Pub Date : 2021-04-10DOI: 10.21475/ajcs.21.15.04.p2779
Aleck Kondwakwenda, J. Sibiya, R. Zengeni, C. Musvosvi
Breeding for drought tolerance in plants is challenging because it is controlled by multiple genes. Grain yield, the trait of primary interest in maize, is characterized by low heritability, high genotype by environment interaction, and low variation under drought conditions, which further complicates selection. To circumvent these challenges, secondary traits that are highly correlated with grain yield are indirectly selected under drought conditions. Although considerable success in terms of yield gains under drought stress has been reported in both temperate and tropical maize breeding programmes, climate change exacerbated droughts coupled with high population growth necessitates continuous improvement of maize varieties. Understanding the genetics of associated secondary traits is essential in elucidating drought tolerance. The identification of quantitative trait loci (QTL) and candidate genes conferring drought tolerance and the subsequent development of relevant molecular markers ushered in the era of molecular assisted breeding. There is empirical evidence that marker-assisted selection and genomic selection have great potential to increase the yield gains while comprehensive and accurate phenotyping using secondary traits remains the pillar of drought tolerance breeding
{"title":"Aspects in breeding maize for drought tolerance: Progress and modern breeding approaches","authors":"Aleck Kondwakwenda, J. Sibiya, R. Zengeni, C. Musvosvi","doi":"10.21475/ajcs.21.15.04.p2779","DOIUrl":"https://doi.org/10.21475/ajcs.21.15.04.p2779","url":null,"abstract":"Breeding for drought tolerance in plants is challenging because it is controlled by multiple genes. Grain yield, the trait of primary interest in maize, is characterized by low heritability, high genotype by environment interaction, and low variation under drought conditions, which further complicates selection. To circumvent these challenges, secondary traits that are highly correlated with grain yield are indirectly selected under drought conditions. Although considerable success in terms of yield gains under drought stress has been reported in both temperate and tropical maize breeding programmes, climate change exacerbated droughts coupled with high population growth necessitates continuous improvement of maize varieties. Understanding the genetics of associated secondary traits is essential in elucidating drought tolerance. The identification of quantitative trait loci (QTL) and candidate genes conferring drought tolerance and the subsequent development of relevant molecular markers ushered in the era of molecular assisted breeding. There is empirical evidence that marker-assisted selection and genomic selection have great potential to increase the yield gains while comprehensive and accurate phenotyping using secondary traits remains the pillar of drought tolerance breeding","PeriodicalId":8309,"journal":{"name":"April 2021","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89125388","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-04-10DOI: 10.21475/ajcs.21.15.04.p2803
D. C. Reginatto, J. G. D. Silva, I. Carvalho, Francine Lautenchlegere, J. A. D. Rosa, C. L. Peter, Luana Henrichsen, M. S. Jung, N. Basso, C. V. Argenta, Leonardo Norbert, C. M. Babeski
Adjusting the nitrogen dose at sowing and topdressing with the time of application can improve nutrient management and increase oat productivity. The objective of the study is the most efficient and sustainable management of nitrogen use in the adjusted combination of nutrient dose at sowing and for topdressing with the moment of application on the productivity of biomass and oat grains, considering the main systems of cereal succession in southern Brazil.. The experiment was conducted in the years 2015, 2016 and 2017, in Augusto Pestana, RS, Brazil. The design was a randomized block with four replications, in a 4 x 4 factorial model, consisted of four doses of nitrogen at sowing time (0, 10, 30 and 60 kg ha-1), and topdressing dose by the total supplied of 70 and 100 kg ha-1 in succession system soybeans / oats and corn / oats, respectively, in the expectation of grain yield of 4000 kg ha-1, with the supply for topdressing considering four application times (0, 10, 30 and 60 days after emergence). The most efficient and sustainable management of nitrogen use for biomass and oat grains productivity occurs with the total supply of the covered nutrient around 30 days after emergence, regardless of the condition of the agricultural year and succession system.
