bookmarks  16

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    This study describes the relationship of the natural wetland habitats in Agusan Marsh to nearby rice fields and its implication to ecological rice production. Aquatic insects play multiple roles in the ecosystem such as predators, prey to other animals and decomposers which help in maintaining ecological balance. Results revealed that the diversity of odonates was highest in the sedge-dominated swamp among natural habitats which corresponds to the adjoining ricefields. The pattern of clustering of odonates show 3 groups; the rice-sago and rice-sedges sub-cluster, the rice-bangkal, rice-Terminalia, rice-fern, bangkal, sago and sedges sub-cluster, and the Terminalia forest as the outlier. The diversity of semi-aquatic and aquatic bugs was highest in the Bangkal forest while the lowest was in the fern-dominated swamp. The pattern of clustering shows 2 sub-clusters and the outlier Bangkal forest. On aquatic beetles, highest diversity was in the Terminalia forest. The sub-cluster consists of Terminalia habitat and rice-fern, while the other sub-cluster includes rice-Bangkal and rice-Terminalia. The resulting patterns of similarity in diversity and distribution of species in natural habitats and nearby ricefields indicate that ricefields are important temporary habitats for some aquatic insect species and serve as stepping stones for the movement of the insects.
    2 days ago by @mdashikurr
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    Management practices that simultaneously improve soil properties and yield are crucial to sustain high crop production and minimize detrimental impact on the environment. The objective of this study was to determine the influence of tillage, rice straw mulch and nitrogen fertilization on soil quality and upland rice yield in northern Benin, West Africa. The 2-year (2014-2015) field experiment was conducted with two tillage systems (no-tillage, and manual tillage), two rice straw managements (no rice straw, and rice straw mulch at 3 Mg ha-1) and three nitrogen fertilizer levels (no nitrogen, moderate level of nitrogen: 60 kg ha-1, and high level of nitrogen: 120 kg ha-1). Rice yield was not significantly different as a function of tillage systems. On the contrary, rice yield significantly increased with application of rice straw mulch and nitrogen fertilizer. The highest response of rice yield to nitrogen fertilizer addition was obtained for 60 kg N ha-1 in combination with 3 Mg ha-1 of rice straw for the two tillage systems. Soil moisture and soil microbial carbon were higher under no-tillage, rice straw mulch and nitrogen fertilizer. No-tillage combined with rice straw mulch and 60 kg N ha-1 could be used by smallholder farmers to improve soil quality and achieve higher grain yield in upland rice fields in northern Benin.
    4 days ago by @mdashikurr
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    The suspended algal life forms (SALF) were studied in the high altitude rice fields (WRF) covering five randomly selected sites of Apatani Plateau in Arunachal Pradesh, India. The samples were collected fortnightly from WRF in three inundated phases viz. water accumulation (April- May), flooding (June-July) and early recession (August –September) during the rice growing season of 2013. A total of 62 taxa of SALF belonging to the classes Chlorophyceae, Bacillariophyceae and Cyanophyceae were recorded. Closterium sp., Spondylosium sp., Scenedesmus sp., Ulothrix sp., Zygnema sp., Spirogyra sp., Docidium sp. of Chlorophyceae, Navicula sp., Pinnularia sp., Rhizosolenia sp., Tabellaria sp. of Bacillariophyceae and Oscillatoria sp., Nostoc sp., Phormidium sp. of Cyanophyceae were in high abundance in WRF. The study also revealed that Chlorophyceae was the most dominant and diverse class of SALF followed by Bacillariophyceae and Cyanophyceae which was ensued for concurrent existence of rice stems as the affixing substrate of attached algal life forms (AALF) in WRF.
    18 days ago by @mdashikurr
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    The field experiment was conducted at the BRAC Agricultural Research and Development Centre, Gazipur from June to October, 2012 to investigate the effect of different fertilizer rates on the growth and yield of transplanted aman rice genotypes. The experiment was carried out in split-plot design with three replications accommodating the genotypes (G1= CNI 9012, G2= GSR IRRI I 2, G3= BINA dhan7 and G4= Aloran) in sub plot and different fertilizer rates (F1= No fertilizer, F2= Half of recommendation rate, F3= Two third of recommendation rate and F4= Recommendation rate) in the main plot. Crop growth duration, plant height, tillers no. hill-1, panicle no. hill-1, panicle length, total grains panicle-1, fertility%, 1000 grain-wt. and grain yield were compared for different treatments. Genotypes showed significant results for all the traits except grain yield but fertilizer and their interaction exhibit insignificant results for most of the characters studied. The maximum mean for producing grain yield was observed in F2 (5.0 t ha-1) but the minimum in F1 (4.6 t ha-1). Therefore, application of no fertilizer had negative impact on grain yield. Apparently, the highest value for grain yield (5.2 t ha-1) was found in the combinations of G1 × F3, G3 × F2 and G4 × F2 as well as the lowest (4.2 t ha-1) from G1 × F1 combination. Maximum gross return (62500 Tk. ha-1) and gross margin (58255 Tk. ha-1) with F2 suggested that this fertilizer rate was best for profitable cultivation on tested transplanted aman rice genotypes.
