60 SSR primers were re-designed to adjust the PCR product size. Together with the
application of four different fluorescent dyes, a high-throughput 10-plex capillary electrophoresis platform was
explored. The 60 core SSR markers were further divided into three groups (20 SSRs per group) according to
peak morphology and DP value. Groups I, II and III were used in DNA fingerprinting analysis as a basic core, an
expanded core and a candidate core set respectively. The allele number per locus varied from three to 22 with an
average of 8.95; the average number of alleles per group I, II and III was a respective 7.35, 7.8 and 11.4. The DP
values ranged from 0.366 to 0.913, with an average of 0.718 among all loci; the average group DP values were
0.697, 0.718 and 0.737 for groups I, II and III respectively; and the cumulative values of discrimination power (CDP)
approached 1 for all groups. Cluster analysis results using 60 selected loci divided the Chinese inbred lines into six
groups, including Luda Red Cob, P, Improved Reid, Tang-si-ping-tou, Waxy and Lancaster. The USA inbred lines
were segregated into four groups, including SSS, Lancaster, Iodent and Oh43/Oh07Mid mixed
Silvicultural and phytosanitary researches in thinned chestnut coppices at different elevations in Sila (Calabria)
Get PDFThe results of mensurational and phytosanitary researches ten years after thinning trials in chestnut coppices (Castanea sativa Miller) in Sila, are reported.. Eight experimental areas, four located at an average elevation of 1200 m a.s.l. aged 20 yrs and four located on average at 1050 m a.s.l. aged 13 yrs, were compared. Three sub-plots were installed in each area and mensurational and phytosanitary surveys were carried out in 1997 (before and after thinning trials) and ten years later (2007) on 30 stools per sub-plot to assess bio-ecological, structural and compositional status of the standing crops. At each elevation, the experimental protocol included the following theses: thesis T (control: release of the standing crop and removal of dried up stems on the ground, only); thesis A (light thinning: removal of the dominated storey, on average 30% of coppice shoots, poorly shaped, both withered and green); thesis B (moderate thinning: removal from the dominated up to the dominant storey = 43% of the shoots, both dried up and green); thesis C (heavy thinning: removal = 62% of coppice shoots, both withered and green). Results highlighted the significance of thinnings in the cultivation of chestnut coppices. As for silviculture and growth pattern, the surveying ten years later showed the following outcomes: reduction of shoots mortality, according to the thinning intensity from A to C (by comparing the number of dried up coppice shoots surveyed in the control theses); a higher number of coppice shoots in the commercial category “average stems” in the thinned plots; the higher percentage increment in dbh, basal area and volume in the sub-plots undergoing thinning A and C at the elevation of 1050 m and, in general, with thesis C at both elevations; the complete recovery of canopy cover even in the sub-plots heavily thinned. As for the phytosanitary aspects, the research has been oriented on the chestnut blight caused by Cryphonectria parasitica, due to the lack of symptomatology of “ink disease” in the sub-plots, even though present on the same territory. The hypovirulence is predominant and steady with time for the high presence of healing and healed cankers. Among the factors of coppice shoots mortality, blight plays a minor role here. The disease spreads regardless of thinnings and silviculture can operate therefore independently to get a wide range of assortments, from poles to timber. Basically, thinning release has to ensure the predominance and steady presence of hypovirulence in the chestnut stands. In this way, foci for the natural spreading of hypovirulent strains are being created and preserved. This seem to be a basic tool to ensure a phytosanitary equilibrium between the parasite and the host in chestnut coppices, which still represent an important economic resource in Calabria as well as in several other Italian regions
Effects of silvicultural treatment on the stability of black pine plantations.
