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Under the climate change scenario, high-temperature stress declines crop yields. The present study was designed with the objectives to identify the stable heat-tolerant genotypes for grain yield under normal and heat stress conditions at three locations. The 80 mung bean genotypes and 3 check varieties were sown in three agro-ecological zones of Pakistan, namely, Chakwal, Piplan, and Bhakkar. The experiments were planted in two sowing dates, i.e., the normal sowing and late sowing by using an augmented randomized block design with 6 blocks at each location. The plot size for each genotype was 2.4 m2 at all the locations. All cultural and agronomic practices were carried out as per recommendations. Ten randomly selected plants were used to record the yield-related traits. An infrared gas analyzer (IRGA) was used to measure physiological traits like photosynthesis rate and stomatal conductance. To study the nature of relationship among traits, Pearson correlation analysis was done using SPSS software (v. 16.0). The GGE biplots were constructed to graphically represent the genotype and GE interaction of multi-environment data using the software plant breeding tools. Three views of the GGE biplot were generated to display the comparative performance, rank, and stability of each genotype in the tested environments. Correlation and principal component analysis (PCA) revealed a positive interaction of grain yield with pods plant−1, seed pod−1, 100 grain weight, and harvest index, while days to flowering and maturity had a negative association under normal and heat-stressed conditions. The GGE biplot analysis efficiently explained 85.1% of the total variation and demonstrated that among 8 vertex genotypes of polygon biplot, the G14 and G38 were heat tolerant as these genotypes outclassed others in all the heat-stressed environments. In contrast, the genotypes G51 and G74 produced maximum yield under normal conditions (E3 and E5). Among all the genotypes, genetic diversity was observed for grain yield and other morpho-physiological traits. Significant G × E interaction was observed. The genotypes G14, G38, and G51 were identified as stable and heat tolerant in most of the environments. These findings will be helpful for development of heat-tolerant mung bean breeding material in the future.

Parthenium hysterophorus L. is a noxious annual weed rapidly spreading in cropped areas of the irrigated Punjab and other parts of Pakistan. It has become a major threat to grazing lands and crops in Punjab province. The main objective of this study was to explore the efficacy of different herbicides with various concentrations viz. pendimethalin, S-metolachlor + atrazine, bromoxynil + 2-methyl-4-chloorphenoxyacetic acid, and atrazine at their recommended (407, 711, 445 and 469 g a.i./ha, respectively), 50% lower and 50% higher doses against Parthenium hysterophorus L. Weeds were allowed to grow in a field for three years (2010-2013) where this spring maize experiment was conducted during the years 2013 and 2014. All herbicide treatments at their recommended and higher doses significantly reduced Parthenium dry weight. Minimum density (2.3 and 2.0/m) and dry biomass (39.74 and 43.47 g/m) of parthenium weed was observed with S-metolachlor + atrazine at 711.36 g/ha treatment during 2013 and 2014, respective...

Climate variability and extreme weather might increase in frequency due to climate change, which could have significant effect on chickpea production. Recently, a study was conducted, aided with simulation modeling approach, in different rainfed regions of Pakistan to check the potential impacts of climate variability on chickpea. Initially, varieties were screened on the basis of germination percentage. Two varieties, Balkasar and Thal 2006, performed best in the germination test and thus grown at two locations, i.e., University Research Farm (URF), Koont, Chakwal Road, Rawalpindi (medium), and Bijwal Farm, Fateh Jang (low), rainfall zones of Pothwar, for field evaluation of best-performing varieties of chickpea. During the course of study, different phenological and yield component parameters have been recorded. Collected data was analyzed statistically to see the performance of varieties under different climatic conditions of these two sites. DSSAT_CROPGRO_Chickpea model was used to simulate crop phenology and yield, i.e., above-ground mass and grain yield of chickpea under rainfed conditions. The model was calibrated and validated on the basis of experimental data. Values obtained from model runs were compared with observed values by using validation scores. Simulation outcomes from days to anthesis, days to maturity, and above-ground mass, i.e., biological yield and grain yield, showed that the location URF-Koont proved better for chickpea crop. Observed and simulated data were compared for model efficiency. At both locations, Thal 2006 performed best under water-limited conditions of Pothwar. Based upon these values, further yield was predicted for varying environmental scenarios in order to recommend best-performing varieties in this particular climate.

