Handheld SERS coupled with QuEChERs for the sensitive analysis of multiple pesticides in basmati rice

Pesticides are a safety issue globally and cause serious concerns for the environment, wildlife and human health. The handheld detection of four pesticide residues widely used in Basmati rice production using surface-enhanced Raman spectroscopy (SERS) is reported. Different SERS substrates were synthesised and their plasmonic and Raman scattering properties evaluated. Using this approach, detection limits for pesticide residues were achieved within the range of 5 ppb-75 ppb, in solvent. Various extraction techniques were assessed to recover pesticide residues from spiked Basmati rice. Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERs) acetate extraction was applied and characteristic spectral data for each pesticide was obtained from the spiked matrix and analysed using handheld-SERS. This approach allowed detection limits within the matrix conditions to be markedly improved, due to the rapid aggregation of nanogold caused by the extraction medium. Thus, detection limits for three out of four pesticides were detectable below the Maximum Residue Limits (MRLs) of 10 ppb in Basmati rice. Furthermore, the multiplexing performance of handheld-SERS was assessed in solvent and matrix conditions. This study highlights the great potential of handheld-SERS for the rapid on-site detection of pesticide residues in rice and other commodities.

Detection of basmati rice using microsatellite markers

Basmati rice is a fine and aromatic rice grown mainly in certain areas of Punjab province in Pakistan. It has high demand in the international market and a source of earning foreign exchange via export. Adulteration of non-basmati rice grains is a major challenge to secure its export standards. Hence, the development of a simple and cost-effective method is necessary to screen the basmati and non-basmati rice samples. In this study, we have validated the efficiency of different molecular markers by screening seven unknown rice samples. Our results demonstrated that three markers namely RM1, RM19 and RM225 proved to be efficient microsatellite molecular markers that could be used to screen basmati and non-basmati rice samples. Further, these results are validated based on expression pattern of Badh2 gene among the basmati and non-basmati rice. Thus, this study provides a contribution towards development of a simple and cost-effective method for rapid screening of basmati rice.

Biofortification of Diverse Basmati Rice Cultivars with Iodine, Selenium, and Zinc by Individual and Cocktail Spray of Micronutrients

Given that an effective combined foliar application of iodine (I), selenium (Se), and zinc (Zn) would be farmer friendly, compared to a separate spray of each micronutrient, for the simultaneous biofortification of grain crops, we compared effectiveness of foliar-applied potassium iodate (KIO3, 0.05%), sodium selenate (Na2SeO4, 0.0024%), and zinc sulfate (ZnSO4∙7H2O, 0.5%), separately and in their combination (as cocktail) for the micronutrient biofortification of four Basmati cultivars of rice (Oryza sativa L.). Foliar-applied, each micronutrient or their cocktail did not affect rice grain yield, but grain yield varied significantly among rice cultivars. Irrespective of foliar treatments, the brown rice of cv. Super Basmati and cv. Kisan Basmati had substantially higher concentration of micronutrients than cv. Basmati-515 and cv. Chenab Basmati. With foliar-applied KIO3, alone or in cocktail, the I concentration in brown rice increased from 12 to 186 µg kg−1. The average I concentration in brown rice with foliar-applied KIO3 or cocktail was 126 μg kg−1 in cv. Basmati-515, 160 μg kg−1 in cv. Chenab Basmati, 153 μg kg−1 in cv. Kisan Basmati, and 306 μg kg−1 in cv. Super Basmati. Selenium concentration in brown rice increased from 54 to 760 µg kg−1, with foliar-applied Na2SeO4 individually and in cocktail, respectively. The inherent Zn concentration in rice cultivars ranged between 14 and 19 mg kg−1 and increased by 5–6 mg Zn per kg grains by foliar application of ZnSO4∙7H2O and cocktail. The results also showed the existence of genotypic variation in response to foliar spray of micronutrients and demonstrated that a foliar-applied cocktail of I, Se, and Zn could be an effective strategy for the simultaneous biofortification of rice grains with these micronutrients to address the hidden hunger problem in human populations.

