Pub Date : 2023-06-15DOI: 10.1080/02571862.2023.2206166
K. Konan, Kouadio I Kouassi, B. S. Bonny, B. T. S. Doubi, B. Zoro, D. O. Dogbo
The objective of this study was to propose a profitable cropping association date between cassava (Manihot esculenta) and Bambara groundnut (Vigna subterranea, also known as voandzou) through the examination of competition indices. The association of the cassava varieties Allada agba, Bonoua, Six mois and Yacé with the bouquet and creeping morphotypes of Bambara groundnut was tested at different cassava sowing dates: 0, 15 and 30 days after sowing of the bouquet Bambara groundnut and 0, 15, 30, 45 and 60 days after sowing the creeping Bambara groundnut. These cropping association systems were evaluated through competition indices in Côte d’Ivoire: the area–time equivalent ratio (ATER), the competitiveness rate (CR) and the relative dominance coefficient (K). ATER and K values were greater than unity when cassava was sown 15 to 30 days after sowing the bouquet Bambara groundnut and 30 to 45 days after sowing the creeping Bambara groundnut. Cassava varieties were more competitive than the Bambara groundnut morphotypes (CRC > CRV). The best results in terms of efficient land use (ATER > 1) and yield gain (K > 1) were obtained when cassava was sown 30 days after Bambara groundnut. However, for the Bonoua–Bambara groundnut creeping association, the yield gain was obtained when cassava was sown 45 days after Bambara groundnut.
{"title":"The efficiency of cassava–Bambara groundnut intercropping according to the sowing date of cassava","authors":"K. Konan, Kouadio I Kouassi, B. S. Bonny, B. T. S. Doubi, B. Zoro, D. O. Dogbo","doi":"10.1080/02571862.2023.2206166","DOIUrl":"https://doi.org/10.1080/02571862.2023.2206166","url":null,"abstract":"The objective of this study was to propose a profitable cropping association date between cassava (Manihot esculenta) and Bambara groundnut (Vigna subterranea, also known as voandzou) through the examination of competition indices. The association of the cassava varieties Allada agba, Bonoua, Six mois and Yacé with the bouquet and creeping morphotypes of Bambara groundnut was tested at different cassava sowing dates: 0, 15 and 30 days after sowing of the bouquet Bambara groundnut and 0, 15, 30, 45 and 60 days after sowing the creeping Bambara groundnut. These cropping association systems were evaluated through competition indices in Côte d’Ivoire: the area–time equivalent ratio (ATER), the competitiveness rate (CR) and the relative dominance coefficient (K). ATER and K values were greater than unity when cassava was sown 15 to 30 days after sowing the bouquet Bambara groundnut and 30 to 45 days after sowing the creeping Bambara groundnut. Cassava varieties were more competitive than the Bambara groundnut morphotypes (CRC > CRV). The best results in terms of efficient land use (ATER > 1) and yield gain (K > 1) were obtained when cassava was sown 30 days after Bambara groundnut. However, for the Bonoua–Bambara groundnut creeping association, the yield gain was obtained when cassava was sown 45 days after Bambara groundnut.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48423008","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 : 2023-03-15DOI: 10.1080/02571862.2023.2196733
Neliswa A. Matrose, Z. A. Belay, Obikeze Kenechukwu, L. Mokwena, O. J. Caleb
This study investigated the effect of processing and freeze-drying on targeted volatile compounds (terpenes) of Helichrysum odoratissimum (L.) Sweet. Air-dried plant material was processed to obtain: (i) roughly ground leaves and stems (RGMHO); (ii) finely ground leaves and stems (FGMHO); and (iii) wool-like fraction (WLMHO). Terpene content of the air-dried samples, crude ethanol extract (CE, filtrate), sediments and freeze-dried (FDE) powders from the different processed fractions were analysed using gas chromatography-mass spectrometry (GC-MS). Results showed that the highest α-pinene (91.3 µg l−1) was obtained in the CE compared to the freeze-dried (≈3.0 µg l−1) extracts (p ≤ 0.05). Eucalyptol was significantly higher in the air-dried leaves (27.3 µg l−1) than were CE and FDE (4.0 and 0.9 µg l−1 respectively), while β-caryophyllene, pulegone and humulene contents were significantly higher in the FDE samples (p ≤ 0.05). These results demonstrated that processing had significant impact on the concentration of targeted terpenes in H. odoratissimum. This study is the first report on the identification and quantification targeted terpenes in H. odoratissimum (L.) Sweet.
