Baseline and differential sensitivity to mandipropamid among isolates of Peronophythora litchii, the causal agent of downy blight on litchi

Litchi downy blight caused by Peronophythora litchii is a devastating disease of litchi plants in China. Control of litchi downy blight requires numerous fungicide applications. A new carboxylic acid amide (CAA) fungicide, mandipropamid, was examined for its in vitro effects on multiple asexual stages of four single-sporangium P. litchii isolates and protective activity against downy blight in detached fruit assays. Though mandipropamid did not affect discharge of zoospores from sporangia, it strongly inhibited mycelial growth (mean EC₅₀ = 0.0048 μg ml⁻¹), sporangia production (mean EC₅₀ = 0.0032 μg ml⁻¹), germination of encysted zoospores (mean EC₅₀ = 0.0023 μg ml⁻¹), and germination of sporangia (mean EC₅₀ = 0.0061 μg ml⁻¹). On detached fruit, 0.39, 1.56 and 6.25 μg ml⁻¹ of mandipropamid were superior in reducing downy blight compared to metalaxyl and flumorph, however, the 25 μg ml⁻¹ application rate was necessary for all three CAA fungicides to completely inhibit the disease. In 2007, 100 isolates from Fujian, Guangdong, and Guangxi Provinces of China were characterized for the baseline sensitivity to mandipropamid. The isolates obtained from different provinces showed similar baseline sensitivities to mandipropamid. Baseline sensitivities formed a unimodal curve with mean EC₅₀ values of 0.0055 ± 0.0012 μg ml⁻¹ for inhibition of mycelial growth. The described baseline sensitivities of P. litchii populations will be useful for monitoring possible shifts in sensitivity to mandipropamid.     

Analysis of yield attributes and crop physiological traits of Liangyoupeijiu,a hybrid rice recently bred in China

Crop physiological traits of Liangyoupeijiu, a “super” hybrid rice variety recently bred in China, were compared with those of Takanari and Nipponbare in 2003 and 2004 in Kyoto, Japan. Liangyoupeijiu showed a significantly higher grain yield than Nipponbare in both years, and achieved a grain yield of 11.8 t ha⁻¹ in 2004, which is the highest yield observed under environmental conditions in Kyoto. Liangyoupeijiu had longer growth duration and larger leaf area duration (LAD) before heading, causing larger biomass accumulation before heading than the other two varieties. Liangyoupeijiu had a large number of grains and translocated a large amount of carbohydrates from the vegetative organ to the panicle during the grain filling period. The three yield components measured were panicle weight at heading (P₀), the amount of carbohydrates translocated from the leaf and stem to the panicle during the grain filling period (ΔT), and the newly assimilated carbohydrates during grain filling (ΔW). It was found that the sum of P₀ and ΔT were strongly correlated with grain yield when all the data (n = 8) were combined (r = 0.876**). However, there was no significant difference in the radiation use efficiency (RUE) of the whole growth period between Liangyoupeijiu and Nipponbare for both years. Even though the growth duration was shorter, Takanari, an indica/japonica cross-bred variety, showed a similar yield to Liangyoupeijiu in both years. The mean RUE of the whole growth period was significantly higher in Takanari, 1.60 and 1.64 g MJ⁻¹ in 2003 and 2004, respectively, than in Liangyoupeijiu, which had a RUE of 1.46 and 1.52 g MJ⁻¹ in 2003 and 2004, respectively. The high grain yield of Takanari was mainly due to its high RUE compared with Liangyoupeijiu and its large P₀ and ΔT. Our result showed that the high grain yield of Liangyoupeijiu was due to its large biomass accumulation before heading, which resulted from its large LAD rather than its RUE.     

