Using CERES-Wheat to simulate durum wheat production and phenology in Southern Sardinia,Italy

Durum wheat is a crop of great economic relevance for Mediterranean regions, especially in developing countries. A decreasing trend in durum production is expected in the near future because of several factors, in particular environmental constraints due to climate change and variability. The aim of this work was to test the predictive performance of CERES-Wheat model, implemented in DSSAT software systems, under Mediterranean climate condition and soil types of Southern Sardinia, Italy. CERES-Wheat model was calibrated for three durum wheat Italian varieties (Creso, Duilio, and Simeto) using a 30-year data set (1974–2004) and a trial and error iterative procedure. Then, the model was validated and evaluated using several statistics. The model showed a quite good performance in predicting grain yield and anthesis date, with errors comparable with those reported by other studies conducted on bread and durum wheat. Predictions of grain weight and grain number did not match very well observations, confirming the difficulties of CERES-Wheat in estimating grain yield components. The results of this study suggest the need of specific field experiments and further model evaluations and improvements to better understand model simulation results of grain yield components of durum wheat.     

Three-year field evaluation of early and late 20th century spring wheat cultivars to projected increases in atmospheric carbon dioxide

Carbon dioxide (CO₂), along with light, water and nutrients, represents an essential resource needed for plant growth and reproduction. Projected and recent increases in atmospheric carbon dioxide may allow breeders and agronomists to begin intra-specific selection for yield traits associated with CO₂ sensitivity. However, selection for maximum yield, particularly for cereals, is continuous, and it is possible that modern cereal cultivars are, in fact, the most CO₂ sensitive. To test CO₂ responsiveness, we examined two contrasting spring wheat cultivars, Marquis and Oxen, over a 3-year period under field conditions at two different planting densities. Marquis was introduced into North America in 1903, and is taller, with greater tiller plasticity (i.e. greater variation in tiller production), smaller seed and lower harvest index relative to modern wheat cultivars. Oxen, a modern cultivar released in 1996, produces fewer tillers, and has larger seed with a higher harvest index relative to Marquis. As would be expected, under ambient CO₂ conditions, Oxen produced more seed than Marquis for all 3 years. However, at a CO₂ concentration 250 μmol mol⁻¹ above ambient (a concentration anticipated in the next 50–100 years), no differences were observed in seed yield between the two cultivars, and vegetative above ground biomass (e.g. tillers), was significantly higher for Marquis relative to Oxen in 2006 and 2007. Significant CO₂ by cultivar interaction was observed as a result of greater tiller production and an increased percentage of tillers bearing panicles for the Marquis relative to the Oxen cultivar at elevated carbon dioxide. This greater increase in tiller bearing panicles also resulted in a significant increase in harvest index for the Marquis cultivar as CO₂ increased. While preliminary, these results intimate that newer cultivars are not intrinsically more CO₂ responsive; rather, that yield sensitivity may be dependent on the availability of reproductive sinks to assimilate additional carbon. Overall, understanding and characterizing vegetative vs. reproductive sink capacity between cultivars may offer new opportunities for breeders to exploit and adapt varieties of wheat to projected increases in atmospheric carbon dioxide concentration.     

Old and modern durum wheat varieties from Italy and Spain differ in main spike components

Four field experiments comparing 24 durum wheat varieties grown at different periods during the 20th century in Italy and Spain were carried out to assess the changes caused by breeding activities on the number of grains per main spike and its determinants: number of spikelets per spike, number of grains per spikelet, fertile flowering and grain setting. Increases of 0.14 grains spike⁻¹ year⁻¹ (0.43% year⁻¹ in relative terms) and 0.08 grains spike⁻¹ year⁻¹ (0.22% year⁻¹) were observed in Italian and Spanish varieties, respectively. The overall change in the number of grains per spike in Italian germplasm (29.5%) was due to increases in both, the number of spikelets per spike (7.5%) and the number of grains per spikelet (20.3%), while in Spanish varieties the increase in the number of grains per spike (19.5%) was only attributed to the improvement of the number of grains per spikelet. The increase in the number of fertile florets per spike (about 12%) was similar in both countries, but while it explained more than 70% of the changes in the number of grains per spike in Spanish varieties, grain setting was responsible for most of the improvement in the number of grains per spike in the Italian germplasm. The percentage of florets setting grains was 68 and 64% in modern Italian and Spanish varieties, respectively. Most of the changes in the number of grains per spikelet were found in the upper part of the spike on Italian varieties, whilst they were more evenly distributed in the Spanish ones. The main achievement derived from the introduction of the Rht-B1 dwarfing gene was an increase in the number of grains per spikelet, but it did not have any effect on the number of spikelets on the main spike. The lack of genetic associations between grain setting and both the number of spikelets per spike and the number of fertile florets per spike suggests that future yield gains may be obtained through increases in the three components independently.     

