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The huge rise in seaweed-derived bioactive compounds demands immediate attention of under-explored seaweed species. The oceanic bio-resources in the tidal stretch of the Andaman Islands are relatively unknown. The present study explores seven intertidal regions of South Andaman Island to understand the species richness and existing seaweed biomass. Biochemical and fatty acid components were assessed for 15 seaweed species, commonly available in the study sites. A total of 67 species of seaweeds were collected during a one-year survey, most of which belonged to Chlorophyta, Rhodophyta and a few in Phaeophyta. The species richness was higher in sandy and coarse substrata, while highest species density was found on rocky shores. The P value for species richness at 5.05E-15 also validated the variation in seaweed distribution and diversity in the selected locations. The nutritional composition varied significantly among the species and was mostly characterized by higher levels of carbohydrate especially in Gracilaria spp. Carbohydrate content ranging from 3.52–48.22% accounted for most of the nutrient component. The overall protein ranged between 2.41–18.67%, whereas the total lipid varied from 2.16–11.90% and about 10% of total lipid content was available in most species. The significant outcome of this study was the detection of 6.34% EPA in Boergesenia forbesii and 2.40% of gamma linolenic acid in Acetabularia acetabulum which could be of significant importance in the food, bioenergy, pharmaceutical and cosmetic industries. [ABSTRACT FROM AUTHOR]

Bacterial blight ( BB) is a major disease of rice for which host resistance is the only effective solution. The three genes pyramid xa5 + xa13 + Xa21 is recently the most utilized combination for developing resistant varieties through marker-assisted breeding. Our study was carried out to elicit the detailed response of twenty lines possessing these three genes in five genetic backgrounds to twelve diverse BB pathotypes in India. The lines developed from ADT 47 variety showed incomplete resistance to most of the pathotypes, whereas susceptibility varied from 8.3% to 16.6% in ADT 43 and IR24, respectively. However, in IMP ASD16/60 and Improved Samba Mahsuri, complete resistance against all pathotypes was observed. The overall results confirmed that genetic background plays crucial role for the effective expression of xa5 + xa13 + Xa21 combination. Molecular studies did not reveal correlation between origin of pathotypes and their virulence potential. It is suggested to deploy Improved Samba Mahsuri, IMP ASD 16/60 and AD1306 varieties in the bacterial blight prone areas or use them as donors for realizing wider and durable resistance. [ABSTRACT FROM AUTHOR]