Optimizing nitrogen (N) application timings and rate can improve nutrient uptake and nutrient efficiencies in wheat, particularly under rainfed conditions. Climatic stress in the form of high temperature and drought resulted in the decreased crop physiological traits, hastened maturity and, ultimately, caused lower grain yield. The impact of N application rates as full and split dose at three diverse locations of rainfed Pothwar, Pakistan was studied through field experiments for two years (2013&ndash, 14 and 2014&ndash, 15). Treatments include T1 = control (no fertilizer applied), full dose of N applied at the time of crop sowing, i.e., T2 = 50 kg N ha&minus, 1, T3 = 100 kg N ha&minus, 1 and T4 = 150 kg N ha&minus, 1, and split application of N at different timings at different stages of the crop, called split application of N, i.e., T5: application of 50 kg N ha&minus, 1 (15 kg N ha&minus, 1 (sowing, BBCH (Biologische Bundesanstalt Bundessortenamt und Chemische Industrie) 0): 20 kg N ha&minus, 1 (tillering, BBCH20): 15 kg N ha&minus, 1 (anthesis, BBCH 60), T6: application of 100 kg N ha&minus, 1 (30 kg N ha&minus, 1 (sowing, BBCH 0): 40 kg N ha&minus, 1 (tillering, BBCH 20): 30 kg N ha&minus, 1 (anthesis, BBCH 60) and T7: application of 150 kg N ha&minus, 1 (45 kg N ha&minus, 1 (sowing, BBCH 0): 60 kg N ha&minus, 1 (tillering, BBCH 20): 45 kg N ha&minus, 1 (anthesis, BBCH 60). The three study sites were Islamabad (high rainfall with optimum temperature), University Research Farm (URF)-Chakwal Road, Koont (medium rainfall with moderate temperature), and Talagang (low rainfall with high temperature). Results revealed that the highest stomatal conductance (0.80 mole H2O m&minus, 2 s&minus, 1), net photosynthetic rate (20.07 &mu, mole CO2 m&minus, 1), transpiration rate (9.58 mmole H2O m&minus, 1), intercellular CO2 concentration (329.25 &mu, mole CO2 mol&minus, 1 air), SPAD values (58.86%) and proline contents (35.42 &mu, g g&minus, 1) were obtained from split application of N (T6 = split N100) compared to control and full dose N treatments. Among the sites, these physiological traits remained highest at Islamabad and lowest at Talagang, while between the years, the maximum values of the measured parameters were obtained during 2013&ndash, 14. A similar trend was observed for crop total N, N efficiencies, and agronomic traits of the crop. The results suggested that the optimum N application rate at appropriate timings can help to harvest the real benefits of N. The split dose resulted in the maximum performance of the crop from the physiological parameters to the agronomic traits of the crop.

Optimizing the nitrogen (N) timings and rate can improve nutrient uptake, and nutrient-efficiencies, especially of N in wheat under the changing climate scenario. Climatic stress in the form of high temperature and drought resulted in the decreased crop physiology and, ultimately, grain yield. Taking the example of rainfed wheat, we quantified the impact of N application rates as full and split-dose at three variable sites of rainfed Pothwar, Pakistan by conducting field experiments for two years (2013-14 and 201-15). Treatments include, T1 = Control (No fertilizer applied), full dose of N applied at the time of crop sowing, i.e. T2 = 50 kg N ha-1, T3 = 100 kg N ha-1 and T4 = 150 kg N ha-1 and split application of N at different timings during different stages of the crop called as split application of N, i.e. T5: Application of 50 kg N ha-1 (15 kg N ha-1 (Sowing) : 20 kg N ha-1 (Tillering) :15 kg N ha-1 (Anthesis), T6: Application of 100 kg N ha-1 (30 kg N ha-1 (Sowing): 40 kg N ha-1 (Tillering) : 30 kg N ha-1 (Anthesis) and T7: Application of 150 kg N ha-1(45 kg N ha-1 (Sowing) : 60 kg N ha-1 (Tillering) : 45 kg N ha-1 (Anthesis). Three study sites include viz. Islamabad (High rainfall with optimum temperature), University Research Farm (URF)-Koont (Medium rainfall with moderate temperature), and Talagang (low rainfall with high temperature). Results showed that the highest stomatal conductance (0.80 mole m-2 sec-1), net photosynthetic rate (20.07 μmole m-2s-1), transpiration rate (9.58 mmole m-2s-1), intercellular CO2 concentration (329.25 μmole CO2 mol-1 air), SPAD values (58.86 %) and proline contents (35.42 μg g-1) were obtained for split application of N (T6 = Split N100) compared to control and full dose of N treatments. Among sites, these physiological traits remained highest at Islamabad and lowest at Talagang, while among years, maximum values of the measured parameters were obtained in 2013-14. A similar trend was observed for crop total N, N efficiencies, and agronomic traits of the crop. Our results suggest that optimum N application rate and its suitable timings can help to harvest real benefits of N as in our findings, split dose resulted in the maximum performance of the crop from physiological parameters to the agronomic traits of the rainfed wheat crop.

