Weed Survey Associated in Tobacco (Nicotiana tabacum L.) in Bilatte Tobacco Farm, Ethiopia

An in-field weed survey method was conducted to estimate the most frequently, density and abundance weed species present in Bilatte tobacco farm, Ethiopia during 2014 totally covered approximately 145 hectares. During study period a total number of 14 weed species belonging to 06 monocot and 08 dicot families were recorded out of 7 families of weed reported form study site. The most predominate was shown by monocot Poaceae having 4 weed species followed by dicot family Composite having 3 weeds. The families Cyperaceous, Solanaceae and Amaranthaceous each having 2 weeds, and the family Papaverceae represented by 1 weed. Based on % of frequency Cyperus esculentus (sedges) family Cyperaceous was 99.30. The data showed that Cynodon dactylon and Digitaria abyssinica belong to family Poaceae and Cyperus esculentus family Cyperaceous were the most abundant weed with a density of 35.9, 14 and 12 of plant m-2 respectively. Relative abundance values quantify the overall weed problem posed by specie Cyperus esculentus that had higher relative abundance was 98.97. The importance value index indicated that Cyperaceous and Poaceae families can be considered the great potential to cause reduce tobacco production. Whereas, Solanium nigrum and Datura stramonium were observed with least population density 0.00 and 1.03 plant m-2, least frequently 2.7 and 13.51 %, least relative weed abundance, 0.07 and 1.03 with importance value index 2.8 and 14.8 occurring weed respectively.

Qualitative and Quantitative Assessment of Common Weed Species in West Gondar Sesame Growing Area, Ethiopia

Weeds compete with crops grown for resource limits such as water, nutrients, and light. Weed infestation is one of the major factors limiting sesame production, as its seedlings grow slowly during the first few weeks making it a weak competitor at earlier crop growth stages. Weed induced sesame yield reductions of up to 65 percent, and a need for a crucial weed-free duration of up to 50 days following planting. Weed surveys are useful for determining the occurrence and relative importance of weed species in crop production systems. Weed survey on a farm basis is needed to establish efficient weed management and decision making mechanisms and to evaluate weed control measures. Therefore this survey was conducted to assess qualitative and quantitative weed species in sesame growing areas of west Gondar, Ethiopia. Weed survey was conducted in 2012 at Metema and 2013 main cropping season at Metema, Tach Armachiho, and Mirab Armachiho district. data on weed species type and count were taken along the diagonal with 50cm x 50cm quadrate at a 15-meter interval at three points. Visual identification, manuals, photographs, leaflets, and books were used for identifying weed species. They conducted interviews with farmers, development agents, and district experts working in the region. Weed species compositions were analyzed by frequency, abundance, dominance, and similarity index. In the districts, 31common weed species or groups of species from 17 families were recorded. Ipomea cordofana Br., Grass spp’, Commelina benghalensis L. Andropogon abyssinicus (Fresen) R.Br., Boerhaavia erecta L., Corchorus olitorius L.kudra, Corchorus trilocularis L., Leucas martinicensis (Jacq) ait.f. and Ipomea triloba are the most prevalent, abundant, and important weeds in sesame fields in north Gondar. As to this on-farm and practical training on identification and demonstration management options should be given on the low land of north Gondar farmers.

Differences in efficacy, resistance mechanism and target protein interaction between two PPO inhibitors in Palmer amaranth (Amaranthus palmeri)

A weed survey was conducted on 134 Palmer amaranth (Amaranthus palmeri S. Watson) populations from Mississippi and Arkansas in 2017 to investigate the spread of resistance to protoporphyrinogen oxidase (PPO) inhibitors using fomesafen as a proxy. Fomesafen resistance was found in 42% of the A. palmeri populations. To investigate the resistance basis of different PPO inhibitors, we further characterized 10 representative populations by in planta bioassay in a controlled environment and molecular characterizations (DNA sequencing and TaqMan® gene expression assay). A total of 160 plants were sprayed with a labeled field rate (1X) of fomesafen or salfufenacil and screened for the presence of three known resistance-endowing mutations in the mitochondrial PPX2 gene (ΔGly-210, Arg-128-Gly, Gly-399-Ala). To compare the potencies of fomesafen and saflufenacil, dose–response studies were conducted on two highly resistant and one sensitive populations. The interaction of the two herbicides with the target protein harboring known PPX2 mutations was also analyzed. Our results showed that: (1) 90% of the fomesafen- or saflufenacil-resistant plants have at least one of the three known PPX2 mutations, with ΔGly-210 being the most prevalent; (2) saflufenacil is more potent than fomesafen, with five to nine times lower resistance/susceptible (R/S) ratios; (3) fomesafen selects for more diverse mutations, and computational inhibitor/target modeling of fomesafen suggest a weaker binding affinity in addition to a smaller interaction volume and volume overlap with the substrate protoporphyrinogen IX than saflufenacil. As a result, saflufenacil shows reduced sensitivity to PPX2 target-site mutations. Results from current study can help pave the way for designing weed management strategies to delay resistance development and maintain the efficacy of PPO inhibitors.