Highly efficient in vitro regeneration of the industrial oilseed crop Crambe abyssinica

A highly efficient regeneration protocol for oilseed crop Crambe abyssinica has been developed using hypocotyls as explants in this study. Crambe is a potential engineering oilseed crop for industrial purposes as it contains 55-60% erucic acid in its oil and, more importantly, it does not outcross with any food oil seed crops. However, the low regeneration frequency with the currently available protocols is still a limiting factor for genetic modification of Crambe. In this study, we investigated the effects of N-source, C-source, AgNO₃, cultural conditions as well as the concentration and combination of plant growth regulators (PGR) on the regeneration frequency of C. abyssinica. The results showed that all these factors, especially the N-source and PGR concentrations and combinations, played an important role in shoot regeneration. Among all the factors tested, the combination of using hypocotyls from C. abyssinica cv. galactica, the Lepiovre basal medium supplemented with 16 g l⁻¹ glucose, 0.5 g l⁻¹ AgNO₃, 2.2 mg l⁻¹ thidiazuron (TDZ), 0.5 mg l⁻¹ α-naphthaleneacetic acid (NAA), 2.5 g l⁻¹ Gelrite, seeds germinated in dark for 3 days and explants cultured in light, gave the best regeneration frequency (over 95%). The results also suggest that reducing the content of NH₄⁺ or keeping a suitable NO₃⁻/NH₄⁺ ratio in the regeneration medium would be crucial to Crambe shoot regeneration.     

Effect of irrigation frequency and amount on water use efficiency and yield of sesame (Sesamum indicum L.) under field conditions

The water-use characteristics of sesame (Sesamum indicum L.) were studied in the field under furrow irrigation. Irrigation water quantities were based on pan evaporation (E_pan) from a screened class-A pan. Treatments consisted of three irrigation intervals (I₁: 7 days; I₂: 14 days, I₃: 21 days), and four pan coefficients (K_cp 1: 0.60; K_cp 2: 0.80, K_cp 3: 1.00 and K_cp 4: 1.20). Average irrigation values for each treatment varied from 467 to 857 mm in 2003 and 398 to 654 mm in 2004. The highest seasonal evapotranspiration was obtained from the I₃K_cp 4 treatment in 2004 (1019 mm); the lowest value was observed in the I₁K_cp 1 treatment in the same year (598.0 mm). Data collected in 2003 and 2004 showed that the amount of irrigation water applied significantly the affected seed yield. However, the effects of irrigation interval on yield were not significant. On average, the K_cp 3 treatment gave the highest seed yield (1.915 t ha⁻¹), whereas K_cp 1 treatment gave the lowest (1.538 t ha⁻¹). Seasonal yield response factors (k_y) were 1.01 and 0.54 in 2003 and 2004, respectively. ET/E_pan ratios for each treatment varied from 0.3 to 1.3 in 2003 and from 0.1 to 1.1 in 2004. In conclusion, the K_cp 3 plant-pan coefficient is recommended for sesame grown under field conditions in order to maximise yield.     

The impact of free-air CO2 enrichment (FACE) and nitrogen supply on grain quality of rice

Because CO₂ is needed for plant photosynthesis, the increase in atmospheric CO₂ concentration ([CO₂]) has the potential to enhance the growth and yield of rice (Oryza sativa L.), but little is known regarding the impact of elevated [CO₂] on grain quality of rice, especially under different N availability. In order to investigate the interactive effects of [CO₂] and N supply on rice quality, we conducted a free-air CO₂ enrichment (FACE) experiment at Wuxi, Jiangsu, China, in 2001–2003. A long-duration rice japonica with large panicle (cv. Wuxiangging 14) was grown at ambient or elevated (ca. 200 μmol mol⁻¹ above ambient) [CO₂] under three levels of N: low (LN, 15 g N m²), medium (MN, 25 g N m²) and high N (HN, 35 g N m² (2002, 2003)). The MN level was similar to that recommended to local farmers. FACE significant increased rough (+12.8%), brown (+13.2%) and milled rice yield (+10.7%), while markedly reducing head rice yield (−13.3%); FACE caused serious deterioration of processing suitability (milled rice percentage −2.0%; head rice percentage −23.5%) and appearance quality (chalky grain percentage +16.9%; chalkiness degree +28.3%) drastically; the nutritive value of grains was also negatively influenced by FACE due to a reduction in protein (−6.0%) and Cu content (−20.0%) in milled rice. By contrast, FACE resulted in better eating/cooking quality (amylose content −3.8%; peak viscosity +4.5%, breakdown +2.9%, setback −27.5%). These changes in grain quality revealed that hardness of grain decreased with elevated [CO₂] while cohesiveness and resilience increased when cooked. Overall, N supply had significant influence on rice yield with maximum value occurring at MN, whereas grain quality was less responsive to the N supply, showing trends of better appearance and eating/cooking quality for LN or MN-crops as compared with HN-crops. For most cases, no [CO₂] × N interaction was detected for yield and quality parameters. These data suggested that the current recommended rates of N fertilization for rice production should not be modified under projected future [CO₂] levels, at least for the similar conditions of this experiment.     