{"title":"Bioprospecting for active compounds: impact of milling, extract fractions and freeze-drying on targeted terpene compounds of Helichrysum odoratissimum (L.) Sweet","authors":"Neliswa A. Matrose, Z. A. Belay, Obikeze Kenechukwu, L. Mokwena, O. J. Caleb","doi":"10.1080/02571862.2023.2196733","DOIUrl":"https://doi.org/10.1080/02571862.2023.2196733","url":null,"abstract":"This study investigated the effect of processing and freeze-drying on targeted volatile compounds (terpenes) of Helichrysum odoratissimum (L.) Sweet. Air-dried plant material was processed to obtain: (i) roughly ground leaves and stems (RGMHO); (ii) finely ground leaves and stems (FGMHO); and (iii) wool-like fraction (WLMHO). Terpene content of the air-dried samples, crude ethanol extract (CE, filtrate), sediments and freeze-dried (FDE) powders from the different processed fractions were analysed using gas chromatography-mass spectrometry (GC-MS). Results showed that the highest α-pinene (91.3 µg l−1) was obtained in the CE compared to the freeze-dried (≈3.0 µg l−1) extracts (p ≤ 0.05). Eucalyptol was significantly higher in the air-dried leaves (27.3 µg l−1) than were CE and FDE (4.0 and 0.9 µg l−1 respectively), while β-caryophyllene, pulegone and humulene contents were significantly higher in the FDE samples (p ≤ 0.05). These results demonstrated that processing had significant impact on the concentration of targeted terpenes in H. odoratissimum. This study is the first report on the identification and quantification targeted terpenes in H. odoratissimum (L.) Sweet.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":"40 1","pages":"127 - 132"},"PeriodicalIF":0.9,"publicationDate":"2023-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"59237600","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 : 2023-03-15DOI: 10.1080/02571862.2023.2236075
Sibongiseni Silwana, Azwimbavhi Reckson Mulidzi, Nebo Jovanovic
AbstractCover crops are used in sustainable agricultural practices to improve soil quality and minimise the effect of climate change, water restrictions and drought. The South African citrus industry produces and exports a diverse range of citrus fruits; however, knowledge of cover crops in citrus orchards in South Africa is limited. This review focuses mostly on evaluating cover crop selection, effects on the soil microbial community, weed control, citrus yield and fruit quality. In terms of cover crop selection, legumes seem to be preferred over non-legume cover crops. The reviewed literature reported that legume cover crops increased nitrogen by 67 to 209 kg N ha−1 through the nitrogen fixation process. Additionally, the cultivation of legume cover crops substantially improved the cost savings of nitrogen fertiliser. The fruit yield improved by 7.6 to 64%, while fruit quality improved by 2.3 to 12.4% fruit weight and 2.4 to 5.8% Bx. This demonstrates that the benefits of cover crops to South African citrus growers include improved soil quality and fruit yields and decreased costs.Keywords: fruit yieldlegumesnitrogen fixationorganic carbonorganic mattersoil microbial communitySouth Africatree shading
覆盖物作物被用于可持续农业实践，以改善土壤质量并最大限度地减少气候变化、水资源限制和干旱的影响。南非柑橘产业生产和出口各种柑橘类水果;然而，对南非柑橘果园覆盖作物的了解有限。本文主要从覆盖作物的选择、对土壤微生物群落的影响、杂草控制、柑橘产量和果实品质等方面进行综述。在覆盖作物选择方面，豆类似乎比非豆类覆盖作物更受青睐。据文献报道，豆科覆盖作物通过固氮过程增加氮素67 ~ 209 kg N ha - 1。此外，豆科覆盖作物的种植大大提高了氮肥的成本节约。果实产量提高7.6 ~ 64%，果实品质提高2.3 ~ 12.4%，单果重提高2.4 ~ 5.8%。这表明覆盖作物对南非柑橘种植者的好处包括改善土壤质量和水果产量以及降低成本。关键词:果实产量豆科植物固氮有机碳有机质土壤微生物群落南非树木遮荫
{"title":"Evaluating the effects and benefits of cover crops in citrus orchards: a review","authors":"Sibongiseni Silwana, Azwimbavhi Reckson Mulidzi, Nebo Jovanovic","doi":"10.1080/02571862.2023.2236075","DOIUrl":"https://doi.org/10.1080/02571862.2023.2236075","url":null,"abstract":"AbstractCover crops are used in sustainable agricultural practices to improve soil quality and minimise the effect of climate change, water restrictions and drought. The South African citrus industry produces and exports a diverse range of citrus fruits; however, knowledge of cover crops in citrus orchards in South Africa is limited. This review focuses mostly on evaluating cover crop selection, effects on the soil microbial community, weed control, citrus yield and fruit quality. In terms of cover crop selection, legumes seem to be preferred over non-legume cover crops. The reviewed literature reported that legume cover crops increased nitrogen by 67 to 209 kg N ha−1 through the nitrogen fixation process. Additionally, the cultivation of legume cover crops substantially improved the cost savings of nitrogen fertiliser. The fruit yield improved by 7.6 to 64%, while fruit quality improved by 2.3 to 12.4% fruit weight and 2.4 to 5.8% Bx. This demonstrates that the benefits of cover crops to South African citrus growers include improved soil quality and fruit yields and decreased costs.Keywords: fruit yieldlegumesnitrogen fixationorganic carbonorganic mattersoil microbial communitySouth Africatree shading","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135747771","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 : 2023-01-01DOI: 10.1080/02571862.2022.2160881
Johannes Stephanus Theron, G. J. van Coller, L. Rose, J. Labuschagne, P. Swanepoel