{"title":"Nitrogen management at sowing and topdressing with the time of supply in the main biotype of oats grown in southern Brazil","authors":"D. C. Reginatto, J. G. D. Silva, I. Carvalho, Francine Lautenchlegere, J. A. D. Rosa, C. L. Peter, Luana Henrichsen, M. S. Jung, N. Basso, C. V. Argenta, Leonardo Norbert, C. M. Babeski","doi":"10.21475/ajcs.21.15.04.p2803","DOIUrl":"https://doi.org/10.21475/ajcs.21.15.04.p2803","url":null,"abstract":"Adjusting the nitrogen dose at sowing and topdressing with the time of application can improve nutrient management and increase oat productivity. The objective of the study is the most efficient and sustainable management of nitrogen use in the adjusted combination of nutrient dose at sowing and for topdressing with the moment of application on the productivity of biomass and oat grains, considering the main systems of cereal succession in southern Brazil.. The experiment was conducted in the years 2015, 2016 and 2017, in Augusto Pestana, RS, Brazil. The design was a randomized block with four replications, in a 4 x 4 factorial model, consisted of four doses of nitrogen at sowing time (0, 10, 30 and 60 kg ha-1), and topdressing dose by the total supplied of 70 and 100 kg ha-1 in succession system soybeans / oats and corn / oats, respectively, in the expectation of grain yield of 4000 kg ha-1, with the supply for topdressing considering four application times (0, 10, 30 and 60 days after emergence). The most efficient and sustainable management of nitrogen use for biomass and oat grains productivity occurs with the total supply of the covered nutrient around 30 days after emergence, regardless of the condition of the agricultural year and succession system.","PeriodicalId":8309,"journal":{"name":"April 2021","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91476873","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-04-10DOI: 10.21475/ajcs.21.15.04.p2858
J. Beltrão, Márcio Koetz, Edna M. B. Silva, T. D. Silva, J. V. José
Correct management of water and fertilizers can enable the profitable and ecologically correct cultivation of pout pepper (Capsicum chinense). In this context, the objective of this study was to assess the effect of drip irrigation depths and nitrogen doses on the cultivation of pout pepper in a Latossolo Vermelho (Oxisol) of the Cerrado region. The experiment was conducted in the field in a randomized block design, at the Federal University of Mato Grosso –Campus of Rondonópolis. The treatments were five irrigation depths (40, 60, 80, 100 and 120% of ETc) and five nitrogen doses (0, 60, 120, 180 and 240 kg ha-1), with 4 replicates. Fresh and dry weights of fruits, number of fruits, plant yield and water productivity were analyzed. Nitrogen fertilization caused significant differences in fresh and dry weights of fruits (873.95 and 133.03 g plant-1), respectively, as well as in the number of fruits (319.05 fruits plant-1) and plant yield (14.9 t ha-1). Water productivity showed a response surface with a stationary point of minimum (7.13 kg L-1). Adequate doses of nitrogen and irrigation depths promote good development of pout pepper cultivated in Latossolo Vermelho (Oxisol) of the Cerrado region
正确的水、肥管理可以实现辣椒的经济效益和生态正确栽培。在此背景下，本研究的目的是评估滴灌深度和氮剂量对塞拉多地区Latossolo Vermelho (Oxisol)辣椒栽培的影响。该实验在马托格罗索联邦大学校园(Rondonópolis)以随机分组设计的方式进行。处理为5个灌深(40、60、80、100和120% ETc)和5个施氮量(0、60、120、180和240 kg ha-1)，共4个重复。分析了果实鲜重、干重、果实数、单株产量和水分生产力。施氮对果实鲜重(873.95 g)和干重(133.03 g)、果数(319.05 g)和单株产量(14.9 t ha-1)均有显著影响。水分生产力呈响应面，最低点为7.13 kg L-1。适当的施氮量和灌溉深度有利于塞拉多(Cerrado)地区辣椒的生长发育
{"title":"Production of pout pepper (Capsicum chinense) under irrigation depths and nitrogen doses in the Brazilian Cerrado","authors":"J. Beltrão, Márcio Koetz, Edna M. B. Silva, T. D. Silva, J. V. José","doi":"10.21475/ajcs.21.15.04.p2858","DOIUrl":"https://doi.org/10.21475/ajcs.21.15.04.p2858","url":null,"abstract":"Correct management of water and fertilizers can enable the profitable and ecologically correct cultivation of pout pepper (Capsicum chinense). In this context, the objective of this study was to assess the effect of drip irrigation depths and nitrogen doses on the cultivation of pout pepper in a Latossolo Vermelho (Oxisol) of the Cerrado region. The experiment was conducted in the field in a randomized block design, at the Federal University of Mato Grosso –Campus of Rondonópolis. The treatments were five irrigation depths (40, 60, 80, 100 and 120% of ETc) and five nitrogen doses (0, 60, 120, 180 and 240 kg ha-1), with 4 replicates. Fresh and dry weights of fruits, number of fruits, plant yield and water productivity were analyzed. Nitrogen fertilization caused significant differences in fresh and dry weights of fruits (873.95 and 133.03 g plant-1), respectively, as well as in the number of fruits (319.05 fruits plant-1) and plant yield (14.9 t ha-1). Water productivity showed a response surface with a stationary point of minimum (7.13 kg L-1). Adequate doses of nitrogen and irrigation depths promote good development of pout pepper cultivated in Latossolo Vermelho (Oxisol) of the Cerrado region","PeriodicalId":8309,"journal":{"name":"April 2021","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89933868","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-04-10DOI: 10.21475/ajcs.21.15.04.p1517
