Implications of the Red Beet Ripening on the Colour and Betalain Composition Relationships

The evolution during ripening of Beta vulgaris (var. Pablo) on colour and betalain composition, not previously conducted in conjunction in red beets, has been examined. According to the results, it could be asserted that the ripening stage significantly (p?<?0.05) influenced on all the studied parameters. On the basis of the betalain content, the optimum ripening stage corresponded to a medium weigh-to-calibre ratio, in the light of the significantly (p?<?0.05) higher content of betalains, especially betanin and vulgaxanthin I. Moreover, colour attributes also differed during ripening, having the medium-ripened beetroots a significantly (p?<?0.05) more reddish hue (h_ab) and lower lightness (L*), probably due to the higher content of betaxanthins in this stage. The colour differences among red beets in the stage II and the rest of stages were visually appreciable (ΔE*_ab?>?3) and mainly qualitative. A new range of opportunities for diversification of colorant market, from a nutritional and colorimetric point of view, could be possible by employing red beets with different stages of ripening.     

<Emphasis Type="Italic">Lupinus albus</Emphasis> Conglutin Gamma Modifies the Gene Expressions of Enzymes Involved in Glucose Hepatic Production <Emphasis Type="Italic">In Vivo</Emphasis>

Lupinus albus seeds contain conglutin gamma (Cγ) protein, which exerts a hypoglycemic effect and positively modifies proteins involved in glucose homeostasis. Cγ could potentially be used to manage patients with impaired glucose metabolism, but there remains a need to evaluate its effects on hepatic glucose production. The present study aimed to analyze G6pc, Fbp1, and Pck1 gene expressions in two experimental animal models of impaired glucose metabolism. We also evaluated hepatic and renal tissue integrity following Cγ treatment. To generate an insulin resistance model, male Wistar rats were provided 30% sucrose solution ad libitum for 20 weeks. To generate a type 2 diabetes model (STZ), five-day-old rats were intraperitoneally injected with streptozotocin (150 mg/kg). Each animal model was randomized into three subgroups that received the following oral treatments daily for one week: 0.9% w/v NaCl (vehicle; IR-Ctrl and STZ-Ctrl); metformin 300 mg/kg (IR-Met and STZ-Met); and Cγ 150 mg/kg (IR-Cγ and STZ-Cγ). Biochemical parameters were assessed pre- and post-treatment using colorimetric or enzymatic methods. We also performed histological analysis of hepatic and renal tissue. G6pc, Fbp1, and Pck1 gene expressions were quantified using real-time PCR. No histological changes were observed in any group. Post-treatment G6pc gene expression was decreased in the IR-Cγ and STZ-Cγ groups. Post-treatment Fbp1 and Pck1 gene expressions were reduced in the IR-Cγ group but increased in STZ-Cγ animals. Overall, these findings suggest that Cγ is involved in reducing hepatic glucose production, mainly through G6pc inhibition in impaired glucose metabolism disorders.     

Effects of Amylose/Amylopectin Ratio and Baking Conditions on Resistant Starch Formation and Glycaemic Indices

The possible improvement of the nutritional properties of starch in barley flour-based bread by using barley genotypes varying in amylose content (3–44%) was evaluated. Breads were made from 70% whole-meal barley flour and 30% white wheat flour. Test breads were baked from waxy barley (WB), ordinary barley (OB), ordinary Glacier barley (OGB) and high-amylose barley (HAB). Each bread was baked either at conventional baking conditions (45 min, 200 °C) or at pumpernickel conditions (20 h, 120 °C). A white wheat bread (WWB) was used as reference. The resistant starch (RS) content and rate of starch hydrolysis were measuredin vitro. The glycaemic index (GI) and the insulinaemic index (II) of the high-amylose breads were determined in healthy subjects. The amount of RS (total starch basis) varied from <1% (WB) to approximately 4% (HAB) in conventionally baked bread, and from about 2% to 10% in the corresponding long-time/low-temperature baked products. The long-time/low-temperature baked HAB displayed a significantly lower rate of starch hydrolysisin vitrocompared with WWB and reduced the incremental blood-glucose response in healthy subjects (GI=71). In contrast, the GI of the conventionally baked HAB was similar to that for WWB. It is concluded that a barley flour-based bread of low GI and high RS content can be obtained by choosing high-amylose barley and appropriate baking conditions.     

