Vernalization gene combination to maximize grain yield in bread wheat (Triticum aestivum L.) in diverse environments

The major vernalisation genes of VRN1 are well understood at the molecular level. However, their quantitative contributions to flowering time and grain yield related traits are not clear. In this study, we used a double haploid population (225 lines) of Westonia × Kauz in which the Vrn-A1a (Westonia), Vrn-B1a (Westonia) and Vrn-D1a (Kauz) were segregating, and a high resolution genetic map of 1,159 loci, to determine the quantitative contributions of Vrn-A1a, Vrn-B1a and Vrn-D1a for the days to anthesis and grain yield related traits in diverse environments. The major quantitative trait loci (QTL) of spikelet number per spike and days to anthesis were contributed by the winter alleles of VRN1. The QTL of the time of grain filling were contributed by the spring alleles of VRN1. The wild genotype (vrn-A1vrn-B1vrn-D1) showed the latest flowering, the highest spikelet number per spike, lowest peduncle proportion and thousand grain weight in three environmental analyses, and the largest spikelet number per spike, which resulted in high kernel number per spike (KN) and grain weight (GW) in well-watered environments. One QTL of KN was located on 5B, contributed by winter allele of vrn-B1 in three environmental analyses, and one GW QTL was detected on 5A, contributed by the spring allele of Vrn-A1a in a drought environment. The results indicated that the genotype Vrn-A1avrn-B1Vrn-D1a would shorten the time to anthesis and give high GW and KN in drought environments. The early anthesis associated phenotype, peduncle proportion would provide an indicator in breeding programs.     

Efficacy of strain RB51 vaccine in protecting infection and vertical transmission against Brucella abortus in Sprague-Dawley rats

Immunizing animals in the wild against Brucella (B.) abortus is essential to control bovine brucellosis because cattle can get the disease through close contact with infected wildlife. The aim of this experiment was to evaluate the effectiveness of the B. abortus strain RB51 vaccine in protecting infection as well as vertical transmission in Sprague-Dawley (SD) rats against B. abortus biotype 1. Virgin female SD rats (n = 48) two months of age were divided into two groups: one group (n = 24) received RB51 vaccine intraperitoneally with 3 × 10¹⁰ colony forming units (CFU) and the other group (n = 24) was used as non-vaccinated control. Non-vaccinated and RB51-vaccinated rats were challenged with 1.5 × 10⁹ CFU of virulent B. abortus biotype 1 six weeks after vaccination. Three weeks after challenge, all rats were bred. Verification of RB51-vaccine induced protection in SD rats was determined by bacteriological, serological and molecular screening of maternal and fetal tissues at necropsy. The RB51 vaccine elicited 81.25% protection in SD rats against infection with B. abortus biotype 1. Offspring from rats vaccinated with RB51 had a decreased (p < 0.05) prevalence of vertical transmission of B. abortus biotype 1 compared to the offspring from non-vaccinated rats (20.23% and 87.50%, respectively). This is the first report of RB51 vaccination efficacy against the vertical transmission of B. abortus in the SD rat model.     

Unravelling the diversity and assemblage of phytoplankton in homestead ponds of central coastal belt,Bangladesh

Homestead ponds may offer an ideal opportunity in contribution to household income, fish consumption through fish culture. Phytoplankton plays a key indicator in pond productivity. However, the phytoplankton communities in the homestead ponds are nearly undetermined in Bangladesh. This study summarizes the phytoplankton diversity, assemblage and ecological parameters of the homestead ponds in central coastal belt, Bangladesh, based on two seasons. The results revealed that significant differences (p < .05) were found in pH, DO, conductivity, TDS, nitrates, phosphates and sulphates except temperature in monsoon, and transparency in both seasons. A total of 34 phytoplankton genera representatives of five major groups were recorded such as Euglenophyceae (41.5%), Chlorophyceae (30.5%), Cyanophyceae (13%), Dinophyceae (10%) and Bacillariophyceae (5%). A significant difference (p < .05) in phytoplankton abundance was found in both seasons with the highest mean of 186.13 ± 129.34 × 10⁴ cells L^?1 in monsoon and the lowest mean of 144.40 ± 107.26 × 10⁴ cells L^?1 during winter. The diversity (H'), evenness (J'), richness (d) and dominance (D) ranged from 1.62 to 2.47, 0.52 to 0.97, 0.37 to 1.15 and 0.10 to 0.28 respectively. Based on SIMPER, the most dominant (>10%) genera for dissimilation within stations and seasons were Euglena spp., Phacus spp., Chlorella spp., Strombomonas spp. and Peridinium spp. ANOSIM results stated that 12 genera of phytoplankton were significant contributors based on average dissimilarity. Pearson's correlation coefficient and canonical correspondence analysis (CCA) revealed that phytoplankton abundance, diversity and community were mainly governed by transparency, dissolved oxygen and nitrates.     