Get PDFBlack pine plantations have been established at the purpose of recovering a forest cover to marginal soils, mostly throughout the Apennines range in Italy, since the end of the eighteenth century and up to the mid 1900. Both the decay of forest cover and soil erosion were the outcome of the long-lasting overuse through the intensive forest exploitation practices, grazing of the forest floor and wildfires, occurring since many centuries ago. The primary function of pine reafforestation was therefore to re-establish a first cover with a pioneer species, preparatory to future mixed forest types based on the natural reintroduction of broadleaves originally living in the same areas, mainly deciduous oaks and beech in the upper part. These goals have been partly met over the wide reafforestation area; the key functions of pine stands are today the protection against soil erosion and the hydrological regulation of catchments. The pine stands have been assuming today also a scenic role because they have been incorporated in the landscape physiognomy. A series of thinning up to the regeneration phase had been planned by foresters since the design of these plantations, but many stands have grown unthinned and fully stocked for a long time, this condition contributing a less mechanical stability of trees. Alternative forms of regeneration in grown-up stands have been and are being tested to improve both the natural and artificial establishment of indigenous species, but thinnings remain, even if a tardy measure, the main practice enforceable to these pine forests. The results of experimental trials undertaken in the black pine forest stand located in Pratomagno casentinese (Arezzo) are being reported in the paper. The study started in 1978 and the following theses were tested (A) heavy thinning from below; (B) moderate thinning from below; (C) control. Three thinnings were carried out in 1978, 1999 and 2009 at the ages of 24, 45 and 55. The action over time of each intervention on the mensurational and mechanical stability parameters (H/D ratio H/Ddom ratio), are being analyzed. The stability parameters of the pine forest after three interventions (H/D ratio, crown ratio, horizontal crown projection and eccentricity of the crown) have been also analyzed on a sample of trees per thesis and compared with those of trees grown in absence of competition. Sampled trees were sorted per social class. Results proved that type, interval and intensity of thinning related to the age of intervention are the main determinants of a successful treatment. Thinnings from below increase individual stability over time only when also trees living in the main crop layer are being removed. The trials showed the improvement of stability parameters following the intermediate thinning applied at the age of 45. The thesis of heavy thinning had the best performance as for the awaited purpose
The Turkey oak high forests in the Molise region (central Italy). Analysis of past silvicultural system and current management choices.
Get PDFAim of the work is to provide further knowledge on the silvicultural system applied to Quercus cerris hight forests in the Molise Region (Central Italy). An historical analysis, based on a number of forest management plans applied since 1940 referred to 19 municipalities and on other historical documents, is provided in the paper. Forest management has been traditionally applied in the Molise Region and therefore is at now possible to reconstruct in detail the management of the forests of Molise Region. The historical study has been integrated with the analysis of a chronosequence including four steps of stand development in a Turkey oak stand: the regeneration phase (1-2 yrs) - the unthinned young stand (46 yrs) - the unthinned adult stand (aged 60 to 100) - the mature stand (126 yrs). Mensurational surveys were carried out at each phase in order to characterize both stand structure and derive information on the silvicultural practices applied in the past, but not documented in the available papers. The stand age was determined by tree coring and count of annual rings. At the beginning of the last century, the silvicultural system to be applied in oak high forests wasn’t strictly defined and a particular kind of selection cutting was carried out. It was named taglio a salto per sezioni i.e. “compartment selection cutting”, partly leading back to a real selection cutting, partly to a shelterwood system. The use of the reported silvicultural system gave rise to irregular forest structures and led to management problems well-described in the management plans at the end of 1940s. Another consequence of the applied practices was the absence or the inadequate natural regeneration establishment. The contemporary unregulated practice of grazing the forest floor contributed to the unsuccessful regeneration and made the situation worse. The presence of an understorey layer made up by sproutings from Carpinus betulus stools clearcutting, was a further hindrance to the establishment of natural oak regeneration. In the fifties, the rate of forest management increased as a consequence of the coming up economic concern in sleeper production. The silvicultural shelterwood system was therefore codified. The system resulted to be more effective and adopted up to the present time. The traditional shelterwood system was based on a 90 yrs rotation length, three thinnings performed from the age of 25 up to 75, time of the seed cutting with a release of 90 trees per hectare. In the seventies, following the much more reduced and even null concern in wood production from oak high forests, practices into the same forests were suspended or postponed. At now, the renewed concern for fuelwood production, the only assortment marketable, as well as the increased attention paid to the multifunctional role of these forests, made again actual the problem of oak high forest management. The effectiveness of shelterwood system is the main outcome of the documental analysis performed. The study of the Carovilli’s chronosequence confirmed the close link between the current stand structures and the prescribed rules adopted in the past, in accordance with the management plans. The experimental trials in progress are now focused at defining an improvement of the shelterwood system practice as for the following issues: reduction of cutting areas; establishment of a more complex structural mosaic at neighbouring forest patches, setting up of a consistent release of seed trees i.e. number and dendrotypes to be selected at the purpose, with a special care to the crown cover to the forest floor, effective control of the understorey development due to the resprouting of Carpinus betulus stools, to enhance the establishment of oak natural regeneration
Effect of the silvicultural treatment on canopy properties, litter and seed production in beech coppices under conversion to high forest.