Sorghum is an important forage crop having good drought tolerance and high dry matter accumulation in a short growing season, and grown under diversified environments. Based on this, a 2-year field study was executed to evaluate the effect of seed rate and nitrogen (N) levels on the fiber quality of forage sorghum cultivars harvested at different growth stages under semiarid condition. Three forage sorghum cultivars (‘JS–2002’, ‘JS–263’ and ‘Chakwal Sorghum’) were sown with three N levels (0, 60 and 120 kg ha−1) by using three seed rates (75, 100 and 125 kg ha−1). Results showed that cv. ‘JS–2002’ had higher contents of neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL) and cellulose, while ‘JS–263’ produced greater soluble carbohydrate, total digestible nutrients (TDN), relative feed value (RFV) and net energy (NE) than other cultivars. Increasing N rates (0–120 kg ha−1) enhanced ADF, ADL, RFV and NE, but not NDF and TDN. Similarly, increased seed rate enhanced accumulation of NDF, ADF and ADL, while caused reduction of TDN, RFV and NE. In conclusion, cv. ‘JS–2002’ performed better than the other two cultivars, whereas, sorghum seeded at 75 kg ha−1 with 120 kg N ha−1 application produced better quality forage at 50% heading stage.

Field experiments were carried out during two consecutive years at the National Agricultural Research Centre, Islamabad, with the hypothesis that seed rate and nitrogen (N) application improves plant morphology, yield production and brix value of forage sorghum cultivars. Twenty-seven treatment combinations comprising three sorghum cultivars, namely, ‘JS–2002,’ ‘Chakwal sorghum’ and ‘JS–263’ were sown with three seed rates (75, 100 and 125 kg ha−1) and three N levels (0, 60 and 120 kg ha−1). Experiments were laid out in randomized complete block design with split–split plot arrangement in triplicate. Seed rate changed the plant morphology, yield traits and brix value variably. Increasing N application (0–120 kg ha−1) had a positive impact on growth and yield traits except brix value. Results revealed that ‘JS–2002’ surpassed the other two cultivars for plant height, number of leaves, leaf area per plant, leaf to stem ratio, green forage yield and dry biomass yield, dry matter content and brix value at given developmental stages at seed rate of 125 kg ha−1 with applied N level of 120 kg ha−1, during both the years. The highest N application (120 kg ha−1) in ‘JS–2002’ gave an increase of 45% forage yield as compared to control.

Phenology, the first step of calibration of models.Robustness of APSIM-Wheat and CERES-Wheat in simulating spring wheat phenology, LAI, biomass and yield.Calibration is necessary to minimize uncertainty.Models as decision support tools in agriculture under climate variability. Crop growth in process based crop models is controlled by different parameters. Model calibration is necessary for application to new cultivars and environment. We applied a manual method to calibrate APSIM-Wheat and CERES-Wheat for the flowering day, maturity day, leaf area index, biomass and grain yield of five spring wheat cultivars under rainfed conditions in Pakistan. Five wheat cultivars of diverse origin namely Tatara, NARC-2009, Sehar-2006, SKD-1 and F-Sarhad were planted on 19th November, at Islamabad during the years 2007-2011. The experiments were laid out in Randomized Complete Block Design (RCBD) replicated four times with individual plot size of 5m?3m. APSIM-Wheat and CERES-Wheat were calibrated for all five wheat cultivars using genetic coefficients estimated based upon measured data during 2008-09 cropping year and validated with independent data sets (experimental data of 2009-10 and 2010-11 cropping seasons) which were not used for models calibration. Both models were able to accurately simulate anthesis and maturity days, maximum leaf area index, biomass and grain yield, with normalized root mean square error (RMSE) less than 10%, D-index greater than 0.80 and model efficiency above 80% in most cases. The temporal changes in maximum LAI accumulation for all cultivars indicate that both measured and simulated values match each other. Evaluation with the measured data showed that performance of both models was realistic as indicated by the accurate simulation of crop phenology, LAI, biomass and grain yield against measured data. Climate variability results depicted that an increase in temperature from 0?C to 5?C resulted in a 60% average decline in the yield of wheat cultivars while increased CO2 increased yield similar to the combined effect of increased temperature and CO2. We concluded that to bring accuracy in the simulation outcomes of models, new cultivars should be calibrated to minimize uncertainty to allow judicious recommendations in response to climate variability.

Drought is a major constraint in drylands for crop production. Plant associated microbes can help plants in acquisition of soil nutrients to enhance productivity in stressful conditions. The current study was designed to illuminate the effectiveness of desert rhizobacterial strains on growth and net-return of chickpeas grown in pots by using sandy loam soil of Thal Pakistan desert. A total of 125 rhizobacterial strains were isolated, out of which 72 strains were inoculated with chickpeas in the growth chamber for 75 days to screen most efficient isolates. Amongst all, six bacterial strains (two rhizobia and four plant growth promoting rhizobacterial strains) significantly enhanced nodulation and shoot-root length as compared to other treatments. These promising strains were morphologically and biochemically characterized and identified through 16sRNA sequencing. Then, eight consortia of the identified isolates were formulated to evaluate the growth and development of chickpea at three moisture levels (55%, 75% and 95% of field capacity) in a glass house experiment. The trend for best performing consortia in terms of growth and development of chickpea remained T2 at moisture level 1 &gt, T7 at moisture level 2 &gt, T4 at moisture level 3. The present study indicates the vital role of co-inoculated bacterial strains in growth enhancement of chickpea under low moisture availability. It is concluded from the results that the consortium T2 (Mesorhizobium ciceri RZ-11 + Bacillus subtilis RP-01 + Bacillus mojavensis RS-14) can perform best in drought conditions (55% field capacity) and T4 (Mesorhizobium ciceri RZ-11 + Enterobacter Cloacae RP-08 + Providencia vermicola RS-15) can be adopted in irrigated areas (95% field capacity) for maximum productivity of chickpea.

