Development and validation of HS-SPME-GCMS/MS method for quantification of 2-acetyl-1-pyrroline in rice cultivars.

The commercial significance of accurate and simple quantification of 2-Acetyl-1-pyrroline (2-AP) cannot be overstated. Present study was carried out to standardize a method for extraction and accurate quantitation of 2-AP from rice grain using GC-MS/MS equipped with HS-SPME auto sampler. The effect of sample quantity, addition of solvent, grinding process, sample particle size, head space parameters and SPME fiber incubation parameters, were optimized in the developed method. Dehusked rice powder (2 g) prepared under liquid nitrogen, and passed through the 80-mesh sieve, incubated for 40 min at 80 °C in headspace, followed by fiber (DVB/Carbon WR/PDMS) saturation time of 15 min, could produce the maximum response. The recovery of 2-AP from fortified sample ranged between 7.02 and 9.02% at 50-200 ng g-1 fortification irrespective of the grain matrices used. Standard addition method was appropriate to overcome the matrix effect and recovery of 2-AP was more than 90% using this method. The developed method was further utilized for quantification of 2-AP in four Basmati and two non-Basmati aromatic rice samples. The content of 2-AP ranged between 57.17 and 147.10 ng g-1 of rice and varied with geographical location. This fully automated method could improve the work efficiency and reduce error during the volatile extraction and adsorption phase. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-023-05674-7.

Characterization and exploring genetic potential of landraces from Odisha with special emphasis on grain micronutrient content for benefaction of biofortification in rice.

Assessing genetic variability of micronutrient content in association with qualitative and quantitative traits in germplasm is prerequisite for effective biofortification programme. Odisha, a state of eastern India is considered as one of the most potential hot spot of diversity of cultivated rice for grain yield and nutritional traits. Significant variability for most of the qualitative and quantitative traits including Fe and Zn content was observed in a set of 293 germplasm with varying kernel colour encompassing 14 districts of Odisha. Mostly these landraces were low yielding with some exception (Haldigundi: AC 36454, 50.08 g/plant). These landraces were mostly represented by medium Fe (10-20 ppm)-medium Zn group (20-30 ppm). Fe and Zn content had positive association with each other and also with grain size. Landraces with red kernel colour were observed to have slightly higher average Zn content (26.30 ppm) as compared to white (25.87 ppm) grains. Diversity analysis of 14 districts revealed that Nayagarh, a south-eastern district was rich in Fe content while Deogarh, Keonjhar and Mayurbhanj, all north-western districts were rich in Zn content. This study identified 10 superior micronutrient dense genotypes with medium to high Fe and Zn content. This set of donors for micronutrient content was validated in another year. Champeisiali (AC 43368) and Gedemalati (AC 34306) with highest Fe (44.1 ppm) and Zn (40.48 ppm) content, respectively were detected over the environments. Identified donors and associated traits could be utilized in biofortificaion programme using appropriate breeding methodologies for enhancing micronutrients in high yielding background. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s12298-021-01119-7.

Genetic diversity analysis of specialty glutinous and low-amylose rice (Oryza sativa L.) landraces of Assam based on Wx locus and microsatellite diversity.

The sticky rice of Assam is traditionally classified as bora (glutinous) and chokuwa (semi-glutinous) based on their stickiness after cooking. The Waxy (Wx) gene encodes for granule-bound starch synthase (GBSS) that controls the synthesis of amylose, which is a key determinant of rice end-use quality attributes. In this report, we analysed the level of variation in grain quality traits in a collection of bora and chokuwa cultivars, and examined the nucleotide diversity at the Wx locus of selected rice accessions to identify the possible cause of low-amylose in these rice cultivar groups. The Wx gene sequencing from 24 bora and chokuwa cultivars revealed several nucleotide variations that can explain the variation in the amylose phenotypes. The nucleotide polymorphisms in the downstream intron regions were similar to those reported in Bangladeshi Beruin cultivars. Among the Wx polymorphisms, the CTn microsatellite in exon 1 and G/T SNP in intron 1 (G/T-Int1) should be considered for marker assisted breeding involving bora cultivars. The Wx gene tree, classified the bora accessions possessing the G/T-Int1 SNP as japonicas. However, cluster analysis using microsatellite markers classified the bora and chokuwa cultivars as indica, and intermediate of indica-aus. The findings of this study supplemented our understanding on the evolution of the Wx gene under human selection. The results will assist plant breeders to effectively improve the bora and chokuwa landraces.

Evaluation of sensory, physicochemical properties and Consumer preference of black rice and their products.

