Comparative Assessment of Nutritional, Industrial and Agronomic Valuable Traits of Underutilized Guar Genotypes

Guar (Cyamopsis tetragonoloba), also known as cluster bean, is an annual legume with a high gum (galactomannan) content that is widely used in food, biopharmaceutical and other non-food industries. Despite the fact that several studies have been conducted to develop genomic resources for guar, information on its nutritional and other important biochemical profile is largely unknown.

In the present study, we investigated the extent of genetic variability of nutritional characteristics and gum content among different indigenous guar genotypes, as well as the correlation between them. A total of 40 guar genotypes were morphologically and biochemically characterized in order to be classified into nutritional and industrial usage groups.

Genotypes RGC-1055, RGR-7, RGC-1033, RGC-1002, RGC-1031, RGC-1038 and RGC-1055 were found to be superior for galactomannan, whereas genotypes HG-2-20, HG-258, HG-832, RGC-936, RGC-1066 and Pusa Navbahar were found to contain important quantitative traits such as a greater number of pods/cluster and clusters/plant, which is directly related to higher yield. Furthermore, correlation and PCA (principal component analysis) revealed that chlorophyll content is positively correlated with protein (0.2%) and gum content (0.16%). The data generated from this study could help breeders and biotechnologists for developing novel potential hybrids with desirable morphological, nutritional and industrial properties. Furthermore, enhanced crop quality may be achieved in the future by genetically modifying the nutritional and industrially significant targeted genes from the selected superior guar genotype using CRISPR/Cas9 precision gene editing technology.