A study on the behavior of adult fruit fly after emergence from pupae under laboratory condition was undertaken at Bangabandhu Sheikh Mujibur Rahman Agricultural University Gazipur during the period from February to April 2000. The results revealed that the maximum adults emerged during 5:00 am -5:30 am of the day, just before sunrise between 5:35 am -5:40 am. Maximum numbers of adults spent 2.80-3.69 min for their resting. After taking a rest, maximum adults spent 3-4 min for cleaning antennae, mouthparts, eye and genitala. Adults completed their wing spreading within 2.25-2.75 min. The maximum number of individuals completed closing and spreading of their wings within 2.3-2.5 min. Upward flying behavior was also observed among most of the adults though they were in the net house.

To investigate the uptake behaviour, interactions with nutrient elements and growth of maize plants, a pot experiment was conducted under controlled conditions using a stimulated nutrient culture solution with different chromium (0.0, 0.5, 0.8, 1.0, 2.0, and 4.0 ppm) and copper concentrations (0.0, 0.2, 0.5, 0.8 and 1.0 ppm). Fresh and dry weight of root and shoot showed significant (P= <0.001) decrease with increase of the concentration of Cu and Cr in the nutrient solution. At the highest concentration of Cu (1.0 ppm) and Cr (4.0 ppm), the decrease of the dry root and shoot presented the value of 82% and 65% for Cu and 82% and 68% for Cr, respectively. Threshold value at 0.5 ppm concentration dry weight of maize plant showed a significant (P=<0.001) decrease for both Cu and Cr treatments. Application of Cu and Cr also had antagonistic effect against the uptake of N, P, K, Ca, Mg and Fe. The threshold value was 0.5 ppm for Cr and Cu in case of uptake of N, P, K, Ca, Mg and Fe. Plants grown in the higher concentration of Cu and Cr rather than the 0.5 ppm of nutrient solution significantly increased the accumulated Cu and Cr in both the root and shoot of maize plants.

The hybrid rice, the first of its kind in Bangladesh, had been released in 2001 as ‘BRRI hybrid dhanl’ was evaluated in a participatory approach at the on-station (Bangladesh Rice Research Institute (BRRI), Regional Station, Bhanga, Faridpur, Bangladesh) and on-farm (13 villages of Faridpur district) during Boro 2001-2002. At the on-station, BRRI hybrid dhanl, three imported hybrids and three popular inbred varieties were grown for comparison. At the on-farm, BRRI hybrid dhanl and BRRI dhan29 were grown side by side. The plot size for each variety was 20mx10m for all the locations. Results revealed that at the on-station the BRRI hybrid dhanl took 163 days to mature and the grain yield was 8.2 t/ha while at the on-farm it took 158.1 days and the grain yield was 8.3 t/ha. With BRRI hybrid dhanl, 12.8 and 10.7% increases in productivity were gained over BRRI dhan29 at on-station and the on-farm trials, respectively. At on-station, the highest productivity (50.3 kg/ha/day) was recorded for BRRI hybrid dhanl followed by BRRI dhan29 (44.6 kg/ha/day) and Sonar Bangla (44.5 kg/ha/day). At the on-farm, the increased productivity of BRRI hybrid dhanl over BRRI dhan29 ranged from 2.6-21.5% and the mean was 10.7%. All the visiting and participating farmers expressed their satisfaction with BRRI hybrid dhanl. They held the opinion that the hybrid seed cost should be reasonable, the hybrid variety must fit into their cropping patterns, adopt to the local environment, meet household requirements. The required management practices should also be affordable to them. Thus, the BRRI hybrid dhanl variety adoption rate would be improved by increased farmer participation.

1. Effect of temperature on reproductive investment and population increase in melon aphid, Aphis gossypii Glover was studied under controlled conditions of 16L: 8D and 75±5% RH using brinjal (Solanum melongena) as host plant.

2. Four different levels of temperature viz. 15°C, 20°C, 25°C and 30°C were considered as treatments.

3. Body weights of newly born nymphs and freshly moulted adults, development time, mean relative growth rate (mrgr), intrinsic rate of population increase (r_m), number and size of embryos in freshly moulted adult apterae, net reproductive rate (R0), capacity for increase (r_c) and finite capacity of natural increase (λ) were measured.

