Application strategies for an anthraquinone-based repellent to protect oilseed sunflower crops from pest blackbirds

Non-lethal alternatives are needed to manage the damage caused by wild birds to oilseed sunflower crops (Helianthus annuus Linnaeus). We evaluated field residues and experimental applications of an anthraquinone-based repellent (active ingredient 50% 9,10-anthraquinone) to minimize red-winged blackbird (Agelaius phoeniceus Linnaeus) depredation of oilseed sunflower. Chemical residues from experimental applications of the anthraquinone-based repellent (4.7 l/ha and 9.4 l/ha; low, high) in a ripening oilseed sunflower field were 481 ppm and 978 ppm anthraquinone at the beginning of blackbird damage, and 385 ppm and 952 ppm anthraquinone at the end of blackbird damage, respectively. Prior to harvest, we observed 402 ppm and 462 ppm anthraquinone in the oil, and 27 ppm and 165 ppm anthraquinone in the pomace from crushed sunflower achenes previously sprayed with the low and high applications, respectively. For the purpose of developing application strategies useful for avian repellents, we subsequently investigated blackbird feeding response to oilseed sunflower treated with the anthraquinone-based repellent and either a registered insecticide or a registered fungicide popularly used for ripening sunflower. We observed a positive concentration–response relationship among blackbirds exposed to anthraquinone and the insecticide (a.i. 8.4% esfenvalerate), or anthraquinone and the fungicide (a.i. 23.6% pyraclostrobin). Blackbirds reliably discriminated between untreated sunflower and that treated with 1810 ppm anthraquinone and 0.1% of the insecticide or 1700 ppm anthraquinone and 0.14% of the fungicide during our preference experiments. Given that ripening achenes are inverted from conventional pesticide applications throughout much of the period associated with blackbird depredation, we also evaluated blackbird repellency of the anthraquinone-based repellent applied to involucral bracts (i.e., the back of sunflower heads) of oilseed sunflower. Blackbirds did not discriminate between untreated involucral bracts and those treated with foliar applications comparable to 4.7 l/ha or 9.4 l/ha; blackbirds consumed more achenes from untreated sunflower heads than from those treated with 18.7 l/ha of the anthraquinone-based repellent. Supplemental repellent efficacy studies should investigate blackbird response to anthraquinone-based repellents (e.g., ≥4.7 l/ha) within 10–100 ha sunflower fields and include independent field replicates with predicted bird damage, repellent application strategies developed for protection of ripening crops, pre- and at-harvest repellent residues, and bird damage and crop yield measurements.     

Barley (1→3; 1→4)-β-glucan and arabinoxylan content are related to kernel hardness and water uptake

Harder kernels in barley are thought to be a factor affecting the modification of the endosperm during malting by restricting water and enzyme movement within the endosperm. The objective of this study was to investigate the relationship between kernel hardness, water uptake and the endosperm composition in barley. A range of barley samples from 2003 and 2004 crops were analyzed for kernel hardness by the Single Kernel Characterization System, water uptake during steeping and chemical composition of the endosperm including (1→3; 1→4)-β-glucan, arabinoxylan and total protein. Both (1→3; 1→4)-β-glucan and arabinoxylan content of the endosperm were correlated significantly with kernel hardness in barley samples from both 2003 (r=0.873 and 0.601, respectively, p<0.01) and 2004 seasons (r=0.764 and 0.501, respectively, p<0.01). Hardness of the kernel was highly correlated with its water uptake in both 2003 and 2004 samples (r=−0.853 and −0.752, respectively, p<0.01). β-Glucan content of the endosperm was also correlated significantly with the kernel water uptake for both years (2003: r=−0.752, p<0.01; 2004: r=−0.551, p<0.01). Arabinoxylan content of the endosperm was correlated significantly with the kernel water uptake for the 2003 barley but not for 2004 barley (2003: r=−0.523, p<0.01; 2004: r=−0.151, p>0.01). Protein content of the endosperm was not correlated with the kernel hardness in either year. These results demonstrate that endosperm cell wall components may have significant impact on kernel hardness as well as water uptake of barley.     

