Genetic diversity among watermelon (Citrullus lanatus and Citrullus colocynthis) accessions

Genetic diversity was estimated among 42 U.S. PlantIntroduction (PI) accessions of the genusCitrullus (of these, 34 PIs are reported tohave disease resistance), and 5 watermelon cultivars, using 30RAPD primers. These primers produced 662 RAPD markers that could berated with high confidence. Based on these markers, geneticsimilarity coefficients were calculated and a dendrogram wasconstructed using the unweighted pair-group method witharithmetic average (UPGMA). The analysis delineated threemajor clusters. The first cluster consisted of a group of fivewatermelon cultivars, a group of C.lanatus var. lanatusaccessions, and a group of C.lanatus var. lanatusaccessions that contained some C.lanatus var. citroidesgenes. The second cluster consisted of the C.lanatus var. citroidesaccessions, while the third cluster consisted of theC. colocynthis accessions.The two C. lanatus clustersdifferentiated from each other and from the C.colocynthis cluster at the level of 58.8%and 38.9% genetic similarity, respectively. Assessment ofgenetic diversity among accessions that have been reported to havedisease resistance indicated that resistance to either anthracnose,downy mildew, powdery mildew, or watermelon mosaic virus is foundamong all major groups of Citrullus PIs.Additionally, resistance to gummy stem blight or Fusarium wilt mayexist among C. lanatus var.citroides PIs. This study demonstrates thatmolecular markers can be useful in assessing genetic diversity, andin sorting Citrullus PIs into phylogeneticgroups prior to their evaluation for disease or pestresistance.     

全球气候变暖对中国种植制度可能影响ⅩⅢ. 东北三省春玉米熟型调整的降水限制及其对产量的可能影响

【目的】研究气候变化背景下东北三省春玉米品种熟型调整敏感区域内的降水条件变化及其对产量的可能影响,为当地春玉米种植品种熟型的调整提供科学参考。【方法】以1985年为时间节点,将1961—2017年分为2个时间段（1961—1985年和1986—2017年）。基于东北三省春玉米品种熟型调整敏感区域内的24个地面气象观测站点1961—2017年地面气象观测资料和16个农业气象试验站点1981—2007年玉米生育期的观测资料,分析春玉米不同生育阶段水分条件的变化特征,并运用作物生产潜力逐级订正法计算降水条件变化对生产潜力的影响。【结果】（1）1961—2017年,东北三省春玉米品种熟型调整的敏感地带内实际播种期呈提前趋势,成熟期呈推迟趋势,实际生产中品种熟型的调整导致实际生育期延长。（2）敏感区域内春玉米品种熟型的调整,使生育前期（播种—拔节）和后期（开花—成熟）需水量增加,生育中期（拔节—开花）需水量减少;同时,生育前期有效降水量呈现增加趋势,生育中期和后期有效降水量呈现减少趋势。（3）品种熟型调整后,春玉米生育中期有效降水量满足率最低。（4）品种熟型调整后,气候生产潜力在中晚熟品种调整为晚熟的区域5南部和西部的宽甸和通榆站点呈减小趋势,波动性增加,在特早熟品种调整为早熟的区域1和早熟品种调整为中熟的区域3北部气候生产潜力呈增加趋势且波动性降低。【结论】全球气候变化的背景下,东北地区敏感区域内有效降水量满足率在生育中期和后期降低,气候生产潜力在研究区域的西部和南部减小、东部增大且不稳定性高。因此,在敏感区域的东部、西部和南部仍要进一步关注品种熟型的选取,同时在春玉米生育中期和后期,及时进行灌溉补充水分,确保春玉米产量。     

Inflorescence and seed production in festuca pratensis var. apennina (2n\t=28)

Summary Plants of tetraploid Festuca pratensis var. apennina (2n=28) collected from Switserland and Northern Italy produced few inflorescences when grown in the field and under glasshouse conditions. The effects of winter and spring treatments upon reproductive growth were investigated and it was concluded that exposure to low winter temperatures and the control of tiller density in the spring were two important factors controlling the production of inflorescences. A procedure for the production of seed is suggested which will allow breeders to obtain efficient multiplication of collected plant material.     

