Vegetable oils rich in oleic acid are more desirable than oils rich in polyunsaturated and saturated fatty acids. The biological switch of oleic acid to linoleic acid is facilitated by fatty acid desaturase 2 enzyme that is further classified into FAD2-1, FAD2-2, FAD2-3, and FAD2-4. The genes coding these enzymes have high sequence similarity, but differ mostly in their expression patterns. The seed-type FAD2 genes had evolved independently after segregation by duplication from constitutively expressed FAD2 genes. Temperature, light and wounding effectively regulate FAD2 expression in plants. FAD2 genes are expressed differently in different tissues of the plant, and the over-expression of FAD2 modifies physiological and vegetative characteristics. The activity of FAD2 leads to an increase in the content of dienoic fatty acids, and hence increases the resistance toward cold and salt stress. The thorough study of the FAD2 gene is important for understanding the expression, regulation and mechanism that will help in improving the quality of oil and stress resistance in plants.

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Information on the variability available in lignan and fatty acid content in the oilseed crop of Sesamum indicum has been limited. This article presents and discusses the composition, quantity, and variability available for the two traits in the sesame germplasm that are grown in diverse agro climatic regions of India. HPLC and GC analysis of sesame seeds harvested over a period of three crop seasons revealed a considerable amount of variability in lignan and fatty acids. The antioxidant lignans sesamol, sesamin and sesamolin were observed to be in the range of 0.16-3.24, 2.10-5.98 and 1.52-3.76 mg/g of seed, respectively. Similarly oleic and linoleic acids, respectively, have ranged from 34.71 to 45.61% and 38.49 to 49.60%. The black sesame seeds were found rich in sesamin, sesamolin, total lignan content and oleic acid and are thus identified nutritionally and pharmaceutically more important than white and brown seeds. Pearson statistics showed a strong correlation between the components within a particular trait and also some correlation was found between the traits. The study revealed promising cultivars for use in sesame breeding aimed at improving lignan and fatty acid contents, and can be thus directly used in human foods, nutrition, health and welfare.

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The genetic variation, marker attributes and population structure was assessed in 104 genotypes of cucumber using 23 SSR primer pairs. The total number of alleles produced was 67 with an average of 2.91 per locus. Allele frequency was in the range of 0.215 to 0.561 with mean value of 0.403, polymorphic information content ranged from 0.158 to 0.495 with the mean of 0.333, marker index ranged from 0.316 to 1.54 with an average value of 0.954 and resolving power ranged from 0.346 to 2.692 with mean of 1.392. The maximum allele frequency was reported with primer SSR65, whereas the maximum value of polymorphic information content and resolving power was found with SSR61 and the maximum value of marker index was reported with SSR60. Jaccard's similarity coefficient ranged from 0.07 to 0.897 with maximum similarity between genotype G40 and G41 and minimum between G16 and G20, and G16 and G100. Clustering and PCA grouped the genotypes in two clusters, and majority of them were found in cluster B. The population structure analysis also showed two major populations, in which 47 genotypes were found in population 1, 39 genotypes in population 2, whereas remaining 18 genotypes were admixtures. The study provides researchers a valuable information for genotype identification, gene mapping, molecular breeding, and future exploration of cucumber germplasm in India and other major cucumber growing countries.