Muhammad Ijaz

BACTERIA IN COMBINATION WITH FERTILIZERS IMPROVE GROWTH, PRODUCTIVITY AND NET RETURNS OF WHEAT (Triticum aestivum L.)

Plant growth promoting rhizobacteria (PGPR) associate with roots of plants and improve plant growth by utilizing diverse mechanisms like nitrogen fixation, phosphorus solubilization and phytohormone production. Current study was conducted to isolate, characterize, and identify the wheat associated PGPR and investigate the inoculation effect of selected strains for growth promotion of wheat in combination with different levels of chemical fertilizer at two different ecological locations (Multan and Layyah, Pakistan). Among the total 22 bacterial isolates, 11 were positive for acetylene reduction assay (ARA), 9 isolates exhibited P solubilization activity and 19 bacterial isolates produced growth hormone indole -3-acetic acid (IAA) in culture medium. From these, two bacterial isolates with maximu m potential to fix nitrogen, solubilize phosphorous and to produce IAA were identified through 16S rRNA gene sequence analysis as Pseudomonas sp. LYT-1 (accession no. KT933231) and Bacillus sp. MWT-14 (accession no. KT933232). Their performance as PGPR along with different levels of nitrogen (N) and phosphorous (P) chemical fertilizers (0-0, 105-75 and 150-100 NP kg ha -1 ) was evaluated under field conditions at two different locations (Multan and Layyah) in 2014-15. The experiments were laid out in Randomize Complete Block Design (RCBD). Results indicated that bacterial strain Pseudomonas sp. LYT-1 (with maximu m in vitro nitrogenase activity), increased the growth parameters like plant height, chlorophyll contents, product ive tillers, spike length and straw yield of wheat at both the locations. The inoculation of Bacillus strain MWT-14 (with highest in vitro phosphate solubilization and IAA production) in combination with 0-0, 105-75 and 150-100 kg ha -1 N-P fertilizer improved the 1000-grain weight by 9.8%, 5.4%, 4.6% and 2.1%, 6.6%, 4%, respectively at Multan and Layyah, and grain yield by 16.3%, 12.3%, 4.7% and 17.1%, 14.2%, 8.5%, respectively at Multan and Layyah over their respective non -inoculated control treatments. These results concluded that plant growth promoting strains Pseudomonas sp. LYT-1 and Bacillus sp. MWT-14 enhance the growth, productivity and net returns of wheat when used as bio -inoculant along with 30% reduced of the recommended NP fertilizer dose.

Influence of Seed Priming and Seed Size on Wheat Performance under Different Tillage Systems

This field study was conducted to assess the effect of seed priming and seed size on emergence, growth and productivity of wheat under conventional and conservation tillage during winter season 2012‒2013. Seeds of wheat cultivar Punjab-2011 were separated into small sized (1000 grain weight = 22.5 g) and bold sized (1000 grain weight = 44.4 g) seeds by winnowing. Both bold and small sized seeds were soaked in aerated solution of CaCl2 (ψs -1.25 MPa; osmopriming) for 24 h while untreated (dry) seeds were taken as control. Osmoprimed and dry seeds of both sizes were sown under conventional and conservation (zero tillage) tillage practices. Results indicated that wheat sown under conventional tillage observed quick, uniform and better early stand establishment compared with zero tilled wheat. However, seed primed with CaCl2 significantly lowered the days to start emergence, mean emergence time and improved final emergence count compared with dry seeds sown, particularly of zero tilled wheat. Zero tilled crop observed a significant cut in leaf area index (LAI), crop growth rate (CGR) and net assimilation (NAR), while bold seed size and osmopriming improved the LAI, CGR and NAR under both tillage practices, zero tilled wheat in particular. Moreover, zero tilled wheat observed a significant yield penalty due to significant increase in yield related traits; however, osmopriming and bold seed size improved wheat productivity due to substantial expansion in yield related traits under conventional and zero tillage, zero tillage in particular, practices. In conclusion, bold sized seed osmoprimed with CaCl2 was better able to produce higher yield of conventionally tilled and zero tilled wheat.

INFLUENCE OF DIFFERENT METHODS AND TIME OF PHOSPHORUS FERTILIZER APPLICATION IN WHEAT UNDER ARID CONDITION

A field experiment was conducted to study the effect of different time and methods of application of phosphatic fertilizer to wheat crop under Arid condition. Experiment was comprised of five treatments viz: T1= Control, T2= P2O5 broadcast at the time of seedbed preparation in the form of (TSP), T3 = P2O5 side drilling after sowing, 5 cm apart rows and 5 cm deep with Rabi hand drill, T4= P2O5 broadcast after sowing at the time of first irrigation and T5= P2O5 mixed with seed of wheat. Results showed that although all the treatments tested were differing significantly from the control in all aspects studied but, application of phospahtic fertilizer (P2O5) side drilling after sowing, 5 cm apart rows and 5 cm deep with Rabi hand drill, produced maximum germination percentage (82.15), plant height (108.50 cm), number of fertile tillers m (356), number of grains spike (41.50), 1000 grains weight (42.40 g) and grain yield (5.08 t ha) as compared to other treatments. Maximum P contents in the straw, grain, total P uptake and protein contents in grain were recorded in T5 was statistically at par with the T4 and T3. On the basis of these results, it can be concluded that application of phosphatic fertilizer at 5 cm apart side dressing of the rows at a depth of 5 cm not only increase the plant vigor but also produced better yield under arid condition.