Flooding tolerance of spelt (Triticum spelta L.) compared to wheat (Triticum aestivum L.) – A physiological and genetic approach

In marginal, agroclimatic zones, yield is often affected by flooding, but the effect is much less for winter spelt (Triticum spelta L.) than for winter wheat (Triticum aestivum L.). This study evaluates the reaction of a wheat x spelt population (F₅ RILs of Forno x Oberkulmer) to flooding stress in the early phase of germination. Lines with greater tolerance to 48 h flooding just after imbibition showed less electrolyte leakage (r = -0.79) indicating greater membrane integrity and better survival. Five QTL explaining 40.6% of the phenotypic variance for survival to flooding were found, and localized on the chromosomes 2B, 3B,5A, and 7S. The tolerance to 48 h flooding four days after sowing was best correlated with the mean germination time (r = 0.8), indicating that the plants with a fast coleoptile growth during flooding are less susceptible to flooding. Ten QTL were found for seedling growth index after flooding explaining 35.5% of the phenotypic variance. They were localized on chromosomes 2A, 2B, 2D, 3A, 4B, 5A, 5B, 6A, and 7S. Standard varieties of spelt and wheat showed the same tolerance characteristics. The possibility to use marker assisted selection for flooding tolerance is discussed. This revised version was published online in August 2006 with corrections to the Cover Date.     

Association of Obesity with Serum Leptin,Adiponectin, and Serotonin and Gut Microflora in Beagle Dogs

Background

Serotonin (5‐hydroxytryptamine, 5HT) is involved in hypothalamic regulation of energy consumption. Also, the gut microbiome can influence neuronal signaling to the brain through vagal afferent neurons. Therefore, serotonin concentrations in the central nervous system and the composition of the microbiota can be related to obesity.

Objective

To examine adipokine, and, serotonin concentrations, and the gut microbiota in lean dogs and dogs with experimentally induced obesity.

Animals

Fourteen healthy Beagle dogs were used in this study.

Methods

Seven Beagle dogs in the obese group were fed commercial food ad libitum, over a period of 6 months to increase their weight and seven Beagle dogs in lean group were fed a restricted amount of the same diet to maintain optimal body condition over a period of 6 months. Peripheral leptin, adiponectin, 5HT, and cerebrospinal fluid (CSF‐5HT) levels were measured by ELISA. Fecal samples were collected in lean and obese groups 6 months after obesity was induced. Targeted pyrosequencing of the 16S rRNA gene was performed using a Genome Sequencer FLX plus system.

Results

Leptin concentrations were higher in the obese group (1.98 ± 1.00) compared to those of the lean group (1.12 ± 0.07, P = .025). Adiponectin and 5‐hydroytryptamine of cerebrospinal fluid (CSF‐5HT) concentrations were higher in the lean group (27.1 ± 7.28) than in the obese group (14.4 ± 5.40, P = .018). Analysis of the microbiome revealed that the diversity of the microbial community was lower in the obese group. Microbes from the phylum Firmicutes (85%) were predominant group in the gut microbiota of lean dogs. However, bacteria from the phylum Proteobacteria (76%) were the predominant group in the gut microbiota of dogs in the obese group.

Conclusions and Clinical Importance

Decreased 5HT levels in obese group might increase the risk of obesity because of increased appetite. Microflora enriched with gram‐negative might be related with chronic inflammation status in obese dogs.     

Effects of exogenous amylase on the in vitro digestion kinetics of whole-crop maize silages made from flint or dent grain type at different phenological stages grown in tropical condition

The effect of exogenous amylase on the in vitro rumen digestion kinetics of whole-crop maize silage made from dent (RB9004) or flint grain type (RB9308) was evaluated at different phenological stages: soft dough (SOD), early dent (EAD), ½ milkline (½M) and ¾ milkline (¾M). Forage was harvested from 70 to 110 days after sowing. Two rumen-cannulated cows receiving or not exogenous amylase (0.7 g/kg dry matter—DM, provided to achieve 396 kilo Novo units of amylase activity/kg of TMR DM) were used as donor of ruminal fluid. The in vitro gas production kinetics was evaluated according to a dual-pool logistic model. The chemical composition and gas production kinetics were affected by the hybrid and phenological stages. The flint hybrid had lower range for chemical analysis among physiological stages. Harvesting at ½M and ¾M improved DM content, bromatological composition and silage quality parameters compared to dent or flint types. Amylase (i) increased methane (CH₄) production and in vitro dry matter digestibility (IVDMD) in ½M stage, (ii) improved digestion kinetics by reducing lag time and increasing total gas production and fermentation rates of non-fibrous carbohydrates (NFC) and fibrous carbohydrates (FC), and (iii) increased extent and fermentation rate of NFC and increased fermentation rate of FC fraction in whole-crop maize silages produced from dent or flint types in all phenological stages. Harvesting between ½M and ¾M is the best phenological stage to improve chemical composition and silage quality parameters. Exogenous amylase showed improvements on fibre digestion of silages at ½M and ¾M phenological stages in both grain types of corn.     

