Climate change impact uncertainty assessment and adaptations for sustainable maize production using multi-crop and climate models

Future climate scenarios are predicting considerable threats to sustainable maize production in arid and semi-arid regions. These adverse impacts can be minimized by adopting modern agricultural tools to assess and develop successful adaptation practices. A multi-model approach (climate and crop) was used to assess the impacts and uncertainties of climate change on maize crop. An extensive field study was conducted to explore the temporal thermal variations on maize hybrids grown at farmer's fields for ten sowing dates during two consecutive growing years. Data about phenology, morphology, biomass development, and yield were recorded by adopting standard procedures and protocols. The CSM-CERES, APSIM, and CSM-IXIM-Maize models were calibrated and evaluated. Five GCMs among 29 were selected based on classification into different groups and uncertainty to predict climatic changes in the future. The results predicted that there would be a rise in temperature (1.57-3.29 °C) during the maize growing season in five General Circulation Models (GCMs) by using RCP 8.5 scenarios for the mid-century (2040-2069) as compared with the baseline (1980-2015). The CERES-Maize and APSIM-Maize model showed lower root mean square error values (2.78 and 5.41), higher d-index (0.85 and 0.87) along reliable R² (0.89 and 0.89), respectively for days to anthesis and maturity, while the CSM-IXIM-Maize model performed well for growth parameters (leaf area index, total dry matter) and yield with reasonably good statistical indices. The CSM-IXIM-Maize model performed well for all hybrids during both years whereas climate models, NorESM1-M and IPSL-CM5A-MR, showed less uncertain results for climate change impacts. Maize models along GCMs predicted a reduction in yield (8-55%) than baseline. Maize crop may face a high yield decline that could be overcome by modifying the sowing dates and fertilizer (fertigation) and heat and drought-tolerant hybrids.

Conformance of sowing dates for maximizing heat use efficiency and seed cotton yield in arid to semi-arid cotton zone of Pakistan

Pakistan is placed among the most vulnerable countries with relation to climate change and its impacts on agricultural productivity. Cotton is staged as the cash crop of the country and the main source of raw material for textile, oil, and feed industry. Varying environmental attributes have significant effects on the duration of vegetative and reproductive stages of cotton crop. To evaluate the potential impacts of varied temperatures regimes in different sowing times, field experiments were carried out throughout the cotton growing areas of Pakistan from Faisalabad in Central Punjab to RYK in Southern Punjab and Sakrand in Sindh to Dera Ismail Khan in Khyber Pakhtunkhwa (KPK) Province. Crop was sown on six different sowing dates starting from 1st March towards 15th May with 2-week intervals for two crop seasons (2016 and 2017). The timing of phenological events like emergence, squaring, flowering, and boll opening was recorded on calendar days and cumulative heat units (GDDs) were calculated for flowering and boll opening stages. Heat use efficiency for these sowing times was estimated. Data regarding yield-related parameters like opened bolls per plant, average boll weight, and seed cotton yield were also recorded during the study. Results revealed that duration of the growth stages was significantly affected by variation in mean thermal kinetics in varied sowing times in all four different environments. Seed cotton yield and heat use efficiency were also varied among the locations and sowing dates. The maximum seed cotton yield was recorded in Sakrand location at 15th April sowing date. The dependence of the phenological advancement on temperature and negative impacts of higher thermal stress on cotton productivity were also confirmed throughout the cotton growing zone of Pakistan.