Inventarisasi Jenis Gulma di Areal Perkebunan Karet (Hevea brasiliensis) Pada Ketinggian Tempat Yang Berbeda di Negeri Liang Kecamatan Teluk Elpaputih Kabupaten Maluku Tengah

The purpose of this study was to analyze the types of dominant weeds in rubber plantation areas at altitudes of 4 m above sea level (asl) and 104 m asl and to find differences in the types of weeds in the rubber plantation areas at an altitude of 4 m asl and 104 m asl. This research conducted in Negeri Liang, Teluk Elpaputih District, Central Maluku Regency. This research used a "weed survey" method to collect data by direct observation in the field. This research was conducted by analyzing weed types using the quadratic method by purposive sampling with a sample plot size of 1 m × 1 m. From this study, it was found that there were 20 weed species from 14 families, with details of 11 species of full leaf weeds, 3 species of grasses, 3 species of sedges, in rubber plantation habitat in Liang Village, Teluk Elpaputih District, Central Maluku Regency. Keywords: plantation altitude, rubber plants, weeds ABSTRAK Tujuan penelitian ini adalah untuk menganalisis jenis-jenis gulma dominan di areal perkebunan karet pada ketinggian 4 m dpl dan 104 m dpl dan untuk menemukan perbedaan jenis-jenis gulma di areal perkebunan karet pada ketinggian 4 m dpl dan 104 m dpl. Penelitian ini dilaksanakan di Negeri Liang Kecamatan Teluk Elpaputih Kabupaten Maluku Tengah. Dengan menggunakan metode “survey gulma” untuk mengumpulkan data dengan pengamatan langsung di lapangan. Dengan melakukan analisis jenis gulma digunakan metode kuadrat secara purposive sampling dengan petak sampel berukuran 1 m × 1 m. Penelitian ini di peroleh terdapat 20 jenis gulma 14 famili, dengan rincian gulma daun lebar 11 jenis, rerumputan 3 jenis, tekian 3 jenis, dan pakisan 3 jenis pada habitat perkebunan karet di Negeri Liang Kecamatan Teluk Elpaputih Kabupaten Maluku Tengah. Kata kunci: gulma, ketinggian tempat yang berbeda, tanaman karet

Floristic diversity of the soil weed seedbank in boro rice fields: in situ and ex situ evaluation

This study was conducted at the research fields of Agronomy Field Laboratory and in the net house of Department of Agronomy, Bangladesh Agricultural University, Mymensingh. The objective of this study was to compare the in situ and ex situ floristic diversity of soil weed seedbank in boro rice. The soil weed seedbank status was observed through weed survey at research fields and seed germination method in the net house. Five fields were selected randomly with four replications. Soil samples were collected to a depth up to 15 cm and placed in plastic pots in the net house. Weed seedlings that emerged were identified, counted and removed at 30 day intervals throughout the four months emergence period. At the same time, weed survey was done using a 0.25 m–2 quadrate. Diversity was computed by the Shannon index (H’). Under in situ condition, 31 weed species belonging to 15 families germinated and 33 weed species belonging to 17 families germinated under ex situ condition. The family Cyperaceae had the highest species richness under both in situ and ex situ conditions. The five most dominant weed species under in situ condition based on importance value were Eleocharis atroperpurea > Cyperus difformis > Echinochloa crusgalli > Monochoria vaginalis > Lindernia antipoda whereas, under ex situ condition, two new weed species, Fimbristylis miliacea and Echinochloa colonum were observed in the dominant list instead of Monochoria vaginalis and Lindernia antipoda having slightly different rank and order. The ex situ density was 2721 plants m–2, approximately four times higher than the 700 plants m–2 observed under in situ situation and similarly ex situ condition had higher Shannon Index (H’) value (H’=2.412) indicating greater diversity than in situ (H’=2.211) condition. The information obtained from the study would help determine the infestation potential of identified species, which could lead to improved management strategies. J. Bangladesh Agril. Univ. 16(3): 396–402, December 2018

STUDI KOMUNITAS GULMA DI AREAL PERTANAMAN CENGKEH (Syzygium aromaticum L.) TANAMAN MENGHASILKAN PADA KETINGGIAN TEMPAT YANG BERBEDA DI NEGERI HATU KECAMATAN LEIHITU BARAT KABUPATEN MALUKU TENGAH

