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Suitable cotton variety selection is imperative to cope with temporal variations for yield enhancement and sustainability under unpredictable climatic conditions. Cotton varieties including transgenic (Bacillus thuringiensis) and non-transgenic (non Bt.) were sown from 10-March to 21-June with 20 days interval for two growing seasons (2012 and 2013) consecutively while cotton sowing after wheat harvest is normal practice at farmers' field in Cotton-Wheat cropping system of Punjab-Pakistan. Phenology, growth indices, seed cotton yield (SCY) and its heat use efficiency of varieties were estimated on daily basis by using statistical models. Seed cotton yield (SCY) was significantly correlated with crop duration exhibiting delays in planting (21-June) impact on shortening of phenophases i.e. first square, flower, boll initiation and boll opening by 8, 7, 4 and 6 days, respectively compared with 10-May planting in first season while second season advanced 0-3 days owing to deviation in frequency of cold shock <11 °C and heat stress >35 °C. Long crop cycle varieties AA-802 and IR-3701 took 6-9 days more compared to short season NIAB-112. More heat units accretion 46, 33, 20 and 13 % to switch into next phenophase (first square, flower, boll initiation and boll opening) was computed in 10-May planting than 10-March due to excessive heat stress (>40 °C) during early phenophases while reduced variations observed in later phases. Reproductive stage initiation and accumulated higher thermal time delayed in late mature varieties compared to short one with lower root mean square error (RMSE) and higher coefficient of determination (R²). Significant reduction in days after planting to attain maximum LAI, CGR, TDM and SCY-heat use efficiency (HUESCY) decreased with delay in planting with good statistical indices. Less impact of cold shock and heat stress on 21-April and 10-May plantings noted while 10-March and 21-June planting had higher incidence during early growth phases. Cotton varieties MNH-886 and NIAB-9811 (NIAB-Kiran) planted 30-March to 10-May exhibited higher resilience to variable weather conditions with fostered growth potential and yield. Variety NIAB-112 seemed heat tolerant and it can be recommend for early and especially for late plating while MNH-886 and NIAB-Kiran can be adopted at farmer's field in the region for maximizing cotton production under variable environment. [ABSTRACT FROM AUTHOR]

Rapid and reliable flood information is crucial for minimizing post-event catastrophes in the complex river basins of the world. The Chenab River basin is one of the complex river basins of the world, facing adverse hydrometeorological conditions with unpredictable hydrologic response. Resultantly, many vicinities along the river undergo destructive inundation, resulting in huge life and economic losses. In this study, Hydrologic Engineering Centre–Hydrologic Modeling System (HEC-HMS) and HEC–River Analysis System (HEC-RAS) models were used for flood forecasting and inundation modeling of the Chenab River basin. The HEC-HMS model was used for peak flow simulation of 2014 flood event using Global Precipitation Mission (GMP) Integrated Multisatellite Retrievals-Final (IMERG-F), Tropical Rainfall Measuring Mission_Real Time (TRMM_3B42RT), and Global Satellite Mapping of Precipitation_Near Real Time (GSMaP_NRT) precipitation products. The calibration and validation of the HEC-RAS model were carried out for flood events of 1992 and 2014, respectively. The comparison of observed and simulated flow at the outlet indicated that IMERG-F has good peak flow simulation results. The simulated inundation extent revealed an overall accuracy of more than 90% when compared with satellite imagery. The HEC-RAS model performed well at Manning's n of 0.06 for the river and the floodplain. From the results, it can be concluded that remote sensing integrated with HEC-HMS and HEC-RAS models could be one of the workable solutions for flood forecasting, inundation modeling, and early warning. The concept of integrated flood management (IFM) has also been translated into practical implementation for joint Indo-Pak management for flood mitigation in the transboundary Chenab River basin. [ABSTRACT FROM AUTHOR]

Changing climates and frequent spells of drought have increased the risk of crop failure, especially in arid and semi-arid regions, thus multiplying the vulnerability of food-insecure populations. The exogenous application of potassium (K) can potentially ameliorate the adverse effects of drought in maize by maintaining cell osmotic potential and turgidity, provided its optimum doses are applied. The present experiment comprised two maize cultivars, viz. Islamabad Gold (drought tolerant) and Azam (drought susceptible), grown under well-watered (80% water-holding capacity (WHC)), mild drought (60% WHC) and severe drought (40% WHC) conditions. Different doses of K, viz. 0%, 1% and 2%, were also tested to screen out the most superior concentration. Drought stress markedly reduced root and shoot lengths (25% and 16%, respectively) along with their dry weights (20% and 10%, respectively). Moreover, a substantial reduction in leaf relative water content (RWC) (24%), stomatal conductance, transpiration and photosynthesis rates, chlorophyll pigments a, b and total chlorophyll contents (31%) were recorded, compared with well-watered conditions. However, foliar application of K2SO4 at 2% concentration outperformed other doses by improving growth attributes, RWC (10%), total chlorophyll (9%) and proline (12%) under severe drought conditions. Our findings confirmed the effectiveness of foliage-applied K2SO4 in ameliorating drought effects in rainfed maize; however, more doses and sources of K could be tested for developing it as a potent source to cope with water stress. [ABSTRACT FROM AUTHOR]

Sunflower (Helianthus annuus L.) is the leading non-conventional oilseed crop in Pakistan. Nitrogen fertilizer can affect plant growth and productivity by changing canopy size which has an effect on the radiation use efficiency (RUE) of the crop. The response of sunflower hybrids in terms of phenology, fraction of intercepted radiation (F i ), and RUE to nitrogenous rates (0, 60, 120, 180, and 240 kg ha -1 ) was studied in three field experiments conducted in three various environments: Multan (arid), Faisalabad (semi-arid), and Gujranwala (sub-humid) during spring seasons 2008 and 2009. The treatments were laid out according to a randomized complete block design with split plot arrangements, keeping the sunflower hybrids in main plots and nitrogen rates in sub-plots, and replicated three times. The results showed Hysun-38 took a maximum number of days to anthesis (101) as compared to Pioneer-64A93 (100) and Hysun-33 (99). The mean values of F i were 0.850, 0.903, and 0.978, and the estimated values of RUE for total aboveground dry matter were 2.14, 2.47, and 2.65 g MJ -1 at experimental locations of Multan, Faisalabad, and Gujranwala, respectively. The values of RUE for grain yield (RUE GY ) were 0.78, 0.98, and 1.26 g MJ -1 at experimental locations of Multan, Faisalabad, and Gujranwala, respectively. The average RUE GY values over three locations were 2.61, 2.60, 2.43, and 2.36 g MJ -2 in N 4 (180 kg ha -1 ), N 5 (240 kg ha -1 ), N 3 (120 kg ha -1 ), and N 2 (60 kg ha -1 ) treatments, respectively. Increasing rates of N increased RUE GY over the standard treatment N 3 (120 kg N ha -1 ); however, the averaged values over three locations were 1.22, 1.08, 0.99, and 0.92 g MJ -2 in N 4 , N 5 , N 3 , and N 2 treatments, respectively. Therefore, optimum water and N doses are important for attaining higher RUE, which may enhance sunflower growth and yield.