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[en] Aim: Several national forest inventories use a complex plot design based on multiple concentric subplots where smaller diameter trees are inventoried when lying in the smaller-radius subplots and ignored otherwise. Data from these plots are truncated with threshold (truncation) diameters varying according to the distance from the plot centre. In this paper we designed a maximum likelihood method to fit the Weibull diameter distribution to data from concentric plots. Material and methods: Our method (M1) was based on multiple truncated probability density functions to build the likelihood. In addition, we used an alternative method (M2) presented recently. We used methods M1 and M2 as well as two other reference methods to estimate the Weibull parameters in 40000 simulated plots. The spatial tree pattern of the simulated plots was generated using four models of spatial point patterns. Two error indices were used to assess the relative performance of M1 and M2 in estimating relevant stand-level variables. In addition, we estimated the Quadratic Mean plot Diameter (QMD) using Expansion Factors (EFs). Main results: Methods M1 and M2 produced comparable estimation errors in random and cluster tree spatial patterns. Method M2 produced biased parameter estimates in plots with inhomogeneous Poisson patterns. Estimation of QMD using EFs produced biased results in plots within inhomogeneous intensity Poisson patterns. Research highlights:We designed a new method to fit the Weibull distribution to forest inventory data from concentric plots that achieves high accuracy and precision in parameter estimates regardless of the within-plot spatial tree pattern.
[en] The barley is a autonomous cereal originated of the wild subspecies H. vulgare L. Only at the end of last century it acquired commercial importance with the establishment of the industry brewer (Chaparro and Moreno 1894); at the moment its national production is far from supplying the demand of the market. The Andean area is the most appropriate region for its cultivation in Colombia, mainly between 1800 and 3200 meters on the level of the sea, in the Boyaca, Cundinamarca and Narino departments. Their production is dedicated in a 80 at 85 for the industry brewer and malt industry and of the 15 at 20 for seeds, human food and animal
[en] Water deficit (WD) is becoming an alarming problem in many regions of the world. Jasmonic acid (JA) is considered an important intracellular plant growth regulator. The aim of the current research was to investigate the important role of JA in mitigating the negative effects of WD on plant growth. Sugar beet production systems of two locations in Chaharmahal-Bakhtiari province, Iran. A field trial was conducted to assess the foliar applications of JA (0, 5 µM and 10 µM) and WD (50%, 75%, 100% plant water requirements) effects on physiological yield components of sugar beet (Beta vulgaris L.) plants. WD significantly (p<0.05) increased catalase, ascorbate and peroxidase activities, and malondialdehyde, hydrogen peroxide and white sugar content (WSC); however, it caused a reduction in white sugar yield and root yield (RY). JA foliage applications further enhanced the enzymes activity in WD treated plants resulting in higher WSC, potassium concentrations, white sugar and final RY. Interestingly the effects of JA applications were more pronounced under severe WD (50%) compared to mild (75%) or well-watered plants (100%). JA (10 µM) foliage applications increased the RY and white sugar production by 21% and 24% under severe WD. JA can ameliorate the adverse effects of WD and increase the WD tolerance of sugar beet crop by upregulating the antioxidant enzyme activities to withstand adverse environmental conditions.
[en] Preliminary yield trial of 7 selected soybean lines (line numbers 2035, 2037, 2125, 2156, 2160, 2180 and 2192) obtained from crosses between mutants and Doi Kham variety and one line (line number 58608) obtained from gamma irradiated Doi Kham along with four check varieties (Doi Kham, S.J.4, S.J.5 and CM.60) was carried out in order to select for short stature, early maturity and high yielding mutant. Line numbers 2156, 58608, 2160 and 2180 expressed short stature and early maturity. Their heights at maturity time were shorter than the original Doi Kham for 13, 15, 17 and 22 cm respectively, and their maturity were 13, 11, 11 and 13 days earlier than Doi Kham, respectively. Their yields were similar to Doi Kham. These four lines will be further tested at different locations in the dry and rainy seasons. The best line will be selected and used as a variety
[en] Aim of study: The purpose was to determine the type of dormancy and the optimal germination conditions of Phillyrea angustifolia (Oleaceae) seeds. Area of study: Germination requirements of P. angustifolia seeds collected from wild plants growing in the province of Ávila (Central Spain) were studied. Materials and methods: Seed water uptake was measured. Seeds with and without an endocarp were germinated at different temperatures, and several treatments were tested. Main results: The lignified endocarp interferes mechanically with the emergence of the radicle, and the treatments that achieved the highest germination percentages were the total removal of the endocarp with pliers (84%) or the immersion in liquid nitrogen for 1 min (97%). Scarification with concentrated sulphuric acid did not significantly increase germination compared to the control seeds, and treatments with dry heat or wet heat were detrimental to seed germination. The optimum temperature for germination was 15 ºC. A pre-sowing treatment of soaking in distilled water for 24 h slightly increased germination speed. Neither cold stratification at 5 ºC nor soaking in a gibberellic acid solution improved seed germination. Research highlights: Phillyrea angustifolia seeds have physiological dormancy – that is, the embryo does not have enough growth potential to overcome the mechanical restriction of the lignified endocarp. The seeds do not exhibit physical dormancy, given their water-permeable lignified endocarp. Our results suggest that the optimum germination protocol for P. angustifolia would be the total removal of the endocarp or immersion in liquid nitrogen for 1 min, followed by immersion in distilled water for 24 h and then seed incubation at 15 ºC in light or darkness.
