Assessment of the Allelopathic Potential of Cumin Accessions in Different Soil Water Potential

Allelopathy is one effective solution to reach a healthy life without any pollution. This study was carried out to evaluate the allelopathic potential of 92 Iranian cumin accessions grown under normal conditions and drought stress, according to the sandwich method in the laboratory. In addition, weed infestation of the same cumin accessions was examined in a field by measuring total weed species richness and diversity under normal irrigating conditions. Results indicated that length and fresh weight of radish radicle and hypocotyl are more sensitive than the other germination indices against exuded allelochemicals of cumin seeds. Furthermore, all genotypes showed the average germination percentage to be less than the control samples. They could significantly reduce total species richness and diversity in their surroundings. Weed suppressive percentage of cumin genotypes in the field experiments was positively correlated with inhibition percentage of radicle growth in the laboratory. Water stress increases the allelopathic effects of cumin accessions in laboratory screening. Classification based on principle component method indicated that cumin genotypes were categorized into two clusters in both moisture regimes. Despite having stress factors, only the genotypes 13CGOGK1, 35CSESH1, 65CEAAS, 68CKERF2, 75CYAAR2, and 84CKRTJ2 remained in a group with strong allelopathic activity. According to these results, there is the significant diversity for allelopathic strength in the Iranian cumin germplasm, which can be useful in cumin breeding for weed suppression. © 2018, Korean Society of Crop Science and Springer Nature B.V.