Predicting hot-press wheat tortilla quality using flour,dough and gluten properties

A cost-effective, faster and efficient way of screening wheat samples suitable for tortilla production is needed. This research aimed to develop prediction models for tortilla quality (diameter, specific volume, color and texture parameters) using grain, flour and dough properties of 16 wheat flours. Another set of 18 samples was used to validate the models. The prediction models were developed using stepwise multiple regression. Dough rheological tests had higher correlations with tortilla quality than grain and flour chemical tests. Mixograph mixing time and dough resistance to extension (from extensibility test using a texture analyzer) were correlated best with tortilla quality, particularly tortilla diameter (r = −0.87 and −0.86 respectively, P < 0.01). Insoluble polymeric proteins (IPP) and gluten index were significantly correlated with tortilla diameter (r = −0.70 and −0.67 respectively, P < 0.01) and specific volume (r = −0.73, P < 0.01). Tortilla diameter was the quality parameter best explained (R² = 0.86) by the prediction models using mixing time and dough resistance to extension. Rheological parameters such as rupture distance and maximum force were also successfully predicted. These prediction models, developed from linear equations, will be an easy and fast tool for breeders to advance or eliminate wheat lines specifically bred for tortilla production.     

Determination of selection criteria for seed yield and seed oil content in Vernonia (Vernonia galamensis variety ethiopica)

The magnitude of relationships among different traits is important in plant breeding programs to identify the best selection criteria and improve the efficiency of selection. This study was conducted to determine relationships between seed yield and seed oil content with other important agronomic traits among 36 diverse accessions of Vernonia (Vernonia galamensis variety ethiopica), a potentially novel industrial oilseed crop. Field evaluations were conducted during 2005, 2006 and 2007 at the Limpopo Province in South Africa using a partially balanced lattice design. Simple correlation and path analysis were performed to identify the best selection criteria for increased seed yield and seed oil content. Simple correlation and path analyses revealed that the formation of productive primary heads strongly associated with increased seed yield (r_g = 0.81, p < 0.001). Furthermore, path analysis indicated selection for increased number of primary heads would bring about simultaneous and favorable change towards reduced days to maturity and shorter plant height. Further associational study of traits with seed oil content showed a significant (p < 0.05) correlation between oil content with 1000 seed weight (r_g = 0.4). The path analysis, however, exposed seed yield followed by 1000 seed weight with significant direct effect on seed oil content. The study demonstrated that selection for increased number of productive primary heads is the principal selection criterion to improve seed yield. Whereas selection for 1000 seed weight and increased seed yield serve as major selection criteria to achieve increased oil content in V. galemanesis.     

Heritability of,and genotypic correlations between,aflatoxin traits and physiological traits for drought tolerance under end of season drought in peanut (Arachis hypogaea L.)

More rapid progress in breeding peanut for reduced aflatoxin contamination should be achievable with a better understanding of the inheritance of, aflatoxin trait and physiological traits that are associated with reduced contamination. The objectives of this study were to estimate the heritability of aflatoxin traits and genotypic (r_G) and phenotypic (r_P) correlations between drought resistance traits and aflatoxin traits in peanut. One hundred-forty peanut lines in the F_4:6 and F_4:7 generations were generated from four crosses, and tested under well-watered and terminal drought conditions. Field experiments were conducted under the dry seasons 2006/2007 and 2007/2008. Data were recorded for biomass (BIO), pod yield (PY), drought tolerance traits [harvest index (HI), drought tolerance index (DTI) of BIO and PY, specific leaf area (SLA), and SPAD chlorophyll meter reading (SCMR)], and aflatoxin traits [seed infection and aflatoxin contamination]. Heritabilities of A. flavus infection and aflatoxin contamination in this study were low to moderate. The heritabilities for seed infection and aflatoxin contamination ranged from 0.48 to 0.58 and 0.24 to 0.68, respectively. Significant correlations between aflatoxin traits and DTI (PY), DTI (BIO), HI, biomass and pod yield under terminal drought conditions were found (r_P = −0.25** to 0.32**, r_G = −0.57** to 0.53**). Strong correlations between SLA and SCMR with A. flavus infection and aflatoxin contamination were also found. Positive correlations between SLA at 80, 90, and 100 DAP and aflatoxin traits were significant (r_P = 0.13** to 0.46**, r_G = 0.26** to 0.81**). SCMR was negatively correlated with aflatoxin traits (r_P = −0.10** to −0.40**, r_G = −0.11** to −0.66**). These results indicated that physiological-based selection approaches using SLA and SCMR might be effective for improving aflatoxin resistance in peanut.     

