Drought stress strongly affects soil biota and impairs crop production, which under climate change will be exacerbated in semi-arid cropping regions such as the Sahel. Hence soil management systems are needed that can...Drought stress strongly affects soil biota and impairs crop production, which under climate change will be exacerbated in semi-arid cropping regions such as the Sahel. Hence soil management systems are needed that can buffer against drought. In West Africa, field studies have found intercropping of millet with the native shrub Piliostigma reticulatum improves soil-plant-water relations, microbial activity and diversity, and suppress parasitic nematodes, which can significantly increase crop yield. However, little information is available on its beneficial or negative effects on soils or crops during water stress. Therefore, the objective was to investigate the impact of P. reticulatum in moderating water stress effects on soil properties and pearl millet (Pennisetum glaucum [L.] R. Br.) productivity. In the greenhouse, soil chemical and microbial properties and millet growth were investigated with a factorial experiment of varying levels of soil moisture (favorable, moderately stressed, or severely stressed water conditions) that was imposed for 55 days on soils containing sole P. reticulatum or millet, or millet + P. reticulatum. The results showed that the presence of P. reticulatum did not buffer soils against water stress in relation to soil chemical and microbial properties measured at the end of the experiment. Severe water stress did significantly decrease the height, number of leaves, and aboveground biomass of millet plants. Additionally, respiration, nematofauna trophic structure and abundance decreased as water stress increased. Lastly, bacterial feeders and plant parasitic nematodes were the most sensitive to severe water stress while fungal feeding nematodes remained unaffected. The results suggested that the intensity of water stress had more negative effects on soil basal respiration rather than soil microbial biomass.展开更多
为确定适合美洲狼尾草(Pennisetum glaucum)种子更新的发芽率,采用人工梯度老化的方法,对其在45℃、99%相对湿度条件下分别处理0、4、8、12、16、20、24 h,再对梯度老化后的材料进行遗传完整性分析。结果表明:与对照组相比,经人工梯度...为确定适合美洲狼尾草(Pennisetum glaucum)种子更新的发芽率,采用人工梯度老化的方法,对其在45℃、99%相对湿度条件下分别处理0、4、8、12、16、20、24 h,再对梯度老化后的材料进行遗传完整性分析。结果表明:与对照组相比,经人工梯度老化后的美洲狼尾草的发芽率、多态性条带百分率(percentage of polymorphic bands,PPB)、等位基因数(number of alleles,Na)、有效等位基因数(effective number of alleles,Ne)、Nei’s基因多样性指数(Nei's gene diversity index,H)和Shannon-Wiener多样性指数(Shannon's information index,I)均有不同程度降低,且与老化时间负相关;发芽率为68.23%时,除等位基因数以外,其他遗传多样性相关参数均与对照组差异显著(P<0.05),说明美洲狼尾草种子更新的发芽率为68.23%。综上,当美洲狼尾草种子的发芽率为68.23%时,应进行种质资源的更新;gSSR分子标记可以作为探究种子老化对种质资源遗传完整性的影响的检验手段,对于异质种质资源材料,低发芽率不利于种质资源遗传完整性的保持。展开更多
The objective of this work was to evaluate the progress of the areolate mildew of cotton under different soil cover and spacing conditions. The experiment was carried out using randomized blocks and a 2 × 3 facto...The objective of this work was to evaluate the progress of the areolate mildew of cotton under different soil cover and spacing conditions. The experiment was carried out using randomized blocks and a 2 × 3 factorial design, with two spacings (0.45 m and 0.90 m) and three soil covers (no cover, Pennisetum glaucum and Crotalaria spectabilis) with four replications. The plants were inoculated with R. areola, sixty DAS. A total of 14 evaluations of disease severity were performed. At the lower, middle and upper thirds of plants, a diagram scale with nine levels of severity was used and the resulting data were converted into the AUDPC. Gompertz, logistic, and monomolecular mathematical models were tested in the disease severity curves for each third. Agronomics characteristics were evaluated as well. Significant differences of AUDPC were found for the cotton plants thirds, and the middle third was the highest AUDPC. Significant difference for the lower and upper thirds, whose AUDPC were highest on 0.90 m spacing, was observed too. The disease progress curves of the thirds did not fit the tested models. Significant results to the both covers situations, where the treatments grown on crotalária cover and without cover had highest AUDPC, were evidenced. The treatments with C. spectabilis cover were taller than other treatments. Significant data were observed for the cover crops used and in the treatments grown at 0.90 m spacing, to residual cover and crop yield, respectively.展开更多