Rainwater harvesting in small dams has good potential to provide supplementary agricultural irrigation during critical crop growth stages. Field experiments were conducted to evaluate cropping patterns: fallow–wheat (FW), mash–wheat (MaW), sorghum–wheat (SW), maize (grain)–wheat (MW), maize (grain)–gram (MG) and mung–canola (MuC); under two conditions: irrigated (Command area of Pira Fatehial small dam) and rainfed (Un-command area) on sandy loam soil during three years (2009 to 2011). Treatments were arranged in a randomized complete block design, three factor factorial (cropping patterns, irrigated/non-irrigated conditions and years) using four replications. The highest grain yield of wheat (5.6 Mg ha−1) was obtained from the MaW cropping pattern as compared to those from MW, FW and SW cropping patterns. Summer crops (sorghum fodder, maize grain and mash) performed excellent under irrigated conditions. Water use efficiency of wheat (14.3 kg ha−1mm−1) following mash under both the conditions exhibited higher values than when compared with those from SW, FW and MW cropping patterns. However, nutrient use efficiency in SW cropping pattern surpassed the others. Performance of all crops remained better under the irrigated condition during both all seasons and years, as rainfall deficiency was compensated by supplementary irrigations. Hence, this study concluded that farmers having water resources for supplemental irrigation should adopt the MW cropping pattern, based on grain yield, efficient utilization of available supplemental water and better utilization of nutrients. Similarly, based on improved nutrient utilization and monitory outputs, the MaW sequence should be followed in rain-fed areas for better resource management. Copyright © 2015 John Wiley & Sons, Ltd.

Silicon has the potential to improve drought tolerance in crops. Seeds primed with silicon were used in the present study to explore its potential benefit to withstand water stress. Seeds of two wheat varieties, NARC-2009 and Chakwal-50, were sown in pots after priming with distilled water and different concentrations (0.5%, 1.0% and 1.5%) of silicon sources (silicic acid, sodium silicate and silica gel) at PMAS, Arid Agriculture University, Rawalpindi. Maximum silicon uptake at three-leaf stage (0.028 µg g−1 dry weight (DW)), anthesis (0.072 µg g−1 DW) and maturity (0.103 µg g−1 DW) was recorded for silica gel. Silicon uptake increased significantly in response to increase in Si concentration from 0.5% to 1.5%. Leaf membrane stability index, epicuticular wax, relative water content and proline remained maximum – 78.90%, 2.6 mg g−1 DW, 83.88% and 54.90 µg g−1 – for silica gel treatments compared with others. Silica gel with 1.5% silicon concentration resulted in maximum spike length (14.3 cm), biological ...

In Pothwar area of Punjab Pakistan (33 o N to 74 o E), intensive soil tillage, soil erosion and low crop residue input are the reasons which have lead to the deterioration of soil structure. Structurally unstable soils are more susceptible to erosion which, in turn, leads to poor crop productivity. Therefore, a field study was conducted in dry land region of Punjab, Pakistan to improve soil physical health at campus of University R esearch Farm (PMAS Arid Agriculture University, Rawalpindi). Two different grades (Laboratory and commercial grade) of humic acid along with eight levels were applied for two years. The treatments were HL 0 (control), HL 1 10 kg H.A ha - 1 , HL 2

Wheat (Triticum aestivum) production in the rainfed area of Pothwar Pakistan is extremely vulnerable to high temperature. The expected increase in temperature due to global warming should result in shorter crop life cycles, and thus lower biomass and grain yield. Two major factors control wheat phenological development: temperature and photoperiod. To evaluate wheat development in response to these factors, we conducted experiments that created diverse temperature and daylength conditions by adjusting the crop sowing time. The study was conducted during 2013-14 and 2014-15 using five spring wheat genotypes, four sowing times, at three sites under rainfed management in Pothwar, Pakistan. Wheat crops experienced more cold days with early sowing, but later sowing dates resulted in higher temperatures, especially from anthesis to maturity. These treatments produced large differences in phenology, biomass production, and yield. To investigate whether growing degree days (GDD) and photoperiod algorithms could predict wheat phenology under these changing conditions, GDD was calculated based on the method proposed by Wang and Engel while photoperiod followed the approach introduced in the APSIM crop growth model. GDD was calculated separately and in combination with photoperiod from germination to anthesis. For the grain filling period, only GDD was calculated. The observed and predicted number of days to anthesis and maturity were in good agreement, showing that the combination of GDD and photoperiod algorithms provided good estimations of spring wheat phenology under variable temperature and daylength conditions.