Source–sink relations and kernel weight differences in maize temperate hybrids

Maize (Zea mays L.) kernel weight (KW) response to changes in assimilate availability per kernel during grain filling suggests that plants establish an early kernel sink potential that place them to grow close to a saturating assimilate availability condition during late grain-filling, meaning source limitations are common only early in kernel development. As maize reproductive efficiency in kernel set is not constant across different plant growth rates (PGR) around flowering, we used PGR per kernel during this period as an indicator of source availability per kernel. We tested whether PGR per kernel during flowering or during the effective grain-filling period were correlated to genotypic and environmental differences in final KW. Plant growth rate during both periods, KW, kernel growth rate during the effective grain-filling period, total duration of grain filling and kernel number per plant were measured in 12 commercial genotypes differing in KW sown at two sites under full irrigation. As expected from the curvilinear response relating kernel number per plant and PGR around flowering, increased PGRs resulted in higher PGR per kernel around this period (r² = 0.86; p < 0.001). Differences in final KW due to genotypes or environments were significantly explained by the PGR per kernel around flowering (r² = 0.40; p < 0.001), and not by the PGR per kernel during the effective grain-filling period. Genotypes differed in kernel growth rate (p < 0.001) and grain-filling duration (p < 0.001). The former was well explained by PGR per kernel around flowering (r² = 0.66; p < 0.001), but showed no relationship with the PGR per kernel during the effective grain-filling period. Grain-filling duration was partially explained (r² = 0.27; p < 0.01) by the ratio between PGR per kernel during the effective grain-filling period and kernel growth rate, but differences in duration were negligible compared to those observed in the ratio (∼41% versus ∼130%, respectively). Together, these results support the importance of source availability per kernel during early grain filling on the determination of maize potential sink capacity and final KW. Early resource availability per kernel was accurately estimated as PGR per kernel around the period of kernel number determination, which helped explain genotypic and environmental differences in maize final KW as well as in kernel growth rate.     

Dissection of antioxidant activity of durum wheat (Triticum durum Desf.) grains as evaluated by the new LOX/RNO method

Antioxidant activity (AA) of durum wheat (Triticum durum Desf.) grains was studied using the innovative LOX/RNO method, able to simultaneously detect different antioxidant mechanisms, and the TEAC assay, one of the most widely used assays. Insoluble-bound and free-soluble phenols, hydrophilic and lipophilic compounds were extracted from eight different whole flour samples; extracts were analyzed for AA and their content in several antioxidants. The LOX/RNO method measured very high AA values, with the highest ones [850–1500 μmol Trolox eq./g whole flour (dry weight)] for insoluble-bound phenolic extracts, highly correlated to total phenolic (r = 0.761, P < 0.001) and ferulic acid (r = 0.816, P < 0.001) contents. Hydrophilic and lipophilic extracts showed lower AA [70-140 and 40–60 μmol Trolox eq./g (dry weight), respectively], highly correlated to flavonoid (r = 0.583, P < 0.01) and protein (r = 0.602, P < 0.01), as well as β-tocotrienol (r = 0.684, P < 0.05) contents, respectively. Interestingly, the LOX/RNO method suggests that insoluble-bound phenolic compounds may exert very strong synergistic interactions within the extract. Contrarily, the TEAC assay did not correlate to any antioxidant content, resulted unable to highlight differences among samples, measured much lower AA values and did not suggest synergism. The use of the LOX/RNO method is useful to unearth new properties of phytochemicals from durum wheat grains, potentially giving health benefits.     

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.     