This study aims to evaluate the possible allelopathic effects of young and mature leaf extract from of two eucalyptus genetic materials on the physiological performance of millet seeds. The experiment was carried out ...This study aims to evaluate the possible allelopathic effects of young and mature leaf extract from of two eucalyptus genetic materials on the physiological performance of millet seeds. The experiment was carried out in a completely randomized design, in a 5 × 2 × 2 factorial arrangement [five concentrations of the extract (0, 25%, 50%, 75%, and 100%) × two genetic materials (1 - Eucalyptus grandis × Eucalyptus urophylla and 2 - Eucalyptus grandis × Eucalyptus camaldulensis) × two maturation stages of leaves (young and mature leaves)] with four replicates, each one with 25 seeds. Seeding was performed on the germitest paper substrate distributed in Petri dishes, moistened with the extract according to the treatments, being allocated in biochemical oxygen demand (B.O.D) adjusted at 25°C and 12 h photoperiod. Percentage, speed index, mean germination time, aerial part and primary root length, and dry matter weight of aerial part and root system of seedlings were evaluated. The leaf extracts of the two eucalyptus clones had all the analyzed variables changed with effect more evident on young leaf extract of the genetic material 1. It can be concluded that the tested genetic materials have a detrimental effect on the physiological performance of millet seeds.展开更多
Boumkaye is a traditional fermented millet-based drink (Pennisetum glaucum L.) produced in Casamance (region in Senegal). Unknown and circumcised beverage, it has therapeutic properties due to aqueous creeper extracts...Boumkaye is a traditional fermented millet-based drink (Pennisetum glaucum L.) produced in Casamance (region in Senegal). Unknown and circumcised beverage, it has therapeutic properties due to aqueous creeper extracts from Abrus pulchellus plant and naturally present during the process. The objective of this work was to investigate the fabrication process of a millet-based beverage as an alternative source of nutrients. The diagnosis of beverage production by monitoring its physical and chemical parameters during two months of storage at room temperature was studied. The established manufacturing process, composed by a production of aqueous extracts after maceration of the Abrus pulchellus vines, a preparation of millet slurry, and a fermentation step to obtain the Boumkaye, has several features. The study of aging process showed probable lactic and alcoholic fermentations. Further, the finished Boumkaye was characterized by a high acidity (pH of 3), an alcohol content of 5 g/100g and contains an appreciable amount of polyphenols (54.46 mg/100g).展开更多
Prospects for deploying perennial grasses that are currently considered leading candidates for dedicated energy crops over large acreages are debatable because of several limitations, including vegetative propagation ...Prospects for deploying perennial grasses that are currently considered leading candidates for dedicated energy crops over large acreages are debatable because of several limitations, including vegetative propagation or small seed size, low biomass production during the first growing season, and incomplete assessments of crop invasiveness risk. Pearl Millet-Napiergrass hybrids (“PMN”;Pennisetum glaucum [L.] R. Br. × P. purpureum Schumach.), in contrast, are large-seeded, sterile feedstocks capable of high biomass production during establishment year. Novel methods are warranted for confirmation of PMN hybrids, as traditional morphological observations can be inconclusive and chromosome number determination using cytological methods is laborious and time consuming. Six putative PMN lines were produced in this study, and 10 progeny from each line were evaluated using morphological traits, seed fertility, flow cytometry, and expressed sequence tag-simple sequence repeat (EST-SSR) markers. All putative hybrid lines were sterile and failed to produce seed. The PMN hybrids could not be distinguished from either parent using flow cytometry due to highly similar nuclear genome DNA contents. A number of paternal napiergrass-specific EST-SSRs were identified for each PMN line, and four paternal-specific EST-SSRs conserved across all napiergrass accessions were selected to screen the putative PMN hybrids. These EST-SSRs confirmed that all F1 individuals analyzed were PMN hybrids. The use of paternal-specific markers therefore provides a valuable tool in the development of both “Seeded-yet-Sterile” biofuel PMN feedstocks and additional PMN cultivar-and parental species-specific markers.展开更多