Clove (Syzygium aromaticum L) is a spice to be cultivated in Mollucas, Recently the population of colve plant has be decressed as a result of weeds that impended the growth of clove, especially in the nursery phases. The identification of weeds is the first step in controlling weeds, however until now there has been no research on the influence of weed communities in important as the base of an accurate weed control. This research on weed composition in clove planting area is important as the base of an accurate is based on summed Dominance Ratio (SDR), the point was obtained from 100 m dpl, 200 m dpl and 300 m dpl at the productive plant in Hatu Vilagge, Village Central Mollucas District). This research using weed survey method type quadrat method with sample plot size 1 m × 1 m. The result show that 35 species of weed, 19 family, with details of weeds 23 broad leaves, 6 grasses, and 4 cyperaceae in the clove areal planting in Hatu village. Keywords: weed vegetation analiysis, clove plant, different altitude ABSTRAK Tujuan penelitian ini adalah Untuk mengenal jenis-jenis gulma dominan di areal pertanaman cengkeh Tanaman Menghasilkan (TM) pada ketinggian 100 m dpl, 200 m dpl, 300 m dpl dan untuk mengenal perbedaan antara komunitas gulma di areal pertanaman cengkeh Tanaman Menghasilkan (TM) dengan ketinggian 100 m dpl, 200 m dpl, dan 300 m dpl. Penelitian ini di laksanakan di Negeri Hatu Kecamatan Leihitu Barat Kabupaten Maluku Tengah. Metode survei gulma digunakan untuk mengumpulkan data dengan pengamatan langsung di lapangan. Dengan melakukan analisis vegetasi digukan metode kuadrat dengan petak sampel berukuran 1 m × 1 m penelitian ini di peroleh terdapat 33 jenis gulma 19 famili, dengan rincian gulma daun lebar 23 jenis rerumputan 6 jenis 4 jenis tekian pada habitat pertanaman cengkeh di Negeri Hatu Kecamatan Leihitu Barat Kabupaten Maluku Tengah. Kata kunci: gulma, tanaman cengkeh, ketinggian yang berbeda

Hubungan kualitas air tercemar dengan keragaman gulma air di daerah aliran sungai Cikeruh dan Cikapundung Provinsi Jawa Barat

Penelitian dilaksanakan pada bulan Mei sampai Agustus dengan tujuan untuk mengetahui keragaman gulma air dan hubungan keberadaan gulma air yang tumbuh pada DAS Cikeruh dan DAS Cikapundung Propinsi Jawa Barat dengan kualitas air yang tercemar limbah pertanian, limbah pemukiman, dan limbah industri. Metode penelitian metode weed survey dengan cluster sampling diletakkan pada komunitas vegetasi di daerah hulu, tengah, dan hilir sungai. Hasil penelitian menunjukkan bahwa gulma dominan tumbuh di sungai Cikeruh adalah : Drymaria cordata (L), daerah tengah dan hilir adalah: Eleusine indica (L), sedangkan gulma di DAS Cikapundung bagian hulu adalah Drymaria cordata (L), daerah tengah dan hilir adalah Ageratum conyzoides (L), dan Cyperus difformis (L). Nilai C sungai Cikeruh dan sungai Cikapundung menunjukkan lebih kecil dari 75% atau tidak terdapat kesamaan populasi, sedangkan nilai H’ termasuk dalam kategori rendah, dan nilai E termasuk dalam kategori sedang. Tidak terdapat korelasi antara keragaman jenis gulma dengan kualitas air di DAS Cikeruh dan DAS Cikapundung. Kata Kunci : dominasi gulma, pencemaran, keragaman gulma air

Hubungan kualitas air tercemar dengan keragaman gulma air di daerah aliran sungai Cikeruh dan Cikapundung Provinsi Jawa Barat

Penelitian dilaksanakan pada bulan Mei sampai Agustus dengan tujuan untuk mengetahui keragaman gulma air dan hubungan keberadaan gulma air yang tumbuh pada DAS Cikeruh dan DAS Cikapundung Propinsi Jawa Barat dengan kualitas air yang tercemar limbah pertanian, limbah pemukiman, dan limbah industri. Metode penelitian metode weed survey dengan cluster sampling diletakkan pada komunitas vegetasi di daerah hulu, tengah, dan hilir sungai. Hasil penelitian menunjukkan bahwa gulma dominan tumbuh di sungai Cikeruh adalah : Drymaria cordata (L), daerah tengah dan hilir adalah: Eleusine indica (L), sedangkan gulma di DAS Cikapundung bagian hulu adalah Drymaria cordata (L), daerah tengah dan hilir adalah Ageratum conyzoides (L), dan Cyperus difformis (L). Nilai C sungai Cikeruh dan sungai Cikapundung menunjukkan lebih kecil dari 75% atau tidak terdapat kesamaan populasi, sedangkan nilai H’ termasuk dalam kategori rendah, dan nilai E termasuk dalam kategori sedang. Tidak terdapat korelasi antara keragaman jenis gulma dengan kualitas air di DAS Cikeruh dan DAS Cikapundung. Kata Kunci : dominasi gulma, pencemaran, keragaman gulma air