Sensitivity and cross-resistance patterns to demethylation-inhibiting fungicides in California populations of Alternaria alternata pathogenic on pistachio

Alternaria late blight (ALB) caused by Alternaria spp. is an annual production concern for pistachio growers in California. In this study, isolates of Alternaria alternata collected from California pistachio orchards between 1998 and 2003 (population A, n = 46) and in 2010 (population B, n = 38) prior to the registration and use of sterol demethylation-inhibiting (DMI) fungicides for ALB control, were tested for their sensitivity to difenoconazole, propiconazole, and tebuconazole using an in vitro mycelial growth assay. The 50% effective dose (EC₅₀) values for isolates in population A to difenoconazole, propiconazole, and tebuconazole, respectively, ranged from 0.02 to 0.82 μg/mL (mean = 0.17), 0.25–5.73 μg/mL (mean = 1.29), and 0.02–2.76 μg/mL (mean = 0.96), and from 0.02 to 0.93 μg/mL (mean = 0.21), 0.13–5.36 μg/mL (mean = 1.25), and 0.17–5.47 μg/mL (mean = 1.03) for those in population B. Among 65 isolates collected in 2012 from orchards with very limited exposure to difenoconazole, propiconazole or metconazole (population C, n = 65), the EC₅₀ values for tebuconazole ranged from 0.02 to 2.99 μg/mL (mean = 0.51), while EC₅₀ values for difenoconazole of 55 of these isolates varied from 0.01 to 0.44 μg/mL (mean = 0.06). The DMI-exposed population C was found to be on average two to four times less sensitive compared with the populations A and B. Pearson correlation analyses of EC₅₀ values for the three fungicides showed significant positive correlations between the sensitivities of tebuconazole and propiconazole (P < 0.01, r = 0.32), tebuconazole and difenoconazole (P < 0.01, r = 0.26), and difenoconazole and propiconazole (P < 0.01, r = 0.40). Results indicate a clear difference in fungicide intrinsic activity, with difenoconazole being more active than the two other DMIs. Although wide variations in sensitivities for tebuconazole and propiconazole were observed in the non- and DMI-exposed Alternaria populations, efficacy of DMI products has been excellent against ALB. The data collected here will be crucial for the rational use of DMIs in fungicide spray programs for ALB management and serve as a reference to detect any shifts in A. alternata sensitivity to these fungicides in subsequent years as they become more frequently used in California pistachios.     

Morphological and molecular diversity of Agave tequilana Weber var. Azul and Agave angustifolia Haw. var. Lineño

The genetic diversity in forty-nine Agave tequilana Weber var. Azul accessions from different regions of the Appellation of Origin Tequila, and eighteen Agave angustifolia Haw. var. Lineño accessions from the south of the state of Jalisco, were evaluated using morphological traits and RAPD (Randomly Amplified Polymorphic DNA) markers. Thirteen morphological characters and three different random 10-mer primers were used. Statistical analysis for these traits revealed that all of them were statistically different (α = 0.05). Three principal components (PC) accounted for 79.9% of the total variability. The number of teeth found in 10 cm, the distance between the last lateral and the apical spine, tooth length, tooth basal width, maximum distance between teeth and leaf width were the most important traits. Besides the wide morphological variation found in both varieties, we were able to separate A. angustifolia from A. tequilana in two main groups using the dendrogram (r = 0.82) and plot from the PCA analysis. The RAPD analysis generated 46 clear and reproducible fragments, 24 of them (52%) were polymorphic, and this polymorphism was higher in A. tequilana (35%) than in A. angustifolia (24%). The dendrogram that was based on RAPD data, revealed two main groups similar to the morphological analysis with some discrepancies. Despite the low correlation found between morphological and molecular data (r = 0.31), these analyses were able to separate the agave varieties used in this study and were informative and complementary.     

Variation in vitamin E level and aflatoxins contamination in different rice varieties

In the present study, a total of 380 samples of 5 rice varieties were investigated for the presence of aflatoxins (AFs) and tocopherols (Vitamin E) using HPLC, equipped with a fluorescence detector. The data revealed that super basmati rice has the highest mean level of total AFs (12.45 μg/kg) followed by KS-282 (11.2 μg/kg), basmati PK-385 (9.8 μg/kg), Irri-6 (9.7 μg/kg) and the lowest mean level was found in Irri-9 (8.9 μg/kg). Furthermore, the results have shown that the variety with lowest level of AFs has the highest level of tocopherol content; i.e. Irri-9 (53.2 mg/100 g), basmati PK-385 (45.9 mg/100 g), Irri-6 (45.3 mg/100 g), KS-282 (40.4 mg/100 g) and super basmati rice (40.2 mg/100 g). The data has shown correlation (r = −0.62, p < 0.05) between vitamin E content and AFs concentration in different rice varieties. The results are interesting and need further study to investigate the mechanistic background of vitamin E content and its effect on aflatoxins contamination.     

