Forage Yield in some Iranian Wild Trifolium Genetic Resources under Different Climatic and Irrigation Conditions

Clovers (Trifolium spp.) are one of the main forage crops in temperate regions. This research was conducted to identify water-stressed tolerance among Iranian wild annual clovers under different climatic regions. Seventeen accessions, belonging to seven species, were planted in a field in two consecutive years, at two locations (Mashhad and Urmia) in Iran, under normal and water-stressed conditions. Combined analysis of variance, Scheffe analysis, and Duncan’s new multiple range test showed significant differences in forage production among clover accessions as well as species. In addition, drought-tolerance/susceptibility indices were calculated for each accession and species. Then, these indices were applied in factor analysis. Extracted Bi-plot based on factor analysis confirmed the results of Duncan and Scheffe analyses. In water-stressed conditions, T. resupinatum (cultivated accession) produced the highest forage in Urmia with 349 mm annual rainfall, whereas in Mashhad, with 149.8 mm annual precipitation, T. purpureum and T. echinatum (both, wild species) had the highest production. The accessions as well as species were ranked based on their forage production for each location and experiment. Ultimately, this work proposed some new Trifolium species, such as T. echinatum, T. diffusum, and T. purpureum, for forage production in agronomic systems.