Short-term daily forecasting of crop evapotranspiration of rice using public weather forecasts

Accurate forecasts of daily crop evapotranspiration (ET_c) are essential for real-time irrigation management and water resource allocation. This paper presents a method for the short-term forecasting of ET_c using a single-crop coefficient approach and public weather forecasts. Temperature forecasts with a 7-day lead time in 2013–2015 were retrieved and entered into a calibrated Hargreaves–Samani model to compute daily reference evapotranspiration (ET₀) forecasts, while crop coefficient (K_c) empirical values were estimated from both observed ET_c value and calculated ET₀ values using the Penman–Monteith equation for the period of 2010–2012. Daily ET_c forecasts of irrigated double-cropping rice were determined for three growing seasons during the period of 2013–2015 and were compared with ET_c values measured by the weighing lysimeters at the Jiangxi experimental irrigation station in southeastern China. During the early rice season, the average mean absolute error (MAE) and root-mean-square-error (RMSE) values of ET_c forecasts ranged from 0.95 to 1.06 mm day^?1 and from 1.18 to 1.31 mm day^?1, respectively, and the average correlation coefficient (R) ranged from 0.39 to 0.54; for late rice, the average MAE and RMSE values ranged from 1.01 to 1.09 mm day^?1 and from 1.32 to 1.40 mm day^?1, respectively, and the average R value ranged from 0.54 to 0.58. There could be three factors responsible for errors in ET_c forecasts, including temperature forecast errors, K_c value errors and neglected meteorological variables in the HS model, including wind speed and relative humidity. In addition, ET_c was more sensitive to changes in temperature than K_c. The overall results indicated that it is appropriate to forecast ET_c with the proposed model for real-time irrigation management and water resource allocation.     

Influence of different nitrogen forms application on rice photosynthesis: fluorescence with water-saving irrigation in black soil region of Songnen Plain,Northeast China

In order to study the response of the rice photosynthetic-fluorescence characteristics to the application of different nitrogen forms with water-saving irrigation, by using LI-6400XT-type photosynthetic apparatus and other equipment, the fluorescence parameters, stomatal resistance and photosynthetic-CO₂ response curves of rice were measured at the critical stages under water-saving irrigation methods. Results showed that the change trend of ETR and photochemical fluorescence quenching coefficient (Q_p) with different nitrogen forms were declining–rising–declining. Compared with CK (control treatment), ETR and Q_p with NO₃^? treatment were better than the others, which indicated that this treatment was most advantageous to increasing ETR. The electron flow from PSII oxidation-lateral to PSII was enhanced. The potential quantum efficiency (F_v/F_m) was the lowest at tillering stage and the highest at heading stage. Compared with CK, at heading stage, F_v/F_m with NO₃^?, NH₄⁺ NO₃^? and NH₄⁺ treatments was increased by 1.68, 0.61 and 1.81%, respectively, while NO₃^? and NH₄⁺ played a more important role in promoting the ability to capture light. The change trend of non-photochemical fluorescence quenching coefficient with different treatments was not obvious. During the growth period, the stomatal resistance (R_s) was changed dynamically, reaching the second peak at the jointing stage and the highest peak at the milk-ripe stage, and both were higher than CK. The R_s of different nitrogen forms was as NH ₄ ^+? >?NH₄⁺NO ₃ ^?? >?NO₃^?, which showed that with different nitrogen forms, R_s of NO₃^? treatment was low, stomatal opening was correspondingly greater than the other nitrogen forms, and under the same moisture conditions, this treatment of stomatal opening was more beneficial for gas exchange and external CO₂ flowing into the leaf cells, which could increase photosynthetic physiological response. By fitting the parameters of photosynthetic-CO₂ response curve, it was concluded that the photorespiration rate (R_P) was greater than CK, but it was different for three nitrogen treatments during different periods. Rice light saturation point and apparent carboxylation efficiency (α) of NO₃^? treatment during three growth periods were more uniform, indicating that this treatment had a higher utilization rate for low concentration of CO₂. Maximum photosynthetic rate (P_max) with NO₃^? and NH₄⁺ treatments of the three growth periods was 29.396–31.208 and 28.969–31.371, respectively. The CO₂ compensation point and curve angle (θ) had no stable trend during the whole growth period. Therefore, the nitrogen forms could influence the photosynthetic characteristics of the rice leaves, and the result can provide theoretical guidance and scientific basis for increasing the efficiency of nitrogen utilization.     

