Morphological, biological, productive and qualitative characterization of 68 guar (Cyamopsis tetragonoloba (L.) Taub.) genotypes

Guar (Cyamopsis tetragonoloba (L.) Taub.) is a valuable industrial crop, widely cultivated in India and Pakistan forthe high galactomannan content of its endosperm. The present multi-trait characterization of 68 guar genotypeswas conducted to identify an ideotype combining desirable traits suitable for cultivation in a Mediterraneanclimate and that allows an easy harvest. Plant height, branch number, stem diameter, length of crop cycle,number of cluster, number of pods per plant, number of seeds per pod, 1000 seeds weight, seed production perplant, galactomannan and protein content were measured. In addition, correlations between morphological andproductive traits were applied, calculating the relationships between traits, and giving biological meaning to theideotype. To select high performance genotypes under Mediterranean climate, we mainly took into considerationnon-branching (easy harvestability, uniformity of maturation) and short crop cycle genotypes with valuableproductive and qualitative traits. From this viewpoint, the results showed that 17 genotypes resulted non-branching, 11 genotypes showed a short crop cycle and seven genotypes were characterized by a seed productiongreater than 50 g plant−1. Four of the 17 genotypes (PI 288757, PI 340263, NC70300525and PI 288745) possessall these desirable traits along with good seed production and therefore should be selected as multi-trait highperformance genotypes. As far as the galactomannan and protein contents are concerned, a lower coefficient ofvariation emerged when compared to those of the morphological or productive traits. Correlation analysisshowed that plant production was related to cluster number, number of pods per plant, seeds per pod, number ofbranches and length of crop cycle. Finally, an interesting negative association between galactomannan andprotein content was found.