Improvement of growth and gymnemic acid production by altering the macro elements concentration and nitrogen source supply in cell suspension cultures of Gymnema sylvestre R. Br

Gymnema sylvestre is an important medicinal plant which bears bioactive compound namely gymnemic acids. The present work deals with optimization of cell suspension culture system of G. sylvestre for the production of biomass and gymnemic acid and we investigated effects of macro elements (NH₄NO₃, KNO₃, CaCl₂, MgSO₄ and KH₂PO₄ - 0.0, 0.5, 1.0, 1.5 and 2.0× strength) and nitrogen source [NH₄⁺/NO₃⁻ ratio of: 0.00/18.80, 7.19/18.80, 14.38/18.80, 21.57/18.80, 28.75/18.80, 14.38/0.00, 14.38/9.40, 14.38/18.80, 14.38/28.20 and 14.38/37.60 (mM)] of Murashige and Skoog medium on accumulation of biomass and gymnemic acid content. The highest accumulation of biomass (165.00 g l⁻¹ FW and 15.42 g l⁻¹ DW) was recorded in the medium with 0.5× concentration of NH₄NO₃ and the highest production of gymnemic acid content was recorded in the medium with 2.0× KH₂PO₄ (11.32 mg g⁻¹ DW). The NH₄⁺/NO₃⁻ ratio also influenced cell growth and gymnemic acid production; both parameters were greater when the NO₃⁻ concentration was higher than that of NH₄⁺. Maximum biomass growth (159.72 g l⁻¹ of FW and 14.95 g l⁻¹ of DW) was achieved at an NH₄⁺/NO₃⁻ ratio of 7.19/18.80, and gymnemic acid production was also greatest at the same concentration of NH₄⁺/NO₃⁻ ratio (11.35 mg g⁻¹ DW).     

Identification and antimicrobial activity of two alkaloids from traditional Chinese medicinal plant Tinospora capillipes

Two antimicrobial alkaloids, palmatine and jatrorrhizine, were isolated from tubers of traditional Chinese medicinal plant Tinospora capillipes using activity-guided isolation method and chromatography. Their antimicrobial activity was determined in vitro. The results showed that palmatine and jatrorrhizine had inhibitory activity against plant pathogens Colletotrichum gloeosporioides, Fusarium oxysporum f. sp. niveum, Mycosphaerella sentina, Pestalotia mangiferae, Cercospora kaki, Gymnosporangium haraeanum, Rhizoctonia solani and Colletotrichum graminicola, with the EC₅₀ values of 0.0348-0.8356 g L⁻¹ and 0.0240-0.8649 g L⁻¹, respectively. Palmatine and jatrorrhizine also exhibited inhibition against animal pathogens Bacillus cereus, Bacillus megaterium, Bacillus subtilis, Staphyloccocus aureus, Staphylococcus epidermidi, Micrococcus lysodeikticus, Proteus vulgaris, Salmonella typhi and Escherichia coli, with the MIC values of 0.1-0.8 g L⁻¹ and 0.1-0.6 g L⁻¹, respectively. These results suggested that palmatine and jatrorrhizine showed relatively broad spectrum antimicrobial activity against plant and animal pathogens.     