Zinc-Coated Urea for Enhanced Zinc Biofortification, Nitrogen Use Efficiency and Yield of Basmati Rice under Typic Fluvents

Deficiency of Zn in human diet is an emerging health issue in many developing countries across the globe. Agronomic Zn biofortification using diverse Zn fertilization options is being advised for enhancing Zn concentration in the edible portion of rice.A field study was carried out to find out the Zn fertilization effects on biofortification of basmati rice and nutrient use efficiencies in the Himalayan foothills region. Amongst the Zn nutrition treatments, 4.0% Zn-coated urea (ZnCU) + 0.2% Zn foliar spray (FS) using ZnSO4·7H2O recorded the highest grain (3.46 t/ha) and straw (7.93 t/ha) yield of basmati rice. On average, the rice productivity increase due to ZnCU application was ~25.4% over Commercial Urea. Likewise, the same Zn fertilization treatment also resulted in the maximum Zn (35.93 and 81.64 mg/kg) and N (1.19 and 0.45%) concentration in grain and straw of rice, respectively. Moreover, N use efficiency (NUE) was also highest when ZnCU was applied at 4.0% (ZnSO4·7H2O) in comparison to soil application. From the grain quality viewpoint, Zn ferti-fortification had significant effect on elongation ratio and protein concentration of grain only and respective Zn fertilization treatment recorded highest quality parameters 1.90 and 7.44%, respectively. Therefore, ZnCU would be an important low-cost and useful strategy for enhancing yield, NUE and biofortification, and also in minimizing the Zn malnutrition related challenges in human diet in many developing economies.

SSR based molecular profiling of elite cultivars of basmati rice (Oryza sativa L.)

The experiment was conducted to assess the available genetic variability amongst Indian Basmati rice and identify co-dominant and reproducible robust simple sequence repeat markers for drought resistance and their utilization in marker assisted selection for developing drought resistant / tolerant aromatic rice cultivars in various parts of India as well as in world. DNA was isolated from fresh and young leaf tissues of 35 cultivars of basmati rice using the CTAB procedure of Doyle and Doyle with slightly modifications. The DNA was further quantified by spectrophotometer at 260 nm and 280 nm. The quality and quantity of DNA were checked by agarose gel electrophoresis. Out of 60 SSR markers, 18 were found to be polymorphic and the rest 42 primers were monomorphic. One of the main purposes of SSR markers in genomic study is the characterization of genetic resources to help gene bank management. The informative (18) SSR markers were capable to discriminate the entire cultivars of basmati rice used in this research work. A total of 52 alleles at 18 loci could be scored. The allelic richness per locus diversified from 2 to 5 with an average of 2.89 alleles per locus. The amplitude of Polymorphism Information Content (PIC) value is 0.066 (RM 1068) to 0.730 (RM 1059) with an average of 0.505. The Jaccard’s similarity coefficient ranged from 0.79 to 0.95. Polymorphic finding content showed a positive correlation (r =0.69) with number of alleles at the SSR locus. However it is recommended that SSR markers can be efficiently utilized for this purpose. The maximum similarity coefficient was observed between Jeerakasab and Kalanamak with a coefficient value of 95% and the minimum similarity was found between Jeerakasab and Pusa basmati-1 with a coefficient value of 79%.

Genotype × Environment Interaction and Stability Analysis in Basmati Rice (Oryza sativa L.) Genotypes

Background: Basmati rice is an important cereal crop occupying a unique position in Indian agriculture. More than 90% of global rice is produced and consumed in Asia and plays a crucial role in the entry of mineral nutrients into the food chain. Identification of stable genotypes is of great significance because the environmental conditions vary from season to season and year to year. Methods: Thirty six Basmati rice genotypes were evaluated in four production environments during kharif 2016 and kharif 2017 at two locations Kaul and Uchani to study the G × E interaction for milling, appearance, cooking and eating quality parameters. The genotypes were grown in randomized block design with three replications. Result: Based on the stability analysis of Eberhart and Russell model, genotypes viz., Haryana Mahak 1, Pusa 1826-12-271-4 and HKR 06-434 were found stable across the environments for milling%, grain length before cooking and length breadth ratio before cooking, respectively.