Understanding the relationships between genetic and phenotypic structures of a collection of elite durum wheat accessions

A collection of 191 durum wheat accessions representing Mediterranean Basin genetic diversity was grown in nine different environments in four countries, with productivities ranging from 0.99 to 6.78 t ha⁻¹. The population breeding structure comprised eight genetic subpopulations (GSPs) using data derived from 97 evenly distributed SSR markers. The phenotypic structure was assessed: (i) from the mean values of six agronomic traits across environments (multivariate), and (ii) from data representing each trait in each environment (univariate). Mean daily maximum temperature from emergence to heading was significantly (P < 0.05) and negatively associated to yield, accounting for 59% of yield variations. Significant but weak relationships were obtained between the genetic similarities among accessions and their overall agronomic performance (r = 0.15, P < 0.001), plant height (r = 0.12, P < 0.001), spike–peduncle length (r = 0.06, P < 0.01) and thousand kernel weight (r = 0.03, P < 0.05), suggesting a very low possibility of prediction of the agronomic performance based on random SSR markers. The percentage of variability (measured by sum of squares) explained by the environment varied between 76.3 and 98.5% depending on the trait, while that explained by genotypes ranged between 0.4 and 12.6%, and that explained by the GE interaction ranged from 1.1 to 12.5%. The clustering of the accessions based on multivariate phenotypic data offered the best explanation of genotypic differences, accounting for 30.3% (for yield) to 75.1% (for kernel weight) of the observed variation. The genotype × environment interaction was best explained by the phenotypic univariate clustering procedure, which explained from 28.5% (for kernel weight) to 74.9% (for days to heading) of variation. The only accessions that clustered both in the genetic dissimilarities tree and the tree obtained using Euclidean distances based on standardized phenotypic data across environments were those closely related to the CIMMYT hallmark founder ‘Altar 84’, the ICARDA accessions adapted to continental-dryland areas, and the landraces, suggesting that genetic proximity corresponded to agronomic performance in only a few cases.     

20世纪茶与健康研究的主要进展

相传,茶叶最早是以"药物"面世的,直到1300余年前的唐朝,由于茶树种植的普及,它才成为人们日常生活的必需品.即使是这样,当17世纪茶叶由中国传到欧洲各国时,也是在药房中出售的.茶之所以能风靡欧洲大陆,也是由于它的神奇的药效.因此在漫长的历史长河中,茶叶在很大程度上是以其"药效"而经久不衰的.但是这种药效主要是经验性的,缺乏严实的科学依据,因此其主导地位逐渐被茶叶的色、香、味所替代.尽管如此,茶叶的药效功能并没有被人们所遗忘.随着科学技术的发展、研究手段的提高,特别是由于环境污染等引起人类癌症和心血管疾病的高发病率,而人工合成药物的效果并不理想时,医学界又将注意力转到从植物中寻找有效组分,来预防和治疗疾病.中国古代就已提出的"药食同源"的理论再一次引起全世界的重视,茶叶成为备受关注的一种植物.从20世纪下半叶起,各国科学家集中研究茶的药用功效.本文对半个世纪以来,世界茶与健康的研究作一综述.     