J. R. Pimentel, Cristian Troyjack, Í. Dubal, M. Peter, L. Jaques, F. Koch, I. Carvalho, N. D. S. Bilhalva, S. Dellagostin, G. H. Demari, F. Lautenchleger, E. G. Martinazzo, T. Pedó, T. Z. Aumonde
The objective of this work was to evaluate the influence of nitrogen in association with sulfur applied in the field and the influence of this fertilization on the vigor of wheat seeds produced and later evaluated in the laboratory. Field experiments were carried out in the municipalities of Caibaté-RS and Pelotas-RS using the TBIO Sinuelo cultivar adapted to all the regions of Rio Grande do Sul. The experimental design was a randomized block design with a 2x5x2 trifractory scheme (cultivation environments x doses of nitrogen x sulfur management) with 4 replicates. The treatments consisted of the combination of two cultivation environments [Caibaté-RS and Pelotas-RS], five nitrogen doses Urea 45%, [0; 22.5; 45; 67.5 and 90 kg ha-1] applied at the beginning of tillering and sulfur, Sulfuric 90% sulfur, [0 and 60 kg ha-1] applied before sowing, about 7 days. After reaching physiological maturity, the seeds were harvested manually and taken to the seed laboratory. The seeds were dried in a forced ventilation oven at 41ºC until the moisture content stabilized at 12% (wet bulb). We evaluated the first germination count (FGC), accelerated aging (AA), field emergence (FE), shoot length (RL) and seedling root length (SL). The seeds produced in Caibaté-RS have greater vigor in relation to Pelotas-RS. Nitrogen fertilization favors the production of seeds with greater vigor, while sulfur can influence the vigor according to the environment in which the plants are cultivated
这项工作的目的是评估在田间施用氮与硫的影响，以及这种施肥对小麦种子的活力的影响，后来在实验室进行了评估。在caibat - rs市和Pelotas-RS市进行了田间试验，使用了适应南里奥格兰德州所有地区的TBIO Sinuelo品种。试验设计采用随机区组设计，采用2 × 5 × 3个试验方案(栽培环境x氮剂量x硫管理)，设4个重复。处理包括两种栽培环境[caibat - rs和Pelotas-RS]的组合，5个氮肥剂量尿素45%，[0;22.5;45;分蘖初施67.5和90 kg ha-1]，播前施硫，硫为90%，[0和60 kg ha-1]，约7天。在达到生理成熟后，人工收获种子并带到种子实验室。种子在41ºC的强制通风烘箱中干燥，直到水分含量稳定在12%(湿球)。对幼苗的首次发芽数(FGC)、加速老化(AA)、田间出苗率(FE)、茎长(RL)和幼苗根长(SL)进行了评价。与Pelotas-RS相比，caibat - rs生产的种子具有更大的活力。氮肥有利于产生活力更强的种子，而硫则会根据植物的栽培环境对活力产生影响
{"title":"Nitrogen (N) and sulphate (S) fertilization in wheat crop: effect on the vigor of seeds produced","authors":"J. R. Pimentel, Cristian Troyjack, Í. Dubal, M. Peter, L. Jaques, F. Koch, I. Carvalho, N. D. S. Bilhalva, S. Dellagostin, G. H. Demari, F. Lautenchleger, E. G. Martinazzo, T. Pedó, T. Z. Aumonde","doi":"10.21475/ajcs.21.15.04.p1517","DOIUrl":"https://doi.org/10.21475/ajcs.21.15.04.p1517","url":null,"abstract":"The objective of this work was to evaluate the influence of nitrogen in association with sulfur applied in the field and the influence of this fertilization on the vigor of wheat seeds produced and later evaluated in the laboratory. Field experiments were carried out in the municipalities of Caibaté-RS and Pelotas-RS using the TBIO Sinuelo cultivar adapted to all the regions of Rio Grande do Sul. The experimental design was a randomized block design with a 2x5x2 trifractory scheme (cultivation environments x doses of nitrogen x sulfur management) with 4 replicates. The treatments consisted of the combination of two cultivation environments [Caibaté-RS and Pelotas-RS], five nitrogen doses Urea 45%, [0; 22.5; 45; 67.5 and 90 kg ha-1] applied at the beginning of tillering and sulfur, Sulfuric 90% sulfur, [0 and 60 kg ha-1] applied before sowing, about 7 days. After reaching physiological maturity, the seeds were harvested manually and taken to the seed laboratory. The seeds were dried in a forced ventilation oven at 41ºC until the moisture content stabilized at 12% (wet bulb). We evaluated the first germination count (FGC), accelerated aging (AA), field emergence (FE), shoot length (RL) and seedling root length (SL). The seeds produced in Caibaté-RS have greater vigor in relation to Pelotas-RS. Nitrogen fertilization favors the production of seeds with greater vigor, while sulfur can influence the vigor according to the environment in which the plants are cultivated","PeriodicalId":8309,"journal":{"name":"April 2021","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76236723","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-04-10DOI: 10.21475/ajcs.21.15.04.p2831