文摘Drought stress strongly affects soil biota and impairs crop production, which under climate change will be exacerbated in semi-arid cropping regions such as the Sahel. Hence soil management systems are needed that can buffer against drought. In West Africa, field studies have found intercropping of millet with the native shrub Piliostigma reticulatum improves soil-plant-water relations, microbial activity and diversity, and suppress parasitic nematodes, which can significantly increase crop yield. However, little information is available on its beneficial or negative effects on soils or crops during water stress. Therefore, the objective was to investigate the impact of P. reticulatum in moderating water stress effects on soil properties and pearl millet (Pennisetum glaucum [L.] R. Br.) productivity. In the greenhouse, soil chemical and microbial properties and millet growth were investigated with a factorial experiment of varying levels of soil moisture (favorable, moderately stressed, or severely stressed water conditions) that was imposed for 55 days on soils containing sole P. reticulatum or millet, or millet + P. reticulatum. The results showed that the presence of P. reticulatum did not buffer soils against water stress in relation to soil chemical and microbial properties measured at the end of the experiment. Severe water stress did significantly decrease the height, number of leaves, and aboveground biomass of millet plants. Additionally, respiration, nematofauna trophic structure and abundance decreased as water stress increased. Lastly, bacterial feeders and plant parasitic nematodes were the most sensitive to severe water stress while fungal feeding nematodes remained unaffected. The results suggested that the intensity of water stress had more negative effects on soil basal respiration rather than soil microbial biomass.
文摘为确定适合美洲狼尾草(Pennisetum glaucum)种子更新的发芽率,采用人工梯度老化的方法,对其在45℃、99%相对湿度条件下分别处理0、4、8、12、16、20、24 h,再对梯度老化后的材料进行遗传完整性分析。结果表明:与对照组相比,经人工梯度老化后的美洲狼尾草的发芽率、多态性条带百分率(percentage of polymorphic bands,PPB)、等位基因数(number of alleles,Na)、有效等位基因数(effective number of alleles,Ne)、Nei’s基因多样性指数(Nei's gene diversity index,H)和Shannon-Wiener多样性指数(Shannon's information index,I)均有不同程度降低,且与老化时间负相关;发芽率为68.23%时,除等位基因数以外,其他遗传多样性相关参数均与对照组差异显著(P<0.05),说明美洲狼尾草种子更新的发芽率为68.23%。综上,当美洲狼尾草种子的发芽率为68.23%时,应进行种质资源的更新;gSSR分子标记可以作为探究种子老化对种质资源遗传完整性的影响的检验手段,对于异质种质资源材料,低发芽率不利于种质资源遗传完整性的保持。
基金thank the Coordination for the Improvement of Higher Education Personnel(CAPES),for the grant given to the first authorto the Graduate Environment and Agricultural Production Systems Program(PPGAT)and all faculty members for the support and assistance given during the study period.
文摘The objective of this work was to evaluate the progress of the areolate mildew of cotton under different soil cover and spacing conditions. The experiment was carried out using randomized blocks and a 2 × 3 factorial design, with two spacings (0.45 m and 0.90 m) and three soil covers (no cover, Pennisetum glaucum and Crotalaria spectabilis) with four replications. The plants were inoculated with R. areola, sixty DAS. A total of 14 evaluations of disease severity were performed. At the lower, middle and upper thirds of plants, a diagram scale with nine levels of severity was used and the resulting data were converted into the AUDPC. Gompertz, logistic, and monomolecular mathematical models were tested in the disease severity curves for each third. Agronomics characteristics were evaluated as well. Significant differences of AUDPC were found for the cotton plants thirds, and the middle third was the highest AUDPC. Significant difference for the lower and upper thirds, whose AUDPC were highest on 0.90 m spacing, was observed too. The disease progress curves of the thirds did not fit the tested models. Significant results to the both covers situations, where the treatments grown on crotalária cover and without cover had highest AUDPC, were evidenced. The treatments with C. spectabilis cover were taller than other treatments. Significant data were observed for the cover crops used and in the treatments grown at 0.90 m spacing, to residual cover and crop yield, respectively.