Effect of foliar treatments to durum wheat on flag leaf senescence, grain yield, quality and deoxynivalenol contamination in North Italy

Since the production of durum wheat in the drier areas of the Mediterranean Basin is characterized by high variability in terms of yield and grain quality, there is also considerable interest in developing durum wheat in the northern regions, where the pedo-climatic conditions can offer the possibility of obtaining grain yields with higher technological quality and stability. However, the climatic conditions in the northern regions make durum wheat more prone to fungal foliar disease, particularly to Septoria Tritici Blotch (Septoria tritici Rob.) and to Fusarium Head Blight (Fusarium graminearum Petch and Fusarium culmorum Sacc.), with the consequent occurrence of DON in grains.Field experiments have been conducted over two growing seasons at four sites in North West Italy to evaluate the effect of fungicides and foliar nitrogen fertilizer application on durum wheat yield and grain quality. Five combinations of foliar application were compared at each site and each year (untreated control, azole fungicide application at heading, strobilurin fungicide at the stem elongation stage and/or at heading, the addition of a foliar N fertilizer to a fungicide programme). The following parameters were analysed: Septoria Tritici Blotch (STB) severity, flag leaf greenness using a chlorophyll meter, grain yield, test weight, grain protein content, ash content, vitreousness, Fusarium Head Blight (FHB) incidence and severity and deoxynivalenol (DON) contamination. The collected data underline that the cultivation of durum wheat at the climatic conditions of North Italy is actually risky and needs a direct control of fungal disease, which would be able to reduce the development of both foliar and head attacks. The double treatment, with a strobilurin application during the stem elongation stage and azole at heading, results to be an essential practice and showed advantages in terms of the delay of flag leaf senescence (+27%), STB control (+31), FHB control (+11%), yield (+32%) and DON contamination (−45%), compared to the untreated control. Other foliar treatments at heading, such as strobilurin or foliar N fertilizer applications, do not seem to provide any further advantage, for either grain yield or quality. No significant effect of fungicide or foliar N fertilizer application was recorded on the protein or ash concentration or vitreousness.     

Variation in the levels of the different xylanase inhibitors in grain and flour of 20 French wheat cultivars

A xylanase from Aspergillus aculeatus (glycoside hydrolase family 10), uninhibited by TAXI, and a xylanase from Bacillus subtilis (family 11), uninhibited by XIP-I, were selected to quantify the respective apparent levels of XIP-I and TAXI inhibitors, in flours and grains of 20 wheat varieties. The apparent TAXI amount ranged from 0.05 to 0.19 mg/g in flour (mean: 0.11 mg/g) and from 0.07 to 0.2 mg/g in grain (mean: 0.14 mg/g). The range observed for XIP-I was 0.12–0.6 mg/g in flour (mean 0.32 mg/g), and 0.21–0.56 mg/g in grain (mean: 0.41 mg/g). The inhibition profile of the xylanase from A. aculeatus by a crude inhibitor preparation suggested the presence of an additional component in wheat flour, responsible for an increase in inhibition.     

EST-SSR标记在45份冬小麦品种遗传多样性分析和新品种测试应用中的研究

本研究利用21对小麦EST-SSR引物对45份黄淮海地区新育成冬小麦品种的遗传多样性进行了分析。在23份新育成品种中,共检测到61个位点,每个位点的等位基因个数在2-8之间,平均2.90;基因遗传多样性指数在0.08-0.79之间,平均为0.38。23份新育成品种的遗传距离在0.12-0.69之间, 平均为0.40。在23份亲本品种中,共检测到63个位点,每个位点的等位基因个数在2-7之间,平均3.00;基因遗传多样性指数在0.08-0.79之间,平均为0.43,23份亲本品种的的遗传距离在0.09-0.81之间, 平均为0.46。新育成品种遗传多样性低于其亲本品种。聚类分析表明,45份品种可分为6个类群,部分申请品种和近似品种聚在一起,但其他申请品种和近似品种并未聚在一起,其中有些甚至距离较远。据此认为EST-SSR标记用于DUS测试中近似品种的选择是可行的。     

Agronomic and physiological contributions to the yield improvement of soybean cultivars released from 1950 to 2006 in Northeast China