This study was aimed to evaluate the physicochemical, textural, sensory and antioxidative attributes of various rice products such as boiled rice, beaten rice, popped rice, puffed rice and raw milled rice, prepared from the Indian black rice cultivars Chakha (CH), Kalobhat (KB), Mamihunger (MA) and Manipuri Black (MN). A popular white rice variety Swarna Sub-1 (SW) was considered as control. Significant differences in most of the physicochemical and cooking parameters of raw rice were observed across different cultivars. The head rice recovery, amylose content, elongation ratio (ER) and kernel length after cooking of MA were most satisfactory among the black rice cultivars and are found to be 50.67%, 17.6%, 1.87 and 10.10 mm respectively, while popped rice of MA recorded highest length (10.83 mm) and elongation ratio (ER; 2.01). MA showed the highest adhesiveness (11.18 mJ) in boiled rice but hardness (183.53 N) was medium in raw rice. Other textural quality varied differentially according to the various products and cultivars. The highest a* value was obtained from puffed rice of MA (6.61) but L value was highest in raw rice of MN. Popped and boiled rice of MA displayed higher DPPH-antioxidant activity (88.74% and 84.74% respectively) as compared to all other products. The raw rice of KB registered higher anthocyanin (57.23 mg/100 g) content while boiled rice of SW recorded the least (0.21 mg/100 g). A survey on the consumer preference of these products indicated that boiled rice was usually preferred in lunch and dinner by most of the consumers whiles other products in breakfast. With respect to most of the traits, MA showed the good potential for rice Industry as well as for breeding material.

Detection of stable QTLs for grain protein content in rice (Oryza sativa L.) employing high throughput phenotyping and genotyping platforms.

Lack of appropriate donors, non-utilization of high throughput phenotyping and genotyping platforms with high genotype × environment interaction restrained identification of robust QTLs for grain protein content (GPC) in rice. In the present investigation a  BC3F4 mapping population was developed using grain protein donor, ARC10075 and high-yielding cultivar Naveen and 190 lines were genotyped using 40 K Affimetrix custom SNP array with the objective to identify stable QTLs for protein content. Three of the identified QTLs, one for GPC (qGPC1.1) and the other two for single grain protein content (qSGPC2.1, qSGPC7.1) were stable over the environments explaining  13%, 14% and 7.8% of the phenotypic variances, respectively. Stability and repeatability of these additive QTLs were supported by the synergistic additive effects of multi-environmental-QTLs. One epistatic-QTL, independent of  the  main effect QTL was detected over the environment for SGPC. A few functional genes governing seed storage protein were hypothesised inside these identified QTLs. The qGPC1.1 was validated by NIR Spectroscopy-based high throughput phenotyping in BC3F5 population. Higher glutelin content was estimated in high-protein lines with the introgression of qGPC1.1 in telomeric region of short arm of chromosome 1. This was supported by the postulation of probable candidate gene inside this QTL region encoding glutelin family proteins.

Novel Trichoderma strains isolated from tree barks as potential biocontrol agents and biofertilizers for direct seeded rice.

This study is the first time report of utilization of Trichoderma spp. isolated from different tree bark from Odisha state of India for rice crop health management and higher productivity. Six isolates of Trichoderma spp. were identified based on the morphological characteristics and species determination was performed by molecular assays. One of the isolated strains determined as Trichoderma erinaceum outperformed others. Trichoderma erinaceum controlled three soil borne plant pathogens i.e. Rhizoctonia solani, Sclerotium rolfsii and Sclerotium oryzae effectively under controlled condition and R. solani and Helminthosporium oryzae under filed condition. Seed treatments with the formulated isolates improved the germination rate of rice and enhanced vigour. These parameters along with higher chlorophyll content could be related to higher yield observed in two rice varieties; Karuna and Sahabhagidhan. Among the six isolates tested, Trichoderma erinaceum treatment recorded highest yield. Significantly higher expression of some stress related enzymes was observed in Trichoderma treated plants which helped in better crop growth both under biotic and abiotic stresses. These isolates helped both the varieties to accumulate more nutrients. This study proves that Trichoderma erinaceum obtained from tree bark may be incorporated in integrated rice crop management both as biocontrol agent and biofertilizer.

Evaluation of variability and environmental stability of grain quality and agronomic parameters of pigmented rice (O. sativa L.).

Eleven pigmented rice genotypes were evaluated to estimate genetic parameters, heritability and association. The results indicated that, genotypic variation was high among the lines. The distinct seasonal effect on plant performance for antioxidant capacity, anthocyanin, flavonoids, head rice recovery and test weights was also observed. Wet season favoured the crop performance in all genotypes as compared to drought conditions. The differential accumulation of different quality traits such as AOA, anthocyanin content, flavonoids content, etc showed high heritability, which would be transfer to high yeilding popular rice cultivars through conventional or geneticaly modification techniques. The line Mamihunger was chosen as donor of the high-quality rice grain and Annapurna for high yield. Further, Mamihunger are foreseen to be good in nutritional quality and industry use.

Development of NIRS models to predict protein and amylose content of brown rice and proximate compositions of rice bran.

With the escalating persuasion of economic and nutritional importance of rice grain protein and nutritional components of rice bran (RB), NIRS can be an effective tool for high throughput screening in rice breeding programme. Optimization of NIRS is prerequisite for accurate prediction of grain quality parameters. In the present study, 173 brown rice (BR) and 86 RB samples with a wide range of values were used to compare the calibration models generated by different chemometrics for grain protein (GPC) and amylose content (AC) of BR and proximate compositions (protein, crude oil, moisture, ash and fiber content) of RB. Various modified partial least square (mPLSs) models corresponding with the best mathematical treatments were identified for all components. Another set of 29 genotypes derived from the breeding programme were employed for the external validation of these calibration models. High accuracy of all these calibration and prediction models was ensured through pair t-test and correlation regression analysis between reference and predicted values.