Characterization of the surface properties of cellulosic fibers in fibrous and ground forms by IGC and contact angle measurements

Surface properties of fibrous and ground cotton and linen were investigated by inverse gas chromatography (IGC) and the contact angle with different liquids was also measured on fabrics composed of both fibers. Results proved that dispersion component of surface tension (γ _s ^d ) determined by IGC depends not only on the surface energy, but also on several factors influencing the adsorbability of probe molecules on the cellulosic substrates. For cotton samples, the trapping of n-alkanes among waxy molecules in the outer layer of fibers can be presumed. This effect results in larger γ _s ^d for cotton fibers than for linen in spite of the higher wettability of the linen fabrics. Besides the surface energy and trapping effects, the grinding also influences the γ _s ^d values. Specific enthalpy of adsorption (ΔH _A ^ab ) of polar probes could be determined on all linen samples, but only on the ground cotton sample. Lewis acid-base character calculated for linen and ground cotton samples depends on the same effects as the γ _s ^d does. The similar ΔH _A ^ab values of chloroform (acidic) and THF (basic) measured on each of the samples support the conclusion that the surface character is amphoteric, which is also proved by the high ΔH _A ^ab values of the amphoteric ethyl acetate and acetone probes.     

Colorimetric Analysis of <Emphasis Type="Italic">Hibiscus</Emphasis> Beverages and their Potential Antioxidant Properties

In food industry, roselle beverages and their subproducts could be functional ingredients since they are an excellent source of bioactive compounds with improved performance due to their important anthocyanins content. The aim of this study was to analyze anthocyanin content and antioxidant properties of aqueous infusions elaborated with color contrasting Hibiscus materials and design a mathematical model in order to predict color-composition relationship. Color measurements of beverages from roselle (Negra, Sudan and Rosa) were made by transmission spectrophotometry, anthocyanins quantification was determined by HPLC, and antioxidant potential was evaluated by in vitro methods (ABTS and FRAP assays). Beverages prepared with particle size minor of 250 μm presented until 4- and 2- times more anthocyanins content and antioxidant capacity respectively, in comparison to beverages prepared with powders with particle size major of 750 μm. Positive correlations among pigments composition and color parameters were found (p?<?0.05), showing that anthocyanins content, antioxidant capacity, C*_ab and h_ab values increased in relation with the smallest particle size of flours. Also, mathematical models were stablished to predict anthocyanin content (r?≥?0.97) and antioxidant capacity (r?≥?0.89) from color data; we propose equations for quick estimation of the antioxidant capacity in the Hibiscus beverages with high anthocyanin content. The obtained models could be an important tool to be used in food industry for pigment characterization or functional compounds with potential health benefits.     

