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The experiment was conducted at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh during July to November 2016 to investigate the performance of separated tillers of hybrid rice variety Dhani Gold. The experiment comprised three times of tiller transplantation viz. 3, 4 and 5 week aged tiller seedlings and four levels of number of tiller seedlings transplanted hill-1 viz. 2, 3, 4 and 5 tiller seedlings hill-1 laid out in a split plot design with 3 replications. The highest plant height was obtained when 3-week aged tiller seedlings were transplanted at the rate of 3 tiller seedlings hill-1. The highest number of total tillers hill-1 and number of effective tillers hill-1 were found when 3-week aged tiller seedlings were transplanted with 5 tiller seedlings hill-1. The highest grains panicle-1 was obtained when 4-week aged tiller seedlings were transplanted with 5 tiller seedlings hill-1. The highest grain yield was found when 3-week aged tiller seedlings were transplanted with 5 tiller seedlings hill-1. The lowest grain yield was found when 5-week aged tiller seedlings were transplanted with 2 tiller seedlings hill-1 in hybrid rice variety Dhani Gold. Based on the findings of the present study it may be concluded that 3-week old tiller seedlings of Dhani Gold should be transplanted at the rate of 4 or 5 tiller seedlings hill-1 for higher yield. Thus present study confirms the potentiality of growing hybrid rice from separated tillers in case of unavailability of seedlings or to minimize the seed cost of high value hybrid rice seeds. J Bangladesh Agril Univ 17(4): 507–513, 2019

Growing two or more cultivars of same crop species in mixture reduces intra-specific competition for natural resources and increases competitive ability of crops against weeds and thus enhances crop yield. The objective of this study was to evaluate the potentiality of growing rice cultivars in mixtures for minimizing weed pressure and increasing rice yield. The experiment was conducted at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh during Aman season (July-December) 2017. Two transplant Aman rice cultivars viz. Binadhan-13 (tall, late- maturing and fine grain aromatic cultivar) and BRRI dhan49 (semi-dwarf, mid-maturing and coarse grain cultivar) were grown following two spatial arrangements viz., alternate row and alternate hill, and nine different cultivar mixture (Binadhan-13:BRRI dhan49) row ratios viz., 1:0, 1:2, 2:1, 2:3, 3:2, 2:4, 4:2,1:1 and 0:1. The experiment was laid out in a randomized complete block design (RCBD) with three replications. Results confirmed the positive influence of spatial arrangement and cultivar mixture ratio on rice productivity. Both the cultivars showed better growth and higher yield when grown in mixture irrespective of ratios compared to their sole culture performances. But cultivar mixture ratio showed no advantages over sole culture in suppressing weeds. Based on the total yield Binadhan-13 and BRRI dhan49 inter-planted in 1:1 row ratio following alternate hill performed the best resulting in 50% and 12% yield advantages over sole culture of Binadhan-13 and BRRI dhan49, respectively. Therefore, growing tall and dwarf rice cultivars in mixture can be adopted as a tool for increasing rice productivity. J. Bangladesh Agril. Univ. 17(2): 133–141, June 2019