Relative persistence of di-and tri-chlorophenoxyalkanoic acid herbicides in Saskatchewan soils

The persistence of 2,4-D, 2,4-DB, dichlorprop, 2,4,5-T, and fenoprop at the 2 ppm level was studied in the laboratory on three prairie soils at 85% of field capacity and 20°C. Following extraction of the soils with aqueous acetonitrile containing acetic acid, the herbicidal acids remaining were analysed gas chromatographically. Breakdown was rapid on all soils and the average half-lives for 2,4-D, 2,4-DB, dichloroprop, 2,4,5-T, and fenoprop were < 7, < 7, 10, 12, and 12 days respectively. Degradation on air-dried soils (15% of field capacity) was negligible with over 85% of the applied herbicides being recoverable after incubation periods during which the herbicides remaining in the moist soils accounted for less than 30% of the original treatments. Persistance relative des acides di et tri-chlorophénoxy-alkanoï-ques herbicides dans des sols du Saskatchewan. La persistance du 2,4-D, du 2,4-DB, du dichlorprop, du 2,4,5-T et du fénoprop, à la concentration de 2 ppm, a étéétudiée au laboratorire, sur trois sols de prairie, a 85% de la capacité au champ et a 20°C. Après leur extraction des sols par l'acétonitrile aqueux contenant de l'acide acétique, les acides herbicides restants ont été analysés par chromatographie en phase gaseuse. La dégradation a été rapide pour tous les sols et les demi-vies moyennes du 2,4-D, du 2,4-DB, du dichlorprop, du 2,4,5-T, et du fénoprop ont été respectivement de <7, <7, 10, 12 et 12 jours. La dégradation sur des sols séchés a l'air (15% de la capacité au champ), a été négligeable, plus de 85% des quantités d'herbicides appliquées étant récupérables après des périodes d'incubation durant lesquelles les herbicides restant dans les sols humides ne représentaient plus que moins de 30% des quantités apportées à l'origine. Relative Persistenz von Di-und Trichlorphenoxyalkansäure-Her-biziden in Böden Saskatchewan In Laborversuchen wurde die Persistenz von 2,4-D, 2,4-DB, Dichlorprop, 2,4,5-T und Fenoprop in drei Prärieböden festgestellt. Die Versuche wurden bei 20°C, 85 % der Feldkapazität und einem anfänglichen Herbizidgehalt der Böden von 2 ppm durchgeführt. Die Extraktion der Böden erfolgte mit wässerigem Acetonitril mit einem geringen Anteil an Essigsäure. Die Herbizide wurden gaschromatographisch nachgewiesen. In allen Böden wurde ein schneller Abbau festgestellt. Die Halbwertszeiten betrugen für 2,4-D, 2,4-DB, Dichlorprop, 2,4,5-T und Fenoprop < 7, < 7,10, 12 bzw. 12Tage. Der Abbau im lufttrockenen Boden (15% der Feldkapazität) war zu vernachlässigen. Hier waren noch mehr als 85% der ausgebrachten Herbizidmenge vorhanden, wenn in den feuchten Böden die Konzentration bereits weniger als 30% betrug.     

Alterations in the brain monoaminergic neurotransmitters of rainbow trout related to naphthalene exposure at the beginning of vitellogenesis

The contents of dopamine (DA), noradrenaline (NA), serotonin (5HT), and some related metabolites were studied in different brain regions of rainbow trout at two different stages of sexual maturation (at the beginning of vitellogenesis), after naphthalene (NAP) administration. The effects of NAP varied according to duration of exposure, brain region and vitellogenesis stage of the trout, and were more significant during previtellogenesis. The changes observed in DA metabolism were generally stimulatory after exposure for 3 h, and either stimulatory or inhibitory (depending on the brain regions) after exposure for 3 days to NAP. NA levels were altered by NAP in various brain regions, but only during previtellogenesis. With respect to 5HT, treatment with NAP reduced levels of the amine and/or its main metabolite in most of the brain regions studied, particularly 3 h after treatment. The results suggest that NAP might interfere with the processes regulating brain monoamine metabolism, either locally or indirectly by altering steroid feedback to brain centres, and thus disrupt endocrine control of reproductive development through the brain–pituitary axis.