Thermo-Mechanical Characterization of a Thermoplastic Copolyetherester (TPC): Experimental Investigation

In this article, the thermo-mechanical characterization of poly(butylene terephthalate)/poly(tetramethylene oxide) (PBT/PTMO) is studied by thermal analysis, dynamic mechanical analysis, and uniaxial tensile tests. The results of poly(ether esters) show that the melting temperature is equal to T _m =193 °C, which is 31 °C, lower than that of the melting temperature of poly(butylene terephthalate) (PBT). Its glass transition temperature, T _g is equal to -61 °C, determined by DMA. The melting and cooling temperatures (T _m , T _c ) after aging at T₀+48 h and T₀+week are virtually unchanged. Moreover, the results of the tensile tests show that the effect of the low deformation rate reduces the friction resulting from the sliding mechanisms between the amorphous and crystalline parts.     

Antioxidant Properties of Extracts Obtained from Raw,Dry-roasted,and Oil-roasted US Peanuts of Commercial Importance

Raw, skinless peanut kernels from US commercial production lines were dry- and oil-roasted according to standard industrial practices. Eighty percent (v/v) methanolic extracts from the peanut cultivars were prepared and characterized by RP-HPLC: five predominant compounds were found comprising free p-coumaric acid and potential p-coumaric acid derivatives, as elucidated by DAD-UV spectra with comparisons to those of commercial standards. A Spanish high-oleic peanut possessed the greatest naturally-occurring level of p-coumaric acid and its derivatives, followed by a high-oleic Runner, a normal Runner, and a Virginia peanut. Upon thermal processing, p-coumaric acid was liberated at the expense of its derivatives according to the relationship: oil roasting > dry roasting > raw. A high-oleic Runner exhibited the greatest increase (～785%) in free p-coumaric acid levels after oil roasting. For many of the samples from the 2007 crop, processing increased the TPC and antioxidant capacities in the order of raw < dry roast < oil roast, but results were cultivar dependent. Oil-roasted peanuts were more effective at scavenging O₂ ^●- than their dry-roasted counterparts, as determined by a photochemiluminescence assay. Overall findings indicate that although thermal processing altered the composition of peanut kernel antioxidants, TPC values and radical-scavenging activities are preserved. Depending on peanut type, cultivar, and harvest date, enhanced antioxidant capacities can result.     

Validation of dual-crop coefficient method for calculation of rice evapotranspiration under drying–wetting cycle condition

Based on data collected from rice fields under drying–wetting cycle condition, the procedure of dual-crop coefficient (K _cd) approaches was calibrated and validated to reveal its feasibility and improve its performance in rice evapotranspiration (ET _c) estimation. It was found that K _cd based on FAO-recommended basal crop coefficients (K _cb) underestimated dual-crop coefficients in monsoon climate region in East China. The recommended coefficient (K _cp) value of 1.2 was not high enough to reflect the pulse increase of rice ET _c after soil wetting. The K _cb values were calibrated as 1.52 and 0.63 in midseason and late season, and the K _cp value was adjusted as 1.29 after soil wetting in rice field under drying–wetting cycle condition. The dual-crop coefficient curves based on locally calibrated K _cbCal and K _cpCor matched well with the measured crop coefficients and performed well in calculating rice evapotranspiration from paddy fields under drying–wetting cycle condition. So it can be concluded that the procedure of dual-crop coefficient method is feasible in rice ET _c estimation, and locally calibrated K _cb and K _cp can improve its performance remarkably.     

Natural Dyeing of Wool by Madder (<Emphasis Type="Italic">Rubia tinctorum L</Emphasis>.) Root Extract Using Tannin-based Biomordants: Colorimetric,Fastness and Tensile Assay

In this work, the natural dyeing behavior of woollen yarn with madder (Rubia tinctorum L.) root extract was studied. The effects of different tannin-rich plants (Rhus coriaria, Eucalyptus, Terminalia chebula, Quercus castaneifolia, Pomegranate) extract as biomordants and alum (as a chemical mordant) with two mordanting procedures (pre- and metamordanting) on color characteristics of the dyed samples were also investigated. The CIEDE2000 values, color strength (K/S), washing fastness and tensile property of the mordanted and dyed samples were assessed. Visually, a range of hues from orange to brownish-red were obtained. In general, pre-biomordanted samples with Rhus coriaria (10 %owf), Eucalyptus (10 %owf), Terminalia chebula (5 %owf), Quercus castaneifolia (5 %owf) and Pomegranate (5 %owf) showed almost the same color difference (ΔE₀₀) and wash fastness values compared to those treated with 3 %owf alum. Finally, it was concluded from the comparative studies that the biomordants have good potential to be considered as alternatives to the common chemical mordants.     

