Evaluation and management of acetyl-CoA carboxylase inhibitor resistant littleseed canarygrass (Phalaris minor) in Pakistan

A field survey was conducted for the sampling of Acetyl-CoA carboxylase (ACCase) inhibitor resistance littleseed canarygrass, a major weed of wheat, from Punjab, Pakistan in 2014 for confirmation of resistance. The surveyed regions encompassed four different cropping systems including rice–wheat, maize–wheat, cotton–wheat and mixed cropping. Dose–response assay was conducted for confirmation of resistance. Efficacy of herbicide mixtures including clodinafop–propargyl, metribuzin, pinoxaden and sulfosulfuron at a range of doses was investigated to manage littleseed canarygrass. Results revealed that all populations were resistant to fenoxaprop except PM-BWL-2. The higher level resistance (6.5) was found in populations collected from rice–wheat cropping system. The tested herbicide mixtures at 75% and 100% of the recommended dose of each mixture component provided the effective control of resistant littleseed canarygrass. Mixtures at 50% provided more than 80% control and reduced growth and seed production potential of surviving plants. The confirmation of ACCase inhibitor resistance as the first case of herbicide resistance in Pakistan, leads us to discourage use of ACCase inhibitor herbicides alone. However, herbicide mixtures at 75% and 100% of the recommended dose are suggested to manage this weed for sustainable wheat production in the surveyed cropping systems.     

Induced morphological mutants in soybean [<Emphasis Type="Italic">Glycine max</Emphasis> (L.) Merrill]

The seeds of two soybean cultivars viz., Pusa-16 and PK-1042 were treated with 15, 30, and 45 kR of gamma rays, three concentrations of ethyl methane sulphonate (EMS) (0.1%, 0.2%, and 0.3%), and their combinations. Various morphological mutants were recorded in M₂ and M₃ generations. These morphological mutants were named on the basis of the part of the plant body affected. Eight different morphological mutants, i.e., tall, dwarf, gigas, black pod, smooth pod, black spotted seed, bold seeded, and early maturing were isolated. Among them, early maturing and bold seeded mutants had the potential to be incorporated into breeding programs.     

Waste-Derived Siliceous Materials as a Novel Sorbent for Removal of Ni2+ from Aqueous Solutions

In the present study, the preparation of sorbent from waste-derived siliceous materials has been investigated for the removal of nickel ion (Ni²⁺) from aqueous solutions. Three types of ashes, i.e., rice husk ash (RHA), palm oil fuel ash (PFA), and coal fly ash (CFA), were used in the preparation of sorbent. Batch studies were carried out to examine the effect of various experimental parameters, i.e., RHA/CFA/PFA ratio in the sorbent preparation, contact time, initial concentration of Ni²⁺, agitation rate, and pH. Among all the ratios of the prepared sorbent, it was found that sorbent containing RHA and PFA gave the highest Ni²⁺ removal efficiency. The optimum conditions for Ni²⁺ removal using RHA/PFA sorbent were obtained at contact time of 30?min, Ni²⁺ concentration of 100?mg/L, agitation rate of 130?rpm, and pH?4. During the optimum condition, more than 90% of Ni²⁺ could be removed in all experiment studies. It was also found that the spent RHA/PFA sorbents had a narrow range of particle size distributions as compared to prepared RHA/PFA sorbent. In addition, the surface morphology of the spent RHA/PFA sorbents had more compact structures.     

Effect of pre-harvest foliar application of amino acids and seaweed (Ascophylum nodosum) extract on growth,yield, and storage life of different bell pepper (Capsicum annuum L.) cultivars grown under hydroponic conditions

The study was set up to evaluate the efficiency of amino acids and seaweed on vegetative growth, reproductive phase, yield, and postharvest storage quality of hydroponically grown bell pepper cultivars “Sven Rz F-1” and “Red Knight.” Different concentrations of amino acid and seaweed were sprayed on bell pepper plants under hydroponic conditions. Pre-harvest foliar application of amino acids and seaweed significantly increased plant height, number of leaves, leaf area, yield per plant, number of marketable fruits per plant, average fruit diameter, fruit wall thickness, and average single fruit weight. Amino acid and seaweed significantly improved postharvest physicochemical quality of both bell pepper cultivars under extended cold storage conditions. Conclusively, amino acid as well as seaweed extract not only improved growth, development, yield, and overall quality of bell pepper cultivars but also increased storage life with reduced weight loss and decay along with better physicochemical quality.     

Characterization of Drought Tolerance in Bread Wheat Genotypes Using Physiological Indices

Wheat (Triticum aestivum L.) is a staple food in many countries and is regarded as a vital source of nutrition. Drought is one the most prevalent limitations to wheat growth and development. Herein a two year study was conducted using 25 diverse wheat genotypes obtained from the gene pool of various research institutes of Pakistan to characterize their drought tolerance using various physiological indices like relative water content (RWC), relative dry weight (RDW), water saturation deficit (WSD), relative water loss (RWL), flag leaf area (LA), chlorophyll content index (CC) and their association with the grain yield (GY). Analysis of variance (ANOVA) indicated the presence of significant amount of differences and genetic diversity among genotypes under study. Correlation analysis exposed positive association of CC and LA with GY. However, RWC was shown to have a highly significant and negative association with WSD and RWL. Principal component analysis (PCA) showed that out of the 7 PCs only 2 were significant having eigenvalues >?1; cumulatively accounting for 88.70% and 73.03% of the total variation under control and drought stress conditions, respectively. Strikingly the results of the PCA biplots and cluster heat map exposed G1 (Barani-17), G2 (Dharabi-11), G3 (Ehsan-16), G4 (Chakwal-50), G17 (Ujala-2016) and G23 (Kohistan-97) as potential drought tolerant genotypes. Selection of the positively associated indices would be fruitful and the tolerant genotypes having drought tolerance potential could be utilized in future wheat breeding programs to develop high yielding and drought tolerant genotypes.

