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Labour scarcity, harvesting loss, timely harvesting and harvesting cost are crucial in rice and wheat harvesting in Bangladesh. Combine harvester is a newly introduced harvesting machine in Bangladesh. This study was undertaken to evaluate the technical and economic performance of combine harvester available in farmers" field and farmer"s perception regarding the use of combine. Field tests of two new (CLASS andDaedong) and two refresh (Kukje and Anower) combine harvesters were conducted for harvesting rice and wheat in the farners" field of Jessore, Pabna,Dinajpurand Thakurgaon districts during 2011-12. Primary data were collected from 30 adopter and 30 non-adopter farmers from each district of Bogra, Rangpur, Dinajpur and Thakurgaon through direct interviewingduring 2012-13. Information was also collected from different combine harvester traders available in Bangladesh. Average time, cost and grain saving by combine harvester over manual methods were 97.50, 35.00 and 2.75%, respectively. Benefit cost ratio of CLASS, Daedong, Kukje and Anower combine harvesters were found to be 2.68, 2.11, 2.29 and 2.70, respectively. The payback periods of refresh combine harvesters were lower than the new combine harvester. There were some mechanical problems observed in refresh combine harvesters during field operations. New harvester was observed almost trouble free and popular to the famers. Scarcity of spare parts and mechanic service were the main problems for repair and maintenance of the combine harvesters in farm level. Considering the technical performance of combine harvester and demand of the farmers, new combine harvester may be introduced in commercial basis in Bangladesh.

The study was carried out at the farmer's field of Juri Upazilla, Maulavibazar District during 2008-2009, 2009-2010, and 2011-2012 to find out the proper combination of fertilizer nutrients that promotes better fruit yield and quality of mandarin (cv. Khashi Kamla). The treatments were Native nutrient i.e., control (TI), N150P50K150Mg30 (T2), N200P75K175Mg40 (T3), N250P100 K200Mg50 (T4), N300P125K225Mg60 (T5), and N200P75K175Mg0 (T6) g/plant/year. In addition, 20 kg cowdung/plant was used as blanket dose. Yield components, yield, and TSS content (%) of mandarin varied significantly due to variation of nutrients in all the test years. Fruit yield/plant was improved significantly with increase in NPK and Mg dose irrespective of years. Application of Mg in combination with NPK increased 17-157% mean fruit yield over magnesium control. Significantly the highest yield and yield attributes were recorded under treatment N300 P125 K225 Mg60 g/plant (T5) along with 20 kg cowdung/plant in all the years. Total soluble sugar (%) content was also maximum in trees receiving N300P125K225Mg30 g/plant. The highest gross margin and marginal rate of return were achieved by the same treatment (T5). The lowest fruit yield/plant was obtained from untreated control plot (native nutrient). Three years’ study revealed that application of N300P125K225Mg60 along with 20 kg cowdung/plant would be economically optimum for achieving higher yield and better fruit quality in mandarin grown under piedmont plain soil. DOI: http://dx.doi.org/10.3329/bjar.v38i3.16969 Bangladesh J. Agril. Res. 38(3): 425-433, September 2013

One of the important trigger molecules for innate immunity is a serine protease that activates zymogen phenol oxidase (PPO). Central to wound healing response is the activation of phenol oxidase zymogen. Molecular characterization of phenol oxidase has been recently reported by us. Here, we report isolation, cloning, expression, and purification of prophenol oxidase activating enzyme 1 (slppae1) from polyphagous pest, Spodoptera litura. SLPPAE1 is induced within 6 h of physical injury. The structural features of the mature polypeptide are reminiscent of other lepidopteran PPAE in having a signal peptide, propeptide, and catalytically active polypeptide. The cDNA has been expressed in Sf21 cells using baculovirus expression vector. Fractionation of expressing Sf21 cells revealed its expression in the membranes. The recombinant protein was solubilized from membranes and purified by Ni-NTA affinity chromatography. The purified enzyme is catalytically active on chromogenic substrate, activates recombinantly expressed prophenol oxidase (PPO) of S. litura, and is sensitive to inhibition by aprotenin. N-terminal sequencing of processed phenol oxidase revealed 11 kDa propeptide instead of in-silico predicted 6 kDa polypeptide.

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This paper presents the drying kinetics of ginger rhizome under blanched and nonblanched conditions using hybrid solar dryer and mechanical tray dryer at three temperature levels. The drying rate increases with the increase in drying air temperature and blanching also increases the drying rate. The drying rate depends on shape and size of the ginger rhizomes. The highest drying rate was found for sliced samples of ginger rhizome followed by splitted and whole root samples. Five thin layer drying models were fitted to the experimental data of blanched and sliced ginger rhizomes. The Page equation was found to be the best to predict the moisture content of sliced ginger rhizome in thin layer. The agreement between the predicted and experimental results was excellent. Colour of ginger rhizomes was slightly changed after drying. Lightness of ginger rhizomes decreased with an increase in drying temperature for all samples except sliced and blanched samples. For drying of ginger rhizome, it should be sliced and blanched and dried below 70 0 C for better quality dried products.

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