Assessing the climate change impacts and adaptation strategies for rice production in Punjab, Pakistan

Climate change is a serious threat to agriculture and food security. The development of adaptation measures is one of the key strategies to offset the climate change impacts on rice crop. A study was planned to develop adaptation strategies for future rice crop through simulation model. This study was consisted of six transplanting dates and three seedling densities which were tested to develop adaptations at three locations, i.e., Faisalabad, Hafizabad, and Gujranwala during the years 2015 and 2016. Climate change scenarios were developed for selected locations through statistical downscaling by selecting five general circulation models under representative concentration pathways (RCPs 8.5) for mid-century (2039-2069). The APSIM-ORYZA model was calibrated well with experimental data which showed an error of 2.35% between observed and simulated grain yield. The impact of climate change was studied by calculating the difference of baseline (1980-2010) and future yield. Model simulated results indicated that the rise in temperature will reduce the rice yield by 7.3%. To overcome this decrease in rice yield, suitable adaptation strategies were tested for mid-century. The developed adaptations, i.e., increased in plant population, nitrogen amount, and early transplanting, improved the rice yield by 8.7% under RCPs 8.5 for mid-century scenarios. Overall, this study provide better understanding of the adaptation processes for sustainable rice yield under anticipated future climate change.

Performance of four crop model for simulations of wheat phenology, leaf growth, biomass and yield across planting dates

Robustness of four wheat simulation model were tested with 2-year field experiments of three cultivars across a wide range of sowing dates in two different climatic regions: Faisalabad (semi-arid) and Layyah (arid), in Punjab-Pakistan. Wheat growing season temperature ranged from -0.1°C to 43°C. The wide series of sowing dates was a unique opportunity to grow the wheat in an environment which temperatures varies from -0.1°C to 43°C. The CERES-Wheat, Nwheat, CROPSIM-Wheat and APSIM-Wheat model were calibrated against the least-stressed treatment for each wheat cultivar. Overall, the four models described performance of early, optimum and late sown wheat well, but poorly described yields of very late planting dates with associated high temperatures during grain filling. The poor accuracy of simulations of yield for extreme planting dates point to the need to improve the accuracy of model simulations at the high end of the growing temperature range, especially given the expected future increases in growing season temperature. Improvement in simulation of maximum leaf area index of wheat for all models is needed. APSIM-Wheat only poorly simulated days to maturity of very and extremely late sown wheat compared to other models. Overall, there is a need of improvement in function of models to response high temperature.

Optimizing irrigation and nitrogen for wheat through empirical modeling under semi-arid environment

Nitrogen fertilizer availability to plants is strongly linked with water availability. Excessive or insufficient use of nitrogen can cause reduction in grain yield of wheat and environmental issues. The per capita per annum water availability in Pakistan has reduced to less than 1000 m³ and is expected to reach 800 m³ during 2025. Irrigating crops with 3 or more than 3 in. of depth without measuring volume of water is not a feasible option anymore. Water productivity and economic return of grain yield can be improved by efficient management of water and nitrogen fertilizer. A study was conducted at post-graduate agricultural research station, University of Agriculture Faisalabad, during 2012-2013 and 2013-2014 to optimize volume of water per irrigation and nitrogen application. Split plot design with three replications was used to conduct experiment; four irrigation levels (I₃₀₀ = 300 mm, I₂₄₀ = 240 mm, I₁₈₀ = 180 mm, I₁₂₀ = 120 mm for whole growing season at critical growth stages) and four nitrogen levels (N₆₀ = 60 kg ha^-1, N₁₂₀ = 120 kg ha^-1, N₁₈₀ = 180 kg ha^-1, and N₂₄₀ = 240 kg ha^-1) were randomized as main and sub-plot factors, respectively. The recorded data on grain yield was used to develop empirical regression models. The results based on quadratic equations and economic analysis showed 164, 162, 158, and 107 kg ha^-1 nitrogen as economic optimum with I₃₀₀, I₂₄₀, I₁₈₀, and I₁₂₀ mm water, respectively, during 2012-2013. During 2013-2014, quadratic equations and economic analysis showed 165, 162, 161, and 117 kg ha^-1 nitrogen as economic optimum with I₃₀₀, I₂₄₀, I₁₈₀, and I₁₂₀ mm water, respectively. The optimum irrigation level was obtained by fitting economic optimum nitrogen as function of total water. Equations predicted 253 mm as optimum irrigation water for whole growing season during 2012-2013 and 256 mm water as optimum for 2013-2014. The results also revealed that reducing irrigation from I₃₀₀ to I₂₄₀ mm during 2012-2013 and 2013-2014 did not reduce crop yield significantly (P < 0.01). The excessive nitrogen application ranged from 31.2 to 55.4% at N₁₈₀ and N₂₄₀ kg ha^-1 for different levels of irrigation. It is concluded from study that irrigation and nitrogen relationship can be used for efficient management of irrigation and nitrogen and to reduce nitrogen losses. The empirical equations developed in this study can help farmers of semi-arid environment to calculate optimum level of irrigation and nitrogen for maximum economic return from wheat.

