Seed yield, galactomannan content and quality traits of different guar (Cyamopsis tetragonoloba L.) genotypes

The aim of this study was to assess the productive and qualitative traits of seeds of six guar genotypes coming from India, South Africa and the USA, grown in a Mediterranean environment, both for industrial use (galactomannans) and as animal feed (guar meal). Yield of the six varieties ranged from 1.49 t ha−1 to 2.05 t ha−1. Galactomannan content reached values from 28.6 g/100 g to 34.6 g/100 g with the highest significative value exhibited by Indian genotype, Lewis and South African genotype. Galactomannan yield resulted 0.55 t ha−1, on average, with small differences among genotypes. The mean values of protein content of the guar seeds showed an average value of all the genotypes of 283 g/kg on a DM basis of 896 g/kg with the significantly highest values in Indian and South African genotypes. Lipids (on a DM basis) was of 28.3 g/kg DM on average, with the significantly highest value in South African and Indian genotypes. Crude Fibre, ranged from 107 to 122 g/kg. The fibrous fractions were on average 496 g/kg DM, 133 g/kg DM and 5.08 g/kg DM for NDF, ADF and ADL, respectively. Polyphenols ranged from 3.61 mg gallic acid/g of Matador to 6.63 mg gallic acid/g of Kinman and tannins from 2.01 mg/g of catechin equivalents of Kinman to 4.05 mg/g of catechin equivalents of South African genotype. Monument showed the highest content of n6-PUFA, whereas, the highest content of n3-PUFA was observed in Indian genotype. The ratio n3/n6 PUFA, the Atherogenic and Thrombogenic indices underline the high quality of guar oil for human and animal nutrition. This study underlines the double aptitude of guar seed of gum extraction and the by-product, assessing, respectively, its productive traits for industrial use and nutritional traits for increasing its use in feedstuff in the Mediterranean crop-livestock system. This double use represents an important added value to promote the widespread cultivation of the crop.