D. P. Costa, Janisson Bispo Lino, Neyla Thayná Lima, Cícero Luiz Franco Junior, F. Brito, Lucas Felipe Prohmann Tschoeke, Rafaela Felix da França, Renata Oliveira Silva, É. Medeiros
The processing of cassava roots for starch extraction in factories generates a large amount of cassava wastewater (CW), which is rich in nutrients that are beneficial to plants. The reuse of this agro-industrial by-product is important for farmers and the environment as an alternative means to support soil fertility and plant production. Lettuce is the most important salad vegetable grown in the world. The objective of this study was to evaluate the impact of CW doses on soil organic carbon, basal respiration, microbial biomass, enzymatic activities, and lettuce growth in an Entisol. The experiment was conducted in pots in a greenhouse at room temperature in a completely randomized design with ten replications. The treatments consisted of the application of CW in increasing volumes that corresponded to fractions of the field capacity (FC) of the soil (100% FC = 206.6 ml dm-3): 0% (negative control), 10%, 20%, 30%, 40%, and 50% of field capacity (FC) per pot. An additional treatment without CW was also included, applying only 1.0 g of mineral fertilizer per pot (20% N, 10% P, and 20% K). After 28 days of emergence, the 10% FC treatment responded similarly to mineral fertilizer, increasing the length of the branches (+42%), number of leaves (+45%), aerial fresh matter (+202%) and the concentrations of Chlorophyll A (+ 33%), and Chlorophyll B (+40%), in addition to soil organic carbon (+15%), all compared to the control. The enzymatic activities in the soil were shown to be sensitive to CW dosage, especially for urease, which grew linearly as a function of the increased pH and K+ ions in the soil with the application of CW. The dose 20.7 ml CW dm-3 (10% FC) was that most increased plant variables, but the nutritional status of the soil and microbial activities benefited more from higher doses, starting from 30% FC, a scenario that could benefit plants more in future phenological stages, when there will be greater nutritional demand
工厂对木薯根进行淀粉提取加工会产生大量的木薯废水，其中含有丰富的对植物有益的营养物质。作为支持土壤肥力和植物生产的替代手段，这种农工副产品的再利用对农民和环境都很重要。莴苣是世界上最重要的沙拉蔬菜。本研究的目的是评估CW剂量对Entisol土壤有机碳、基础呼吸、微生物生物量、酶活性和生菜生长的影响。试验在室温温室盆栽中进行，采用完全随机设计，重复10次。处理包括按土壤田间容量(FC)的比例(100% FC = 206.6 ml dm-3)增加CW的施用量;0%(负控制),10%,20%,30%,40%,和50%的田间持水量(FC)每锅。没有连续波还包括一个额外的治疗,应用只有1.0克的矿物肥料每锅(20% N, P, 10%和20% K)。经过28天的出现,10% FC治疗反应类似于矿物肥料,增加分支的长度(+ 42%),数量的叶子(+ 45%),空气新鲜的物质(+ 202%)和叶绿素A的浓度(+ 33%)和叶绿素B (+ 40%),除土壤有机碳(+15%)外，均与对照相比。土壤酶活性对连施量敏感，脲酶活性随连施土壤pH和K+离子的增加呈线性增长。20.7 ml CW dm-3(含10% FC)剂量是增加最多的植物变量，但从30% FC开始，更高剂量对土壤营养状况和微生物活动更有利，这种情况可能在未来物候阶段对植物更有利，届时将有更大的营养需求
{"title":"Cassava wastewater as ecofriendly and low-cost alternative to produce lettuce: impacts on soil organic carbon, microbial biomass, and enzymatic activities","authors":"D. P. Costa, Janisson Bispo Lino, Neyla Thayná Lima, Cícero Luiz Franco Junior, F. Brito, Lucas Felipe Prohmann Tschoeke, Rafaela Felix da França, Renata Oliveira Silva, É. Medeiros","doi":"10.21475/ajcs.21.15.04.p2831","DOIUrl":"https://doi.org/10.21475/ajcs.21.15.04.p2831","url":null,"abstract":"The processing of cassava roots for starch extraction in factories generates a large amount of cassava wastewater (CW), which is rich in nutrients that are beneficial to plants. The reuse of this agro-industrial by-product is important for farmers and the environment as an alternative means to support soil fertility and plant production. Lettuce is the most important salad vegetable grown in the world. The objective of this study was to evaluate the impact of CW doses on soil organic carbon, basal respiration, microbial biomass, enzymatic activities, and lettuce growth in an Entisol. The experiment was conducted in pots in a greenhouse at room temperature in a completely randomized design with ten replications. The treatments consisted of the application of CW in increasing volumes that corresponded to fractions of the field capacity (FC) of the soil (100% FC = 206.6 ml dm-3): 0% (negative control), 10%, 20%, 30%, 40%, and 50% of field capacity (FC) per pot. An additional treatment without CW was also included, applying only 1.0 g of mineral fertilizer per pot (20% N, 10% P, and 20% K). After 28 days of emergence, the 10% FC treatment responded similarly to mineral fertilizer, increasing the length of the branches (+42%), number of leaves (+45%), aerial fresh matter (+202%) and the concentrations of Chlorophyll A (+ 33%), and Chlorophyll B (+40%), in addition to soil organic carbon (+15%), all compared to the control. The enzymatic activities in the soil were shown to be sensitive to CW dosage, especially for urease, which grew linearly as a function of the increased pH and K+ ions in the soil with the application of CW. The dose 20.7 ml CW dm-3 (10% FC) was that most increased plant variables, but the nutritional status of the soil and microbial activities benefited more from higher doses, starting from 30% FC, a scenario that could benefit plants more in future phenological stages, when there will be greater nutritional demand","PeriodicalId":8309,"journal":{"name":"April 2021","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83904905","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-04-10DOI: 10.21475/ajcs.21.15.04.p2676