Increasing yield is a high priority in most breeding programs. Approximately 600 soybean cultivars had been released by the end of the last century in Northeast China. Understanding the agronomic and physiological changes is essential for planning further plant breeding strategies in soybean. In this study, 45 representative soybean cultivars, from maturity groups 00 and 0, released from 1950 to 2006 in Northeast China were compared in field conditions for 3 consecutive years. A positive correlation between seed yield and year of cultivar release was indicated with a 0.58% average annual increase. Seed number per plant was the most important contributor to yield gain, with a 0.41% increase per year. Pod number per plant and seed size varied slightly with the year of cultivar release. Although variation in protein was from 37.0% to 45.5%, and oil concentration was from 16.7% to 22.0%, their concentrations were not consistently related to year of cultivar release. A 33% increase in the photosynthetic rate, 10.6% increase in plant dry weight and 19.0% increase in harvest index (HI) were found, while leaf area index (LAI) decreased by 17.3%. Modern cultivars have higher photosynthetic rates than their predecessors. The reduced plant height gave increased resistance to lodging, with the lodging score dropping from 3.2 in 1951 to 1.0 in 2006. Seed resistances to disease and pest infestation were also improved. Yield stability was enhanced over years, which could be attributed to the stable pod production across different environments. A flow diagram to explain the contributors to genetic improvement of soybeans in Northeast China was developed.     

中国如何面向21世纪的全球性大豆食品热(Ⅰ)

中国是大豆的故乡，也是大豆食品的发源地，近十年来人们对大豆食品的保健功能有了新的认识，一个面向21世纪的全球性大豆食品热正兴起，作为大豆和大豆食品的发源地，中国应该怎么办？本文试图以世界（（特别是美国）和中国大豆产业的历史和发展为基础，分析扩大大豆食物应用的全球机遇和动力，探讨回答这个问题的意义和答案。     

Partitioning of dry matter and nitrogen to the spike throughout the spike growth period in wheat crops subjected to nitrogen deficiency

Experiments were conducted over four seasons, in the field, with five cultivars. Nitrogen (N) fertilizer was applied to crops at various dates and rates to achieve various N deficiencies. Crop N status and the accumulation of dry matter (DM) and N in the vegetative parts and in the spike was assessed regularly throughout the spike growth period. Changes in partitioning during the spike growth period were studied using cv. Soissons. For crops subjected to continuous N deficiencies starting on various dates, the proportion of aerial DM in the spike was lower and the proportion of aerial N in the spike was higher than in well-fertilized crops. The earlier the deficiency, the larger were the differences in partitioning. Some crops were subjected to temporary nitrogen deficiencies. In these cases, a nitrogen deficiency starting on a particular date was brought to an end by applying N fertilizer. Crops exposed to temporary N deficiencies displayed a higher proportion of aerial DM and a lower proportion of aerial N in the spike than did crops subjected to continuous deficiencies. Differences in DM and N partitioning became significant at the beginning of the spike growth period if crop N status had been affected by deficiency as early as 800 or 700 degree days before anthesis. At anthesis, the relative proportion of aerial N in the spike (proportion of aerial N in the spike of a crop divided by the proportion of aerial N in the spike of its well-fertilized control) was linearly related to nitrogen nutrition index (NNI), an indicator of crop N status. This relationship was determined for Soissons and four other cultivars. It did not differ significantly between cultivars or between crops subjected to temporary or continuous deficiency. Relative aerial N content and relative spike N content were also related to NNI at anthesis.     

中国如何面向21世纪的全球性大豆食品热(Ⅱ)

另一方面是发达国家的营养过剩 ,导致多种“富贵病” ,如高血压、心脏病和癌症等。富裕社会日饮食以高脂肪、高胆固醇和高热量为特徵 ,比如 ,美国人平均的饮食营养为每日 3 70 0卡热量和 1 0 6ｇ蛋白 ,远超过成人正常活动所需求的 ,况且 ,蛋白质来源主要基于动物食品。结果 ,心脏病和癌症成为美国两个头号杀手 ,而医治这些疾病每年要花费上百亿美元。一种新的观点是强调通过健康食物进行病的预防 ,大豆食品因为能帮助预防许多慢性病 ,包括上面两个主要的杀手 ,乃为健康食物之上选。由于发展大豆食品能同时帮助解决当今世界营养问题的两个方…     

Grain quality changes and responses to nitrogen fertilizer of japonica rice cultivars released in the Yangtze River Basin from the 1950s to 2000s