Appraisal of Thai glutinous rice husk for health promotion products

Rice husks of the RD 6 variety were refluxed with water for 30, 60 and 120 min. The longest extraction time resulted in the greatest yield (0.089 ± 0.008%), radical scavenging activity (IC₅₀ = 37.203 ± 0.421 μg/ml), and total phenolic and flavonoid contents (7.512 ± 0.008 g GAE/100 g extract and 36.886 ± 0.004 g QE/100 g extract). Fatty acids of cosmetic importance, such as hexanoic, heptatonic, octanoic, nonanoic, stearic, palmitic, oleic and linoleic acids, were quantified using the best antioxidant extract (166.004 mg/kg). The total phenolic content was related to the antioxidant activity and total fatty acid content (r = 0.997 and 0.864) in linoleic acid (r = 0.989), which displayed antioxidant properties (r = 0.996). The extract was non-cytotoxic in vero cells. Furthermore, it was compatible and stable in cosmetic formulations. Therefore, rice husks should be further studied for use in health promotion products.     

Evaluation of elevated bait trays for attracting blackbirds (Icteridae) in central North Dakota

Sunflower (Helianthus annuus L.) became an economically important crop in North Dakota in the 1970s, providing a major source of food for post-breeding blackbirds (Icteridae). Reducing local blackbird populations with rice grains treated with an avicide is one proposed alternative for reducing sunflower damage. In fall 2007 and 2008, we evaluated the idea of attracting blackbirds to rice-baited trays attached to wire cages supplied with live blackbirds. During our observations (1011 h), we saw 3888 birds, consisting of 25 species and 12 families, on the bait trays. Blackbirds made up 90.4% of the bird observations, whereas sparrows (Emberizidae) made up 1.6% of the birds observed. Overall risk to non-target species appeared minimal. The bait trays, however, attracted a small number of blackbirds compared to the source population feeding in nearby crop fields. Our results strongly suggest DRC-1339-treated rice used on bait trays is unlikely to be a cost-effective method of reducing blackbird damage to ripening sunflower.     

Grazing management for more resilient mixed livestock farming systems on native grasslands of southern South America

Droughts in southern South America affect grazing systems in many ways. They reduce biomass productivity; decrease livestock feed intake, weight and reproductive performance; increase farmers’ costs; and reduce farm income. It was hypothesized that simple grazing management variables affect the resilience of grazing systems to droughts at the paddock and farm scales. The effects of grazing management on herbage and animal production were assessed at paddock level, and how technological and structural variables relate to the production and economic performances at farm level. Results of a grazing experiment controlling herbage allowance at paddock level showed that resistance of herbage accumulation and animal live weight to drought was significantly higher for paddocks with higher pre‐drought herbage allowance than for those managed to low herbage allowance treatments. A strong positive linear relationship was found between pre‐drought herbage height and resistance of herbage accumulation rate (p < .01). In a longitudinal study of nine farms in Uruguay, resistance of cow pregnancy rate to drought was positively correlated with cow pregnancy rate (r = .72, p = .02) and farm net income (r = .78, p = .02), and negatively correlated with sheep‐to‐cattle ratio (r = ?.80, p = .01). These correlations suggest that farms with higher incomes and low proportions of sheep in the herd withstand drought better (in terms of pregnancy rate). Four common regional production strategies were identified that react differently when farmers face drought, and these results can aid farmers in those regions to design more resilient mixed livestock farming systems and can inform policymakers about effective strategies for mitigating drought impacts in the region.     