G. Sseremba, G. Kagezi, J. Kobusinge, P. Musoli, David Akodi, N. Olango, P. Kucel, Job Chemutai, J. Mulindwa, G. Arinaitwe
Plant density in Robusta coffee is an unresolved issue in low volume producing countries especially when compared with leading producers. In this study, we aimed to compare the response of Robusta coffee to pest incidence, disease severity, growth and yield potential in two contrasting spacing regimes. Two spacing regimes of 3mx3m and 3mx1m were evaluated for selected parameters in a randomized complete block design with three replications. There was a highly significant difference in pest incidence between the spacing regimes (p<0.01) for all the pests except scales (p=0.126). The black coffee trig borer incidence was higher under close spacing of 3mx1m than for 3mx3m with a mean difference of 13.2%. There was no significant association between spacing regime and leaf rust disease incidence while the association was significant for red blister disease (χ2=33.56, df=1, p<0.001). Significant difference in growth response between spacing regimes (p<0.05) were also obtained for change in canopy height (dCAH), number of primaries, number of stems and leaf size. For instance, dCAH was higher under 3mx1m spacing than for 3mx3m spacing. A significant difference in yield potential existed between the spacing regimes (p<0.05) for average yield per tree and average yield per hectare (aYH). Close spacing produced a higher aYH (5.82 t cc/ha) than wide spacing (4.80 t cc/ha). Whereas yield potential is high at high tree densities, associated prevalence of biotic constraints calls for supportive stress management package for farmers.
{"title":"High Robusta coffee plant density is associated with better yield potential at mixed responses for growth robustness, pests and diseases: which way for a farmer?","authors":"G. Sseremba, G. Kagezi, J. Kobusinge, P. Musoli, David Akodi, N. Olango, P. Kucel, Job Chemutai, J. Mulindwa, G. Arinaitwe","doi":"10.21475/ajcs.21.15.04.p2676","DOIUrl":"https://doi.org/10.21475/ajcs.21.15.04.p2676","url":null,"abstract":"Plant density in Robusta coffee is an unresolved issue in low volume producing countries especially when compared with leading producers. In this study, we aimed to compare the response of Robusta coffee to pest incidence, disease severity, growth and yield potential in two contrasting spacing regimes. Two spacing regimes of 3mx3m and 3mx1m were evaluated for selected parameters in a randomized complete block design with three replications. There was a highly significant difference in pest incidence between the spacing regimes (p<0.01) for all the pests except scales (p=0.126). The black coffee trig borer incidence was higher under close spacing of 3mx1m than for 3mx3m with a mean difference of 13.2%. There was no significant association between spacing regime and leaf rust disease incidence while the association was significant for red blister disease (χ2=33.56, df=1, p<0.001). Significant difference in growth response between spacing regimes (p<0.05) were also obtained for change in canopy height (dCAH), number of primaries, number of stems and leaf size. For instance, dCAH was higher under 3mx1m spacing than for 3mx3m spacing. A significant difference in yield potential existed between the spacing regimes (p<0.05) for average yield per tree and average yield per hectare (aYH). Close spacing produced a higher aYH (5.82 t cc/ha) than wide spacing (4.80 t cc/ha). Whereas yield potential is high at high tree densities, associated prevalence of biotic constraints calls for supportive stress management package for farmers.","PeriodicalId":8309,"journal":{"name":"April 2021","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80902741","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-04-10DOI: 10.21475/ajcs.21.15.04.p2938
T. O. Souza, M. C. Nery, M. A. Magalhães, M. Martins, F. Nery, C. Fialho