Seed priming, partial hydration of seeds followed by re-drying before sowing, is found to improve germination rate and seedling growth through triggering some physiological changes and exhilarating the enzyme activities. Wheat in Bangladesh under late sown conditions is often exposed to heat and moisture stresses resulting in poor growth and reduced yield. Seed priming can be a feasible tool to combat those abiotic stresses. The objectives of the present study were to evaluate the efficacy of different seed priming agents for increasing seed emergence, seedling growth, and vigor of wheat. A laboratory experiment was conducted at the Agro Innovation Laboratory, Department of Agronomy, Bangladesh Agricultural University during the 2nd week of November in 2019 with the wheat variety BARI Gom-33. The experiment comprised the following two factors arranged in a completely randomized design with four replications; Factor A: Priming agent (23) namely; i) Control (No priming) ii) Hydropriming (distilled water) iii) 10000 ppm NaCl iv) 20000 ppm NaCl v) 30000 ppm NaCl vi) 50 ppm PEG vii) 100 ppm PEG viii) 150 ppm PEG ix) 1 ppm Na2MoO4 x) 2 ppm Na2MoO4 xi) 3 ppm Na2MoO4 xii)5000 ppm ZnSO4 xiii) 10000 ppm ZnSO4 xiv) 15000 ppm ZnSO4 xv) 25 ppm CuSO4 xvi) 50 ppm CuSO4 xvii) 75 ppm CuSO4 xviii) 10000 ppm KCl xix) 20000 ppm KCl xx) 20000 ppm KCl xxi) 10000 ppm CaCl2 xxii)20000 ppm CaCl2 xxiii) 30000 ppm CaCl2; Factor B: Priming duration (2); i) 6 hours ii) 12 hours. One hundred seeds were placed manually on moist sand maintaining more or less equal distance in each petri dish. Results revealed that seed priming has a positive impact (except CuSO4 and ZnSO4) on seed germination and seedling growth of wheat. Germination parameters and seedling growth traits were significantly affected by priming agents, and a clear advantage of seed priming over non control was evident. Seed priming for 12 hours performed better than6 hours priming. Among the priming agents tried, CaCl2 performed the best in terms of germination percent and index, root and shoot length, seedling length, dry weight and vigor were. It may therefore be concluded that seed priming can increase seed germination rate and improve seedling vigor of wheat to some extent, and pre-sowing seed priming with CaCl2 for 6 hrs can be recommended for wheat. [Fundam Appl Agric 2021; 6(4.000): 444-459]

Highly diversified tropical tree species could be a potential source of allelopathic compounds, which could lead to development of natural bio-herbicides for sustainable weed management. The present study was therefore designed to investigate into the allelopathic potential of sawdust obtained from eleven tropical tree species available in Bangladesh viz., Azadirachta indica, Swietenia macrophylla, Acacia auriculiformis, Tamarindus indica, Eucalyptus camaldulensis, Syzygium cumini, Mangifera. indica, Albizia. saman, Artocarpus. heterophyllus, Diospyros discolor and Tectona grandis. The aqueous sawdust extract of these plant species were diluted into four different concentrations viz. 1:5, 1:10, 1:15, 1:20 (w/v) and tested for their potentiality in inhibiting seedling growth of allelopathic sensitive plant Raphanus sativus under laboratory condition. A control (distilled water without extract) was also maintained in every cases and the bioassay experiment was replicated thrice. The results of this experiment showed that S. macrophylla, E. camaldulensis, M. indica and A. saman inhibited more than 90% shoot and root growth of R. sativus. The sawdust of these four plant species were selected to evaluate their potentiality in controlling paddy field weeds under filed condition. A total of 16 weed control treatments were considered in the field experiment viz., sawdust of selected four tree plant species at three application rates (1, 2 and 3 t ha-1), manual weeding (three times), chemical control (pre- + post- emergence herbicides), chemical + manual control and season long weedy (control). The results showed that the effect of different sawdust on the weed control varied significantly. Weed growth suppression by the sawdust was increased with the increase in application rate. The results revealed that manual, chemical weed control and application of E. camaldulensis saw dust @ 3 t ha-1 reduced the weed density by 79, 77 and 72%, respectively, and weed biomass by 86, 84 and 79%, respectively. On the other hand, manual weed control offered 100% rice yield increase while, chemical control and E. camaldulensis saw dust @ 3 t ha-1 both resulted in 92% rice yield increase over control. Although, manual and chemical weed control offered higher weed control efficiency and resulted in better rice productivity, but from environmental viewpoint application of E. camaldulensis sawdust @ 3 t ha-1 may be considered for sustainable weed management in rice. [Fundam Appl Agric 2019; 4(3.000): 906-915]