Effects of sowing date and nitrogen fertilizer on forage yield,nitrogen‐ and water‐use efficiency and nutritive value of an annual triple‐crop complementary forage rotation

Complementary forage rotation (CFR) systems based on non‐limiting inputs of fertilizer nitrogen (N) (～600 kg N ha^?1) are perceived as uneconomic. An experiment was carried out in Australia to investigate the effects of rates and timing of N fertilizer and sowing date on yield, nutrient‐use efficiency and nutritive value of a triple‐crop (maize, forage rape, field peas) CFR system. Treatments were early‐ and late‐sown maize grown with 0 or 135 kg fertilizer N ha^?1 pre‐sowing (N1) and 0, 79 or 158 kg N ha^?1 post‐sowing (N2). Forage rape was sown with 0 or 230 kg N ha^?1 (N3) and field peas without N. Application of fertilizer N at N1, N2 and N3 increased CFR yield from 28·5 to 48·8 t dry matter (DM) ha^?1 and irrigation water‐use efficiency (IWUE) from 3·4 to 6·1 t DM per megalitre. Increase in yield and IWUE of CFR occurs at the expense of nitrogen‐use efficiency (NUE) as applications of N at N1, N2 and N3 decreased NUE of CFR from 524 to 91 kg DM kg^?1 N. Nutritive value, particularly metabolizable energy content of all forages, was similar among N treatments, and interactions between treatments were minimal. Results indicate that increase in NUE of CFR may occur at the expense of reduced yield, but increased IWUE need not compromise the yield of this CFR system.     

Effects of C/N ratio and periphyton substrates on pond ecology and production performance in giant freshwater prawn Macrobrachium rosenbergii (De Man, 1879) and tilapia Oreochromis niloticus (Linnaeus, 1758) polyculture system

The production performances of giant freshwater prawn Macrobrachium rosenbergii and Nile tilapia Oreochromis niloticus in C/N‐controlled periphyton‐based polyculture systems were evaluated in triplicate. Three different management practices were compared: the traditional practice without addition of periphyton substrates and carbohydrate (Control), addition of maize flour to maintain a carbon: nitrogen rate of 20:1 (treatment CN) and addition of both maize flour and periphyton substrates (treatment CN+P). This experiment used a pre‐optimized stocking density of tilapia and freshwater prawn by Asaduzzaman et al. Aquaculture [286 (2009) 72]. All ponds were stocked with prawn (3 m²) and monosex Nile tilapia (1 m^?2). Bamboo side shoots were posted vertically into the pond bottoms as periphyton substrate covering an additional area of 171 m² for periphyton development. A locally formulated and prepared feed containing 17% crude protein with C/N ratio close to 15:1 was applied twice daily in all ponds considering the body weight of freshwater prawn only. Water quality parameters, except total alkalinity did not vary significantly (P > 0.05) among treatments. Both, organic matter and total heterotrophic bacterial loads (THB) in the sediment were significantly (P < 0.05) higher in treatment CN+P followed by treatment CN and control. Periphyton biomass in terms of dry matter and chlorophyll a values constantly decreased during the culture period. Substrates contributed 66% and 102% higher net yield of freshwater prawn than CN and control treatment respectively.     

Allelopathic potential and an allelopathic substance in mango leaves

The present study was aimed to determine the allelopathic potential of mango (Mangifera indica L.) leaves and to identify allelopathic substances in the leaves. The aqueous methanol extracts of mango leaves inhibited seedling growth of garden cress, radish, rapeseed, foxtail fescue and crabgrass, and the inhibitory effects increased with the increasing extract concentration, suggesting that mango leaves may contain allelopathic substances. The extract was then purified by several chromatographic runs through a bioassay-directed fractionation, and an growth inhibitory substance was isolated and identified by spectral data as methyl-3,4,5-trihydroxybenzoate (methyl gallate). Methyl gallate at the concentration of 10 mM inhibited 98.6% and 99.8% of root and shoot growth of garden cress relative to the control, respectively, and 94.4% and 49.3% of those of foxtail fescue, respectively. The concentrations of methyl gallate required for 50% growth inhibition (I₅₀) on garden cress roots and shoots were 3.9 and 3.3 mM, and those on foxtail fescue roots and shoots were 1.5 and 9.5 mM, respectively. It is the first report of an allelopathic substance in mango leaves and allelopathic activity of methyl gallate. Therefore, the mango leaves may have potential as a soil additive material for the weed management options.     

Economics and Employment Generation of Bamboo-Based Enterprises: A Case Study from Eastern Bangladesh

An exploratory survey was carried out to assess economics and employment generation of the trade of bamboo and bamboo-based secondary products in the eastern Bangladesh, to obtain reliable information about their status, socio-economic significance, production and marketing. The study was undertaken over 30 bamboo-based enterprises in a suburban market of eastern Bangladesh, to investigate regional product details, economic profitability and employment opportunities. The sample entrepreneurs, corresponding to about 25% of the bamboo enterprise population were interviewed using a semi-structured questionnaire. About 202 full and part-time workers were employed in the factories, under categories of artisan (who manufactured secondary products). The average number of worker’s in the large, medium and small factories were 9 (artisan 40%), 6.45 (artisan 35%) and 5 (artisan 25%) respectively. The study revealed that there was always a satisfied demand of skilled artisans. Most of the workers were relatively newly employed (not more than 5 years). The daily wage rate varied between 70 and 130 Tk. ($US 1 equals approximately 70 Bangladeshi Taka (Tk.), as at December 2008). Bambusa balcooa was the most utilized species (39.96%) in terms of monetary value. The price of a single B. balcooa culm in the local market was Tk. 160–210. Nine sizes of articles under seven bamboo categories were identified, these being bera (36″ × 120″ and 72″ × 96″), bookshelf (36″ × 24″), chaluni (12″ × 12″), chatai (48″ × 60″ and 36″ × 48″), jhuri, rickshaw hood and tukri. Net average profit per article was the highest for rickshaw hoods (Tk. 400 at the retailer stage). The total expected annual income for an enterprises from all articles types sold was estimated to be Tk. 85,800. Three distinct marketing channels were identified for selling bamboo and value-added secondary products. The study also generated policy implications for effective management of bamboo-based enterprises.