Brachiaria brizantha is a forage species widely used in Brazilian pastures and its seeds have contamination in several areas of countries. Its high germination is fundamental in pasture formation. However, it is common for seeds of this species to have natural dormancy, negatively influencing pasture formation, resulting in losses to the producer. Thus, the objective of this study was to determine a methodology to overcome dormancy of ‘Marandu’ and ‘Piatã’ B. brizantha seeds. Four batches from the 2016/2017 and 2017/2018 harvests were used. Initially, batch profile was evaluated by the following characteristics: determination of moisture content, weight of a thousand seeds, first germination count, germination, germination speed index, initial stand, emergency, emergency speed index and fungi incidence in seeds. The seeds were subjected to the following treatments to overcome dormancy: mechanical (removal of glume, palea and lemma), sulfuric acid (98%, 36 N), potassium nitrate (0.2%), heat treatment (70 °C and 85 °C, during 5h, 10h, 15h and 20h) and a control. The obtained results allow inferring that the causes of dormancy of ‘Piatã’ seeds are of a physical nature, with the tissues surrounding the seed being the main factor that prevent germination. The mechanical method and scarification with sulfuric acid the most efficient in overcoming dormancy. The mechanical treatment with removal of the glumella is efficient to overcome the dormancy ofB. brizantha seeds, providing an increase in the germination percentage
{"title":"Methods for overcoming dormancy in Brachiaria brizantha seeds","authors":"T. O. Souza, M. C. Nery, M. A. Magalhães, M. Martins, F. Nery, C. Fialho","doi":"10.21475/ajcs.21.15.04.p2938","DOIUrl":"https://doi.org/10.21475/ajcs.21.15.04.p2938","url":null,"abstract":"Brachiaria brizantha is a forage species widely used in Brazilian pastures and its seeds have contamination in several areas of countries. Its high germination is fundamental in pasture formation. However, it is common for seeds of this species to have natural dormancy, negatively influencing pasture formation, resulting in losses to the producer. Thus, the objective of this study was to determine a methodology to overcome dormancy of ‘Marandu’ and ‘Piatã’ B. brizantha seeds. Four batches from the 2016/2017 and 2017/2018 harvests were used. Initially, batch profile was evaluated by the following characteristics: determination of moisture content, weight of a thousand seeds, first germination count, germination, germination speed index, initial stand, emergency, emergency speed index and fungi incidence in seeds. The seeds were subjected to the following treatments to overcome dormancy: mechanical (removal of glume, palea and lemma), sulfuric acid (98%, 36 N), potassium nitrate (0.2%), heat treatment (70 °C and 85 °C, during 5h, 10h, 15h and 20h) and a control. The obtained results allow inferring that the causes of dormancy of ‘Piatã’ seeds are of a physical nature, with the tissues surrounding the seed being the main factor that prevent germination. The mechanical method and scarification with sulfuric acid the most efficient in overcoming dormancy. The mechanical treatment with removal of the glumella is efficient to overcome the dormancy ofB. brizantha seeds, providing an increase in the germination percentage","PeriodicalId":8309,"journal":{"name":"April 2021","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85168808","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-04-10DOI: 10.21475/ajcs.21.15.04.p2827
G. Ferreira, C. Santos, J. A. Alencar, D. O. M. D. Silva
Recurrent selection for resistance to onion Thrips tabaci has not been well studied by breeding programmes. Onion thrips is a pest of major concern and is controlled by insecticide spraying, raising production costs and potentially damaging the environment. This study aimed to estimate onion bulb yield genetic gain through six cycles in the ‘BRS Alfa São Francisco’ developed by recurrent selection for T. tabaci resistance. Experiments were carried out in a randomised block design, with three replications, in two locations. The degree of infestation in plants was evaluated five times after transplanting, as well as plant architecture traits and bulb yield. The latest selection cycle presented bulb commercial yield of 32.1 t.ha-1, while the base population ‘Alfa Tropical’ and IPA 10 check cultivar 15.9 and 14.0 t.ha-1, respectively (p<0.01). The broad sense heritability values ranged from 0.65 to 0.74 for bulb yield. The mean genetic gain was 1.0 t.ha-1 or 6% per selection cycle, indicating the efficiency of the method to increase the frequency of favourable alleles for thrips resistance and the possibility of onion cultivation in the total absence of insecticide applications to control this pest, or a reduction in their number