Wild annual Helianthus anomalus and H. deserticola for improving oil content and quality in sunflower

Within the past decade, the desire for alternative sources of fuels, chemicals, and other industrial materials has received increased attention. Sunflower (Helianthus annuus L.) oil has the potential to be improved for nutritional and industrial purposes through selection and breeding. The narrow genetic base of cultivated sunflower has been broadened by the infusion of genes from wild species, resulting in a continuous improvement in agronomic traits. The genus Helianthus is comprised of 51 species and 19 subspecies with 14 annual and 37 perennial species. Interest in using wild species in breeding programs has increased, but concerns about the introduction of low oil concentration and quality from the wild species persist. Two annual desert species, Helianthus anomalus Blake and H. deserticola Heiser, are excellent candidates for increasing oil concentration and enhancing quality based on their adaptation to desert environments. The objective of this study was to collect achenes of H. anomalus and H. deserticola from the desert southwest USA and assess their potential for improving oil concentration and quality in cultivated sunflower. The sunflower collection took place from 16 to 23 September 2000 and covered a distance of 4100 km in three states: Utah, Arizona, and Nevada. The only H. deserticola population collected had an average oil concentration of 330 g/kg, whereas the two populations of H. anomalus had an oil concentration of 430 and 460 g/kg, the highest concentration recorded in any wild sunflower species. The linoleic fatty acid concentration in the oil of H. anomalus populations was uncharacteristically high for a desert environment, approaching 700 g/kg. A linoleic acid concentration of 540 g/kg in H. deserticola was more typical for a desert environment. H. anomalus has the largest achenes and the highest oil concentration of any wild sunflower species, and the same chromosome number (n = 17) as cultivated sunflower. These features will facilitate the introduction of genes from this wild annual progenitor into cultivated sunflower. The lower saturated fatty acid profile in this species is also a desirable trait offering the potential to reduce saturated fatty acids in cultivated sunflower. Further research will be needed to determine the inheritance of the fatty acids and oil concentration. Other agronomic traits will need to be maintained during the introgression of these traits into cultivated sunflower oil.     

Prediction of total phenols,condensed tannins,and 3-deoxyanthocyanidins in sorghum grain using near-infrared (NIR) spectroscopy

The reported high phenolic levels in sorghum have led an interest from sorghum breeding programs in developing and identifying germplasms with high phenolic levels, which require screening a large number of samples to find those with the highest levels. Since wet chemistry screening methods are slow, expensive, and destructive, the use of NIR calibration curves could be an alternative. The objectives of this project were to determine the variation range in total phenols, condensed tannins, and 3-deoxyanthocyanidin levels in a diverse set of sorghum genotypes and to assess the predictive value of NIR curves to estimate these compounds in sorghum. A calibration curve to estimate each compound was developed and validated with an independent validation set. Calibration curve correlations for total phenols, condensed tannins, and 3-deoxyanthocyanidins were r = 0.98, 0.97, and 0.99, respectively. Correlations between NIR-predicted values and reference values in the validation set were significant for total phenols (r = 0.93), condensed tannins (r = 0.81) and 3-deoxyanthocyanidin (r = 0.82). These indicated that sufficient variation for these compounds existed within sorghum and that NIR calibration curves could be used to rapidly and non-destructively predict total phenols, condensed tannins, and 3-deoxyanthocyanidins concentrations in whole grain sorghum.     

Endogenous arabinoxylans variability in refined wheat flour and its relationship with quality traits

Arabinoxylans (AXs) are the major dietary fiber (DF) component in wheat and their consumption has been associated with several health benefits. Genetic improvement of the AX in refined wheat flour could be a good solution to improve the DF daily consumption while maintaining the flour desirable quality. In this study, 193 common wheat lines were analyzed for their AX content in refined flour and end-use quality. Wide variation in both the total arabinoxylan (TOT-AX) (10.8–16.5 mg/g) and water-extractable arabinoxylan (WE-AX) (3.2–7.6 mg/g) was identified and, in both cases, the genotype had the greatest impact on the observed phenotypes. Variation in the endogenous AX fractions appeared to have a moderate effect on wheat quality. The WE-AX, specifically, were positively correlated with gluten strength (r = 0.11 to 0.32) and bread loaf volume (r = 0.16), whereas the TOT-AX were negatively correlated with dough extensibility (r = −0.11) and bread making quality (r = −0.11). Overall, results of this study show that the genetic improvement of grain AX is feasible and that the AXs present in refined flour do not dramatically alter wheat quality indicating that it is possible to select varieties with high AX endosperm content end desired end-use quality.     