    18 days ago by @mdashikurr
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    Rice is one of the most important cereals in the world for being as the staple food. Rice has widespread popularity across Bangladesh, where it uniquely suited to wet environments. Presently, a large number of germplasm have been collected in gene banks all over the world, but methods for the effective management and utilization of such huge collections remain a challenging task. On the other hand, the concept of core collection provides a new way of management and utilization of plant germplasm resources. Frankel first termed a collection to a core collection which would represent the genetic diversity of a crop species with a minimum of repetitiveness. But systematic study has yet been done on core collection of rice in Bangladesh. The objective of the present review study was, therefore, to select the core collections from previously agro-morphologically, physico-chemically and molecularly characterized Kartiksail and Dhaliboro rice. In the present study, the core collections were selected using the hierarchical cluster analysis, where a representative sample with high phenotypic values was drawn from each group. Moreover, the selection processes were improved by combining several evaluation methods. However, special emphasis was given on the genotypic values of the germplasm. In the conclusion, the core collections for Kartiksail landraces were KS1, KS5, KS6, KS7, KS9, KS11, KS13, KS16, KS19, KS20 and KS21, whereas that of Dhaliboro were DB3, DB4, DB7, DB8 and DB10. The selected landraces may be utilized in different hybridization programmes for developing new variety.
    27 days ago by @mdashikurr
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    Nitrogen and phosphorus deficiencies are some of the main factors restricting irrigated rice (Oryza sativa L.) productivity in Burkina Faso. Urea supergranules (USG) have been proven to increase rice yield but this increased productivity is likely to be constrained because P is becoming limiting in irrigated rice systems. Field experiments were carried out with rice variety Nerica 62N in Sourou valley in the wet season of 2012 and in the dry season of 2013. The effect of two sizes (1.8 and 2.7 g) of USG and five levels of phosphorus (0, 20, 30, 40 and 50 kg P ha-1) were studied in a split plot design on rice yields. The use of USG 2.7 g did not significantly increase rice yields compare with USG 1.8 g in both seasons. P application significantly increased rice yields. The 1.8 g USG significantly increased the agronomic efficiency (AE) by 48.9% over the USG 2.7 g in the 2012 wet season while the increase in AE was 24.4% in the 2013 dry season. The best AE 42 kg kg-1 in 2012 and 25 kg kg-1 in 2013 were obtained with 50P and 30P. This study suggests that USG can be used by farmers in small rate (USG 1.8 g) to improve nitrogen use efficiency and the application of 30 kg P kg-1 seems to be adequate to increase yield in irrigated rice cropping system.
    3 months ago by @mdashikurr
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    An experiment was carried out at the Department of Agricultural Chemistry, Bangladesh Agricultural University, Mymensingh during the period from July to November 2011 to investigate the allelopathic potential of different weeds on aromatic rice cv. BRRI dhan 50. Six weed species viz., joina (Fimbristylis miliacea), mutha (Cyperus rotundus), khude shama (Echinochloa colonum), sobuj nakful (Cyperus difformis), foska begun (Physalis heterophylla) and chapra (Eleusine indica) were used in the experiment to observe their allelopathic effects on seed germination, root length, shoot length and dry matter production of aromatic rice. The result depicts that unboiled and boiled weed extracts have negative influence on germination and primary growth of aromatic rice. The ranking of weed species in respect of inhibitory effect on seed germination were Echinochloa colonum > Cyperus difformis > Cyperus rotundus > Eleusine indica > Fimbristylis miliacea > Physalis heterophylla. Khude shama (Echinochloa colonum) and sobuj nakful (Cyperus difformis) had strong detrimental effects on the early growth of aromatic rice. The experimental results proved that it was important to exclude two allelopathic weeds namely khude shama (Echinochloa colomum) and sobuj nakful (Cyperus difformis) in the aromatic rice field. So, it can be concluded that these two weeds should be avoided from the aromatic rice field during land preparation.