对洋葱蓟马烟粉虱抗性的反复选择尚未通过育种计划得到很好的研究。洋葱蓟马是一种令人担忧的害虫，通过喷洒杀虫剂来控制，这增加了生产成本，并可能破坏环境。本研究旨在通过6个循环对通过反复选择获得的抗烟粉虱抗性的‘BRS Alfa s o Francisco’进行洋葱鳞茎产量遗传增益估计。实验采用随机分组设计，在两个地点进行三次重复。移栽后对植株进行5次侵染程度评价，并对植株结构性状和鳞茎产量进行评价。最新选育周期的球茎商业产量为32.1 t.ha-1，基础群体“热带阿尔法”和IPA 10对照品种分别为15.9 t.ha-1和14.0 t.ha-1 (p<0.01)。鳞茎产量的广义遗传率为0.65 ~ 0.74。每个选择周期的平均遗传增益为1.0 t.ha-1或6%，表明该方法有效地增加了对蓟马抗性有利等位基因的频率，以及在完全不施用杀虫剂控制这种害虫或减少其数量的情况下种植洋葱的可能性
{"title":"Recurrent selection for resistance to Thrips tabaci in a tropical onion population","authors":"G. Ferreira, C. Santos, J. A. Alencar, D. O. M. D. Silva","doi":"10.21475/ajcs.21.15.04.p2827","DOIUrl":"https://doi.org/10.21475/ajcs.21.15.04.p2827","url":null,"abstract":"Recurrent selection for resistance to onion Thrips tabaci has not been well studied by breeding programmes. Onion thrips is a pest of major concern and is controlled by insecticide spraying, raising production costs and potentially damaging the environment. This study aimed to estimate onion bulb yield genetic gain through six cycles in the ‘BRS Alfa São Francisco’ developed by recurrent selection for T. tabaci resistance. Experiments were carried out in a randomised block design, with three replications, in two locations. The degree of infestation in plants was evaluated five times after transplanting, as well as plant architecture traits and bulb yield. The latest selection cycle presented bulb commercial yield of 32.1 t.ha-1, while the base population ‘Alfa Tropical’ and IPA 10 check cultivar 15.9 and 14.0 t.ha-1, respectively (p<0.01). The broad sense heritability values ranged from 0.65 to 0.74 for bulb yield. The mean genetic gain was 1.0 t.ha-1 or 6% per selection cycle, indicating the efficiency of the method to increase the frequency of favourable alleles for thrips resistance and the possibility of onion cultivation in the total absence of insecticide applications to control this pest, or a reduction in their number","PeriodicalId":8309,"journal":{"name":"April 2021","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89567842","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-04-10DOI: 10.21475/ajcs.21.15.04.p3054
C. F. Lewandoski, R. F. Santos, D. Bassegio, Samuel Nelson Melegari de Souza, J. Siqueira, D. M. Souza, Leonardo da S. Reis, P. D. L. Bueno
Temperature and rotation speed are operational parameters that influence oil screw press efficiency. The objective of this study was to evaluate the oil physicochemical properties, cake bromatological properties, and oil extraction yield from crambe (Crambe abyssinica Hochst) seeds by mechanical pressing at different temperatures and rotation speeds in a mechanical extruder. A 4 × 5 factorial experimental design was employed to determine the effects of these parameters. The experimental design incorporated four temperature ranges (110–120, 120–130, 130–140, and 140–150°C) and five screw rotation speeds (1000, 1200, 1400, 1600, and 1800 rotations per minute, RPM), with four repetitions. The physicochemical properties of the oil and crambe cake, and the cake bromatological properties were affected by extraction at different temperatures and extruder rotation speeds. The oil density and viscosity (quality parameters), and the crambe cake bromatological factors, crude fiber, ash, lipid, and moisture content were found to be higher at extraction temperatures in the 140–150°C range. The maximum oil yield was achieved by extraction at a temperature of 140–150°C and a rotation speed of 1800 RPM. The protein and carbohydrate content of the crambe cake decreased with increasing temperature and rotation speed. The oil yield increased by 56% as temperatures increased from the 110–120°C range to the 140–150°C range, and by 41% when the rotation speed increased from 1000 to 1800 RPM. The screw configuration influenced the crambe and cake properties. These results can be used to determine the appropriate configuration of the screw
{"title":"Oil extraction and cake bromatological properties of crambe (Crambe abyssinica) are affected by extraction at different temperatures and rotation speeds","authors":"C. F. Lewandoski, R. F. Santos, D. Bassegio, Samuel Nelson Melegari de Souza, J. Siqueira, D. M. Souza, Leonardo da S. Reis, P. D. L. Bueno","doi":"10.21475/ajcs.21.15.04.p3054","DOIUrl":"https://doi.org/10.21475/ajcs.21.15.04.p3054","url":null,"abstract":"Temperature and rotation speed are operational parameters that influence oil screw press efficiency. The objective of this study was to evaluate the oil physicochemical properties, cake bromatological properties, and oil extraction yield from crambe (Crambe abyssinica Hochst) seeds by mechanical pressing at different temperatures and rotation speeds in a mechanical extruder. A 4 × 5 factorial experimental design was employed to determine the effects of these parameters. The experimental design incorporated four temperature ranges (110–120, 120–130, 130–140, and 140–150°C) and five screw rotation