Assessment of salt tolerance in Populus alba clones using chlorophyll fluorescence

Cuttings of five Populus alba clones (S18 F1-26, A129 F8-35, J3 F1-4, GU1 F16-36, PO9 F21-88), Populus euphratica, and Populusxeuramericana (I-214) were submitted during 45 d to regular watering with NaCl solutions of electrical conductivity of 7 and 14 dS m-1. Chlorophyll a fluorescence in response to the salinity stress was assessed, using F0 and F v/Fm. Differences in reaction to the salt were found in P. alba clones, F0 and Fv/Fm being the fluorescence parameters used to check out this stress. Minimal constant fluorescence of dark-adapted plants (F0) showed a better correlation with the disease index exhibited by plants and also with salinity dose than the parameter Fv/Fm. Some of the P. alba clones showed the same behaviour, assessed through fluorescence parameters, as P. euphratica, which was previously defined as salt tolerant, while the rest exhibited the same characteristics as I-214, which was very sensitive

Using chlorophyll fluorescence induction for a quantitative detoxification assay with metribuzin and chlorotoluron in excised wheat (Triticum aestivum and Triticum durum) leaves

Chlorophyll fluorescence induction was used as a probe to detect herbicide detoxification in tolerant or susceptible wheat cultivars. Experimental conditions have been carefully examined for establishing detoxification kinetics of chlorotoluron and metribuzin, two photosystem‐II‐inhibiting herbicides. After a root treatment, leaves were cut, placed in glass tubes and maintained in the dark. The fluorescence induction rise was examined repeatedly and detoxification kinetics were established from these data for the same position on the individual leaves. The herbicide‐dependent fluorescence rise decreased within hours in chlorotoluron‐tolerant but not in susceptible Triticum aestivum cultivars. In contrast, no significant reversion could be detected after metribuzin application in both tolerant and susceptible cultivars of Triticum durum. Near the fluorescence‐determined half‐inhibition of photosystem II, linear detoxification kinetics were obtained in individual leaves, thus providing an accurate measurement of relative detoxification rates. Copyright © 1993 John Wiley & Sons, Lt

Assessment of the effect of broad-spectrum pre-emergence herbicides in poplar nurseries

This study examines the response of three pre-emergence herbicides (tiazopir, oxifluorfen, pendimethalin) used on unsprouted cuttings of the clone 'I-214' (Populus x euramericana). The effect of the herbicide both on the poplar and on the weeds was assessed. The three herbicides performed well in the case of both the variables (selectivity and effectiveness). The development of the trees were recorded over two growing seasons, during which there was a chemical intervention in the first year, but no treatment during the second year. A second application of these herbicides does not seem to be needed from the point of view of competition between the weeds and the cultivated crop. © 2001 Elsevier Science Ltd

In vitro culture selection increases glyphosate tolerance in barley

In vitro culture of barley calluses has been used to produce plants with increased glyphosate tolerance. Calluses from immature embryos of barley Hordeum vulgare L. 'Jeff') were cultured on Murashige and Skoog medium with 10-6, 10-5, 10-4, 5x10-4, 10-3 or 10-2 M glyphosate for one, four or thirty months. Plants were regenerated from calluses maintained in glyphosate medium at 10-6, 10-5 or 10-4 M for four months, at 10-5 or 5x10-4 M for one month and at 10-5 M for thirty months. The progeny of each regenerated plant was analyzed for response to glyphosate. Some progenies showed increased tolerance to glyphosate

Response to sodium chloride in different species and clones of genus Populus L

A greenhouse study was undertaken to evaluate the response to sodium chloride (control, 68 mM and 137 mM) of different species and genotypes of genus Populus L. (P. x euramericana (Dode) Guinier clones 'I-214', 'Flevo', 'I-MC' and Triplo'; P. deltoides x P. alba clones 'M30' and 'M31'; P. alba L. clones 'Jalón-F-1-22', 'Jalón F-1-4', 'Guadalquivir F-21-38', 'Guadalquivir F-21-39', 'Guadalquivir F-21-40' and 'Montañana F-2-9'; and P. euphratica Oliv.). Survival, visual symptomatology, height growth, dry weight both in shoots and roots, photosynthesis rate and leaf concentrations of Na+, K+ and Ca2+ were evaluated. There were differences in survival between clones (0 per cent for the most sensitive and 100 per cent for the most tolerant) but growth was significantly reduced in all cases except for dry weight of P. euphratica at 68 mM. The photosynthesis rate was significantly reduced in all clones at the end of the experiment (60 days) but not in the same way in the middle (30 days). The leaf levels of Na +, K+ and Ca2+ were also significantly different between clones. Intra- and interspecific variability have been detected in the genus, especially in P. alba. © Institute of Chartered Foresters, 2005

Genetic variation and genotype-environment interactions in short rotation Populus plantations in southern Europe

