Field detection of resistance to isometamidium chloride and diminazene aceturate in Trypanosoma vivax from the region of the Boucle du Mouhoun in Burkina Faso

A longitudinal study assessed the chemoresistance to isometamidium chloride (ISM) and diminazene aceturate (DA) in the region of the Boucle du Mouhoun in Burkina Faso. A preliminary cross-sectional survey allowed the identification of the 10 villages with the highest parasitological prevalences (from 2.1% to 16.1%). In each of these 10 villages, two herds of approximately 50 bovines were selected, one being treated with ISM (1mg/kg b.w.) and the other remaining untreated as control group. All animals (treated and untreated herds) becoming infected were treated with DA (3.5mg/kg b.w.). In total, 978 head of cattle were followed up. Fortnightly controls of the parasitaemia and PCV were carried out during 8 weeks. The main trypanosome species was Trypanosoma vivax (83.6%) followed by Trypanosoma congolense (16.4%). In two villages, less than 25% of the control untreated cattle became positive indicating no need to use prophylactic treatment. These two villages were not further studied. Resistance to ISM was observed in 5 of the remaining 8 villages (Débé, Bendougou, Kangotenga, Mou and Laro) where the relative risk (control/treated hazard ratios) of becoming infected was lower than 2 i.e. between 0.89 (95% CI: 0.43-2.74) and 1.75 (95% CI: 0.57-5.37). In contrast, this study did not show evidence of resistance to DA in the surveyed villages with only 8.6% (n=93) of the cattle relapsing after treatment. Our results suggest that because of the low prevalence of multiple resistances in the area a meticulous use of the sanative pair system would constitute the best option to delay as much as possible the spread of chemoresistance till complete eradication of the disease by vector control operations.     

Variation in cone and seed characters in clonal seed orchards of <Emphasis Type="Italic">Pinus sylvestris</Emphasis>

Cone and seed characters were observed on top, middle and bottom portions of tree crown in 3 ramets/clone in three Turkish Pinus sylvestris seed orchards. Broad sense heritability (clonal repeatability), and correlations among characters were estimated. Around one quarter of the seed production occurred in the top portion, half in the middle and one quarter in the bottom portion of the crown for all orchards. The percentage of filled seeds varied little with the crown position, indicating more or less similar levels of selfing in the bottom of the crown as in the top. The seed weight was typically 11 mg. Differences were found for studied cone and seed characters among orchards and crown positions. Variation among grafts within clone was higher than among clones for most characters. The heritability was on average below 0.5 (e.g., cone diameter, number of filled seed per cone) and rarely rose above that (e.g., cone form, length/diameter; percentage of filled seed) for any individual characters. The coefficient of variation within clones was often higher than among clones. Thus, non-genetic factors seem often more important for the variation in performance of grafts than their genetic constitution. Cone form (length/diameter) was the character where the clone influence was the strongest. Cone number and cone dry weight showed significant correlations with seed characters (numbers of total and filled seed, percentage and weight of filled seeds). Significant correlation was found between seed characters.     

Fertility variation in six populations of Brutian pine (Pinus brutia Ten.) over altitudinal ranges

Fertility (number of strobili) was investigated in six natural populations over three ranges of altitudes (215–960 m) in Brutian pine (Pinus brutia Ten.) for two consecutive years. The fertility and fertility variation varied among populations and years. The average of strobilus production varied between 173 and 269 in female, and between 533 and 1,060 in male, respectively. The fertility variation did not seem closely related to the altitude, and it was not consistently dependent on the richness of strobilus production. Positive significant correlations were found between female and male strobilus production for all populations and years. Coefficient of variation in strobilus production among individual trees varied between 0.638 and 0.838 for female; and between 0.603 and 0.809 for male when flowering assessments were combined. The clone fertility variations among trees were slightly different among all six stands (sibling coefficient ranged from 1.354 to 1.525) and it is unlikely that trees in typical stands vary extremely in reproductive success.     

Growth characters and number of strobili in clonal seed orchards of Pinus sylvestris

Observations were made on six grafts for each of 25 clones in three Scots pine (Pinus sylvestris) seed orchards in Turkey. The characters studied were number of female and male strobili, height below and above the longest branch, total height; diameter at base and breast height, crown diameter, and number of branches. Variation, broad-sense heritability (H ²) and correlations between characters were estimated. Variation among clones was lower than among grafts within clone for all characters. The genetic variation for number of strobili varied between 0 and 17% of total variation, while that for growth characters values varied between 2 and 13%. The number of female strobili appeared more variable among trees than the number of male strobili. H ² was not consistently high for any character or seed orchard. The number of strobili increased with the size of the tree, but not dramatically. Correlations between measures of tree size (both on clone level and individual graft level) and the number of strobili were in the magnitude r ≈ 0.3. Diameter at breast height seems a reasonable predictor for number of strobili.     