Prediction of water quality effect on saturated hydraulic conductivity of soil by artificial neural networks

This study was conducted to investigate the impact of water salinity (EC_w) and sodicity (SAR_w) on saturated (K_s) and relative (K_r) hydraulic conductivities in two clay (C) and sandy clay loam (SCL) soils. The results showed that the K_s decreased with increasing SAR_w, and in all of water quality treatments, the K_s of SCL soil was higher than that of the C soil. Sodicity effect (even at high SAR_w) on the K_r of clay soil was minimized by high salinity. Although K_r of both soils similarly responded to EC_w and SAR_w, microstructure of clay soil was more sensitive to water quality. Effect of EC_w on soil structure was greater than that of SAR_w. In order to assess the applicability of artificial neural networks (ANNs) in estimating K_s and K_r, two types of FFBP and CFBP ANNs and two training algorithms, namely Levenberg–Marquardt (LM) and Bayesian regulation, were employed with two strategies of uniform threshold and different threshold functions. Multiple linear regressions were also used for K_s and K_r prediction. Based on the ANN results of second strategy, best topology (4–5–4–1) was belonged to CFBP network with LM algorithm, LOGSIG–LOGSIG–TANSIG threshold functions, and values of MAE and R² are equal to 0.1761 and 0.9945, respectively. Overall, the efficacy of ANNs is much greater than regression method for K_s prediction.     

Water and air temperature impacts on rice (<Emphasis Type="Italic">Oryza sativa</Emphasis>) phenology

Air temperature (T_a) is commonly used for modeling rice phenology. However, since the growing point of rice is under water during the vegetative and the early part of the reproductive period, water temperature (T_w) is likely to have a greater influence on crop developmental rates than T_a during this period. To test this hypothesis, we monitored T_w, T_a, and crop phenology in three commercial irrigated rice fields in California, USA. Sampling locations were set up on along a transect from the water inlet into the field. (Water warms up as it moves into the field.) T_a averaged 22.7 °C across sampling locations within each field, but average seasonal T_w increased from 22 °C near the inlet to 23.4 °C furthest away from the inlet. Relative to T_w furthest from the inlet, low T_w near the inlet delayed time to panicle initiation (PI 5 days) and heading (HD 8 days) and the appearance of one yellow hull on the main stem panicle (R7 9 days). Using T_w instead of T_a when the active growing point is under water until booting (midway between PI and HD) in a thermal time model improved accuracy (root-mean-square error, RMSE) for predicting time to PI by 2.5 days and HD by 1.6 days and R7 by 1.8 days. This model was further validated under more typical field conditions (i.e., not close to cold water inlets) in six locations in California. Under these conditions, average T_w was 2.6 °C higher than T_a between planting and booting, primarily due to higher daily maximum T_w values. Using T_w in the model until booting improved RMSE by 1.2 days in predicting time to HD. Using T_w instead of T_a during this period could improve the accuracy of rice phenology models.     

