Growth, Yield and Yield Components of American Cotton (Gossypium hirsutum L.) As Affected by Cultivars and Nitrogen Fertilizer
Nitrogen stress in upland cotton addresses significant and visible shortfalls in plant growth. It is an important element both in nature and agricultural conditions, for cotton plant growth and development. To evaluate the response of different yield and yield component of high yielding upland cotton cultivars to various split applications of nitrogen fertilizer, a two season field research was conducted during 2007 and 2008. Different experimental treatments were comprised on cotton leaf curl virus (CLCV) resistant high yielding cotton cultivars i.e. CIM-496, CIM-506, CIM-534 along with different nitrogen rate of Zero, 60, 110 and 160 kg ha -1 . However, cultivar CIM-534 produced significantly the highest plants, nodes per plant and flowering buds plant -1 . While, CIM-496 showed better potential in relation to leaf area index, crop growth rate, relative growth rate and net assimilation rate (physiological), dry biomass and number of bolls m -2 (reproductive) and seed cotton, cotton seed (yield) parameters during both the seasons. On increasing N rates, vegetative characteristics of cotton like plant height, nodes plant -1 and number of flowering buds per plant significantly gave better response with each cultivar. Advanced cotton cultivars produced significantly higher total dry biomass (TDM), bolls m -2 , seed cotton, cotton seed and GOT % age on each increment in applied nitrogen. The nitrogen fertilizer rate i.e. 160 kg ha -1 proved to be the optimum for the highest cotton yield and yield components. Further fibre characteristics such as staple length, uniformity ratio and maturity ratio significantly influenced by different cultivars.
Nitrogen nutrition in cotton and control strategies for greenhouse gas emissions: a review
Cotton (Gossypium hirustum L.) is grown globally as a major source of natural fiber. Nitrogen (N) management is cumbersome in cotton production systems; it has more impacts on yield, maturity, and lint quality of a cotton crop than other primary plant nutrient. Application and production of N fertilizers consume large amounts of energy, and excess application can cause environmental concerns, i.e., nitrate in ground water, and the production of nitrous oxide a highly potent greenhouse gas (GHG) to the atmosphere, which is a global concern. Therefore, improving nitrogen use efficiency (NUE) of cotton plant is critical in this context. Slow-release fertilizers (e.g., polymer-coated urea) have the potential to increase cotton yield and reduce environmental pollution due to more efficient use of nutrients. Limited literature is available on the mitigation of GHG emissions for cotton production. Therefore, this review focuses on the role of N fertilization, in cotton growth and GHG emission management strategies, and will assess, justify, and organize the researchable priorities. Nitrate and ammonium nitrogen are essential nutrients for successful crop production. Ammonia (NH3) is a central intermediate in plant N metabolism. NH3 is assimilated in cotton by the mediation of glutamine synthetase, glutamine (z-) oxoglutarate amino-transferase enzyme systems in two steps: the first step requires adenosine triphosphate (ATP) to add NH3 to glutamate to form glutamine (Gln), and the second step transfers the NH3 from glutamine (Gln) to α-ketoglutarate to form two glutamates. Once NH3 has been incorporated into glutamate, it can be transferred to other carbon skeletons by various transaminases to form additional amino acids. The glutamate and glutamine formed can rapidly be used for the synthesis of low-molecular-weight organic N compounds (LMWONCs) such as amides, amino acids, ureides, amines, and peptides that are further synthesized into high-molecular-weight organic N compounds (HMWONCs) such as proteins and nucleic acids.
Cotton Fiber Growth and Development 2. Changes in Cell Diameter and Wall Birefringence
Cotton (Gossypium hirsutum L, and G. barbadense L.) fiber perimeter is an important textile trait that directly affects quality properties, such as fiber length, strength, and micronaire. The literature is contradictory regarding whether or not fiber diameter changes during development. Changes in maximum fiber diameter, fiber length, and cell wall birefringence were measured throughout development in four cotton genotypes (G. hirsutum, cultivars MD51ne, DP50, and DP90; and G. barbadense). All genotypes exhibited significant increases in fiber diameter during the first 30 d of fiber development. The G. hirsutum genotypes all had similar final diameters; whereas, G. barbadense had a significantly smaller final diameter. The G.