Influence of amylopectin structure on rheological and retrogradation properties of waxy rice starches

A set of 13 waxy rice genotypes prepared by chemical-induced mutation of rice variety TNG67 and 7 waxy rice varieties widely grown in Taiwan were compared for structural, rheological and retrogradation characteristics of starches. Wide differences in retrogradation enthalpy (ΔH_ret), gel firmness and storage modulus (G’_ret) were observed for 2-week stored gels of 20 starches. Ratio of short-to-long amylopectin chains was significantly higher (p < 0.05) in starches from mutant genotypes than in commercial varieties. ΔH_ret and G’_ret of starch pastes stored over 4 weeks showed stronger correlation with amylopectin chain-profile compared to those stored for 2 weeks. Amount of long amylopectin chains was correlated positively (p < 0.05) with ΔH_ret and gel firmness. Overall, ratio of short-to-long amylopectin chains affected almost all the rheological and retrogradation parameters. Results of this study can be useful to plant breeders and food industry for quality improvement and selection of waxy rice mutants for various applications.     

Temporal dynamics of light and nitrogen vertical distributions in canopies of sunflower, kenaf and cynara

To enhance eco-physiological and modelling studies, we quantified vertical distributions of light and nitrogen in canopies of three Mediterranean bio-energy crops: sunflower (Helianthus annuus), kenaf (Hibiscus cannabinus) and cynara (Cynara cardunculus). Field crops were grown with and without water stress in 2008 and 2009. Canopy vertical distributions of leaf area index (LAI), photosynthetically active radiation (PAR), specific leaf area (SLA), nitrogen concentration (N_conc) and specific leaf nitrogen (SLN) were assessed over time for each crop × year × water input combination. Light and nitrogen distributions were quantified by the Beer's law (exponential model) and extinction coefficients for light (K_L) and nitrogen (K_N) were calculated. Within a year, K_L did not change significantly over the studied period in all irrigated crops, but differences in K_L were significant between years (sunflower: 0.74 vs. 0.89; kenaf: 0.62 vs. 0.71; cynara: 0.77). K_L estimates were always lower (−48 to −65%) in water-stressed sunflower and kenaf crops because of the reduction in leaf angle. These results should be taken into account, when simulating water-limited biomass production. Vertical SLN distributions were found in canopies when LAI was >1.5 (40 from 51 cases). These distributions were significantly correlated with the cumulative LAI from the top (r² = 0.75-0.81; P < 0.05), providing parameters to upscale photosynthesis from leaf to canopy levels. Vertical SLN distributions followed species-specific patterns over the crop cycle and varied less compared to PAR distributions between years. Lastly, we observed strong associations between SLN and PAR distributions in irrigated sunflower and kenaf canopies (r² > 0.66; P < 0.001). However, observed SLN distributions were less steep than the distributions that would maximize canopy photosynthesis.     

Kernel number determination differs among maize hybrids in response to nitrogen

In maize, the effects of nitrogen (N) deficiencies on the determination of kernel number per plant (KNP) have been described only by changes in plant growth rate during the critical period for kernel set (PGRcp). We hypothesize that N availability affects KNP also through variations in biomass allocation to the ear, which determines a stable N concentration in this organ. Six maize hybrids of different breeding origin were evaluated in field experiments at two N levels (0 and 400 kg N ha⁻¹ applied). Traits included were KNP and per apical ear (KN_E1), and the allometric estimation of PGRcp, ear growth rate during the critical period (EGRcp), and N content and N concentration in different plant organs. We demonstrated that (i) N availability promoted differences among genotypes (G) in the response of EGRcp and KNP to PGRcp, (ii) variations in KN_E1 were explained by EGRcp (r² = 0.64) and by ear N content at silking + 12 d (r² = 0.64), and (iii) ear N concentration was a highly conservative trait (range between 10.47 and 15.98 mg N g biomass⁻¹) as compared to N concentration in vegetative tissues (range between 4.94 and 18.04 mg N g biomass⁻¹). Three response patterns were detected among hybrids, one for which the relationship between EGRcp and PGRcp did not vary between N levels and experiments, a second one for which N availability affected this relationship, and a third one for which the response was affected by the year (Y) effect. These results, together with the high correlation between EGRcp and ear N content (r² = 0.88), evidenced the importance of both photo-assimilate and N availability on EGRcp and KNP determination. Values of 1.5–2.3 g ear⁻¹ d⁻¹ during the critical period and 0.49–0.70 g of N ear⁻¹ at silking + 12 d were determined as thresholds for maximizing KN_E1, and both could be easily estimated by means of allometric models.     