Conservation agriculture relies on residue retention, crop rotation and reduced tillage. Crop rotation determines residue type, while tillage affects residue load and distribution. Although crop residue retention is often beneficial, residues can create challenges, including obstruction of planters during establishment and stubble-borne diseases. This study determined the effects of crop rotation and tillage on the residue decomposition and response of wheat (Triticum aestivum L.) in the Western Cape Province, South Africa. Wheat response was investigated to determine relationships between residue decomposition and its agronomic performance. Crop rotations in long-term trials in areas of the Swartland and southern Cape consisted of the following: wheat–medics, lupin–wheat–canola–wheat, canola–wheat–lupin–wheat, and a wheat monoculture. Crops were established with four tillage practices: conventional tillage (CT: chisel plough followed by soil inversion/ploughing, tine planter establishment), minimum tillage (MT: chisel plough, tine planter establishment), no-tillage (NT: direct drilling with tine planter) and zero tillage (ZT: direct drilling with double disc planter). Crop rotation had no effect on residue decomposition but increased wheat leaf area and grain yield when rotated with medics, lupin and canola when compared with monoculture wheat. ZT increased residue load and improved seedling establishment. ZT (50.9%) and NT (51.1%) increased residue decomposition compared with CT (34%). Faster residue decomposition could be achieved with less soil disturbance.
{"title":"The effect of crop rotation and tillage practice on residue decomposition and wheat performance in the Western Cape, South Africa","authors":"Johannes Stephanus Theron, G. J. van Coller, L. Rose, J. Labuschagne, P. Swanepoel","doi":"10.1080/02571862.2022.2160881","DOIUrl":"https://doi.org/10.1080/02571862.2022.2160881","url":null,"abstract":"Conservation agriculture relies on residue retention, crop rotation and reduced tillage. Crop rotation determines residue type, while tillage affects residue load and distribution. Although crop residue retention is often beneficial, residues can create challenges, including obstruction of planters during establishment and stubble-borne diseases. This study determined the effects of crop rotation and tillage on the residue decomposition and response of wheat (Triticum aestivum L.) in the Western Cape Province, South Africa. Wheat response was investigated to determine relationships between residue decomposition and its agronomic performance. Crop rotations in long-term trials in areas of the Swartland and southern Cape consisted of the following: wheat–medics, lupin–wheat–canola–wheat, canola–wheat–lupin–wheat, and a wheat monoculture. Crops were established with four tillage practices: conventional tillage (CT: chisel plough followed by soil inversion/ploughing, tine planter establishment), minimum tillage (MT: chisel plough, tine planter establishment), no-tillage (NT: direct drilling with tine planter) and zero tillage (ZT: direct drilling with double disc planter). Crop rotation had no effect on residue decomposition but increased wheat leaf area and grain yield when rotated with medics, lupin and canola when compared with monoculture wheat. ZT increased residue load and improved seedling establishment. ZT (50.9%) and NT (51.1%) increased residue decomposition compared with CT (34%). Faster residue decomposition could be achieved with less soil disturbance.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":"40 1","pages":"13 - 22"},"PeriodicalIF":0.9,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43226748","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 : 2023-01-01DOI: 10.1080/02571862.2023.2168077
Muketiwa Chitiga, G. Soropa, T. Dube, Progress Sengera
A decline in sugarcane yields from Block G (∼400 ha) of GreenFuel’s Chisumbanje Estate in south-eastern Zimbabwe prompted a study on spatial variability of the soil physico-chemical parameters in the 2017–2018 farming season. Using a systematic gridding schema, 123 geo-located soil samples from 16 sub-blocks were extracted from a depth of 0.3 m and analysed for various parameters. The results showed that pH was slightly acidic to alkaline (6.13–7.95) and had the lowest variability (CV ±15%). Low (N, P, Fe and Zn) and adequate (K and Cu) levels of mineral nutrients were also observed. However, some nutrients were highly variable, with P, Fe and Zn revealing the largest variability (CV ±35%). Semivariogram analysis showed a weak (clay, soil organic matter and N), moderate (pH, P, Mn and Zn) or strong (K, Fe and Cu) spatial correlation between the measured and predicted values. To optimise soil fertility and reduce variations, it is recommended that the estate employ variable-rate fertiliser application technologies, nutrient-monitoring systems, and precision satellite-based guidance for machinery. The study generated soil fertility maps using ordinary kriging; this will serve as a future reference for soil test-based fertiliser recommendations, soil fertility monitoring, and identifying spatial variability on the estate.