The Suppression of Verticillium Wilt of Potato Using Corn as a Green Manure Crop

Field studies involving the effects of growing sweet corn (Zea mays var. Jubilee sweet corn and var. Jubilee super-sweet corn) as a green manure for 2 or 3 seasons demonstrated both suppression of verticillium wilt by 60–70% (Verticillium dahliae Kleb.) and increased potato yields. Although these treatments showed no direct effect on V. dahliae soil populations, the colonization of V. dahliae on potato feeder-roots and in potato tissue of stem apices were reduced. Feeder-root colonization by V. dahliae was positively correlated with verticillium wilt incidence (P?≤?0.05 to P?≤?0.01) and negatively correlated with yield (P?≤?0.05). Corn green manures additionally increased populations of several soilborne fungi which included Ulocladium, and Fusarium equiseti. Specific nutritional and microbial effects were secondary to the effects of cropping practices. When compared with the fallow treatments for 1994, 1995, and 1997, the percentage yield increases for 1994 were: +34% for total yield, +57% for U.S. #1’s, and +127% for tubers >280 g; for 1995 (a year of reduced degree-days and decreased verticillium incidence): +14% for total yields, +15% for U.S. #1 yields, and +21% for tubers >280 g; for 1997: +24% for yield totals, +74% for U.S. #1’s and +179% for tubers >280 g. For establishing these yield benefits, stalks with and without ears of corn were used as green manures. Corn varieties differed for effectiveness as a green manure, which could be accounted for by differences of biomass. When compared with the super-sweet corn, the sweet corn produced an increase (>2-fold) of biomass with less than half of the resulting wilt incidence. When potato was grown consecutively for 2 years, the benefits from green manures became mostly eliminated. However, following 2 consecutive years of potato, a single green manure of sweet corn was sufficient to return the potato crop to the original benefits of verticillium suppression and increased yields. This occurred even though soilborne V. dahliae inoculum levels had increased by >4-fold from 45 to 182 cfu g^?1 of soil. Results of this study demonstrate the importance of green manures and soil-ecology to the management of the Russet Burbank potato.     

Multivariable Analysis of Gluten-Free Pasta Elaborated with Non-Conventional Flours Based on the Phenolic Profile,Antioxidant Capacity and Color

The phenolic compounds, color and antioxidant capacity of gluten-free pasta prepared with non-conventional flours such as chickpea (CHF), unripe plantain (UPF), white maize (WMF) and blue maize (BMF) were analyzed. Fifteen phenolic compounds (five anthocyanins, five hydroxybenzoic acids, three hydroxycinnamic acids, one hydroxyphenylacetic acid and one flavonol) were identified in pasta prepared with blue maize, and 10 compounds were identified for samples prepared with white maize. The principal component analysis (PCA) led to results describing 98% of the total variance establishing a clear separation for each pasta. Both the proportion (25, 50 and 75%) and type of maize flour (white and blue) affected the color parameters (L*, C _ab *, h _ab and ΔE* _ab ) and antioxidant properties (DPPH, ABTS and FRAP methods) of samples, thus producing gluten-free products with potential health benefits intended for general consumers (including the population with celiac disease).     

Effects of Different Nitrogen Application Rates on Starch Accumulation,Starch Synthase Gene Expression and Enzyme Activity in Two Distinctive Potato Cultivars