In the present work, the potential of novel cultivar of safflower seed crop with highest 52% oil contents is evaluated for the first time as a feedstock for biodiesel synthesis. The specific aim of this study was to optimize the transesterification process for maximum biodiesel yield using different parameters and to evaluate its fuel compatibility with mineral diesel. Fatty acid methyl esters (FAMEs) of safflower oil were produced by standard transesterification process using potassium hydroxide (KOH) as catalyst. Optimum biodiesel yield of 98% achieved at 65°C, 5:1 methanol: oil molar ratio, 0.32 g catalyst concentration, and reaction time of 80 min. The kinematic viscosity@ 40°C (cSt), flash point, sulfur contents (wt%), pour point and cloud point of pure safflower oil biodiesel (SOB) were found to be 5.32 mm2/s, 80°C, 0.00041%, –9°C and –11°C, respectively. These together with other fuel parameters were in accordance with ASTM standards. The results obtained indicate that SOB appears to be the potenti...

Long-term impact of buctril super (bromoxynil) herbicide in the wheat fields on soil microbial population, nitrate-N, Olsen-P, total organic carbon (TOC) and enzyme activities was evaluated in 18 sites in Pakistan. Nine sites were randomly selected from those places where bromoxynil herbicide had been used for the last 10 years designated as soil ‘X’ and other nine where no herbicide was used in that period designated as soil ‘Y’. Very importantly, it was found that long-term application of this herbicide in wheat fields reduced the actinomycetes and fungi population up to 19.7 and 14.3%, respectively, urease and dehydrogenase activity by 17.5 and 28.2%, respectively, and reduced nitrate-N, Olsen-P and TOC up to 55, 17 and 28.57%, respectively. Presence of high clay and organic matter contents enhanced the detrimental effect of herbicide by prolonging its persistence as compared to light-textured soils with low organic matter. As in Pakistan this herbicide is being used most frequently in wheat fields, da...

Reduced early crop growth and limited branching are amongst yield limiting factors of linola. Field response of seed priming treatments viz. 50 mmol L−1 salicylic acid (SA), 2.2% CaCl2 and 3.3% moringa leaf extract (MLE) including untreated dry and hydropriming controls was evaluated on early crop growth and yield performance of linola. Osmopriming with CaCl2 reduced emergence time and produced the highest seedling fresh and dry weights including Chl. a contents. Osmopriming with CaCl2 reduced crop branching and flowering and maturity times and had the maximum plant height, number of branches, tillers, pods and seeds per pod followed by MLE. Increase in seed weight, biological and seed yields was 9.30, 34.16 and 39.49%, harvest index (4.12%) and oil contents (13.39%) for CaCl2 osmopriming. Positive relationship between emergence and seedling vigor traits, 100-seed weight, seed yield with maturity time, 100-seed weight and seed yield were found. The study concludes that seed osmopriming with CaCl2 or MLE can play significant role to improve early crop growth and seed yields of linola.

The present study aimed to evaluate the effect of bromoxynil herbicide on soil microorganisms, with the hypothesis that this herbicide caused suppression in microbial activity and biomass by exerting toxic effect on them. Nine sites of Punjab province (Pakistan) those had been exposed to bromoxynil herbicide for about last ten years designated as soil 'A' were surveyed in 2011 and samples were collected and analyzed for Microbial Biomass Carbon (MBC), Biomass Nitrogen (MBN), Biomass Phosphorus (MBP) and bacterial population. Simultaneously, soil samples from the same areas those were not exposed to herbicide designated as soil 'B' were taken. At all the sites MBC, MBN and MBP ranged from 131 to 457, 1.22 to 13.1 and 0.59 to 3.70 µg g-1 in the contaminated soils (Soil A), which was 187 to 573, 1.70 to 14.4 and 0.72 to 4.12 µg g-1 in the soils without contamination (soil B). Bacterial population ranged from 0.67 to 1.84x10(8) and 0.87 to 2.37x10(8) cfu g-1 soil in the soils A and B, respectively. Bromoxynil residues ranged from 0.09 to 0.24 mg kg-1 at all the sites in soil A. But no residues were detected in the soil B. Due to lethal effect of bromoxynil residues on the above parameters, considerable decline in these parameters was observed in the contaminated soils. Results depicted that the herbicide had left toxic effects on soil microbial parameters, thus confirmed that continuous use of this herbicide affected the quality of soil and sustainable crop production.