Recent Progress for the Utilization of Curcuma longa, Piper nigrum and Phoenix dactylifera Seeds against Type 2 Diabetes

Background

Diabetes mellitus is an important human disease afflicting many from various walks of life in different countries. Even though modern medicines contribute a variety of effective treatment options, they can have several unfavourable effects. The intention of this review is to organize and discuss various studies that have been previously conducted on the effectiveness of these herbal plants in diabetes.

Method

By using various electronic search databases, a comprehensive English literature search was conducted. Different search terms were used by combining all the search fields in titles, abstracts and keywords.

Results

Curcuma longa,a spice, is commonly known as turmeric and belongs to the family Zingiberaceae. Piper nigrumis also a spice, commonly called black pepper, and belongs to the family Piperaceae. Phoenix dactylifera, commonly known as date fruit, belongs to the family Arecaceae. From ancient times, they have been traditionally used for the treatment of various diseases. Among various activities, regulation of hyperglycaemia is considered one of their important effects. One of the aetiological factors implicated in the development of diabetes and its complications is the damage induced by free radicals. Antioxidant properties of antidiabetic compounds would be more beneficial. Extracts of these plants have shown hypoglycaemic and hypolipidaemic effects by the involvement of several mechanisms. In the future, further studies are needed to investigate the mechanisms involved in their hypoglycaemic potential and their active constituents as synthetic analogues.

Conclusions

This review focusses on some medicinal plants that have antidiabetic effect, thus contributing to the reduction of risk factors associated with diabetes, and related beneficial effects are compiled.

Estimation of atrazine in the stratum corneum and its toxic effects in skin following topical application to rabbits

ABSTRACT For risk assessment, a workable non-invasive method for the estimation of atrazine in skin was needed. Moreover, the dermato-toxic effects of different concentrations of atrazine have not been studied so far. Fifteen milligrams of 35% solution of atrazine in ethanol was topically applied to each of six different clipped sites on the back of rabbits (n = 6). Each site was tape-stripped with 10 consecutive adhesive tapes at 0.5, 1, 2, 3, 4, and 6 h of topical dosing to remove the stratum corneum (SC). Atrazine in tapes was extracted with methanol and analyzed with HPLC. The amount of atrazine detected in the SC at 6 h (1955.79 +/- 47.22 mug) is equivalent to 13.03% of the total applied dose. In dermal toxicity studies, 500 mul of 35%, 70% atrazine in ethanol and a commercial preparation of atrazine (Balance(R)) was dosed on clipped backs of rabbits (n = 4) for 4 days under occluded vs non-occluded conditions. Ethanol alone served as control. On the 5th day, rabbits were euthanized and skin was scored for erythema and then examined microscopically. Significant differences (p < 0.05) in erythema scores were observed with 70% atrazine and Balance(R) as compared to the control under occluded conditions. Significant differences in epidermal thickness and cell layers were observed with Balance(R) and 74% atrazine as compared to control in both dosing conditions. There were non-significant differences in erythema, epidermal thickness, or cell layers in occluded vs non-occluded applications of atrazine in ethanol, indicating that atrazine is equally toxic regardless of its application procedures. Moreover, under non-occluded application, very slight erythema was observed but microscopically significant epidermal hyperplasia was noticed. This indicates that even if there are no significant gross skin manifestations of atrazine this can still produce significant damage to the epidermal barrier and hence can result in increase in penetration of self or other toxic substances.