Effects of Seedbed Density on One-Year-Old <Emphasis Type="Italic">Fraxinus angustifolia</Emphasis> Seedling Characteristics and Outplanting Performance

To assess the effects of seedling spacing on one-year-old seedling morphology in the nursery, seeds of three provenances of Fraxinus angustifolia were sown at five different seedling spacings within rows of two different spacings in the seedbed. Subsequent growth performance of one-year-old seedlings was assessed by planting in the forest. Within row spacings were: 4.3, 5.0, 6.3, 8.3, and 12.5 cm, and there were five rows at 20 cm apart, or three rows at 33 cm apart across the 1.2 m wide seedbeds. Both spacings within and between rows significantly affected shoot height, root collar diameter, root dry weight and shoot dry weight, but not root/shoot ratio. Wider spacings produced larger seedlings, but only the wider spacing within rows significantly increased fine and coarse root mass. Provenances showed significant differences in diameter, root/shoot ratio, and fine and coarse roots, and they also showed interactions with row spacings in height and diameter measurements. One year after outplanting, diameter growth was significantly related to provenance, and diameter growth was 88% greater for trees from 33 cm nursery row spacing than those from 20 cm nursery row spacing.     

Fertility variation in endemic populations of Ehrami black pine (<Emphasis Type="Italic">Pinus nigra</Emphasis> Arnold. subsp. <Emphasis Type="Italic">pallasiana</Emphasis> var. <Emphasis Type="Italic">pyramidata</Emphasis>)

Fertility variation and effective number of parents were estimated in the 100 individuals from each of three plantation populations (P1, P2 and P3) of the endangered Pinus nigra. subsp. pallasiana var. pyramidata established in the Isparta–Golcuk district in southern Turkey in 1990. Potential relations between cone yield and growth characters (height, diameter at breast height, diameter at base and crown diameter) were also investigated. Large differences were found among populations and within populations for cone production and growth characters. Mean cone production was eight (ranging from 6.5 in P2 to 9.1 in P1) for the three populations. The 10 most productive individuals for cones produced 32% of the total cones in P1, 39% in P2 and 34% in P3; 21, 16 and 6 individuals, respectively did not produce any cones in the populations. According to the correlation analyses, the relation between cone yield and growth characters changed for the populations, while height, diameter at breast height and crown diameter were positively significantly correlated (r = 0.182, 0.135 and 0.209; p ≤ 0.05) with cone production for the three populations. Fertility variation was 1.81 in total of three populations, ranging from 1.72 in P3 to 3.45 in P1). Effective number of parents was 142 (55.2 of number of parents censused; 29%, P1; 49.8%, P2; 58.3%, P3).     

基于EFAST的CERES-Wheat模型土壤参数敏感性分析

为了定量讨论DSSAT-CERES-Wheat模型中土壤参数对模拟结果的影响,运用扩展傅里叶幅度检验（EFAST）法,对影响冬小麦生产及生态系统中氮素分布的2类模型参数进行了敏感性研究,重点探讨了模型中土壤参数变化对模型模拟的冬小麦产量、冬小麦氮素分布、土壤氮素分布及土壤氮素转化的影响。结果表明：对冬小麦产量、地上生物量及收获指数影响最敏感的土壤参数为田间持水率,其次是土壤酸碱度;对冬小麦地上生物量中氮素含量影响最敏感的土壤参数为土壤酸碱度,对冬小麦籽粒中氮素含量影响最敏感的参数为田间持水率,对冬小麦根和叶中氮素含量影响最敏感的土壤参数则为土壤总氮含量;对作物吸收土壤中氮素影响最敏感的参数是径流曲线数,对土壤氮淋失量影响最敏感的参数为排水比率,对土壤中硝态氮、铵态氮含量影响最敏感的参数为土壤总氮含量;对土壤中氮素矿化和硝化影响最敏感的土壤参数为土壤总氮含量,对土壤氮素反硝化影响最敏感的参数为排水比率,对氨挥发量影响最敏感的参数为土壤总氮含量,氨挥发量对排水比率和土壤酸碱度的变化也较敏感。当侧重于模拟冬小麦产量及作物氮素研究时,原需测量的15个土壤参数可简化为4个,而当侧重于土壤氮素转化及分布研究时,可简化为重点测量的9个参数。本研究可降低CERES-Wheat模型土壤参数获取难度,方便模型本地化、区域化应用。