文摘This study aims to evaluate the possible allelopathic effects of young and mature leaf extract from of two eucalyptus genetic materials on the physiological performance of millet seeds. The experiment was carried out in a completely randomized design, in a 5 × 2 × 2 factorial arrangement [five concentrations of the extract (0, 25%, 50%, 75%, and 100%) × two genetic materials (1 - Eucalyptus grandis × Eucalyptus urophylla and 2 - Eucalyptus grandis × Eucalyptus camaldulensis) × two maturation stages of leaves (young and mature leaves)] with four replicates, each one with 25 seeds. Seeding was performed on the germitest paper substrate distributed in Petri dishes, moistened with the extract according to the treatments, being allocated in biochemical oxygen demand (B.O.D) adjusted at 25°C and 12 h photoperiod. Percentage, speed index, mean germination time, aerial part and primary root length, and dry matter weight of aerial part and root system of seedlings were evaluated. The leaf extracts of the two eucalyptus clones had all the analyzed variables changed with effect more evident on young leaf extract of the genetic material 1. It can be concluded that the tested genetic materials have a detrimental effect on the physiological performance of millet seeds.
文摘Boumkaye is a traditional fermented millet-based drink (Pennisetum glaucum L.) produced in Casamance (region in Senegal). Unknown and circumcised beverage, it has therapeutic properties due to aqueous creeper extracts from Abrus pulchellus plant and naturally present during the process. The objective of this work was to investigate the fabrication process of a millet-based beverage as an alternative source of nutrients. The diagnosis of beverage production by monitoring its physical and chemical parameters during two months of storage at room temperature was studied. The established manufacturing process, composed by a production of aqueous extracts after maceration of the Abrus pulchellus vines, a preparation of millet slurry, and a fermentation step to obtain the Boumkaye, has several features. The study of aging process showed probable lactic and alcoholic fermentations. Further, the finished Boumkaye was characterized by a high acidity (pH of 3), an alcohol content of 5 g/100g and contains an appreciable amount of polyphenols (54.46 mg/100g).
文摘Prospects for deploying perennial grasses that are currently considered leading candidates for dedicated energy crops over large acreages are debatable because of several limitations, including vegetative propagation or small seed size, low biomass production during the first growing season, and incomplete assessments of crop invasiveness risk. Pearl Millet-Napiergrass hybrids (“PMN”;Pennisetum glaucum [L.] R. Br. × P. purpureum Schumach.), in contrast, are large-seeded, sterile feedstocks capable of high biomass production during establishment year. Novel methods are warranted for confirmation of PMN hybrids, as traditional morphological observations can be inconclusive and chromosome number determination using cytological methods is laborious and time consuming. Six putative PMN lines were produced in this study, and 10 progeny from each line were evaluated using morphological traits, seed fertility, flow cytometry, and expressed sequence tag-simple sequence repeat (EST-SSR) markers. All putative hybrid lines were sterile and failed to produce seed. The PMN hybrids could not be distinguished from either parent using flow cytometry due to highly similar nuclear genome DNA contents. A number of paternal napiergrass-specific EST-SSRs were identified for each PMN line, and four paternal-specific EST-SSRs conserved across all napiergrass accessions were selected to screen the putative PMN hybrids. These EST-SSRs confirmed that all F1 individuals analyzed were PMN hybrids. The use of paternal-specific markers therefore provides a valuable tool in the development of both “Seeded-yet-Sterile” biofuel PMN feedstocks and additional PMN cultivar-and parental species-specific markers.