    3 months ago by @mdashikurr
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    A field experiment was conducted during the period 2014 and 2015 at the farm of Rice Research and Training Center, Sakha, kafr el-sheikh, Egypt for evaluation the performance of promising lines in rice to agronomic and genetic performance under Egyptian conditions. Results revealed that the Giza 179 produced the highest grain yield (5.44 kg/m2) followed by the promising line GZ9461-4-2-3-1 (5.26 kg/m2) and the commercial variety Giza 178 (5.07 kg/m2). Analysis of variance revealed significant differences among genotypes for all traits. The high genotypic coefficient of variability (gcv) and phenotypic coefficient of variability (pcv) recorded for number of filled grains/panicle indicate the existence of wide spectrum of variability for this trait and offer greater opportunities for desired trait through phenotypic selection. The phenotypic variance was higher than the corresponding genotypic variance for traits. Estimation of heritability ranged from 49.16% to 99.52% for number of panicle/plant and duration traits, respectively. High heritability coupled with high genetic advance was observed for growing period and plant height and indicate the lesser influence of environment in expression of these traits and prevalence of additive gene action in their inheritance hence, amenable of simple selection. The promising rice lines GZ9461-4-2-3-1 and GZ10147-1-2-1-1 performed better as compared with the commercial variety. Selection of these traits would be more effective for yield improvement in rice and these promising lines would be more valuable materials for breeders engaged in the development of high yielding cultivars.
    3 months ago by @mdashikurr
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    Emerging rice cultivars and crop management strategies have to be investigated further with the pressing issues on water shortage for enhanced growth, development and productivity. A pot experiment was conducted in the greenhouse to evaluate the impacts of water regimes (aerobic, saturated and continuous flooding), soil textures (clay and silt loam), and cultivars (Cocodrie and Rondo) including their interactions on rice growth, development, grain yield and harvest index. Normal flowering duration of Rondo was sustained with the presence of floodwater at flowering stage. Grain filling duration was longer in aerobic water regime under silt loam soil. Longer maturity in aerobic water regime was affected by water stress during grain filling stage and not at early vegetative stage until flowering. Grain yield of Rondo was higher by 22% and had greater plant height, tiller count and biomass when planted in clay soil. Harvest index of Cocodrie was higher by 70% compared to Rondo. Grain yield of Rondo was best if flooded continuously while Cocodrie can equally produce grain in aerobic, saturated and flooded water regimes. Growing Cocodrie in clay soil with aerobic water regime is a good option to save more water without significant yield losses. With foreseeing drought and limited water supply for rice production, our study suggests that water regime is the major factor to be considered before selecting rice cultivars to be grown at varying soil textures.
    4 months ago by @mdashikurr
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    Twenty-seven Jesso-Balam rice accessions of Bangladesh were studied for 21 qualitative agro-morphological characters at BRRI during T. Aman 2009 and T. Aman 2011 seasons. The presence and shape of penultimate leaf ligule showed no variations among the genotypes. Out of 19 characters, majority of the genotypes showed no anthocyanin color in leaf sheath (93%), medium intensity of anthocyanin color in basal leaf sheath (7%), green leaf blade (74%), strong surface pubescence of penultimate leaf blade (48%), no anthocyanin color in auricles and collar (93%), colorless ligule (93%), white color of stigma (93%), erect blade of flag leaf (52%), erect curvature of lateral tiller (100%), no anthocyanin color in nodes (93%), weak intensity of anthocyanin color in nodes (7%), weak intensity of anthocyanin color in internodes (67%), yellowish to straw anthocyanin color of lemma and palea (48%), medium intensity of anthocyanin color in lemma and palea (41%), yellowish/straw color of apiculus (93%), awnless (89%), awns at tip only (11%), yellowish white to straw color awns (100%) and intermediate type of leaf senescence (74%). On the other hand, the Jesso-Balam germplasm along with BR7, BR16, BRRI dhan50 and Nizersail were grouped into three major clusters according to the UPGMA clustering method based on Dice coefficient. Cluster III was the major group with maximum genotypes (26), while clusters I had two (JBPL9 and JBPL23) and cluster II had three genotypes (JBPL13, JBPL15 and JBPL16), respectively. The genetic distance ranged from 0.000 to 9.969. Three pairs of accessions (2465 and 2464), (2455 and 2454) and (2453 and 2478) in cluster III were found duplicates. Finally, the Jesso-Balam pure lines possessed exclusive variability and unique features which need safe conservation and sustainable use in future rice breeding programmes for issues like intellectual property rights.
    4 months ago by @mdashikurr
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    how to setup a tiling windows manager environment in linux
    8 months ago by @michelc
     
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