     

Cytological effects of different mutagens in soybean [Glycine max (L.) Merrill]

The effect of gamma rays, ethyl methane sulphonate, and their three combinations on various cytological parameters in M1 generation was studied in two soybean cultivars, Pusa-16 and PK-1042. Combined treatments exhibited high meiotic abnormalities in Pusa-16 as compared with the individual treatments of ethyl methane sulphonate and gamma rays. In PK-1042 the highest frequency of meiotic abnormalities was exhibited by gamma rays, while in Pusa-16 the frequencies of univalents were high as compared with other meiotic abnormalities. Fragments/bridges, laggards, ring and rod bivalents were other types of meiotic abnormalities that were noticed in both the cultivars. The frequencies of irregular cells in the two cultivars were high in combined treatments followed by ethyl methane sulphonate and gamma rays. The highest percentage of pollen sterility was exhibited by the combined treatments and the lowest was exhibited by gamma rays. In Pusa-16, the increase in doses of gamma rays and ethyl methane sulphonate increased the pollen sterility percentage, while in the combined treatments, the increase was noticed up to the intermediate dose and then gradually decreased at higher doses. On the other hand, in PK-1042 the increase in ethyl methane sulphonate dose increased sterility percentage, while no definite trend was noticed in gamma rays and combined treatments.     

Studies on induction of chlorophyll mutations in soybean, Glycine max (L.) Merrill

The phenotypic response of two soybean cultivars to a chemical mutagen (ethyl methane sulphonate, EMS), physical mutagen (gamma rays) and their combinations were studied in M1 and M2 generations and the frequency and spectrum of chlorophyll mutations were worked out. Combined treatment was found to be more effective in inducing chlorophyll mutations compared to individual treatments of gamma rays and EMS in both the cultivars. As far as the spectrum of chlorophyll mutations is concerned, a wider spectrum in both the cultivars was observed in 45 kR + 0.2% EMS combined treatment.     

Zinc Ameliorates Fruit Yield and Quality of Mangoes Cultivated in Calcareous Soils

Zinc (Zn) deficiency is frequently observed in mangoes grown in calcareous soils. Inherent inability of mango to extract sufficient Zn from the soil exacerbates this situation. Therefore, mitigating effects of Zn application was investigated on flowering, fruit setting, yield and quality of mango cv. Samar Bahisht Chaunsa growing in calcareous soils. The experiment consisted of five treatments: control—no Zn, soil application of 50 and 100 g ZnSO₄ per tree and foliar application of 0.5? and 1.0?% ZnSO₄ solution. Zn was applied twice in the 2^nd week of November, 2011 and 3^rd week of March, 2012, respectively. The experiment was repeated on the same dates during the next growing season. Zn application significantly increased number of flower panicle, fruits matured panicle, leaf Zn concentrations, fruit size, peel thickness, fruit weights at harvest and after ripening and fruit yield tree, whereas it reduced malformed panicles and early fruit drop. However, flower sex ratio and fruit set remained statistically unaffected. Similarly, fruit quality in terms of total soluble solids, flesh color, aroma, flavor and overall acceptability significantly improved as compared to control. Foliar application mitigated Zn deficiency more effectively than the soil application in calcareous soils.     

Evaluation of attract-and-kill strategy for management of cocoa pod borer,Conopomorpha cramerella,in Malaysia cocoa plantation

Abstract

In South-East Asia, cocoa production is dramatically affected by cocoa pod borer (CPB) infestations. As an alternative tool to chemical control, the efficacy of attract-and-kill strategy (CPB sex-pheromone as attractant and Delta trap without sticky liner sprayed with cypermethrin solution as killing station) was evaluated and compared with current standard CPB management approach as control treatment during two main cocoa harvest seasons in Malaysia (with 100 µg and 33.3 µg CPB-pheromone loading per station, respectively). In both seasons, attract-and-kill strategy was highly effective at reducing male flight activity (p?<?0.05) in attract-and-kill plots comparing with standard CPB management plots. For the percentage of CPB-infested pods, the attract-and-kill strategy (100 µg) was as good as the conventional pesticide spray applications of cypermethrin (p?=?0.083) in first season. However, it was significantly (p?=?0.021) reduced in the second season with lower pheromone loading (33.3 µg), indicating that this semiochemical based strategy is far superior to and more feasible than the currently applied conventional synthetic pesticide treatment and is therefore a good alternative in CPB integrated pest management.     

Baseline sensitivity and the population shifts of Didymella rabiei in chickpea to the QoI fungicide pyraclostrobin in Alberta,Canada

Journal of Plant Diseases and Protection - Ascochyta blight, caused by Didymella rabiei, is one of the most important factors limiting chickpea production worldwide. In western Canada repeated...