{"title":"Spatial interpolation of vertisol physico-chemical properties through ordinary kriging in south-eastern Zimbabwe","authors":"Muketiwa Chitiga, G. Soropa, T. Dube, Progress Sengera","doi":"10.1080/02571862.2023.2168077","DOIUrl":"https://doi.org/10.1080/02571862.2023.2168077","url":null,"abstract":"A decline in sugarcane yields from Block G (∼400 ha) of GreenFuel’s Chisumbanje Estate in south-eastern Zimbabwe prompted a study on spatial variability of the soil physico-chemical parameters in the 2017–2018 farming season. Using a systematic gridding schema, 123 geo-located soil samples from 16 sub-blocks were extracted from a depth of 0.3 m and analysed for various parameters. The results showed that pH was slightly acidic to alkaline (6.13–7.95) and had the lowest variability (CV ±15%). Low (N, P, Fe and Zn) and adequate (K and Cu) levels of mineral nutrients were also observed. However, some nutrients were highly variable, with P, Fe and Zn revealing the largest variability (CV ±35%). Semivariogram analysis showed a weak (clay, soil organic matter and N), moderate (pH, P, Mn and Zn) or strong (K, Fe and Cu) spatial correlation between the measured and predicted values. To optimise soil fertility and reduce variations, it is recommended that the estate employ variable-rate fertiliser application technologies, nutrient-monitoring systems, and precision satellite-based guidance for machinery. The study generated soil fertility maps using ordinary kriging; this will serve as a future reference for soil test-based fertiliser recommendations, soil fertility monitoring, and identifying spatial variability on the estate.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":"40 1","pages":"46 - 57"},"PeriodicalIF":0.9,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49395879","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 : 2023-01-01DOI: 10.1080/02571862.2022.2137591
Alireza Eslami-Firouzabadi, M. Karimi, Ali Abbasi-surki, A. Shafeinia, Fatemeh Derikvand-Moghadam
Nitrogen (N) is the nutrient most used by crop producers and its application may affect the N use efficiency in crop production. The present study was conducted in order to determine the optimum N fertiliser rate and application stages (S) for stevia (Stevia rebaudiana Bertoni) production for the first cutting, under greenhouse conditions. A two-factorial experiment with four N fertiliser rates (0, 40, 80 and 120 kg ha−1 applied as urea) and three stages (sole split N applied at sowing; dual split N applied at sowing and one month after sowing; triple split N applied at sowing, one and two months from sowing) were laid out in a completely randomised design. Each treatment combination was replicated three times. The plants were grown in boxes (1 m−2, 40 cm high) filled with loam soil and the treatments were applied as described. Results showed that stevia growth and metabolites were significantly affected by N rates and application stages. Stevia leaf area index (LAI), leaf yield, leaf/stem ratio and harvest index (HI), steviol glycosides (SVglys) content, SVglys compositions and yield were the highest when 40 kg N ha−1 was applied in two stages. This was also true for leaf and SVglys yield. Splitting of N application of 120 kg ha−1 into three stages showed an inhibitory effect on some stevia traits such as SVglys content and yield. Based on the current results and efficient N application, 40 kg N ha−1 split into two stages is recommended for stevia production under greenhouse conditions.
