ABSTRACT

The study was conducted to observe the effects of seasonal variations (dry and wet) of air pollutant concentration in Narayanganj during November 2016 to October 2017. The highest particulate matter (PM_2.5 and PM₁₀) was found in January (237.04 and 397.56 µg/m³) and lowest particulate matter (PM_2.5 and PM₁₀) was found in July (20.9 and 39.3 µg/m³). Similarly, the maximum SO₂ and NO₂ concentration reached (22.5 and 108 ppb, respectively) in dry season (November to March) compared to wet season (1.06 and 25.5 ppb). The study reveals the strong seasonal variations of atmospheric ozone concentrations with dry season maximum (11.28 ppb) and wet season minimum (1.89 ppb) levels. The concentration of all air pollutants showed several times higher level in dry season than those of the wet season (April to October). The study determined the highest AQI value found 821 in January and lowest value found 13 in August.

Key words: Air pollutants, dry season, wet season, AQI, Bangladesh.

ABSTRACT

This study aimed to evaluate the effect of eleven treatments viz. mixture insecticides namely ripcord 10 EC+ imitaf 20 SL, ripcord 10 EC+ decis 2.5 EC, decis 2.5 EC+ imitaf 20 @ 1ml/L of water, sevin 85 SP+actara 25 WG @ 1.25g/L of water, voliam flexi 300 SC (thiamethoxam+chlorantraniliprole) @ 0.5ml/L of water, novastar 56 EC (bifenthrin+abamectin) @ 1ml/L of water and ripcord 10 EC, imitaf 20 SL, decis 2.5 EC     @ 1ml/L of water, sevin 85 SP @ 2g/L of water, actara 25 WG 0.5g/L of water by application 15 days interval along untreated control on the infestation level of litchi fruit borer and to find out the benefit-cost ratio for managing this pest by insecticide treatments. The results showed that the lowest fruit infestation was found in thiamethoxam+chlorantraniliprole (0.33%) followed by bifenthrin+abamectin(1.60%), sevin+actara (1.68%); imitaf (1.84%), actara (3.52%) and decis (3.85%) which was significantly difference from all other treatments and increased fresh fruit (52.83%), (52.23%) (52.19%) (52.11%) (51.27%) (51.11%), respectively over control. But, the highest benefit was obtained from the treated tree with decis (11.64:1) in single and mix formulation insecticide bifenthrin+abamectin (10.83:1) which was profitable to manage LFB. The maximum fruit infestation was observed (9.53%) in ripcord+decis and single ripcord (6.69%) in the treated fruits.The pre-formulation mixture of bifenthrin+abamectin (novastar 56 EC) was the most effective and decis 2.5 EC (deltamethrin) was the cost-effective approach at the rate of 1ml per liter water which can be used for controlling LFB.

Key words: Conopomorpha sinensis, Litchi chinensis, fruit infestation, insecticides.

ABSTRACT 

An experiment was conducted at the farmer’s field at the Sherpur, Bogura during January-December 2017 to evaluate the snutrient status of pre and post post-harvest soil of the sugarcane field. The experiments consisted of eight treatments viz., T₀ = Control (no fertilizers and manures), T₁ = Control (No fertilizer),T₂ = N₁₆₅P₅₅K₁₂₀S₃₀Zn_2.5Mg₂₀ (as per soil analysis), T₃ = T₂ + Dolomite (1 t ha^–1),T₄ = 50% of T₂ + Poultry manure (10 t ha^–1), T₅ = 50% of T₂ + Poultry manure (10 t ha^–1) + Dolomite (1 t ha^–1), T₆ = 50% of T₂ + Cowdung (12.5 t ha^–1), T₇ = 50% of T₂ + Cowdung (12.5 t ha^–1) + Dolomite (1 t ha^–1) and T₈ = 50% of T₂ + Pressmud (15 t ha^–1). Results revealed that all the treatments showed were more or less statistically similarities. with each other in respect to pH (5.03-5.22), K (0.171-0.220 me 100 g^–1), Mg (1.28-1.58 me 100 g^–1) and Zn (0.92 to 1.05 µg g^–1) contents of the post-harvest soil. Similar observation was also obtained in available             P content with the ranges of 15.25 ppm (T₁) to 17.22 ppm (T₅). On the other hand, N, S and Ca content varied significantly from 0.095 to 0.112%, 13.25 to 17.15 µg g^–1 and 3.46 to 4.25 me 100 g^–1 respectively where the lowest values were recorded in treatment T₁ and the highest values were obtained in treatment T₅.

Key words: Sugarcane, initial soil, post-harvest soil.

ABSTRACT

The research was carried out at the Bangladesh Sugarcrop Research Institute (BSRI) to evaluate the feasibility of incorporating five exotic non-flowering sugarcane genotypes into a traditional breeding programme through somaclonal variations. To generate genetic diversity, explants from the leaf sheath of donor plant were grown on modified MS media supplemented with 3.5 mgl^-1 2,4-D. Callus formation occurred within six to twelve days of cultivation. For shoot regeneration, MS medium supplemented with   1.0 mgl^-1 BA + 0.5 mgl^-1 NAA was utilized, while 5.0 mgl^-1 NAA was used for roots from micro shoots.   834 somaclones were acclimatised and planted in the field for evaluation, where 520 somaclones survived in the G₀ generation. On the basis of three years of field study under three generations, three somaclones were chosen for their profuse flowering and better agronomic traits. The somaclones were found to be significantly different from the mother plants.

Key words: Sugarcane, non-flowering, somaclonal variation.