Nanotechnology has a wide range of applications. Nanotechnology refers to the particle in nanoscale used to improve agricultural productivity and to encounter the unsolved problems conventionally. Nanostructured formulation through mechanisms, such as targeted delivery or slow/controlled release mechanisms as well as conditional release, could release their active ingredients in response to the environmental conditions and biological demands more precisely. Nanotechnology has a great potential for achieving sustainable agriculture, especially in developing countries. Salinity is among the major abiotic stresses which limits the yield and quality of global crops. Zinc (Zn) is a vital micronutrient that is mandatory for the ideal growth of plants and has proved to reduce the hazardous effects of salt stress. To counter the salinity problem, a pot experiment was conducted at wire house of the Institute of Soil and Environmental Sciences (ISES), University of Agriculture, Faisalabad, Pakistan, to observe the effects of zinc oxide (ZnO) nanoparticles (NPs) on wheat variety “Gemmieza” imported from Egypt under salt stress. Notably, 10 dS m–1 salinity was developed artificially, and different doses of Zn conventional fertilizer and ZnO NPs were applied to potted wheat. ZnO NPs (0.12 g pot–1) significantly increased the physical parameters of wheat compared to control under salt stress. Application of ZnO NPs (0.12 g pot–1) significantly increased chlorophyll A and B contents by 24.6 and 10%, plant height at vegetative and maturity stages by 34.6 and 37.4%, shoot and spike lengths by 30.7 and 27.6%, root fresh and dry weights by 74.5 and 63.1%, and wheat grain yield by 42.2%, respectively. ZnO NPs performed better compared to Zn conventional fertilizer under salt stress and could be used in place of Zn conventional fertilizer in salt-affected soils for attaining better crop production.

Background: Rice is the main staple food for the global population and drought is one of the limited factor in rice production. In this research, progeny of a cross between an adapted U.S. rice cultivars with a tropical japonica and an indica rice genotype, were screened for drought resistant (DR) traits to identify DR loci, that would be useful for breeding U.S. rice cultivars for a water saving agricultural system.Results: A recombinat inbred line (RIL) population, generated from selfed progeny of the cross between the drought resistant tropical japonica U.S. cultivar Kaybonnet and an indica drought sensitive cultivar ZHE733, was chosen for quantitative trait locus (QTLs) analysis of drought-resistance related traits. The DR traits were quantified by measuring different parameters of morphological traits, grain yield components and root architectural traits. K/Z RIL population of 198 lines were screened in the field at Fayetteville (AR), by giving controlled drought stress (DS) and well-watered (WW) treatment at the reproductive stage, consequently for three years and the effects of DS were quantify by measuring morphological traits and grain yield components. The effect of abscisic acid (ABA) sensitivity screen on parents and 198 lines at the V3 stage in culture media was quantified by measuring root architectural traits. QTL analysis was performed with a set of 4133 single nucleotide polymorphism (SNP) markers by using QTL IciMapping software version 4.2.53. A total of 41 QTLs and 184 candidate genes within the DR-QTL regions were identified for drought related traits. The potential candidate genes were validated by RT-qPCR of parental lines. The results of candidate DR genes revealed that the gene expression of 15 candidate DR genes with known annotations, and two candidate DR genes with unknown annotations within the DR-QTL regions were up-regulated in the drought resistant parent (Kaybonnet) compared to the drought sensitive parent (ZHE733) under DS conditions.Conclusions: In this study, we detected 41 QTLs and 184 candidate genes within the DR-QTL regions, and most of the candidate genes were up-regulated in Kaybonnet as the drought resistant parent. The findings of this research provide important information to develop drought-resistant rice varieties with greater productivity under DS conditions.