氮是作物生产者使用最多的营养素，其施用可能会影响作物生产中的氮利用效率。本研究旨在确定在温室条件下，甜菊（甜叶菊）第一次扦插生产的最佳氮肥用量和施用阶段（S）。四种氮肥用量（0、40、80和120）的两因子试验 kg ha−1作为尿素施用）和三个阶段（播种时施用单裂氮；播种时和播种后一个月施用双裂氮；在播种时施用三裂氮，播种后一和两个月）以完全随机的设计进行布置。每个治疗组合重复三次。这些植物生长在盒子里（1 m−2，40 cm高），并按所述进行处理。结果表明，施氮量和施用阶段对甜菊的生长和代谢产物有显著影响。甜菊叶面积指数（LAI）、叶产量、叶茎比和收获指数（HI）、甜菊糖苷（SVglys）含量、SVglys成分和产量在40 kg N ha−1分两个阶段施用。叶片和SVglys产量也是如此。120的N应用程序的拆分 kg ha−1分为三个阶段对甜菊糖含量和产量等一些性状表现出抑制作用。根据目前的结果和有效的N应用，40 建议将kg N ha−1分为两个阶段用于温室条件下的甜菊生产。
{"title":"Optimising the rate and stages of application of nitrogen fertiliser for stevia under greenhouse conditions","authors":"Alireza Eslami-Firouzabadi, M. Karimi, Ali Abbasi-surki, A. Shafeinia, Fatemeh Derikvand-Moghadam","doi":"10.1080/02571862.2022.2137591","DOIUrl":"https://doi.org/10.1080/02571862.2022.2137591","url":null,"abstract":"Nitrogen (N) is the nutrient most used by crop producers and its application may affect the N use efficiency in crop production. The present study was conducted in order to determine the optimum N fertiliser rate and application stages (S) for stevia (Stevia rebaudiana Bertoni) production for the first cutting, under greenhouse conditions. A two-factorial experiment with four N fertiliser rates (0, 40, 80 and 120 kg ha−1 applied as urea) and three stages (sole split N applied at sowing; dual split N applied at sowing and one month after sowing; triple split N applied at sowing, one and two months from sowing) were laid out in a completely randomised design. Each treatment combination was replicated three times. The plants were grown in boxes (1 m−2, 40 cm high) filled with loam soil and the treatments were applied as described. Results showed that stevia growth and metabolites were significantly affected by N rates and application stages. Stevia leaf area index (LAI), leaf yield, leaf/stem ratio and harvest index (HI), steviol glycosides (SVglys) content, SVglys compositions and yield were the highest when 40 kg N ha−1 was applied in two stages. This was also true for leaf and SVglys yield. Splitting of N application of 120 kg ha−1 into three stages showed an inhibitory effect on some stevia traits such as SVglys content and yield. Based on the current results and efficient N application, 40 kg N ha−1 split into two stages is recommended for stevia production under greenhouse conditions.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":"40 1","pages":"58 - 63"},"PeriodicalIF":0.9,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42577430","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 : 2023-01-01DOI: 10.1080/02571862.2022.2148007
Marvellous M. Zhou
Cultivar genetic gains quantify the increase in productivity from release of cultivars and measure genetic improvements from plant breeding. The objectives of this study were to evaluate the genetic gains from sugarcane coastal cultivars and evaluate their contribution to productivity. Data were derived from replicated plant breeding and post-release variety evaluation trials conducted by the South Africa Sugarcane Research Institute (SASRI) from 1996 to 2020. There were significant cultivar differences for cane yield, sucrose content, sugar yield, fibre % and purity %. Significant analyses of cultivar by location, cultivar by crop-year and cultivar by location by crop-year indicate further optimisation of cultivar disposition is needed to increase productivity. Cultivar genetic gains were found for cane yield (0.19–0.48 t ha−1), sucrose content (0.01–0.02%), sugar yield (0.03–0.07 t ha−1 per year), fibre % cane (0.04–0.06%) and purity % (0.02–0.04%), highlighting the increased yield and quality from genetic improvement. The best cultivars produced 8–22% higher sugar yields than popular cultivars indicating that planting high yield cultivars did increase yields. Sugar cane production declined at a slower rate than area planted, also showing the benefit of high yield cultivars. Increasing the area planted to new, higher yielding cultivars will increase sugar yields for coastal regions of South Africa.
