An investigation was carried out during aman season, 2005 at the Field Laboratory of Agrotechnology Discipline, Khulna University, Khulna. Local aman rice variety Jatai was tested against 4 different levels of nitrogen viz. 0, 20, 40 and 60 kg N ha-1. The experimental results revealed that nitrogen levels significantly affected plant height (cm), number of tillers hill-1, weight of 1000-grain (g), grain yield (tha-1), biological yield (t ha-1) and harvest index (%). Higher N dose (60 kg ha-1) produced higher plant height (127.57 cm) and panicle length (20.43 cm). The highest number of tillers hill-1 (13), effective tillers hill-1(11.70), filled grains panicle-1 (61.25), weight of 1000 grain (30.25 g), grain yield (4.17 t ha-1), biological yield (12.46 t ha-1) and harvest index (33.48 %) were produced with 40 kg N ha-1. The lowest grain yield and yield contributing characters were produced by control treatment (0 kg N ha-1).

A field experiment was conducted to find out the impact of weeding regime on the performance of three Aus rice. The experimental treatment consisted of three varieties of rice viz. BRRI dhan28, Bere Ratna and Kajol Lata, and four weeding regimes viz. no weeding, one hand weeding at 35 days after sowing (DAS), two hand weedings at 20 and 35 DAS and three hand weedings at 20, 35 and 50 DAS. The experiment was laid out in a factorial randomized complete block design with three replications. Eleven weed species belonging to five families infested the experimental plots; Cyperus rotundus L. and Imperata cylindrica (L.) Baeuv. were the dominant. The effect of weeding regime on weed density (except at 20 DAS) and weed dry weight was statistically significant. The results indicated that three hand weedings at 20, 35 and 50 DAS produced the highest number of effective tillers hill-1, number of filled grains panicle-1, 1000-grain weight and grain yield. Among the varieties Bere Ratna gave the highest grain yield.

A fast and reliable method for ploidy determination of regenerated Triticum aestivum from anther culture is described in the present work. The anthers of 47 hybrid combinations of winter wheat were cultured in vitro and the length of the guard cells was measured in regenerated plants. Thus, plants with a guard cell length of 32-46 mm were haploid, whilst plants with a guard cell length of 54-74 mm were diploid. Plants with a guard cell of 46-54 mm required further chromosome investigation for the exact determination of ploidy level.

In the present study, different isolates of Colletotrichum gloeosporioiedes were collected from different mango growing areas of Bangladesh. Pathogenecity was proved by using healthy excised leaves in laboratory conditions. Effects of mycelial growth and sporulation (formation of acervuli) on six different culture media were tested in vitro. The results revealed significant differences (p<0.05) mycelia growth among the media. The results also indicated that the mycelial growth was maximum in Potato Dextrose Agar (12.8mm) media and the lowest in Green Bean Agar (8.0mm). The study disclosed significant difference (p<0.05) of acervuli formation among the media. Among the 6 different media the maximum acervuli were produced in HLEA (4.0 per square. cm) medium. But the sporulating characters of the fungus were not produced well in PDA and HLEA media rather than OMA. Thus, to find out the best composition of OMA for further research was conducted to obtain better growth and acervuli production and sporulating characters. The results revealed significant difference (p<0.05) of different characters among the concentration of OMA, and 20g/L OMA produced significantly maximum setae, conidia and sticky masses of conidia than others. The study suggested that Oat Meal Agar (20g/L) composition was the best medium for the sporulation of C. gloeosporioiedes (Setae, conidia and sticky masses of spores).

The experiment was conducted to assess the effect of different concentration combination of 2,4D, a-NAA and kinetin on callus induction and regeneration of haploid in anther culture of wheat. Potato-2 liquid medium supplemented with different concentration combinations was used for this purpose. Among all the formulations, efficient callus induction and plant regeneration were observed in liquid potato medium containing following concentrations (mg l-1) of plant growth regulators: 2,4D-0.75; a-NAA-0.1 and kinetin 0.75. This formulation supported to produce haploid plantlets directly without transferring calli to regeneration medium.