Nitrogen (N) is the most important nutrient for potato growth. N fertilizer has an important effect on the tuber yield and starch content in potatoes. In this study, taking the high-starch cultivar Kexin 22 and the low-starch cultivar Kexin 19 as experimental materials, three N fertilizer application rates—0, 150 and 300 kg/ha—were used to investigate the effects of different N application rates on starch accumulation and the expression of starch synthase genes in potato tubers with different starch contents. In the cultivar Kexin 22, the accumulations of amylose, amylopectin and total starch showed a ranking of N150 > N300 > N0 for the entire growth period. The cultivar Kexin 19 showed an accumulation pattern of N0 > N150 > N300 in the early growth period, N150 > N300 > N0 in the middle growth period and N300 > N150 > N0 in the late growth period. Compared with those in Kexin 19, the expressions of the glucose-1-phosphate adenyltransferase (AGPP-L), granule-bound starch synthase (GBSSI), starch-branching enzyme I (SBEI) and soluble starch synthase III (SSIII) genes in Kexin 22 were upregulated, whereas no obvious difference existed in the expression of the alkylglycerone phosphate synthase (AGPP-S) and soluble starch synthase II (SSII) genes between the two cultivars. In Kexin 22, the different N application rates had a significant effect on the peak expression levels of AGPP-L, GBSSI, SBEI and SSIII but had a small effect on the peak expression time for these genes. Among these genes, most showed a ranking of N150 > N300 > N0 in the early and middle growth periods, and all showed a ranking of N300 > N150 > N0 in the late growth period; most showed a peak expression time on the 65th day after emergence (DAE 65). In Kexin 19, the different N application rates had a significant effect on the peak expression levels and peak expression times of the AGPP-L, GBSSI, SBEI and SSIII genes. Among these genes, all showed a ranking of N0 > N150 > N300 in the early growth period, whereas most showed a ranking of N150 > N300 > N0 in the middle growth period, and all showed a ranking of N300 > N150 > N0 in the late growth period. In Kexin 19, the peak gene expression was shifted to an earlier date under the low N levels, and it was delayed under the high N levels. The effects of the N application rate on the activities of starch synthases AGPP, GBSS, SSS and SBE showed largely the same trends as those in the expression levels of the related genes. Therefore, to obtain a high harvest of starch yield, different N application rates should be recommended for different cultivars.     

Effect of water management on soil respiration and <Emphasis Type="Italic">NEE</Emphasis> of paddy fields in Southeast China

Water management is an important factor in regulating soil respiration and the net ecosystem exchange of CO₂ (NEE) between croplands and atmosphere. However, how water management affects soil respiration and the NEE of paddy fields remains unexplored. Thus, a 2-year field experiment was carried out to study the effects of controlled irrigation (CI) during the rice season on the variation of soil respiration and NEE, with flooding irrigation (FI) as the control. A decrease of irrigation water input by 46.39% did not significantly affect rice yield but significantly increased irrigation water use efficiency by 0.99 kg m^?3. The soil respiration rate of CI paddy fields was larger than that of FI paddy fields except during the ripening stage. Natural drying management during the ripening stage resulted in a significant increase of the soil respiration rate of the FI paddy fields. Variations of NEE with different water managements were opposite to soil respiration rates during the whole rice growth stages. Total CO₂ emission of CI paddy fields through soil respiration (total R _soil) increased by 11.66% compared with FI paddy fields. The increase of total R _soil resulted in the significant decrease of total net CO₂ absorption of CI paddy fields by 11.57% compared with FI paddy fields (p < 0.05). There were inter-annual differences of soil respiration and the NEE of paddy fields. Frequent alternate wetting and drying processes in the CI paddy fields were the main factors influencing soil respiration and NEE. CI management slightly enhanced the rice dry matter amount but accelerated the consumption and decomposition of soil organic carbon and significantly increased soil respiration, which led to the decrease of net CO₂ absorption. CI management and organic carbon input technologies should be combined in applications to achieve sustainable use of water and soil resources in paddy fields.     

Thermal characterization of epoxy nanocomposites containing polyhedral oligomeric silsesquioxane: Glass transition temperature and chemical conversion

An epoxy resin (diglycidyl ether of bisphenol-A) was blended with different loadings of a glycidyl-polyhedral oligomeric silsesquioxane (POSS) and isothermally cured with an amine hardener at varying temperatures and times. The glass transition temperature (T _g) of the samples was measured at different chemical conversions (α) using differential scanning calorimetry (DSC). Time-temperature shifts were made for T _g vs. ln(time) data to be superposed at an arbitrary reference temperature in the kinetically controlled reaction regime, and these shift factors were used to obtain an Arrhenius activation energy. The influence of POSS on different reaction systems was investigated in terms of the T _g-α relationship, which was fitted with two models; DiBenedetto and Venditti/Gillham equations. It was found that POSS molecules played different roles at different stages of the curing process. At lower conversions, the inorganic cage of the incorporated POSS (up to 20 wt%) reduced the mobility of the molecular segments, giving rise to an increase in T _g. However, above the 20 wt% POSS, there was a depression of T _g, which may be associated with a plasticizing effect of organic substituents of the POSS molecules. Moreover, the effect of POSS on T _g became less pronounced when the conversion reached 0.8.     