品种遗传增益量化了品种释放后生产力的提高，并衡量了植物育种的遗传改进。本研究的目的是评估沿海甘蔗品种的遗传增益，并评估其对生产力的贡献。数据来源于南非甘蔗研究所（SASRI）在1996年至2020年进行的复制植物育种和释放后品种评估试验。甘蔗产量、蔗糖含量、糖产量、纤维%和纯度%存在显著的品种差异。按地点、按作物年份和按作物年份对栽培品种进行的显著分析表明，需要进一步优化栽培品种配置，以提高生产力。甘蔗产量（0.19–0.48 t ha−1）、蔗糖含量（0.01–0.02%）、糖产量（0.03–0.07 t ha−每年）、甘蔗纤维%（0.04–0.06%）和纯度%（0.02–0.04%）的品种遗传增益突出了遗传改良带来的产量和质量提高。最佳品种的糖产量比流行品种高8-22%，表明种植高产品种确实提高了产量。甘蔗产量的下降速度低于种植面积，这也表明了高产品种的好处。增加种植面积，种植新的高产品种，将提高南非沿海地区的糖产量。
{"title":"Sugarcane cultivar genetic gains for coastal agro-ecological regions of South Africa","authors":"Marvellous M. Zhou","doi":"10.1080/02571862.2022.2148007","DOIUrl":"https://doi.org/10.1080/02571862.2022.2148007","url":null,"abstract":"Cultivar genetic gains quantify the increase in productivity from release of cultivars and measure genetic improvements from plant breeding. The objectives of this study were to evaluate the genetic gains from sugarcane coastal cultivars and evaluate their contribution to productivity. Data were derived from replicated plant breeding and post-release variety evaluation trials conducted by the South Africa Sugarcane Research Institute (SASRI) from 1996 to 2020. There were significant cultivar differences for cane yield, sucrose content, sugar yield, fibre % and purity %. Significant analyses of cultivar by location, cultivar by crop-year and cultivar by location by crop-year indicate further optimisation of cultivar disposition is needed to increase productivity. Cultivar genetic gains were found for cane yield (0.19–0.48 t ha−1), sucrose content (0.01–0.02%), sugar yield (0.03–0.07 t ha−1 per year), fibre % cane (0.04–0.06%) and purity % (0.02–0.04%), highlighting the increased yield and quality from genetic improvement. The best cultivars produced 8–22% higher sugar yields than popular cultivars indicating that planting high yield cultivars did increase yields. Sugar cane production declined at a slower rate than area planted, also showing the benefit of high yield cultivars. Increasing the area planted to new, higher yielding cultivars will increase sugar yields for coastal regions of South Africa.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":"40 1","pages":"1 - 12"},"PeriodicalIF":0.9,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49416879","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 : 2023-01-01DOI: 10.1080/02571862.2023.2185693
B. Coetzee, E. Carstens, G. C. Schutte, E. Basson, Mia J Groeneveld, Tankiso Mpholo, P. Moyo, Jessica C Winn, P. Fourie, A. V. D. van der Merwe
Phyllosticta citricarpa is the causative agent of citrus black spot (CBS), a cosmetic fungal disease that has been reported in most of the citrus-growing regions of the world. The occurrence of CBS in orchards is predominantly controlled by the application of fungicides during the fruit susceptibility period. Benzimidazoles (benomyl and carbendazim) and toluamides (ethaboxam and zoxamide) are two systemic fungicide classes suitable for the control of CBS in South Africa. Both inhibit proper assembly of the fungal β-tubulin protein during mitosis, and resistance to these fungicides is primarily related to alterations in the binding sites on this target protein. In this study, P. citricarpa isolates with known resistance status were subjected to whole genome sequencing, the mutations conferring resistance to benomyl and zoxamide were examined and allele-specific primers targeting these mutations were developed. The allele-specific multiplex PCR assay for the detection of benomyl resistance in P. citricarpa will eliminate the need for laborious and time-consuming sensitivity assays or DNA sequencing.