Silicon (Si) distribution and accumulation in plant organs is widely reported as beneficial to overcome biotic and abiotic stresses. The investigation on distribution of Si in plant organs under water stress conditions was studied through experiments conducted at Arid Agriculture University, Pakistan during 2007–2009. Treatments (Si200: 200 ml l−1 of potassium silicate and Si0: control or absence of silicon) were replicated thrice with two sorghum cultivars; SPV462 (drought susceptible) and Johar-1 (drought tolerant) screened using osmotic media of PEG-6000 (−4.0, −6.0, −8.0 and −10.0 MPa). The results exhibited increased leaf water potential, leaf area index, SPAD chlorophyll with increased silicon concentration in leaves and roots of drought-tolerant genotype as compared to SPV462. Johar-1 exhibited maximum values for net assimilation and relative growth rate under silicon treatment in comparison to silicon absence. Similarly, maintenance of transpiration rate, because of accumulation of silicon in leaves resulted in optimum leaf water potential and optimum growth of crop.

The present investigation on Brassica juncea L. genotypes is an attempt to study variations and to generate variability through hybridization and also to obtain genetic information on some yield attributes for selection in segregating generations. Eight promising genotypes were selected and crossed in all possible combinations under complete diallel system. Data was recorded for seed yield and some important yield attributes. Analysis of variance showed significant differences for all the traits and therefore further analyzed using Hayman’s approach, which showed existence of both additive and dominance gene effects governing all the traits. However, estimates for genetic components of variation revealed that additive effects were more important for seeds per siliqua and 1000-seed weight indicating possibility of selection for these traits in early segregating generations. Dominance effects were more prominent with presence of over-dominance for plant height, number of primary branches per plant, number of siliqua per plant, siliqua length and seed yield per plot, thus suggesting that selection could be effective in latter generations. Only siliqua length showed the presence of directional dominance, while asymmetrical distribution of dominant genes among the parents was identified for all the traits. Key words: Indian mustard, genetic analysis, gene action, yield attributes, complete diallel.

Nitrogen is the most limiting element in the production of cereal crops after water hence leads plant nutrition. Since, nitrogen uptake and supply directly depends upon soil physical conditions, climate and plant genetic features, so N requirement could be varied by place to place. Crop simulation models can be complementary tools in field experiments to develop innovative crop management systems under continuous varying nitrogen regime. Data regarding total nitrogen, nitrogen uptake efficiency, nitrogen utilization efficiency and nitrogen utilization efficiency, drymatter accumulation at three phenological stages (Three leaf, Anthesis and Maturity), and yield parameters (Number of tillers, Biological yield, Thousand grain weight, Grain yield and Harvest index) were recorded. The present study revealed that different nitrogen rates and application methods have significant impact upon crop growth and development. Wheat crop responded well to nitrogen fertilizer. Maximum grain yield obtained for N100 when nitrogen was applied as split dose. Similarly, genotypes responded significantly to nitrogen fertilizers for grain production. Genotype NARC-2009 performed well under different nitrogen regime of rainfed zone of pothwar. APSIM model was parameterized using different agronomic parameters (days after sowing, biomass total nitrogen, root total nitrogen, grain yield and grain total nitrogen). The modeled nitrogen was satisfactory compared to observed nitrogen. The analysis of the modeling results depicted the strong dependency of the mineral nitrogen content upon plant nitrogen uptake and growth. By concluding APSIM model performed well under rainfed conditions of pothwar for modeling nitrogen use efficiency. Modeling approaches should be adopted by farmers and policy makers to get maximum crop production and eliminate extra nitrogen losses.

Phosphorus the macronutrient, a component of nucleic acid and helpful for grain developmental phases (reproductive growth) of crops. It is also component of energy carriers like ATP, ADP, NADPH and FADPH which provide energy for different physiological processes. Phosphorous plays an important role in the growth, development and yield of crops. However, P causes some environmental problems like eutrophication. The importance of the element necessitate its study through modeling and distribution under changing climate. Since P is present as organic and inorganic form but their fate is different in soils. The inorganic P accounts for 35–70 % while organic form of P accounts for 30–65 % of the total P but it is dominantly available as stabilized forms like diesters. The availability of this P depends upon mineralization processes by soil biota which has dependency upon soil moisture, temperature, physiochemical properties and soil pH. However, the transformation of organic p has strong influence on the availability of P in soil. Therefore, availability of P to crop is extremely complex and its needs to be evaluated using modeling approaches. The Phosphorus Use Efficiency (PUE) for crops might be increased by understanding P-dynamics which may be done by models. The understanding of P dynamics will help to optimized balance use of P. By monitoring P for longer period of time might increase P status of soil. The use of computer models will help to modify fertilizer application which can reduce use of P but will increase PUE. The effects of high temperature, elevated CO2 and drought on the availability of phosphorous, PUE and its dynamics could be modeled using dynamics models like APSIM, AEP or by using regression modeling approaches.

