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Aromatic rice of Manipur popularly known as Chakhao is a speciality glutinous rice, for which protection under geographical indication in India has been granted recently. The agronomic and nutraceutical variability of the Chakhao rice germplasm is yet to be genetically characterized. To address this gap, characterization of ninety-three landraces for agro-morphological traits, grain pigmentation, antioxidant properties, and molecular genetic variation was carried out to unravel their population genetic structure. Two major groups were identified based on pericarp color, namely, purple and non-purple, which showed a significant variation for plant height, panicle length, and grain yield. Molecular marker analysis revealed three subpopulations that could be associated with pericarp pigmentation. Deep purple genotypes formed POP3, japonica genotypes adapted to hill environment formed POP1, while POP2 comprised of both indica and aus types. Liquid chromatography-mass spectrometry (LC-MS) analysis revealed two major anthocyanin compounds in pigmented rices, namely, cyanidin-3-O-glucoside (C3G) and peonidin-3-O-glucoside (P3G). The total anthocyanin content among pigmented genotypes ranged from 29.8 to 275.8 mg.100g −1 DW. Total phenolics ranged from 66.5 to 700.3 mg GAE.100g −1 DW with radical scavenging activity (RSA) varying between 17.7 and 65.7%. Anthocyanins and phenolics showed a direct relationship with RSA implying the nutraceutical benefits of deep pigmented rice such as Manipur black rice. Aromatic rices from Manipur were found to be genetically diverse. Therefore, efforts need to be made for maintaining the geographic identity of these rice and utilization in breeding for region-specific cultivar improvement.

An Open Access International Peer Reviewed Quarterly High significant variations were observed for all the traits studied under present investigation. Considering parameters, high phenotypic coefficient of variation (PCV) and genotypic coefficient of variation (GCV) were observed for the number of effective tillers per plant, grain yield per plant, plant height followed by days to 50% flowering. Heritability in broad sense was higher in all of the characters studied under present investigation. High heritability coupled with high genetic advance as percent of mean was observed in plant height, days to 50% flowering, days to maturity, number of spikelets per panicle and number of grains per panicle, indicated that these characters under additive gene control and selection for improvement might be effective. Both at the phenotypic and genotypic level, grain yield per plant had significant and positive association with plant height, panicle length,number of filled grains per panicle and number of spikelets per panicle but had significant negative association with number of effective tillers per plant and 1000-grain weight. Number of spikelets per panicle had the maximum positive and direct effect followed by days to maturity, plant height, spikelet fertility and 1000-grain weight. Based on mean performance and various genetic parameters attributes, advance line namely, MC-34-1-10-6-1-26 was observed to be promising because it is of short duration, and yielded significantly higher than the short duration check RCM-8. Promising culture would be recommended for double cropping in the valley region of the state.