Rice seeds germinating in flooded soils encounter hypoxia or even anoxia leading to poor seed germination and crop establishment. Introgression of AG1 and AG2 QtLs associated with tolerance of flooding during germination, together with seed pre-treatment via hydro-priming or presoaking can enhance germination and seedling growth in anaerobic soils. This study assessed the performance of elite lines incorporating AG1, AG2 and their combination when directly seeded in flooded soils using dry seeds. The QTLs were in the background of two popular varieties PSB Rc82 and Ciherang-Sub1, evaluated along with the donors Kho Hlan On (AG1) and Ma-Zhan Red (AG2) and recipient parents PSB Rc82 and Ciherang-Sub1. In one set of experiments conducted in the greenhouse, seedling emergence, growth, and carbohydrate mobilization from seeds were assessed. Metabolites associated with reactive oxygen species (ROS) scavenging including malondialdehyde (MDA) as a measure of lipid peroxidation, ascorbate, total phenolic concentration (TPC), and activities of ROS scavenging enzymes were quantified in seeds germinating under control (saturated) and flooded (10 cm) soils. In another set of experiments conducted in a natural field with 3-5 cm flooding depths, control and pretreated seeds of Ciherang-Sub1 introgression lines and checks were used. Flooding reduced seedling emergence of all genotypes, though emergence of AG1 + AG2 introgression lines was greater than the other AG lines. Soluble sugars increased, while starch concentration decreased gradually under flooding especially in the tolerant checks and in AG1 + AG2 introgression lines. Less lipid peroxidation and higher α-amylase activity, higher ascorbate (RAsA) and TPC were observed in the tolerant checks and in the AG1 + AG2 introgression lines. Lipid peroxidation correlated negatively with ascorbate, TPC, and with ROS scavengers. Seed hydro-priming or pre-soaking increased emergence by 7-10% over that of dry seeds. Introgression of AG2 and AG1 + AG2 QTLs with seed pretreatment showed 101-153% higher emergence over dry seeds of intolerant genotypes in the field. Lines carrying AG1 + AG2 QtLs showed higher α-amylase activity, leading to rapid starch degradation and increase in soluble sugars, ascorbate, and TPC, together leading to higher germination and seedling growth in flooded soils. Seed hydro-priming or pre-soaking for 24 h also improved traits associated with flooding tolerance. Combining tolerance with seed management could therefore, improve crop establishment in flooded soils and encourage large-scale adoption of direct seeded rice system.

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1 An experiment was conducted at the research farm of Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU) during May to September 2008 to investigate the effect of alley widths of Gliricidia sepium and different nitrogen levels on yield of Aus rice (BR24). The experiment was laid out in a split-plot design with three replications. Three alley widths 3.0, 4.5, and 6.0 m and a control, without tree were compared under five N doses 0, 18.75, 37.5, 56.25 and 75 kg ha -1 . G. Sepium species gave the highest (20.24 t ha -1 ) pruned materials from closer alley width (3m). The highest grain yield (3.54 t ha -1 ) of rice was obtained at 75 kg N from urea and pruned materials (PM) in 4.5 m alley width. The study suggests that G. sepium can contribute to increase rice yield and increase N use efficiency.

Field experiments were conducted during [2007][2008][2009][2010] . In case of rice equivalent yield (REY), Tomato-Mungbean-BRRI dhan33 cropping pattern produced comparatively high average REY (29.95 t ha -1 ) followed by Tomato-Mungbean-BRRI dhan39 (27.33 t ha -1 ) cropping pattern. Among the tested cropping patterns, Tomato-Mungbean-BRRI dhan33 and Tomato-Mungbean-BRRI dhan39 were more profitable than other patterns.

Nitrogenous fertilizer has remarkably improved rice (Oryza sativa L.) yield across the world since its discovery by Haber-Bosch process. Due to climate change, future rice production will likely experience a wide range of environmental plasticity. Nitrogen use efficiency (NUE) is an important trait to confer adaptability across various abiotic stresses such as flooding, drought and salinity. The problem with the increased N application often leads to a reduction in NUE. New solutions are needed to simultaneously increase yield and maximize the NUE of rice. Despite the differences among flooding, salinity and drought, these three abiotic stresses lead to similar responses in rice plants. To develop abiotic stress tolerant rice varieties, speed breeding seems a plausible novel approach. Approximately 22 single quantitative trait loci (QTLs) and 58 pairs of epistatic QTLs are known to be closely associated with NUE in rice. The QTLs/genes for submergence (SUB1A) tolerance, anaerobic germination (AG, TPP7) potential and deepwater flooding tolerance (SK1, SK2) are identified. Furthermore, phytochrome-interacting factor-like14 (OsPIL14), or loss of function of the slender rice1 (SLR1) genes enhance salinity tolerance in rice seedlings. This review updates our understanding of the molecular mechanisms of abiotic stress tolerance and discusses possible approaches for developing N-efficient rice variety.

A field experiment was conducted at the field Laboratory, Horticulture farm, Bangladesh Agricultural University, Mymensingh-2202, Bangladesh during the dry season (October to April) to evaluate the effect of planting time on the growth and yield of two garlic varieties. The experiment was laid-out with two factors, dates of planting (21 October, 6 November, 21 November and 06 December) and variety (BAU garlic-1 and BAU garlic-2) in Randomized Complete Block Design with three replications. Planting time had significant influence on growth and yield attributes as well as bulb yield of garlic. Plant height, leaf length, number of leaves, leaf and root dry weight, bulb diameter, number of cloves per bulb and bulb yield decreased with delay planting. The highest plant height (52.38 cm), leaf length (37.66 cm), number of leaves per plant (7.15), leaf dry weight (1.75 g), bulb diameter (3.89 cm), number of cloves per bulb (22.31), bulb yield per plant (16.42 g) and per hectare (8.13 t ha-1) obtained from 21 October planting. BAU garlic-2 was relatively better than BAU garlic-1 in terms of yield and yield attributes. The interaction effect of planting time and variety showed the highest bulb yield of both varieties from 21 October planting. Early planting of both varieties found better to get maximum yield of garlic.