speeds (1000, 1200, 1400, 1600, and 1800 rotations per minute, RPM), with four repetitions. The physicochemical properties of the oil and crambe cake, and the cake bromatological properties were affected by extraction at different temperatures and extruder rotation speeds. The oil density and viscosity (quality parameters), and the crambe cake bromatological factors, crude fiber, ash, lipid, and moisture content were found to be higher at extraction temperatures in the 140–150°C range. The maximum oil yield was achieved by extraction at a temperature of 140–150°C and a rotation speed of 1800 RPM. The protein and carbohydrate content of the crambe cake decreased with increasing temperature and rotation speed. The oil yield increased by 56% as temperatures increased from the 110–120°C range to the 140–150°C range, and by 41% when the rotation speed increased from 1000 to 1800 RPM. The screw configuration influenced the crambe and cake properties. These results can be used to determine the appropriate configuration of the screw","PeriodicalId":8309,"journal":{"name":"April 2021","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90266285","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-04-10DOI: 10.21475/ajcs.21.15.04.p2789
K. Charif, I. Mzabri, M. Rimani, A. Boukroute, N. Kouddane, A. Berrichi
The turfgrass establishment is an important criterion for the choice of turfgrass species. The faster a lawn is established the more benefits it has to offer for landscapers. The objective of this work is to study the growth speed and development of six species. Four of them are cool-season ones (temperate): Lolium perenne, Festuca arundinacea, Agrostis stolonifera and Poa pratensis while the other two are warm-season ones (tropical): Pennisetum clandestinum and Cynodon dactylon. The species are seeded in two distinct periods: spring and autumn and are studied under the climatic conditions of the eastern region of Morocco which is characterized by a semi-arid Mediterranean climate with continental tendency known for its severe cold in winter. The coverage rate is the parameter considered in order to determine the duration of establishment for each species. The study was conducted in the experimental station of the Faculty of Sciences of Oujda. The results show that the establishment pace differs depending on the season and the nature of the species. Autumn is the suitable season for temperate species, while tropical species have shown a faster growth in spring. Lolium perenne and Cynodon dactylon are the fastest species to establish as they need a maximum of 30 days after the seedlings’ development. Poa pratensis is the last species to cover the total area seeded within 50 and 60 days during the two season’s spring and autumn respectively
{"title":"Effect of the season on establishment of some turf grasses under the climatic conditions in eastern Morocco","authors":"K. Charif, I. Mzabri, M. Rimani, A. Boukroute, N. Kouddane, A. Berrichi","doi":"10.21475/ajcs.21.15.04.p2789","DOIUrl":"https://doi.org/10.21475/ajcs.21.15.04.p2789","url":null,"abstract":"The turfgrass establishment is an important criterion for the choice of turfgrass species. The faster a lawn is established the more benefits it has to offer for landscapers. The objective of this work is to study the growth speed and development of six species. Four of them are cool-season ones (temperate): Lolium perenne, Festuca arundinacea, Agrostis stolonifera and Poa pratensis while the other two are warm-season ones (tropical): Pennisetum clandestinum and Cynodon dactylon. The species are seeded in two distinct periods: spring and autumn and are studied under the climatic conditions of the eastern region of Morocco which is characterized by a semi-arid Mediterranean climate with continental tendency known for its severe cold in winter. The coverage rate is the parameter considered in order to determine the duration of establishment for each species. The study was conducted in the experimental station of the Faculty of Sciences of Oujda. The results show that the establishment pace differs depending on the season and the nature of the species. Autumn is the suitable season for temperate species, while tropical species have shown a faster growth in spring. Lolium perenne and Cynodon dactylon are the fastest species to establish as they need a maximum of 30 days after the seedlings’ development. Poa pratensis is the last species to cover the total area seeded within 50 and 60 days during the two season’s spring and autumn respectively","PeriodicalId":8309,"journal":{"name":"April 2021","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74896809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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