Siliqua and Seed Development in Rapeseed (Brassica campestris L.) as Affected by Different Irrigation Levels and Row Spacing

Accumulation of dry matter in siliqua, number of siliqua per plant, length of siliqua and seeds per siliqua of rapeseed (Brassica campestris L.) plants were studied under three irrigation levels (no irrigation, one irrigation at 30 DAS and two irrigations at 30 and 60 DAS) and three row spacing (20 cm, 30 cm and 40 cm). The experiment was carried out at Sher-e-Bangla Agricultural University (SAU) Farm, Dhaka-1207, Bangladesh during the period from October, 2005 to January, 2006. The results revealed that the maximum dry matter accumulation in siliquae observed with two irrigations (at 30 DAS and 60 DAS) with 40 cm row spacing. Number of siliquae per plant was affected by different irrigation levels and row spacing and the highest number of silique was produced by two irrigations (at 30 DAS and 60 DAS) with 40 cm row spacing. At harvest, two irrigations produced the highest number of siliquae (120.3) which was statistically different from one irrigation (76.14) and no irrigation (control) treatments (30.99) and the differences were 288.2% and 145.7%, respectively over control. Length of silique as well as number of seeds per siliqua were significantly affected by the combination of irrigation levels and row spacing

Ratoon Rice Response to Different Fertilizer Doses in Irrigated Condition

The response of different fertilizer doses was studied on the ratoon crop as well as main crop. The different fertilizer doses under the study were F1 (N=90, P2O5 = 45, K2O=50, S=13, Zn = 4: in kg ha-1), F2 (N=105, P2O5 = 55, K2O=60, S=13, Zn = 4: in kg ha-1), F3 (N=120, P2O5 = 65, K2O=70, S=13, Zn = 4: in kg ha-1), F 4(N =135, P2O5 =75, K2O=80, S=13, Zn=4: in kg ha-1) and F5 (N=150, P2O5 = 85, K2O = 90, S=13, Zn = 4: in kg ha-1). In the main crop, the highest grain and biological yields were produced by F3 dose. The highest straw yield was produced by F4 dose. The lowest grain yield and the lowest biological yield were produced by F1 dose and the lowest straw yield was produced by F2 dose. The highest crop duration was found using F1 dose and the shortest crop duration was found using F3 doses. In the ratoon crop, the highest grain yield, straw yield and biological yield was produced by F5 dose whereas the lowest grain yield, straw yield and biological yield was achieved with F1 dose. The longest crop duration was observed using F2 dose and the shortest crop duration was recorded using F5 dose

Quantifying Some Physiological and Productivity Indices of Canola (Brassica napus L.) Crop under an Arid Environment

Canola (Brassica napus L.) crop ranks third after soybean and palm among oilseed crops for production of vegetable oil and meal for human and livestock, respectively around the globe. The cultivars of canola crop vary greatly in their yield potential in response to eco-edaphic factors under different production environments. Therefore, research studies were undertaken to evaluate eight cultivars of canola crop 'Shiralee', 'Dunkled', 'Bulbul-98', 'Ac-Excel', 'Cyclone', 'Rainbow', 'DGL' and 'Faisal Canola' for quantifying some physiological and productivity indices  under normal growing conditions. The results showed that various cultivars of canola differed significantly amongst themselves with respect to biological yield, chlorophyll content, protein content, nutrient composition and components of seed yield. Among the cultivars, cvs. 'Bulbal-98' and 'Rainbow' produced maximum biological yield and seed yield,  respectively, Furthermore, maximum yield harvested from cv. 'Rainbow' was associated with higher total seed weight plant-1, while cv. 'Faisal Canola' maintained higher chlorophyll content than other ones. Cultivar 'Dunkled' contained higher K+ nutrient by 21.13 mg g-1 in leaf tissues compared to minimum (9.73 mg g-1) in 'DGL' cultivar. The higher amount of Na+ content (12.16 mg g-1) was determined in cv. 'AC Excel'. Cultivar 'Rainbow' maintained higher photosystem (II) activity and had greater partitioning ability of photo-assimilates in the seed tissues. Of various chlorophyll fluorescence parameters, quantum yield of photosystem II and electron transport performance index could be used as a selection criterion for breeding of canola cultivars

Determining the status of chlorinated pesticide residue in some leafy vegetables

A study was carried out to identify the bioaccumulation and the ascertain level of chlorinated pesticide residues in three leafy vegetables viz. red amaranth, spinach and Indian spinach collected from city market. The samples were randomly collected from different shops and analyzed by capillary column of Gas Chromatograph Mass Spectrometry (GCMS) with Electron Impact Ionization (EI) method for the detection of chlorinated pesticide. The results of the study revealed that collected samples of red amaranth and spinach were contaminated with some chlorinated substances. But Indian spinach was free of contamination with organochlorine pesticide