{"title":"An allele-specific PCR assay for detection of mutations that confer benzimidazole resistance and zoxamide sensitivity in Phyllosticta citricarpa","authors":"B. Coetzee, E. Carstens, G. C. Schutte, E. Basson, Mia J Groeneveld, Tankiso Mpholo, P. Moyo, Jessica C Winn, P. Fourie, A. V. D. van der Merwe","doi":"10.1080/02571862.2023.2185693","DOIUrl":"https://doi.org/10.1080/02571862.2023.2185693","url":null,"abstract":"Phyllosticta citricarpa is the causative agent of citrus black spot (CBS), a cosmetic fungal disease that has been reported in most of the citrus-growing regions of the world. The occurrence of CBS in orchards is predominantly controlled by the application of fungicides during the fruit susceptibility period. Benzimidazoles (benomyl and carbendazim) and toluamides (ethaboxam and zoxamide) are two systemic fungicide classes suitable for the control of CBS in South Africa. Both inhibit proper assembly of the fungal β-tubulin protein during mitosis, and resistance to these fungicides is primarily related to alterations in the binding sites on this target protein. In this study, P. citricarpa isolates with known resistance status were subjected to whole genome sequencing, the mutations conferring resistance to benomyl and zoxamide were examined and allele-specific primers targeting these mutations were developed. The allele-specific multiplex PCR assay for the detection of benomyl resistance in P. citricarpa will eliminate the need for laborious and time-consuming sensitivity assays or DNA sequencing.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":"40 1","pages":"69 - 76"},"PeriodicalIF":0.9,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46924886","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 : 2023-01-01DOI: 10.1080/02571862.2023.2180098
Kelebohile Rose Seboko, J. V. van Tol, E. Kotzé
Soil carbon (C) is an important component in quality assessments and efficient models are required to estimate C rapidly. Accurate C assessments are valuable in monitoring land-use changes. Fourier-transform mid-infrared (FT-MIR) spectroscopy has proved to be a powerful tool for assessing C. The potential of FT-MIR spectroscopy to estimate C was evaluated using the following techniques: (1) three algorithms [partial least squares (PLS)], principal component regression (PCR), and classical least squares (CLS); and (2) disaggregating the dataset into subgroups based on soil depth and texture. The C contents of samples collected in the Johannesburg Granite Dome were determined by dry combustion for comparison. The soils ranged considerably in C (0.123–2.650%), clay (2.80–41.20%), and silt content (8.56–23.75%). Using standard normal variant (SNV), Savitzky-Golay smoothing and PLS, the best-performing model was the horizons subgroup which provided values of root mean square error for prediction (RMSEP) between 0.079 and 0.095%, root mean square error for calibration (RMSEC) = 0.041 − 0.092, r 2 pre = 0.6174–0.8459, r 2 cal = 0.6599–0.9778, residual prediction variation (RPD) = 2.404–2.753, and ratio of performance to interquartile range (RPIQ) = 2.667–3.454. The pronounced accuracy of FT-MIR spectroscopy coupled with PLS, pre-processing techniques, and textural subgroups confirms the potential of infrared spectroscopy as an efficient tool for estimating C content. Future studies should investigate the combined effects of FT-MIR spectroscopy and subgroups grouped according to soil types and land-uses when predicting C.
土壤碳（C）是质量评估的重要组成部分，需要有效的模型来快速估计碳。准确的C评估在监测土地利用变化方面很有价值。傅立叶变换中红外光谱（FT-MIR）已被证明是评估C的强大工具。使用以下技术评估了FT-MIR光谱估计C的潜力：（1）三种算法[偏最小二乘（PLS）]、主成分回归（PCR）和经典最小二乘（CLS）；以及（2）根据土壤深度和质地将数据集分解为多个子组。通过干燃烧测定在约翰内斯堡花岗岩圆顶采集的样品的C含量以进行比较。土壤的C（0.123–2.650%）、粘土（2.80–41.20%）和含泥量（8.56–23.75%）变化很大。使用标准正态变量（SNV）、Savitzky Golay平滑和PLS，表现最好的模型是层位亚组，该亚组提供了0.079至0.095%的预测均方根误差（RMSEP）和校准均方根误差 = 0.041−0.092，r 2 pre = 0.6174–0.8459，r 2 cal = 0.6599–0.9778，残差预测方差（RPD） = 2.404–2.753，以及绩效与四分位间距的比率（RPIQ） = 2.667–3.454.FT-MIR光谱与PLS、预处理技术和结构亚组相结合的显著准确性证实了红外光谱作为估计碳含量的有效工具的潜力。未来的研究应该调查FT-MIR光谱和根据土壤类型和土地用途分组的亚组在预测C。
{"title":"Predicting soil carbon in granitic soils using Fourier-transform mid-infrared (FT-MIR) spectroscopy: the value of database disaggregation","authors":"Kelebohile Rose Seboko, J. V. van Tol, E. Kotzé","doi":"10.1080/02571862.2023.2180098","DOIUrl":"https://doi.org/10.1080/02571862.2023.2180098","url":null,"abstract":"Soil carbon (C) is an important component in quality assessments and efficient models are required to estimate C rapidly. Accurate C assessments are valuable in monitoring land-use changes. Fourier-transform mid-infrared (FT-MIR) spectroscopy has proved to be a powerful tool for assessing C. The potential of FT-MIR spectroscopy to estimate C was evaluated using the following techniques: (1) three