Molecular, biochemical and bioassay based evidence of lower allelopathic potential in genetically modified rice

This study examines allelopathic potential of genetically modified rice. The experiment was conducted on two isogenic lines Bacillus thuringiensis (Bt) and non-Bacillus thuringiensis (non-Bt). Both isogenic lines have same allelopathic ability before insect feeding and after limited insect feeding (Spodoptera litura) non-Bt rice genotype demonstrates more allelopathic potential. The S. litura cannot feed Bt rice genotype. The role of shoot herbivory in allelopathic induction is further supported when Bt plants also exhibited higher allelopathic potential after insect regurgitant application to the damaged leaves. Allelopathic potential was assessed through several methods after treatments of mechanical damage, insect feeding and insect regurgitant application to damaged rice leaves. Rhizosphere soil and leaf leachates of non-Bt rice cultivar exhibited higher allelopathic potential on lettuce and barnyard grass after herbivore feeding. Enzyme activities (PAL and C4H) responsible for biosynthesis of phenolic compounds and their concentration were significantly higher in non-Bt plant after herbivore feeding and attain the same level in Bt plants after insect regurgitant application to damaged leaves. Similarly, genes (OsPAL and OsCYC1) responsible for biosynthesis of allelopathic compounds showed high expression in non-Bt plants after herbivore feeding. Our results indicate that herbivore feeding enhance rice allelopathic potential and no insect feeding as incase of Bt plants may reduce allelopathic potential of genetically modified rice.

Paddy Land Pollutants and Their Role in Climate Change

Climate change is one of the biggest concerns because its potential impact on human life is severe. The contribution ratio of CH4, CO2, and N2O to global warming would be high even if their emission rates are small. Paddy lands may become polluted by the aggregation of several pollutants, i.e., organic and inorganic fertilizers; discharges from the quickly extending industrial territories; use of manure, and organic solid waste; and wastewater irrigation system. Paddy lands are considered to be a major source of anthropogenic greenhouse gas (GHG) emissions through methanogenesis (a process of methane production), a microbial process that is strictly restricted to paddy fields. Overall 90% of rice land is at least temporarily flooded and produces GHGs at higher rates. The production of N2O in soils occurs during nitrification, denitrification, and microbiological processes. A positive relationship was found between the climate change and N fertilizer application with N2O emissions from paddy lands. The use of N fertilizer also stimulates and influences the CH4 emission flux between paddy land and atmosphere. The impact of biochar amendments on the CH4 emission expanded by 35.16–40.62% in paddy fields. It is of incredible concern worldwide that gaseous outflows from management of organic solid waste add to local and worldwide scale ecological procedures, for example, eutrophication, fermentation, and climate change. CH4 is generated from the disintegration of organic matter (OM) in anaerobic conditions by methanogens. Soil OM is the most well-known constraining element for methanogenesis in paddy fields. OM obtained from three primary sources: animal fertilizer, green manure, and crop deposits. The amendment of OM, for example, rice deposits and compost application, prompts expanding CH4 outflows because of anaerobic decay and results in climate change.

Combined Application of Natural Plant Water Extracts and Biochar Improves the Productivity of Bread Wheat

Bread wheat (Triticum aestivum L.) is staple of Pakistani people. However, its yield at farmer field is low as compared with its genetic potential. Integration of various crop and soil management strategies might be an option to enhance wheat productivity at farmer field. This 2-year experiment was conducted to check the influence of combine application of natural plant water extracts and biochar on the productvity of wheat during the winter season of 2015-16. The experiment consisted of seven treatment viz. (1) control (2) application of biochar (0.18 kg pot) alone, (3) application of sorghum water extract (SWE) alone, (4) application of moringa water extract (MWE) alone, (5) application of biochar + SWE, (6) application of biochar + MWE, (7) application of biochar + SWE+MWE. The results revealed that application of both crop water extracts in combination with biochar improved the growth and grain yield of wheat. Use of MWE in combination with biochar enhanced the grain weight, grain number and grain yield of wheat by 44, 14, and 24%, respectively than the control treatment. In crux, use of MWE in combination with biochar might be a viable option to improve the productvity of bread wheat.

FOLIAGE APPLIED ZINC IMPROVE THE GROWTH AND PRODUCTIVITY OF WHEAT

A field experiment was conducted to investigate the effect of foliar application of zinc fertilizer on the growth, yield and yield components of wheat. Experiment was laid out in a factorial randomized completely block design consisting of twelve treatments with three replications. The levels of zinc sulfate were 0 (control water spray), 0.25% solution of zinc, 0.5% solution of zinc, 0.75% solution of zinc. Levels of zinc sulfate were applied at tillering, booting and tillering × booting stages of growth. Results revealed that highest values for relative growth rate, leaf area index, net assimilation rate, total number of fertile tillers m -2 , plant height, number of spikelets spike -1 , spike length, grain spike -1 , 1000 grains weight, grain yield, straw yield, biological yield and harvest index was observed with 0.5% solution of zinc sulfate. Foliar application of 0.5% solution of zinc sulfate (at the time of tillering booting) appeared to be the best doze for wheat crop under Multan conditions.