Impact of amylose content on starch retrogradation and texture of cooked milled rice during storage

Milled rice from 11 varieties, with amylose levels from 1.2 to 35.6% dry base, were collected to study the impacts of amylose content on starch retrogradation and textural properties of cooked rice during storage. The relationship between amylose content and different properties was determined using Pearson correlation. Starch retrogradation enthalpy (ΔH_r) of cooked rice was determined by differential scanning calorimetry. ΔH_r values were found to be positively correlated with amylose content (0.603 ≤ r ≤ 0.822, P < 0.01) during storage. Textural properties were determined by a Texture Analyser. The hardness of cooked rice showed a positive correlation with amylose content (0.706 ≤ r ≤ 0.866, P < 0.01) and a positive correlation with ΔH_r of cooked rice (r = 0.650, P < 0.01) during storage. The adhesiveness showed a negative correlation with amylose content (−0.929 ≤ r ≤ −0.678, P < 0.01) and a negative correlation with ΔH_r of cooked rice (r = −0.833, P < 0.01) during storage. Hardness showed a negative correlation with adhesiveness (r = −0.820, P < 0.01). These results indicated that amylose content has significant effects on starch retrogradation and textural properties of cooked rice. The cooked rice with high amylose content is easy to retrograde, the cooked rice with low amylose content retrograded slowly. Sarch retrogradation contributes to the changes of textural properties of cooked rice during storage.     

Measuring volume and density of a barley grain using ellipsoid approximation from a 2-D digital image

A digital imaging method was developed to determine the size, weight, volume and density of individual barley grains. Calibrations were developed using morphological measurements based on 2-D digital images, and were validated using a range of bulk barley samples.The validation of the grain diameter (minor) and grain weight algorithms gave high correlation coefficients (r = 0.93 and 0.97, respectively, P < 0.01), with low standard errors (0.09 mm and 1.37 mg, respectively) when compared to physical measurements.Estimated grain volume and density from image data, using three different mathematical approaches were compared: Model 1, a general ellipsoid; Model 2, a combination of two cone frustums with an ellipse top and base; and Model 3, a set of elliptical cylinders representing pixels along the image length. Derived grain volume data using Model 2 when compared to gas displacement volume measurements gave significant correlations (r = 0.97, P < 0.01) with the lowest standard error (0.97 mm³), in contrast to volume data estimated using Model 1 and Model 3. Even though Model 2 gave accurate and precise results for grain volume, Model 1 (with the slope adjusted) gave the highest correlation (r = 0.63, P < 0.01) with the lowest standard error (0.055 mg/mm³) for estimating grain density from image data, compared to gas displacement density measurements.     

Changes in agronomic traits of sunflower hybrids over 20 years of breeding in central Argentina

This paper applies linear mixed model and pattern analyses to 122 on-farm trials of commercial and near-commercial sunflower (Helianthus annuus L.) hybrids grown over 15 years in 32 locations of central Argentina to determine the contributions of change in characteristics of germplasm pools to increases in oil yield. The ‘Relative Peak Performance’ (best linear unbiased predictors, BLUPs) of 49 hybrids released for the conventional market between 1983 and 2005 showed genetic gains of 11.9 kg ha⁻¹ year⁻¹, 0.19% year⁻¹ and 16.1 kg ha⁻¹ year⁻¹ for oil yield, grain-oil concentration and grain yield, respectively. Oil yield improvement was consistent across three market segments and a biplot of genotype-by-attribute BLUPs summarised 20 years of breeding to demonstrate how the merging of two germplasm pools of differing maturity, achene type and grain-oil concentration resulted in step-wise improvements in grain yield and grain-oil concentration and a move toward an intermediate maturity. The analysis of general combining ability within a breeding program shows that the female and male germplasm pools were improved in different ways over time. On the female side, much of this improvement was to encompass different combinations of the determining traits of oil yield, while on the male side the improvement was more linear in terms of exploitation of genotypic variance for oil yield per se.