Antihyperglycemic and antidyslipidemic agent from Aegle marmelos

The plant Aegle marmelos belongs to the family of Rutaceae. From the leaves of A. marmelos an alkaloidal-amide, Aegeline 2, was isolated and found to have antihyperglycemic activity as evidenced by lowering the blood glucose levels by 12.9% and 16.9% at 5 and 24h, respectively, in sucrose challenged streptozotocin induced diabetic rats (STZ-S) model at the dose of 100mg/kg body weight. Aegeline 2 has also significantly decreased the plasma triglyceride (Tg) levels by 55% (P<0.001), total cholesterol (TC) by 24% (P<0.05), and free fatty acids (FFA) by 24%, accompanied with increase in HDL-C by 28% and HDL-C/TC ratio by 66% in dyslipidemic hamster model at the dose of 50mg/kg body weight. The reasonable mapping of compound 2 to validated pharmacophoric hypothesis and 3D QSAR model with an estimated activity (283nM) suggest that the compound 2 might be a beta(3)-AR agonist.

P53 mutations in carcinoma breast--a clinicopathological study

OBJECTIVES

To find out the incidence of p53 mutations and their possible correlation with clinicopathological presentation in females with breast carcinoma.

SETTINGS

Department of Surgery, Pakistan Institute of Medical Sciences, Islamabad.

PATIENTS AND METHODS

Seventy four patients with operable carcinoma breast that underwent mastectomy were included in this prospective study. Tumour tissue specimens and peripheral blood samples were examined for p53 mutations. Age, tumour size, nodal status and histopathology was assessed in patients with and without p53 mutations.

RESULTS

Ten (13.5%) patients showed p53 mutations in their tumour specimens while 64 (86.48%) had normally functioning p53 gene. Patients were divided into two groups, A (normally functioning p53), and B (mutated p53). Intraductal carcinoma was the most frequent histological variant(A = 57, B = 10), while lymph nodes were involved in 67.19% (A = 47) and 60% (B = 6) cases respectively. The age of patients and clinical parameters (tumour size, nodal status and histopathological diagnosis) were compared between the two groups and no statistically significant correlation between p53 mutations and clinicopathological parameters was found.

CONCLUSIONS

It was concluded that p53 mutation is present in carcinoma breast in Pakistani population but there was no significant correlation between p53 mutation and tumour aggressiveness (size, nodal status and histopathology).

P53 mutations, polymorphisms, and haplotypes in Pakistani ethnic groups and breast cancer patients

Inactivation of the p53 gene has been found to be associated with the pathogenesis of several neoplasias. Three biallelic polymorphisms in the p53 gene have been linked to predisposition to the development of various malignancies. These include a 16-bp duplication in intron 3 and BstU I and Msp I restriction fragment length polymorphisms (RFLPs) in exon 4 and intron 6, respectively. The prevalence of these polymorphisms was studied in breast cancer patients and nine major ethnic groups of Pakistan. Differences in allele frequencies for all three polymorphisms were observed among the various ethnic groups and breast cancer patients. The absence of the 16-bp duplication was common among the northern ethnic groups, being highest in the Hazara (0.90). The Msp I A1 allele frequency in the southern Makrani population was significantly higher in comparison with the other ethnic groups. In the cancer patients, the absence of the 16-bp duplication in combination with the BstU I Pro and absence of Msp I restriction site were the most frequent. In these patients, ten substitution mutations were found in the p53 gene, seven of which have been reported previously for breast cancer. The remaining three mutations have been found in other malignancies, but not in carcinoma of the breast.

Transverse ectopia of the testis: a case report

A case of transverse ectopia of the testis in a man of 30 years is presented. The patient was admitted for a right inguinal herniorrhaphy and the finding of ectopic testis was accidental.