While the yield potential of rice has increased but little is known about the impact of breeding on grain quality, especially under different levels of N availability. In order to investigate the integrated effects of breeding and N levels on rice quality 12 japonica rice cultivars bred in the past60 years in the Yangtze River Basin were used with three levels of N: 0 kg N ha-1, 240 kg N ha-1,and 360 kg N ha-1. During the period, milling quality(brown rice percentage, milled rice percentage, and head rice percentage), appearance quality(chalky kernels percentage, chalky size, and chalkiness), and eating and cooking quality(amylose content, gel consistency, peak viscosity, breakdown, and setback) were significantly improved, but the nutritive value of the grain has declined due to a reduction in protein content. Micronutrients, such as Cu, Mg, and S contents, were decreased, and Fe, Mn, Zn, Na, Ca, K, P, B contents were increased. These changes in grain quality imply that simultaneous improvements in grain yield and grain quality are possible through selection. Overall, application of N fertilizer decreased grain quality, especially in terms of eating and cooking quality. Under higher N levels, higher protein content was the main reason for deterioration of grain quality, although lower amylose content might contribute to improving starch pasting properties. These results suggest that further improvement in grain quality will depend on both breeding and cultivation practices, especially in regard to nitrogen and water management.     

Combined effect of genetic and environmental factors on the accumulation of proteins in the wheat grain and their relationship to bread-making quality

Bread-making quality of wheat flour is largely determined by the accumulation, concentration and composition of the proteins in the grain, which are influenced by genetic (G) and environment (E) variation and their interactions. We have therefore evaluated the importance of G and E factors and their interactions in determining the accumulation and composition of the proteins in the wheat grain. The cultivar determined development time (CDDT), together with the amount and timing of N application, played a significant role in determining the accumulation and final composition of the wheat grain proteins, explaining 21–59% of the variation. At low temperature, N application both at spike formation and at anthesis explained the highest proportion of variation (36%) in the percentage of sodium dodecyl sulphate (SDS) unextractable polymers in the total amount of polymers (% UPP), while at high temperature CDDT contributed most to the variation in % UPP (20%). The largest contributor to variation in the amount of total SDS extractable proteins (TOTE) was N application at anthesis, both at low and high temperatures (12% and 36%, respectively). Thus, the climate should be considered in recommendations for improving the protein quality and thereby the bread-making quality of wheat.     

Foliar resistance to ozone injury in the genetic base of U.S. and Canadian soybean and prediction of resistance in descendent cultivars using coefficient of parentage

Development of ozone (O₃)-resistant cultivars is a potentially important approach for maintaining crop productivity under future climate scenarios in which tropospheric O₃ pollution is projected to rise. A first step in the breeding of resistant cultivars for a crop such as soybean (Glycine max (L.) Merr.) is identification of sources of O₃ resistance genes. Thirty ancestral lines of soybean were screened for differences in O₃ foliar injury under greenhouse conditions. The ancestors represented 92% of the genetic base of North American soybean as determined by pedigree analysis. Injury among ancestors ranged from 5 to 50% of leaf area, based on response of the five oldest main stem leaves, indicating both the presence of substantial genetic variation for O₃ injury among the ancestors as well as resistance levels greater than that of the standard control cultivar, resistant Essex (15% injury). Ancestral types Fiskeby 840-7-3 and Fiskeby III exhibited the greatest foliar resistance and PI 88788 the least. A subsequent field study confirmed the foliar resistance of the Fiskeby types. Resistant ancestors identified here are proposed for inheritance and DNA mapping studies to determine the genetic basis of foliar resistance. Because the presence of O₃-resistant ancestors suggested that resistant descendents may exist in addition to the resistant control Essex, a method was developed to facilitate their identification. A predicted O₃-resistance score was calculated for 247 publicly-released cultivars, based on pedigree analysis and ancestral response to ozone. Using this approach, the 32 public cultivars most closely related to resistant ancestors and, thus, most likely to be resistant were identified as priority candidates for future screening efforts. Predicted scores from the analysis suggested that cultivars from the Midwest may be more sensitive to foliar injury, on average, than Southern cultivars.