Get PDFEuropean beech (Fagus sylvatica L.) is widely distributed in Italy where it covers 1035103 ha, mainly concentrated in the mountainous areas at altitudes above 900 m. The major part is represented by high forest often issued from the conversion of coppice woods, which in the past was the silvicultural system most widely applied mainly to provide fire wood. The social changes occurred in the second half of the last century –fire wood market crisis and the increasing importance of environmental issues- enhanced the conversion into high forest of large areas previously managed as coppice by means of different silvicultural treatments and practices. Nevertheless, the environmental benefits of this choice were not adequately investigated. Results of annual measurements (1992-2009) made in a beech coppice stand aged 65 are here reported. The study area is located on the Alpe di Catenaia, a pre-Apennine outcrop close to Arezzo (Central Italy). Variables strictly related to stand productivity and dynamics such as annual litter and seed production, leaf area index (LAI) and transmittance (PAR) were measured in the research area of Buca Zamponi to estimate the effects of two theses, natural evolution (TEST) and conversion into high forest (DIR). Three thinnings were undertaken in the latter thesis in 1972, 1987 and 2002. Additional theses of natural evolution (CONTR) and advance seed cutting (TS) were added in 2002 in a nearby study area (Eremo della Casella). Results showed the high productivity of coppice stands, under conversion to high forest, with mean values of annual total litter, leaf litter and leaf area index of 5 Mg ha-1, 3 Mg ha-1 and 6 m2m-2, respectively. These findings confirm both the prompt response of beech to intensive thinning cycles and the reliability of undertaking coppice conversion into high forest. Furthermore, the positive trend observed in the ecological parameters and the high consistency of leaf fraction, highlight the still juvenile phase in progress in these stands. These results will be investigated further because of their significance in stands aged over 60. The applied silviculture produced positive outcomes in all the tested theses. Annual total litter, leaf area index and transmittance showed significant differences comparing DIR and TEST. The gap tends to vanish within 8-10 years after thinning occurrence. Seed cutting (TS) produced on the contrary heavy and lasting differences compared with all the theses. Leaf area index and transmittance were 1.97 m2m-2 and 24.8 % in TS vs. 4.22 m2m-2 and 7.89% in DIR. Seed cutting increased also the development of stand canopy and hastened seed production. The amount of seed production in TS was higher than in DIR representing 25% of total litter production. The DIR thesis resulted to be more appropriate for coppice conversion into high forest. Silvicultural practices hasten the conversion process and allow both ecological and economic returns throughout the conversion cycle by the repeated intermediate harvestings that amount to 250-300 m3ha-1 at the age of 60. A 15 yrs timeis recognized as the optimal interval between moderate to heavy thinnings. The complementary thesis of undertaking an advance seed cut (TS) relies more on management planning criteria than on ecologically-based issues
One and two-entry tree volume tables for the new-established ash-sycamore forest types at a pre-alpine territory.