[en] Aim of study: Use the SUBER model to evaluate the influence of the cork debarking rotation period (CDR) on equivalent annual annuity (EAA) value. Area of study: Nine simulated stands, varying in site index (14.4, 15.6, 17.1) and cork quality characteristics (high, medium, low). Material and methods: EAA values were computed considering CDR periods varying from 9 to 14 years, two contrasting structures of cork prices (high and low cork price scenarios), and three discount rate values (0.5%, 2% and 5%). Main results: For discount rates of 0.5% and 2% the impact of different CDR on the EAA is similar. In stands characterized by high to average site index values or high to medium cork quality characteristics, CDR of 9 and 11 years are associated with similar values of EAA. The variation of the CDR in stands characterized by low site index values and/or low cork quality characteristics did not have a relevant effect on the variation of EAA. For the simulations carried out with a discount rate of 5% the EAA decreases with the increase of CDR, indicating that the minimum legal value of 9 years for CDR should be applied. Research highlights: In stands characterized by high to average site index values or high to medium cork quality characteristics, a delay in the debarking may result in a significant increase of cork thickness and, as a result, of cork price. Detailed knowledge of cork and stand characteristics and updated information on cork prices structure and values are essential for the best usage of management tools such as the SUBER model, which can contribute to the decision-making process concerning the debarking operation.
[en] Aim of the stud0y: To assess the impact on two mycoviruses recently described in F. circinatum mitovirus 1, and 2-2 (FcMV1 and FcMV2-2) on i) mycelial growth, ii) spore germination and iii) relative necrosis. Material and methods: Fourteen monosporic strains of F. circinatum (one of each pair infected with mycoviruses and the other without them) of the pathogen with and without viruses were selected for the assay. The statistical analysis, were a linear mixed model of analysis of variance considering one between-subjects factor (isolate) and one within-subjects factor with four levels (1=without viruses, 2=only virus FcMV1, 3=only virus FcMV2-2 and 4=both viruses). Main results: Colony growth rates of F. circinatum isolates were significantly reduced in presence of mycoviruses (p=0.002). The spore germination was also reduced in the F. circinatum isolates containing mycovirus as compared to mycovirus-free isolates (p<0.001). No significant differences in lesion lengths caused by F. circinatum were found in relation to the presence/absence of mycovirus (p<0.61). Research highlights: Reduction of the percentage of spore germination in the isolates of F. circinatum with mycovirus infections, as compared to free isolates, provides indications of reduction of metabolic activity and plant physiology are discussed. The lack of significant differences found in the length of the lesions caused by F. circinatum with respect to the presence/absence of mycovirus, indicates that further studies with a larger number of variables are required.
[en] The present report is the result of five years' experimental work at the Costa Regional Development Institute (IRD-Costa), based in Canete, Lima, Peru, on the reclamation of land affected by salts and hence of seriously limited agricultural value (production lower than 50%). A reclamation method combining surface and at depth washing with artificial drainage of excess water has been tried out and a method of nutrition has been developed which is based on tonification of the seeds before sowing. The results obtained are rather encouraging, so the method looks very promising, especially as it also makes for considerable savings in fertilizers (some 20% less) and for better yields per unit area. Once the ionic behaviour of this method has been studied by means of radioisotopes a large contribution will have been made towards alleviating the problem of saline soils. (author)
[en] A pot culture experiment was conducted to study the effects of 4 different levels of salinity (EC = 1.19, 9.54, 16.48 and 22.38 mS/cm) on the uptake of micronutrients (viz., Cu, Mn, Fe and Zn) by 2 varieties of sunflower (Helianthus annuus L.) at early vegetative stage. Salinity levels were prepared by dissolving calculated amount of NaCl/sub 2/, Na/sub 2/SO/sub 4/, CaCl and MgCl/sub 2/ (4:10:5:1) in half strength Hoagland culture solution. In response to various levels of salinity, the uptake of all mentioned micronutrients of roots and shoots of sunflower exhibited significant response (p <0.05 and p <0.01) while only the response of Mn uptake in shoot was found non significant. A maximum significant uptake of Cu, Mn, Fe and Zn in shoot (19.50, 120.67, 1647.67 and 59.17 mu g/g) is obtained under highest dose of applied salinity (22.23 mS/cm) whereas with the exception of Zn, a maximum significant uptake of Cu (25.67 mu g/g), Mn (144.87 mug/g), and Fe (5837.5 mu g/g) in root as well in highest dose of salinity was observed. With reference to ratio of Fe and Zn uptake in root and shoot, variety DO 730 responded well than variety DO 728. Results on the bases of grand sum values depicted 20.38 and 69.33% decrease in uptake of Cu and Fe, but 7.65 and 18.37% increase in uptake of Mn and Zn in shoot over root in both the varieties, respectively was observed. (author)
[en] Aim of the study: The effect of physical and chemical conditions at proliferation stage was evaluated in order to elucidate if this stage is the determinant phase to induce a marked effect in Pinus halepensis somatic embryogenesis. Area of study: The study was conducted in research laboratories of Neiker (Arkaute, Spain). Material and methods: Pinus halepensis embryonal masses from ten embryogenic cell lines subjected to nine treatments (tissues cultured at three temperatures on media supplemented with three agar concentrations) at proliferation stage. Main results: Significant differences were observed among different proliferation conditions months later at the end of maturation, germination and acclimatization stages. Research highlights: Aleppo pine embryonal masses are cultured under standard conditions on a culture medium supplemented with 4.5 g/L Gelrite® at 23ºC. However, better results in terms of plantlet production can be obtained proliferating the embryonal masses at 18ºC in a culture media with significantly lower water availability.