4. The study revealed a significant influence of temperature on aphids in investment of embryos and its subsequent population build up where the temperature 20° -25°C was found conducive for this aphid species for its rapid growth and population development.

5. A significant positive relationship was found between mrgr (x) and r_m (y) under all the studied temperature.

A study was undertaken to investigate the effect of five levels of drought treatments of soybean [Glycine max (L) Merr. cv. PB-1] in the pot under controlled conditions. The fresh weight of soybean seeds reduced drastically at severe drought stress (20% of F.C) and reduced 32.15% compared to the control (80% F.C.). The reduction was 6.48% at moderate drought stress (50% F.C.). Significant effects (P= <0.001) of drought stress, depending on severity were observed in the accumulation of sugars (glucose, fructose and sucrose), ascorbic acid and malic acid. Significant positive correlation (P= <0.001) was obtained between drought stress and proline content whereas significant negative correlation was obtained between protein content and and drought stress. The nutrient content of soybean leaf and seed also was significantly affected by water deprivation.

Status of various available macro and micronutrients have been studied in twelve soil series developed over three different parent materials viz. Tipam-Surma, Dupi-Tila and Alluvial Valleys of Brown Hill Soils of Bangladesh. The organic matter content were found 2.20 to 3.78%, 1.20 to 2.10% and 1.50 to 2.80% in the soils of the Tipum-Surma formation, Dupi-Tila formation and Alluvial Valley soils, respectively. Nitrogen and phosphorus content were found low and the potassium content was high in all the soils, In the Tipum-Surma formation, the boron content in soil ranges from low to optimum (0.27 to 0.62μg/g), in Dupi-Tila formation and in Alluvial Valley soil it ranges from low to high (0.25 to 0.60μg/g and 0.27 to 0.72μg/g, respectively), Available Zn content was found 1.10 to 1.55 μg/g, 1.40 to 2.90μg/g, and 1.50 to 5.00μg/g in the soils of Tipum-Surma, Dupi-Tila and Alluvial Valley areas, respectively. Fe, Mn and Cu contents, however, were observed to be very high due to parent materials and these hill soils are found inherently fertile.

Previous researches have demonstrated that whole-cellular fatty acid analysis is a useful tool for identifying and establishing taxonomic relationships between the anastomosis groups (AGs) and the species related to the Rhizoctonia. In this experiment, the composition of fatty acid of 20 isolates belonging to the binucleate of AG-A, consisting of R. candida, R. endophytica var. endophytica, R. fragariae and R. ramicola were evaluated using the gas chromatography based fatty acid analysis. The detected fatty acids identified were myristic, pentadecanoic, palmitic, palmitoleic, stearic, oleic, linoleic and linolenic acids in all isolates. The major fatty acids, palmitic, oleic and linoleic acids were presented in the all isolates, constituting 94-96% of the whole-cellular fatty acids. Principal component analysis based on the composition of total cellular fatty acids revealed that isolates of R. candida, R. endophytica and R. fragariae showed similar fatty acid compositions but isolates of R. ramicola differed from the other AG-A isolates. Average linkage cluster analysis also showed that isolates of AG-A were distinguishable between R. ramicola and the other anamorphs of AG-A, representing to R. candida, R. endophytica and R. fragariae, according to the composition of detected whole-cellular fatty acids.

Relationship between growth light intensity condition and water transport regulation in napiergrass plants was examined from the responses of photosynthetic rate (Pn) and transpiration rate (Tr) directly after the plant excision treatment and the difference in exudation rates (ER) between the upper and lower positions of the nodal stem. Pn and Tr in the plants grown in full sunlight condition rapidly and largely increased by excising the leaf sheath that was at the upper position of the nodal stem, while ER at this position was lower than that at the lower position of the nodal stem. However, small increases in Pn and Tr were shown after the rhizome excision, and ER at two positions were almost same in shade-grown plants. These findings suggest that water transport to the leaf was strongly regulated by the nodal stem, but the regulation in the nodal stem decreased in shade condition. Shade plants showed higher water status in stem, and this may be involved in the decrease in water transport regulation in the nodal stem. Pn also decreased in shade condition, but because of high stomatal conductance (Gs) and maintenance of mesophyll conductance (Gm), there was not a significant difference in Pn between treatments.