Rice feeds half of humanity. Global climate change has given rise to food security issues. Changes in temperature and rainfall may affect the yield of rice as its water requirement is higher than other crops. Though rice is adaptable to a variety of environments, seasonal rainfall variability, and even at times complete absence of rainfall, are major issues in rice growing areas. This chapter discusses problems in the rice growing areas and possible solutions. The need of the hour is to find new strategies and ways to exploit the genetic yield potential of rice. Water use efficiency improvement is vital for the crop so that it may be grown under water-limiting conditions. The crop may be improved by selection and breeding techniques as well as molecular and biotechnological techniques. Crop management for enhanced water use efficiency has great significance. Production systems such as the system of rice intensification (SRI), alternate wetting and drying irrigation (AWD), aerobic rice system (ARS), raised beds and ground cover rice production system (GCRPS) to enhance water use efficiency are beneficial. Incorporation of the C4 photosynthetic pathway into rice is another approach to increase rice yield for food security problems in future. The conversion of rice from C3 to C4 will enhance the yield of the crop. All these techniques can help tackle the problems of water scarcity and food security.

Field experiments were conducted at two different locations (Barani Agriculture Research Institute Chakwal and farmer's field in Talagang) in northern rainfed Punjab, Pakistan, to assess relative efficiency of two sources of sulfur (S) in enhancing nitrogen (N) fixation and yield of chickpea (Cicer arietinum L.). The treatments were four combinations of two levels of S (15 and 30 kg ha−1) from two sources [gypsum and ammonium sulfate (AS)] and a no-S control. Application of S significantly increased seed yield up to 12% and 14% at Chakwal and Talagang, respectively. Response (kg seed yield kg−1 S) at economic optimum dose (EOD) was greater for AS than for gypsum. Sulfur application enhanced the S uptake at both locations significantly. Sulfur harvest index and S economic yield efficiency ratio were greater at Talagang than at Chakwal. Sulfur application resulted increases in N uptake by 19% and 20% and N fixation by up to 19% and 30% at Chakwal and Talagang, respectively. Ammonium sulfate was more effecti...

SUMMARY Wide adaptability of sunflower and wide range of climatic conditions existing in Pakistan make it possible to have two crops of sunflower in a year, i.e., in spring and fall. Field experiments, one in spring and another in fall were conducted at the University of Arid Agriculture, Rawalpindi, Pakistan, to evaluate the influence of seasonal variations on yield and yield components of sunflower. Five sunflower hybrids were planted in a randomized complete block design in three replications. Two inner rows were harvested for measurements of yield and yield components. It was observed that head size of spring crop was larger than fall crop. Contrary to head size, 1000-seed weight of the fall crop was larger than that of the spring crop. However, final yield of the spring crop was greater than that of the fall crop. It led to the conclusion that having spring crop is the best option, while fall crop could be supplementary one, to increase the production of oilseeds.

Field experiments have been conducted to quantify the growth and development of sunflower in response to seasonal variation over two seasons, i.e., Spring and Fall. Five sunflower hybrids were sown in a randomized complete block design. Growth and development parameters like stem girth, plant height and dry matter accumulation m⁻² were recorded at the time of maturity. The hybrid Suncross-42 produced the maximum stem girth in Spring which was significantly different from that of XF-263 which was the lowest in both seasons. Plant height followed a pattern similar to stem girth. The hybrid Suncross- 42 produced the tallest plants in both seasons. Stem girth and plant height are considered major contributors to total dry matter production. Dry matter accumulation m⁻² followed a pattern similar to those of stem girth and plant height. The hybrid Suncross-42 produced the maximum dry matter in both seasons. Similarly, it produced maximum seed yields in both seasons. Overall superiority of the Spring crop over the Fall crop, in terms of stem girth, plant height, dry matter and seed yield production, may be related to the duration of crop in the field and environmental factors prevailing during the crop life cycle.

The unpredictability and large fluctuation of the climatic conditions in rainfed regions do affect spring wheat yield and grain quality. These variations offer the opportunity for the production of better quality wheat. The effect of variable years, locations and sowing managements on wheat grain yield and quality was studied through field experiments using three genotypes, three locations for two years under rainfed conditions. The two studied years as contrasting years at three locations and sowing dates depicted variability in temperature and water stress during grain filling which resulted considerable change in grain yield and quality. Delayed sowing, years (2009–10) and location (Talagang) with high temperature and water stress resulted increased proline, and grain quality traits i.e. grain protein (GP) and grain ash (GA) than optimum conditions (during 2008–09, at Islamabad and early sowing). However, opposite trend was observed for dry gluten (DG), sodium dodecyl sulphate (SDS), SPAD content and grain yield irrespective of genotypes. The influence of variable climatic conditions was dominant in determining the quality traits and inverse relationship was observed among some quality traits and grain yield. It may be concluded that by selecting suitable locations and different sowing managements for subjecting the crop to desirable environmental conditions (temperature and water) quality traits of wheat crop could be modified.