Metabolic characteristics in ruminants of the proteins in newly developed hull-less barley varieties with altered starch traits

Recently, new varieties of hull-less barley have been developed with altered carbohydrate traits. To our knowledge, there is no study on metabolic characteristics in ruminants of the proteins in the newly developed hull-less barley varieties. The objectives of this study were to: compare metabolic characteristics of the proteins of zero-amylose waxy (CDC Fibar), low-amylose waxy (CDC Rattan), high-amylose (HB08302), and normal starch (CDC McGwire) hull-less barley. In situ animal trials were carried out to generate the original rumen fermentation data for modeling nutrient supply to dairy cattle by using two dairy nutrition models – Dutch DVE/OEB system and NRC 2001. The major comparisons were made in terms of i) truly absorbed protein in the small intestine (DVE or MP, and ii) degraded protein balance (DPB). The study revealed that zero-amylose waxy hull-less barley was superior (P < 0.05) in both DVE (123 vs. 117, 114, 103 g kg⁻¹ DM) and MP (112 vs. 93, 96, and 87 g kg⁻¹ DM) when hull-less barley was evaluated as a single feed for dairy cattle. All of four hull-less barley varieties had negative DPB (DPB^OEB; −37.4, −17.1, −30.2, and −28.2 g kg⁻¹ DM for normal starch, zero-amylose waxy, waxy, and high-amylose cultivar, respectively), indicating the potential N shortage. In conclusion, the alteration of starch structure in granule provided a relatively balanced energy and protein for microbial synthesis in the rumen. The DVE and DPB predicted by using the DVE/OEB system can be explained (r² > 0.76) by the equivalent parameters, predicted by using the NRC 2001 model. The alteration of starch structure in granule affects metabolic characteristics of the proteins of hull-less barley in ruminants.     

Insecticidal and repellent activity of selected essential oils against of the pollen beetle, Meligethes aeneus (Fabricius) adults

The essential oils from 9 aromatic plants were tested on repellency and mortality of Meligethes aeneus adults. All the tested essential oils caused high mortality of M. aeneus adults in the tarsal tests. The lethal doses after 6 h exposure were ranged between 197 and 1508 μg cm⁻². Essential oils obtained from Carum carvi and Thymus vulgaris were most efficient where LD₅₀ was estimated as 197 and 250 μg cm⁻², respectively.Repellency declined in all the essential oils as a function of time. The longest persistence time was determined for essences obtained from C. carvi and T. vulgaris where significantly the highest repellent index of 65.6% and 63.8%, respectively, was determined. Repellent index lower than 15% was determined for the remaining essential oils.     

Activities of essential oils from Asarum heterotropoides var. mandshuricum against five phytopathogens

Some secondary metabolites of plants function as antimicrobial products against phytopathogens and constitute an increasingly important class of pesticides. In the present study, the essential oil of Asarum heterotropoides var. mandshuricum was analyzed by GC/MS and its antimicrobial activity was evaluated against five phytopathogenic fungi. Major components of the oil were methyleugenol (59.42%), eucarvone (24.10%), 5-allyl-1,2,3-trimethoxybenzene (5.72%), and 3,7,7-trimethylbicyclo(4.1.0)hept-3-ene (4.93%). The essential oil and the most abundant component, methyleugenol, were separately assayed for inhibition of 5 pathogens: Alternaria humicola, Colletotrichum gloeosporioides, Rhizoctonia solani, Phytophthora cactorum and Fusarium solani. Both the oil and methyleugenol strongly inhibited the growth of the test pathogens (IC₅₀ values <0.42 μg ml⁻¹) except F. solani, with the best activity against P. cactorum (IC₅₀ values = 0.073 and 0.052 μg ml⁻¹, respectively). It is concluded that the essential oil of A. heterotropoides var. mandshuricum has a broad antiphytopathogenic spectrum, and that methyleugenol is largely responsible for the bioactivity of the oil. The mode of action of methyleugenol against P. cactorum is discussed based on changes in the mycelial ultrastructure.     