Salt Stress Tolerance in Rice: Emerging Role of Exogenous Phytoprotectants

Excess salinity in soil is one of the major environmental factors that limit plant growth and yield of a wide variety of crops including rice. On the basis of tolerance ability toward salinity, rice is considered as salt-sensitive crop, and growth and yield of rice are greatly affected by salinity. In general, rice can tolerate a small amount of saltwater without compromising the growth and yield. However, it greatly depends on the types and species of rice and their growth stage. Salinity-induced ionic and osmotic stresses reduce rate of photosynthesis and consequently cause oxidative stress, which is also responsible for growth reduction. The negative effects of salt stress that mentioned ultimately reduced yield of most crops including rice, except some halophytes. In recent decades, researchers have developed various approaches toward making salt-tolerant rice varieties. Using phytoprotectants is found to be effective in conferring salt tolerance to rice plants. In this chapter, we reviewed the recent reports on different aspects on salt stress tolerance strategies in light of using phytoprotectants

Seed Priming with Phytohormones: An Effective Approach for the Mitigation of Abiotic Stress

Plants are often exposed to abiotic stresses such as drought, salinity, heat, cold, and heavy metals that induce complex responses, which result in reduced growth as well as crop yield. Phytohormones are well known for their regulatory role in plant growth and development, and they serve as important chemical messengers, allowing plants to function during exposure to various stresses. Seed priming is a physiological technique involving seed hydration and drying to improve metabolic processes prior to germination, thereby increasing the percentage and rate of germination and improving seedling growth and crop yield under normal and various biotic and abiotic stresses. Seed priming allows plants to obtain an enhanced capacity for rapidly and effectively combating different stresses. Thus, seed priming with phytohormones has emerged as an important tool for mitigating the effects of abiotic stress. Therefore, this review discusses the potential role of priming with phytohormones to mitigate the harmful effects of abiotic stresses, possible mechanisms for how mitigation is accomplished, and roles of priming on the enhancement of crop production

Salicylic Acid: An All-Rounder in Regulating Abiotic Stress Responses in Plants

Salicylic acid (SA) is an endogenous growth regulator of phenolic nature and also a signaling molecule, which participates in the regulation of physiological processes in plants such as growth, photosynthesis, and other metabolic processes. Several studies support a major role of SA in modulating the plant response to various abiotic stresses. It is a well-founded fact that SA potentially generates a wide array of metabolic responses in plants and also affects plant-water relations. This molecule also found to be very active in mitigating oxidative stress under adverse environmental conditions. Since abiotic stress remained the greatest constraints for crop production worldwide, finding effective approaches is an important task for plant biologists. Hence, understanding the physiological role of SA would help in developing abiotic stress tolerance in plants. In this chapter, we will shed light on the recent progress on the regulatory role of SA in mitigating abiotic stress

Osmolyte-induced water deficit stress mitigation during panicle initiation stage in transplanted rice (Oryza sativa L.)

A field experiment was conducted to observe the osmolyte-induced water deficit stress mitigation during the panicle initiation stage in transplanted rice (Oryza sativa L. cv. BRRI dhan72). At the panicle initiation stage, plants were simulated with four levels of water regimes viz., well-irrigated (D0), water deficit for 5 d (D1), 10 d (D2) and 15 d (D3). Plants were treated with or without 10 mM of proline (Pro) and trehalose (Tre) as foliar spray started at mid-vegetative stage and continued till the end of stress period. Results revealed that water deficit stress drastically reduced most of the plant morpho-physiological attributes while other yield contributing characters were also affected due to prolonged water deficit stress. However, exogenous application of osmolytes like Pro and Tre significantly increased all those morphological, physiological and yield contributing parameters. Foliar addition of osmolytes concomitantly decreased the number of non-effective tillers hill-1 and the number of unfilled grain panicle-1 under water stress condition. Although both the osmolytes performed well under multiple duration of drought stress, the application of 10 mM Pro markedly improved all growth and yield contributing parameters under D1 water deficit stress compared to other stress durations. Hence, it may be concluded that the use of osmolytes would be a prospective remedy against moderate water deficit stress in transplanted rice production

Approaches to Enhance Salt Stress Tolerance in Wheat

Wheat is consumed as a staple food by more than 36% of world population. Wheat provides nearly 55% of the carbohydrates and 20% of the food calories consumed globally. The productivity of wheat is often adversely affected by salt stress which is associated with decreased germination percentage, reduced growth, altered reproductive behavior, altered enzymatic activity, disrupted photosynthesis, damage of ultrastructure of cellular components, hormonal imbalance, and oxidative stress. Different approaches have been adopted to improve plant performance under salt stress: introduction of genes, screening of better performing genotypes, and crop improvement through conventional breeding methods which are often not so successful and suitable due to time-consuming or reduction of plant vigor with the succession of time. Uses of exogenous phytoprotectants, seed priming, nutrient management, and application of plant hormone are convenient for improving plant performances. This chapter reviews the mechanism of damage of wheat plants under salt stress and also the recent approaches to improve growth and productivity of salt-affected wheat plants emphasizing the use of exogenous phytoprotectants from the available literature