Evaluation of nodule traits in USDA guar genotype accessions

Guar [Cyamopsis tetragonoloba (L.) Taub] is an annual diploid legume (2n = 2x = 14) crop and is drought and heat tolerant. This crop is primarily grown for the high concentration of galactomannan gum that is present in the seed endosperm, and it can improve ecosystem services by fixing atmospheric nitrogen. However, the genetics of guar nodulation remains poorly understood. Therefore, the objective of this study was to assess the variation of nodule and plant growth traits in a set of guar germplasm. A total of 225 United States Department of Agriculture (USDA) guar accessions were evaluated for nodule traits in three runs of a greenhouse pot study. Results showed that all traits except fresh plant biomass varied significantly among genotypes (p-values < 0.05). Broad-sense heritability was high for nodule diameter, nodule weight per plant, and plant biomass production, indicating that genetic gain in these traits can be attained through the plant breeding process. This is promising, since selection for high values in these traits would be expected to increase nitrogen fixation and yield. There were strong and significant positive correlations between nodule number and both fresh and dry nodule weights (r = 0.79 and 0.71, respectively), as well as dry plant biomass and dry nodule weight (r = 0.8), indicating that greater plant growth is associated with increased nodule weight. Many genotypes were found to perform better than checks included in this study, which may be useful in guar breeding initiatives. PI288747 is top performing accession for all traits except nodule diameter which can be a good parent for breeding program. Overall, this research will help breeders enhance guar nodulation, nitrogen fixation, and yield by utilizing the scientific knowledge obtained and superior germplasm identified through this study.Please confirm if the author names are presented accurately and in the correct sequence (given name, middle name/initial, family name). Author 1 Given name: [specify authors given name] Last name [specify authors last name]. Also, kindly confirm the details in the metadata are correct.Author names are correct