Environmental effects on seed yield determination of irrigated peanut crops: Links with radiation use efficiency and crop growth rate

In Argentina, delayed sowing causes a decrease in seed yield and in radiation use efficiency (RUE) of peanut crops (Arachis hypogaea L.), but it is not known if RUE reduction is mainly due to reduced temperature during late reproductive stages or to a sink limitation promoted by decreased seed number in these conditions. We analyzed seed yield determination and RUE dynamics of two cultivars (Florman and ASEM) in four irrigated field experiments (Exp_n) grown at three sites and five contrasting sowing dates (between 17 October and 21 December) in three growing seasons. An additional field experiment was performed with widely spaced plants (i.e. with no interference among them) to evaluate the effect of peg removal on RUE and leaf carbon exchange rate (CER). Seasonal dynamics of mean air temperature and irradiance, biomass production (total and pods), and intercepted photosynthetically active radiation (IPAR) were followed. Seed yield and seed yield components (pod number, seeds per pod, seed number and seed weight) were determined at final harvest. Crop growth rate (CGR) and pod growth rate (PGR) were computed for growth phases of interest. RUE values for crops sown until 14 November were 1.89–1.98 g MJ⁻¹ IPAR, within the usual range. RUE decreased significantly for cv. Florman in the late sowing of Exp₁ (29 November) and for both cultivars in Exp₃ (21 December sowing). Across experiments, seed yield (4.5-fold variation relative to minimum) was strongly associated (r² = 0.87, P < 0.0001) with variations in seed number (3.5-fold variation relative to minimum), and to a lesser extent (r² ≤ 0.54, P ≤ 0.001) to variations in seed weight (1.9-fold variation relative to minimum). Seed number was positively related (P < 0.01) to CGR (r² = 0.66) and to PGR (r² = 0.72) during the R₃–R_6.5 phase (seed number determination window), while crop growth during the grain-filling phase (i.e. between R_6.5 and final harvest) was positively associated with grain number (r² = 0.80, P < 0.001). No association was found between RUE and mean air temperature, neither for the whole cycle nor for the phase between R_6.5 and final harvest, which showed the largest temperature variation (16.4–22.4 °C) across experiments. Use of mean minimum temperature records (range between 13.8 and 18.5 °C) did no improve the relationship. However, grain-filling phase RUE showed a positive (r² = 0.69, P = 0.003) linear response to seed number across experiments. This apparent sink limitation of source activity was consistent with the reduced RUE (from 2.73 to 1.42 g MJ⁻¹ IPAR) and reduced leaf CER at high irradiance (from ca. 30 to 15 μmol m⁻² s⁻¹) for plants subjected to 75% peg removal.     

Effect of boron on the development of brown rot (Monilinia laxa) on peaches

Requirements of consumers for products with low residues of pesticides have increased the need for alternative disease management practices. The concentration of boron in fruit affects its quality, shelf life and the development of physiological disorders. However, the effect of boron on the susceptibility of peach to fruit rots has not been reported. This study investigated the effect of boron (Power B and Borax) on the development of Monilinia laxa on peaches (cv Andross). Mycelial growth of M. laxa was inhibited on potato dextrose agar supplemented with 750 μg ml⁻¹ of Borax or 1000 μg ml⁻¹ of Power B. The EC 50 values were 107.9 and 522.4 for Borax and Power B respectively. Field investigations showed that the incidence of peach infections by M. laxa was negatively correlated with the content of Boron in the leaves. Post-harvest dipping of peaches in Power B or Borax solution, at concentrations recommended by manufacturer (2 μg ml⁻¹ for Power B and 1 mg ml⁻¹ for Borax), significantly reduced the development of M. laxa. Power B, at rates of 6 μg ml⁻¹, and Borax at rates of 3 mg ml⁻¹ were the most effective in reducing infections by M. laxa. Finally, post-harvest dipping of fruit in Power B or Borax reduced losses of fruit weight and improved fruit firmness one month after storage, showing that boron increased the maintainability of peaches in cold storage. Peaches treated with 6 μg ml⁻¹ Power B or 3 mg ml⁻¹ Borax had the highest flesh firmness and the lowest water losses, while untreated control peaches were the least firm. Generally, Borax was significantly less effective than Power B, but better than the control treatment.     