Get PDFAsh-sycamore stands have been assuming a considerable territorial importance in Northern Italy over the last decades. According to the National Forest and Carbon Sinks Inventory (INFC), these stands form the type of “sycamore-lime mountain & ash forests” and “Apennine maple forests”. These forests amount to 153904 hectares (88% in the Northern regions) and 23600 hectares, respectively. In the Veneto Region, ash-sycamore are mainly secondary forests and occupy 9258 hectares. These stands spread easily throughout the agriculture set-aside lands thanks to their colonizing ability and to the favourable soil conditions in the pre-alpine region. Experimental thinnings framed into a wider project aimed at producing management guidelines according to a single-tree oriented approach, provided a sample of 385 trees. On the basis of this dataset, the first tree volume tables for these ash-sycamore stands have been elaborated. Data collection and data processing are being described in the paper. A two-entry tree volume table was set up by the stepwise analysis procedure and a one tree volume table was derived from the two-entry tree volume table
Results 3 decades after the plantation trials with palebark pine in the mountain of the coastal chain in Calabria
Get PDFIn Italy the palebark pine (Pinus leucodermis Antoine) forms natural populations present in Calabria and Lucania at the borderline between the two regions on calcareous soils and litho-soils. The surface range is about 5700 hectares, distributed in four natural groups of vegetation, two Apennine areas (Alpi, Spina -Zàccana, Pollino) and two coastal areas (Palanuda-Pellegrino, Montéa). In the mountain areas the species becomes exclusive and shows resistance to climate harshness at high elevation, ability to colonise ecologically difficult sites, aptitude and specific reliability to artificial spreading. The experimental plan, carried out without any repetition because technically unfeasible in the area, estimated three input variables: plastic bag-grown S2F2 and bare-rooted seedlings S2T2, inter-distance on the terrace (0.5m, 1m, 1.5m), elevation a.s.l. (1400m, 1550m, 1700m). 4 yrs old seedlings, one half plastic bag-grown and one half bare-rooted, were transplanted in autumn in each site on 24 terraces (4x3x2) handmade in summer. Each sampled area was made up of four adjacent terraces for an overall length of 184 m. Transplanting operations were completed in December and an enclosure was set up to protect the plantation from grazing. As a whole, the experimental areas was shaped as a rectangle. Additional terraces, carried out in the lower part, were planted with bare-rooted Austrian pine and Silver fir seedlings at an inter-distance of 1m and provided the direct comparison with the same thesis of palebark pine. Maintenance practices were undertaken in June and in July of the first and second year to eliminate weeds and shrubs along the terraces. The mensurational surveys were carried out in 1982-1983-1987-1994-2007-2009. The quite complete mortality of Austrian pine and Silver fir transplants in 1983-84 made impossible any further comparison among the species. The statistical analysis was applied at yrs 1, 12 and 27 from the plantation and concerned the following dependent variables: survival rate, height to diameter ratio, taper ratio. Over the time-intervals 1982-1983, 1982-1994, 1982-2009, results showed: (i) the higher survival rate (95.5%) and height to diameter ratio at the major elevations and at the wider interplanting distances with plastic bag-grown seedlings; (2) the same system accounted for increasing the taper ratio as compared with the bare-rooted system. Mean diameter is 9.8 cm, mean height is 5.29 m at the age of 27 in the 18 test areas. The first fruiting appeared at the age of 16-18 years
Effects of mixture and thinning in a tree farming valuable broadleaves plantation more than 20 years after the establishment.
Get PDFThe results of peduncolate Oak plantation trials where the Oak is mixed to wild Cherry and narrow-leaf Ash per line and per close mixture with different proportions (25% and 50%) of N-fixing species (Black Locust and Italian Alder) are described in the paper. The plantation, carried out in winter 1988-89, was framed into a reafforestation plan for spoil banks restoration. On a share of the plantation area, free thinnings foreseeing the release of about 70 target trees per hectare, were undertaken in 2001 and 2003; 21% and 27% of basal area were removed, respectively. In the latter trial, the crowns of target trees were completely isolated by felling all the surrounding trees. The performances of valuable timber broadleaves, the effects of intercropping and thinning on the growth of Oak target trees were analysed. Three inventories (2001, 2004 and 2008) and the annual monitoring of target trees growth were performed at the purpose. The two peduncolate Oak and narrow-leaf Ash trees showed the best performances among the set of valuable broadleaves, whilst wild cherry resulted not suited to local site conditions. A higher tree mortality occurred in the mixture with Black Locust. The mixture with both Nfixing species provided a stimulus to the Oak growth both in terms of dbh and tree height. Italian Alder resulted anyway less competitive and easy to manage, considering its progressive self-thinning, while Black Locust was aggressive enough to necessitate the control of its development by pollarding 7 years after the plantation. In the thinned plots, target trees showed significant diameter increments in comparison with control plots; maintaining year by year constant dbh increments of about 1 cm and crown’s diameter increment of about 50 cm. Intercropping with Italian Alder showed to be more effective than thinning on growth of the target trees