Growth and production in the first year, as additional selection criteria, were assessed for nine poplar clones to be used as short rotation woody crops (SRWC) in the production of biomass for energy purposes. In order to identify the most promising clones in terms of growth and yield and also to assess their stability, trials were established at different locations in Spain. The majority of these clones, which form part of the European list of base materials, have frequently been used in plantations aimed at timber production but not for biomass in Mediterranean conditions. Others, such as those selected in Italy specifically for biomass production (currently provisionally admitted), are being tested for the first time under different soil and climatic conditions in Southwest Europe. The early selection of clones for rapid juvenile growth provides a valuable additional input to the clonal selection process, especially where very short rotations are desired (no more than 3 years). In any case, determining clonal stability in terms of growth is of great use not only when deciding on the clones to be used in plantations but also when developing breeding programs. ANOVA and Genotype plus Genotype × Environment (GGE) biplot analyses were used to analyse the growth and stability of the clones, which were then ranked according to mean performance and stability. Differences were detected between clones as well as between the different environments tested. The biplot analysis allowed different groups of clones to be identified according to their performance and degree of interaction displayed, thus providing useful information for the selection process. The production of aboveground biomass in the first vegetative period ranged from 1.7 to 8.0 Mg DM ha-1 at the different sites. 'Monviso', 'Guardi', 'AF2' and '2000 verde' were the most productive clones whereas 'Unal', 'Pegaso' and 'USA 49-177' were the least productive. The stability analysis identified 'AF2', 'Guardi', 'I-214' and 'MC' as more stable clones while 'Monviso', '2000 verde', 'Unal', 'Pegaso' and 'USA 49-177' were found to be specifically adapted to certain environments. This implies that where information on site conditions is not available, the 'AF2' and 'Guardi' clones offer greater assurance of successful establishment and higher initial growth. The growth of 'Monviso' '2000 verde' 'Unal' 'Pegaso' and 'USA 49-177' clones is highly dependent on site conditions during the establishment phase. Similarly, the SH (Shore Henares river) and LT (La Tallada) sites were identified as the most highly discriminative environments for the set of clones while CS (Cubo de la Solana) and AR (Atarfe) were identified as those where performance levels were average. © 2010 Springer Science+Business Media B.V

On the inheritance of tolerance to chlorotoluron application in wheat using a very efficient score test

We present a nondestructive, easy to handle, cheap, fast and efficient assay to score wheat responses to herbicides. The application of the assay is illustrated by the reactions of the bread wheat cultivars ‘Castan’ and ‘Recital’ to the urea her‐bicide, chlorotoluron. The results not only confirm the presence of a major tolerant allele controlling the differences in response between the two cultivars, but also, show the contributions of modifier genes present in ‘Castan’, ‘Recital’ and other related cultivars. Copyright © 1995, Wiley Blackwell. All rights reserve

Smooth additive mixed models for predicting aboveground biomass

Aboveground biomass estimation in short-rotation forestry plantations is an essential step in the development of crop management strategies as well as allowing the economic viability of the crop to be determined prior to harvesting. Hence, it is important to develop new methodologies that improve the accuracy of predictions, using only a minimum set of easily obtainable information i.e., diameter and height. Many existing models base their predictions only on diameter (mainly due to the complexity of including further covariates), or rely on complicated equations to obtain biomass predictions. However, in tree species, it is important to include height when estimating aboveground biomass because this will vary from one genotype to another. This work proposes the use of a more flexible and easy to implement model for predicting aboveground biomass (stem, branches and total) as a smooth function of height and diameter using smooth additive mixed models which preserve the additive property necessary to model the relationship within wood fractions, and allows the inclusion of random effects and interaction terms. The model is applied to the analysis of three trials carried out in Spain, where nine clones at three different sites are compared. Also, an analysis of slash pine data is carried out in order to compare with the approach proposed by Parresol (Can J For Res 31:865-878, 2001)

Thermochemical and physical evaluation of poplar genotypes as short rotation forestry crops for energy use

Short rotation plantations of fast-growing species provide a promising way to produce heat and electricity from renewable sources. The thermo-chemical and physical properties of different genotypes of poplar in short rotation forestry crops grown at three locations with different climatic and edaphic characteristics as well as planting density, have been determined in order to characterize the most appropriate biomass in terms of energy potential. The planting density was 6666 or 13,333 trees/ha (depending on the location) in a rotation of three-four years and the analysis was carried out at the end of the first rotation. For all the genotypes, experimental tests to quantify the moisture content, particle size distribution, bulk density, heating value, ash content and composition as well as the volatile matter were performed. In addition, natural air drying of biomass (stem and branches) was studied in two locations with the aim of determining the humidity loss during raw storage. A significant effect of the genotype and the planting density on the biomass properties was observed. The results obtained indicate that ‘Monviso’ and ‘Viriato’ are the most suitable genotypes. No operational problems related to ash fouling and deposition in combustion devices are expected for any of the genotypes studied. © 2016 Elsevier Lt

Dynamic growth model for I-214 poplar plantations in the northern and central plateaux in Spain

Information required by forest managers about homogeneous, even-aged, single-species stands can be provided by whole-stand models, which are easily built with data often available in forest inventories and which represent a good compromise between generality and accuracy. The objective of the present study was to develop a dynamic growth model for I-214 clonal poplar plantations in the northern and central plateaux in Spain by use of data obtained from a network of 198 experimental plots measured between 2 and 12 times. The overall model is a hierarchical system that consists of three main components a stand height projection function, a stand basal area projection function and a merchantable stand volume equation. In the model, the initial stand conditions at any point in time are defined by two state variables usually collected from common forest inventories stand mean height and stand basal area. The model includes two transition functions, derived by the generalized algebraic difference approach, to enable projection of these variables at any particular time. The projected variables were incorporated into a merchantable stand volume equation to enable calculation of the commercial stand volume at a minimum diameter, which establish a merchantability threshold. Sensitive analysis of the accuracy of the predictions of the submodels according to the length of the time interval was achieved by use of the critical error statistic and the RMSE in relative proportion of the mean. Results indicated that the overall model provides satisfactory predictions for time intervals of between 1 and 4 years