Field-based evaluation of vernalization requirement,photoperiod response and earliness per se in bread wheat (Triticum aestivum L.)

Vernalization requirement, photoperiod response and earliness per se (EPS) of bread wheat cultivars are often determined using controlled environments. However, use of non-field conditions may reduce the applicability of results for predicting field performance as well as increase the cost of evaluations. This research was undertaken, therefore, to determine whether field experiments could replace controlled environment studies and provide accurate characterization of these three traits among winter wheat cultivars. Twenty-six cultivars were evaluated under field conditions using two natural photoperiod regimes (from different transplanting dates) and vernalization pre-treatments. Relative responses to vernalization (RRV_GDD) and photoperiod (RRP_GDD) were quantified using the reciprocal of thermal time to end of ear emergence, whereas earliness per se was estimated by calculating thermal time from seedling emergence until end of ear emergence for fully vernalized and lately planted material. An additional index based on final leaf numbers was also calculated to characterize response to vernalization (RRV_FLN). To test whether the obtained indices have predictive power, results were compared with cultivar parameters estimated for the CSM-Cropsim-CERES-Wheat model Version 4.0.2.0. For vernalization requirement, RRV_GDD was compared with the vernalization parameter P1V, for photoperiod (RRP_GDD), with P1D, and for earliness per se, EPS was compared with the sum of the component phase durations. Allowing for variation in EPS in the calibration improved the relation between observed versus simulated data substantially: correlations of RRP_GDD with P1D increased from r² = .34 (p < .01), to .82 (p < .001), and of RRV_GDD with P1V, from r² = .88 (p < .001), to .94 (p < .001). In comparisons of observed versus simulated anthesis dates for independent field experiments, the estimated model coefficients resulted in an r² of .98 (p < .001) and root mean square error of 1d. Overall, the results indicated that combining planting dates with vernalization pre-treatments can permit reliable, quantitative characterization of vernalization requirement, photoperiod response and EPS of wheat cultivars. Furthermore, emphasize the need for further study to clarify aspects that determine EPS, including whether measured EPS varies with temperature or other factors.     

Production of activated carbon from organic by-products from the alcoholic beverage industry: Surface area and hardness optimization by using the response surface methodology

The ability of activated carbon to remove pollutants from water in packed column systems is dependent on granular material with mechanical strength sufficient to avoid attrition caused by stream flow. Therefore, an appropriate balance between surface area and hardness is essential when using activated carbon in real systems. The purpose of this research is to determine the optimal production conditions that generate activated carbon with adequate physical properties to be used in packed systems from agave bagasse, a waste product from the mezcal industries in Mexico. Activated carbons were produced by chemical activation (ZnCl₂ or H₃PO₄). Response surface methodology (RSM) was used to evaluate the effect of the activation temperature (250-550 °C), activation time (0-50 min), and the concentration of activating agent (0.2-1.4; g activating agent/g bagasse) on both surface area and hardness. The production conditions that generated optimal characteristics in the activated carbon were 392 °C, 1.02 g activating agent/g bagasse and 23.8 min for H₃PO₄ activated samples and 456 °C, 1.08 g activating agent/g bagasse and 23.8 min for ZnCl₂ activated samples. The surface area and hardness of the activated carbon produced from bagasse under these conditions were similar to activated commercial carbons (surface area > 800 m²/g and hardness > 85%).     

Effect of Triticum monococcum glutenin loci on cookie making quality and on predictive tests for bread making quality

The effects of Triticum monococcum glutenin loci on cookie making quality and predictive tests for bread making quality were evaluated in recombinant substitution lines (RSLs) between chromosome 1A^m from T. monococcum and chromosome 1A from Chinese Spring. All four combinations of high molecular weight (H M_r-GS) and low molecular weight glutenin alleles (L M_r-GS) were studied in a factorial design to evaluate their interactions. Grain protein content was used as a covariable to evaluate the effect of these loci independently of the variation in protein content among lines. No significant interactions were detected indicating an additive effect. RSLs carrying the HM_r -GS from T. monococcum showed a 13·6% increase in SDS sedimentation volume (p=0·004) and a significant reduction in cookie diameter (−5·2%,p =0·02), and cookie quality (−6·8%, p=0·02). RSLs carrying the LM_r -GS from T. monococcum showed a significant decrease in the proportion of polymeric protein (−2·8%, p<0·0001), SDS sedimentation volume (−8·1%,p =0·03) and gluten strength (−16·5%, p=0·01), and a significant increase in cookie quality (5·9%, p=0·05). The T. monococcum LM_r. -GS allele has potential value to be used in soft wheat breeding programs. These results suggest that diploid T. monococcum could be a valuable source for new allelic variation for storage proteins loci and new quality characteristics.     