algorithms [partial least squares (PLS)], principal component regression (PCR), and classical least squares (CLS); and (2) disaggregating the dataset into subgroups based on soil depth and texture. The C contents of samples collected in the Johannesburg Granite Dome were determined by dry combustion for comparison. The soils ranged considerably in C (0.123–2.650%), clay (2.80–41.20%), and silt content (8.56–23.75%). Using standard normal variant (SNV), Savitzky-Golay smoothing and PLS, the best-performing model was the horizons subgroup which provided values of root mean square error for prediction (RMSEP) between 0.079 and 0.095%, root mean square error for calibration (RMSEC) = 0.041 − 0.092, r 2 pre = 0.6174–0.8459, r 2 cal = 0.6599–0.9778, residual prediction variation (RPD) = 2.404–2.753, and ratio of performance to interquartile range (RPIQ) = 2.667–3.454. The pronounced accuracy of FT-MIR spectroscopy coupled with PLS, pre-processing techniques, and textural subgroups confirms the potential of infrared spectroscopy as an efficient tool for estimating C content. Future studies should investigate the combined effects of FT-MIR spectroscopy and subgroups grouped according to soil types and land-uses when predicting C.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":"40 1","pages":"23 - 33"},"PeriodicalIF":0.9,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42145230","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 : 2023-01-01DOI: 10.1080/02571862.2022.2144959
R. Gericke, Njj Combrink, M. van der Rijst
Potatoes are an important crop in the Sandveld and Kouebokkeveld regions of South Africa, and one of the challenges in effective potato production is maintaining quality post-harvest. In order to identify tuber characteristics that may be used to predict keeping quality of potatoes from the sandy soils of these regions, tuber, soil, and water samples were taken from different growers who planted the cultivar Sifra. Sampling started in January 2016 and ended in July 2017. Skinning potential, determined by thumb rubbing, chemical composition, and specific gravity (SG) were evaluated one day after hand harvesting. Undamaged tubers were kept at room temperature for 42 days whereafter mass loss and firmness were evaluated. Pearson correlations and Partial Least Squares Regression (PLS-R) were done to investigate the association between tuber quality characteristics and tuber, soil and water cations. Tuber firmness after storage showed a high positive correlation with tuber magnesium (Mg) levels, and was associated with reduced skinning potentials and lower mass loss percentages. Tubers with Mg levels lower than 0.13% had high skinning potentials with mass loss percentages higher than 4.5% during storage. Irrigation with water rich in sodium (Na) tended to limit mass loss, possibly due to the associated high levels of Mg in those water sources.
{"title":"Low magnesium content in potato tubers associated with mass loss during storage","authors":"R. Gericke, Njj Combrink, M. van der Rijst","doi":"10.1080/02571862.2022.2144959","DOIUrl":"https://doi.org/10.1080/02571862.2022.2144959","url":null,"abstract":"Potatoes are an important crop in the Sandveld and Kouebokkeveld regions of South Africa, and one of the challenges in effective potato production is maintaining quality post-harvest. In order to identify tuber characteristics that may be used to predict keeping quality of potatoes from the sandy soils of these regions, tuber, soil, and water samples were taken from different growers who planted the cultivar Sifra. Sampling started in January 2016 and ended in July 2017. Skinning potential, determined by thumb rubbing, chemical composition, and specific gravity (SG) were evaluated one day after hand harvesting. Undamaged tubers were kept at room temperature for 42 days whereafter mass loss and firmness were evaluated. Pearson correlations and Partial Least Squares Regression (PLS-R) were done to investigate the association between tuber quality characteristics and tuber, soil and water cations. Tuber firmness after storage showed a high positive correlation with tuber magnesium (Mg) levels, and was associated with reduced skinning potentials and lower mass loss percentages. Tubers with Mg levels lower than 0.13% had high skinning potentials with mass loss percentages higher than 4.5% during storage. Irrigation with water rich in sodium (Na) tended to limit mass loss, possibly due to the associated high levels of Mg in those water sources.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":"40 1","pages":"64 - 68"},"PeriodicalIF":0.9,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48722659","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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