Soil amendment with two types of composts: animal manure (AC) and vegetable waste (VC) induced composts have potential to alleviate Cd toxicity to maize in contaminated soil. Therefore, Cd mobility in waste water irrigated soil can be addressed through eco-friendly and cost effective organic soil amendments AC and VC that eventually reduces its translocation from polluted soil to maize plant tissues. The comparative effectiveness of AC and VC at 3% rate were evaluated on Cd solubility, its accumulation in maize tissues, translocation from root to shoot, chlorophyll contents, plant biomass, yield and soil properties (pH, NPK, OM). Results revealed that the addition of organic soil amendments significantly minimized Cd mobility and leachability in soil by 58.6% and 47%, respectively in VC-amended soil over control. While, the reduction was observed by 61.7% and 57%, respectively when AC was added at 3% over control. Comparing the control soil, Cd uptake effectively reduced via plants shoots and roots by 50%, 46% respectively when VC was added in polluted soil. However, Cd uptake was decreased in maize shoot and roots by 58% and 52.4% in AC amended soil at 3% rate, respectively. Additionally, NPK contents were significantly improved in polluted soil as well as in plant tissues in both composts amended soil Comparative to control, the addition of composts significantly improved the maize dry biomass and chlorophyll contents at 3% rate. Thus, present study confirmed that the addition of animal manure derived compost (AC) at 3% rate performed well and might be consider the suitable approach relative to vegetable compost for maize growth in polluted soil.

Contamination by petroleum hydrocarbons (PHs) is a great threat to environment due to the higher persistence and bio-toxicity of PHs. Therefore, removal of PHs from contaminated environment and strategies to reduce their toxic effects on living organisms are crucial for environmental safety and human health. The toxic effects of PHs from the polluted soil can be reduced by the addition of microbes and biochar. In this study, a pot trial was carried out to evaluate the effects of sugarcane bagasse (SB) biochar and Bacillus sp. MN54 addition on phytoremediation of PHs and growth of maize (Zea mays L.) in soil artificially contaminated with diesel. Maize seeds were sown in uncontaminated or contaminated (with PHs) soil, treated with biochar and Bacillus sp. MN54. The results revealed that PHs showed significant phytotoxicity to maize plants and the application of strain MN54 and biochar greatly reduced the toxic effects of PHs on plants growth and physiology by increasing the nutrients uptake in PHs contaminated soil. Interestingly, the phytotoxicity of PHs on maize plants was further reduced in the co-supplementation of strain MN54 and biochar. Plants physiological (25–48%) and agronomic (38–47%) attributes were significantly higher as compared to only PHs contaminated soil in the co-supplementation of strain MN54 and biochar. Similarly, nitrogen (41%), phosphorus (43%) and potassium (37%) concentrations were also increased in the co-supplementation of strain MN54 and biochar. Furthermore, maize plants successfully phytoremediate a considerable amount of PHs from soil particularly in the presence of strain MN54 and biochar, and this PHs removal was further enhanced in the co-supplementation of strain MN54 and biochar (i.e., 46% and 77% of initial PHs were removed in unplanted and planted treatments, respectively). The present results indicate that co-supplementation of biochar and Bacillus sp. MN54 could be effective in enhancing the degradation of PHs and improving plant growth in the hydrocarbons contaminated soil.

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Rice (Oryza sativa L.) is the primary food for half of the global population. Recently, there has been increasing concern in the rice industry regarding the eating and milling quality of rice. This study was conducted to identify genetic information for grain characteristics using a recombinant inbred line (RIL) population from a japonica/indica cross based on high-throughput SNP markers and to provide a strategy for improving rice quality. The RIL population used was derived from a cross of “Kaybonnet (KBNT lpa)” and “ZHE733” named the K/Z RIL population, consisting of 198 lines. A total of 4133 SNP markers were used to identify quantitative trait loci (QTLs) with higher resolution and to identify more accurate candidate genes. The characteristics measured included grain length (GL), grain width (GW), grain length to width ratio (RGLW), hundred grain weight (HGW), and percent chalkiness (PC). QTL analysis was performed using QTL IciMapping software. Continuous distributions and transgressive segregations of all the traits were observed, suggesting that the traits were quantitatively inherited. A total of twenty-eight QTLs and ninety-two candidate genes related to rice grain characteristics were identified. This genetic information is important to develop rice varieties of high quality.

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Understanding genetic diversity, association studies, evolution analysis, quantitative trait loci, marker-assisted selection and genome-wide association in tropical crops are important for improving plant characteristics in order to increase food sustainability in tropical countries. Single nucleotide polymorphism (SNP) marker is becoming the most popular molecular marker for those studies. By using SNP marker, genes associated with important traits can be identified efficiently compared to the other molecular markers. This review describes about how SNP can be discovered in the plant genomes and the application of SNP in plant breeding, especially in tropical crops such as rice, maize, peas, potato, tomato, cassava, taro, etc.   Keywords: food sustainability, plant breeding, SNP marker, tropical crops