The present study was aimed at determining the effect of vernalization and Gibberellic Acid (GA3) on seed yield and quality of summer onion. There were three vernalization treatments viz., no vernalization (control), vernalization at 5°C for 14 days and vernalization at 10°C for 14 days and four GA3 treatment viz., 0, 50, 100 and 150 ppm. The two-factor experiment was laid out in the Randomized Complete Block Design with three replications. The results of the experiment showed that the vernalization and GA3 had significant influence on all the parameters studied. Solitary Effect of vernalization and GA3 was significant on the parameters such as plant height, number of leaves plant-1 , the highest number of flowering stalk, number of umbels plant-1 , number of bud umbel-1 , percent flowering at 45 and 60 DAP, number of seeds umbel-1 , weight of seeds umbel-1 , weight of seeds plant-1 , weight of seeds plot-1 , 1000 seed weight, seed yield, number of fruits umbel-1 , percent of fruit set umbel-1 and percent germination. The highest seed yield (248.16 kg ha-1) was obtained from vernalization at 5°C for 14 days. The lowest values of all the parameters were recorded at control treatment. The highest seed yield (191.77 kgha-1) was obtained from 100 ppm GA3. The lowest values of all the parameters were recorded in the 0 ppm GA3 treatment. Use of suitable vernalization of mother bulb and proper concentration of gibberellic acid can be a possible way to expand onion production at the time of summer.

The purpose of the present study was to evaluate the effect of vernalization and GA3 on seed yield and reproductive quality of summer onion. There were three vernalization treatments viz., no vernalization (control), vernalization at 5°C for 14 days and vernalization at 10°C for 14 days and four GA3 treatment viz., 0, 50, 100 and 150 ppm. The two-factor experiment was conducted in the Randomized Complete Block Design (RCBD) with three replications. Combination between vernalization and GA3 was significant on the parameters such as plant height, number of leaves plant-1, the highest number of flowering stalk, number of umbels plant-1, number of bud umbel-1, percent flowering at 45 and 60 DAP, number of seeds umbel-1, weight of seeds umbel-1, weight of seeds plant-1, weight of seeds plot-1, 1000 seed weight, seed yield, number of fruits umbel-1, percent of fruit set umbel-1and percent germination. Combined effect of vernalization & GA3 was considered the highest seed yield (280.42 kgha-1) was obtained from vernalization at 5°C for 14 days with 100 ppm GA3. The lowest values of all the parameters were recorded in the control treatment. No limitation is found in the present experiment.  Combined use of proper vernalization of mother bulb and suitable concentration of gibberellic acid can be one possible way to expand onion production during the summer.

In Bangladesh direct-seeded Aus rice is a conventional rice cultivation practice and weed infestation is a severe problem in direct-seeded rice production due to the existence of favorable environment during this period. So, by minimizing the use of herbicides and replace them with eco-friendly and environmentally sustainable herbicides based on natural plant products or allelochemicals, a factorial experiment based on randomized complete block design with three replications was performed at the research field of Bangladesh Rice Research Institute (BRRI), Gazipur, Bangladesh from July 2018 to August 2019 to evaluate effect of sunflower crop residue on weeds growth and yield of direct seeded Aus rice in Transplanting Aman-Sunflower-Aus cropping pattern. Weed population and weed dry weight were significantly affected by crop residues treatment. Weed population was significantly lower in C3 (Direct sowing of Aus after 7 days of Sunflower residue incorporation) treatment than the control C1 (Direct sowing of Aus without Sunflower residue incorporation) treatment. The lowest weed dry weight (90.5 g m-2) was also obtained from C4 (Direct sowing of Aus after 14 days of Sunflower residue incorporation). The highest reduction of grain yield was obtained from without crop residue and no weeding treatments. The highest number of effective tillers m-2 (403.33), grain panicle-1 (114.67), tillers hill-1 (16.36), and grain yield (3.32 t ha-1) were observed from the treatments where sunflower residue was incorporated and the plots that were weed free. Results of this study indicate that sunflower residues showed potentiality to inhibit weed growth and it has a significant effect on the yield and yield parameters of direct seeded rice. Again weeds played a significant role in the reduction of yield of direct seeded rice. Thus, sunflower residues might be substitute for weed management practice as well as obtaining higher yield of direct seeded rice. Bangladesh Agron. J. 2021, 24(2): 115-125