The effect of variability in temperature, solar radiation and photothermal quotient were studied under varying planting windows in three wheat genotypes to cope environmental vulnerability. Regression models are regarded as valuable tools for the evaluation of temperature, solar radiation and photothermal quotient effects on wheat yield to bring its resilience to climatic vulnerability. The objective of this study was to evaluate sole and cumulative impact of temperature and solar radiation on spring wheat ( Triticum aestivum L.) yield using regression modeling approach. The data collected at maturity for grain number, grain weight and grain yield were regressed against mean temperature, solar radiation and photothermal quotient (PTQ) (temperature plus solar radiation) from emergence to anthesis and maturity, using STATISTICA9 software. Scatter-plot regression model was developed at 95% confidence interval with crop data and climate variables. Results indicate direct relationship of yield with solar radiation, cumulative effect of temperature and solar radiation, whereas yield had an inverse relationship with temperature alone. Direct relationship between PTQ and yield parameters confirmed PTQ as crop-yield determinant, thus, its management needs to be done by choosing a more appropriate sowing time and best suited genotypes as an adapted management strategy for farmers under increased climatic vulnerability. Key words: Photothermal quotient, planting windows, solar radiation, temperature, wheat.

A 72-day greenhouse pot experiment was conducted with a sandy loam or a silt loam soil to examine the effects of farmyard manure (FYM), poultry litter (PL) and biogenic waste compost (BWC) at 10 g dw kg-1 soil on microbial biomass and activity and growth and nutrient uptake by wheat. Soil samples were collected at days 0, 14, 28, 42, 56 and 72 after planting. Growth and nutrient uptake by wheat were determined on day 72. All three amendments increased microbial biomass C, N and P, dehydrogenase activity, plant growth and nutrient uptake with a greater effect by FYM and PL than by BWC. All amendments increased microbial biomass C, N and P and enzyme activity particularly on day 0. These microbial parameters decreased after day 0 indicating microbial biomass turnover. All amendments increased plant growth and nutrient uptake. It is concluded that organicamendments can stimulate microbial growth and nutrient uptake as well as plant growth and nutrient uptake. Microbes can increase plant nutrient availability by nutrient mobilisation but also because nutrients taken up by the microbial biomass initially could become available to plants when the microbial biomass turns over as the easily available C is depleted.

Water stress and high temperature variability are the major constraints for wheat crop productivity and food security in the context of climate change. Impact of high temperature and water stress at anthesis stage of spring wheat was studied through field experiments conducted during 2008 to 2009 and 2009 to 2010. Five wheat varieties of diverse origin namely Tatara, National Agricultural Research Centre (NARC)-2009, Sehar-2006, SKD-1 and F-Sarhad were sown in randomized complete block design (RCBD) replicated four times. Physiological parameters that is, net photosynthesis (An), transpiration rate (E), SPAD chlorophyll contents and prolines were recorded at anthesis stage. The results indicated reduction of An and increased E due to high temperature and moisture stresses. Among genotypes, maximum photosynthetic rate was recorded for Tatara (30.52 μ mole/m2/s) followed by NARC-2009. The E recorded maximum in Sehar-2006 (2.80 mole/m2/s) which had low photosynthetic activity whereas minimum E observed in Tatara (2.27 μ mole/m2/s) followed by NARC-2009. Maximum SPAD value observed in Tatara (53.17) followed by NARC-2009 (49.00) where as Sehar-2006 (37.17) depicted less chlorophyll contents and ultimately reduced photosynthesis and productivity. The highest proline contents were recorded in Tatara (59.69 µg g-1) followed by NARC-2009 (55.05 µg g-1) as compared to SKD-1 (46.27 µg g-1) and F-Sarhad (50.58) which might be due to genetic potential and physiological adaptability of Tatara cultivars against stress conditions. Water stress and high temperature at anthesis led to reduction in photosynthesis resulting reduced biomass and limited yield. Therefore, genotypes having better physiological performance under biotic stresses need to be considered for cultivation under changing environment. Since Tatara performed best in our study, it is recommended for cultivation under high temperature and moisture stresses. The values of all physiological attributes (An and E) were higher during first year (2008 to 2009) as compared to second year (2009 to 2010) which was due to relatively high temperature and low moisture availability during the second year. Key words: Temperature, water stress, photosynthesis, transpiration, proline, SPAD chlorophyll, anthesis, wheat.

The impact of temperature and solar radiations were studied as determinant factor for spring wheat grain yield. The data obtained at anthesis and maturity for grain number (GN), grain weight (GW) and grain yield (Y) were examined with mean temperature at anthesis (T1) and maturity (T2), solar radiation at anthesis (SR1) and maturity (SR2) and photothermal quotient (PTQ) at anthesis (PTQ1) and maturity (PTQ2). The data obtained was subjected to Statistica 8 software and scatter plot regression model was developed at 95% confidence interval with crop data and climate variables (T1, T2, SR1, SR2, PTQ1 and PTQ2). Results clearly indicated that yield remained directly proportional to solar radiation and temperature plus solar radiation (PTQ) while inversely to temperature under optimum other environmental resources. Direct relationship between PTQ and yield parameters confirmed that it determined crop yield and its management for variable environmental conditions need to be opted by adopting suitable sowing time as an adaptation strategy under changing climate.