Phenotypic and Genomic Modifications Associated with <Emphasis Type="Italic">Globodera pallida</Emphasis> Adaptation to Potato Resistances

Studying phenotypic and genomic modifications associated with pathogen adaptation to resistance is a crucial step to better understand and anticipate resistance breakdown. This short review summarizes recent results obtained using experimentally evolved populations of the potato cyst nematode Globodera pallida. In a first step, the variability of resistance durability was explored in four different potato genotypes carrying the resistance quantitative trait loci (QTL) GpaV_vrn originating from Solanum vernei but differing by their genetic background. The consequences of the adaptation to resistance in terms of local adaptation, cross-virulence and virulence cost were then investigated. Finally, a genome scan approach was performed in order to identify the genomic regions involved in this adaptation. Results showed that nematode populations were able to adapt to the QTL GpaV_vrn, and that the plant genetic background has a strong impact on resistance durability. A trade-off between the adaptations to different resistant potato genotypes was detected, and we also showed that adaptation to the resistance QTL GpaV_vrn from S. vernei did not allow adaptation to the colinear locus from S. sparsipilum (GpaV_spl). Unexpectedly, the adaptation to resistance led to an increase of virulent individual’s fitness on a susceptible host. Moreover, the genome scan approach allowed the highlighting of candidate genomic regions involved in adaptation to host plant resistance. This review shows that experimental evolution is an interesting tool to anticipate the adaptation of pathogen populations and could be very useful for identifying durable strategies for resistance deployment.     

Identification of resistant germplasm containing novel resistance genes at or tightly linked to the <Emphasis Type="Italic">Pi2/9</Emphasis> locus conferring broad-spectrum resistance against rice blast

Background

The rice Pi2/9 locus harbors multiple resistance (R) genes each controlling broad-spectrum resistance against diverse isolates of Magnaporthe oryzae, a fungal pathogen causing devastating blast disease to rice. Identification of more resistance germplasm containing novel R genes at or tightly linked to the Pi2/9 locus would promote breeding of resistance rice cultivars.

Results

In this study, we aim to identify resistant germplasm containing novel R genes at or tightly linked to the Pi2/9 locus using a molecular marker, designated as Pi2/9-RH (Pi2/9 resistant haplotype), developed from the 5′ portion of the Pi2 sequence which was conserved only in the rice lines containing functional Pi2/9 alleles. DNA analysis using Pi2/9-RH identified 24 positive lines in 55 shortlisted landraces which showed resistance to 4 rice blast isolates. Analysis of partial sequences of the full-length cDNAs of Pi2/9 homologues resulted in the clustering of these 24 lines into 5 haplotypes each containing different Pi2/9 homologues which were designated as Pi2/9-A5, ?A15, ?A42, ?A53, and -A54. Interestingly, Pi2/9-A5 and Pi2/9-A54 are identical to Piz-t and Pi2, respectively. To validate the association of other three novel Pi2/9 homologues with the blast resistance, monogenic lines at BC₃F₃ generation were generated by marker assisted backcrossing (MABC). Resistance assessment of the derived monogenic lines in both the greenhouse and the field hotspot indicated that they all controlled broad-spectrum resistance against rice blast. Moreover, genetic analysis revealed that the blast resistance of these three monogenic lines was co-segregated with Pi2/9-RH, suggesting that the Pi2/9 locus or tightly linked loci could be responsible for the resistance.

Conclusion

The newly developed marker Pi2/9-RH could be used as a potentially diagnostic marker for the quick identification of resistant donors containing functional Pi2/9 alleles or unknown linked R genes. The three new monogenic lines containing the Pi2/9 introgression segment could be used as valuable materials for disease assessment and resistance donors in breeding program.