Antifungal activity of polyacetylenes isolated from Cirsium japonicum roots against various phytopathogenic fungi

Antifungal substances from a methanol extract of Cirsium japonicum roots were purified and characterized, and their antifungal activities against various plant pathogens were evaluated. Three polyacetylene substances were isolated from roots of C. japonicum using repeated column chromatography; these were identified as ciryneol A, ciryneol C and 1-heptadecene-11,13-diyne-8,9,10-triol by mass and nuclear magnetic resonance spectral analyses. In vitro antifungal activity of the three substances varied according to compound and target species. Magnaporthe oryzae, Colletotrichum coccodes, Colletotrichum acutatum, Pythium ultimum and Botrytis cinerea were relatively sensitive to the three polyacetylenes, with IC₅₀ values below 50 μg mL⁻¹. In vivo, they all showed similar and broad antifungal spectra against the seven plant diseases tested. At 500 μg mL⁻¹, all three compounds effectively suppressed the development of rice blast, rice sheath blight, tomato late blight, wheat leaf rust and red pepper anthracnose, with control values over 90%. They were highly active especially against wheat leaf rust; they controlled the development of this disease more than 88% even at a concentration of 125 μg mL⁻¹. In addition, ciryneol C effectively suppressed barley powdery mildew. This is the first report on the antifungal activities of the three polyacetylenes from roots of C. japonicum against plant pathogenic fungi. Polyacetylenes from roots of C. japonicum may contribute to the development of environmentally safer alternatives to protect crops from various phytopathogenic fungi.     

Multivariate analysis of nitrogen content for rice at the heading stage using reflectance of airborne hyperspectral remote sensing

Airborne hyperspectral remote sensing was adapted to establish a general-purpose model for quantifying nitrogen content of rice plants at the heading stage using three years of data. There was a difference in dry mass and nitrogen concentration due to the difference in the accumulated daily radiation (ADR) and effective cumulative temperature (ECT). Because of these environmental differences, there was also a significant difference in nitrogen content among the three years. In the multiple linear regression (MLR) analysis, the accuracy (coefficient of determination: R², root mean square of error: RMSE and relative error: RE) of two-year models was better than that of single-year models as shown by R² ≥ 0.693, RMSE ≤ 1.405 g m⁻² and RE ≤ 9.136%. The accuracy of the three-year model was R² = 0.893, RMSE = 1.092 g m⁻² and RE = 8.550% with eight variables. When each model was verified using the other data, the range of RE for two-year models was similar or increased compared with that for single-year models. In the partial least square regression (PLSR) model for the validation, the accuracy of two-year models was also better than that of single-year models as R² ≥ 0.699, RMSE ≤ 1.611 g m⁻² and RE ≤ 13.36%. The accuracy of the three-year model was R² = 0.837, RMSE = 1.401 g m⁻² and RE = 11.23% with four latent variables. When each model was verified, the range of RE for two-year models was similar or decreased compared with that for single-year models. The similarities and differences of loading weights for each latent variable depending on hyperspectral reflectance might have affected the regression coefficients and the accuracy of each prediction model. The accuracy of the single-year MLR models was better than that of the single-year PLSR models. However, accuracy of the multi-year PLSR models was better than that of the multi-year MLR models. Therefore, PLSR model might be more suitable than MLR model to predict the nitrogen contents at the heading stage using the hyperspectral reflectance because PLSR models have more sensitive than MLR models for the inhomogeneous results. Although there were differences in the environmental variables (ADR and ECT), it is possible to establish a general-purpose prediction model for nitrogen content at the heading stage using airborne hyperspectral remote sensing.