Genetic studies of available grasses in gene bank and inter-specific hybridization in order to access existing potential in range species.

Bromus tomentellus is a perennial range plant (Poaceae), with a wide adaptability and distribution in most regions of Iran, so that make it an important range plant, especially for renovation of pastures, soil and water conservation and forage production. The objective of this project was to characterize different populations of B. tomentellus for some morphological characteristics such as total tiller number/plant, fertile tiller number/plant, total floret number/panicle, fertile floret number/panicle, 1000-seed weight, panicle length and weight, spikelet number/panicle, node number/panicle, leaf number/tiller, leaf length and width, flag leaf length, maximum plant height, seed length and width, awn length, leaf pubescent frequency, and also dry forage yield/plant, seed yield/plant, fertility index, days to flowering and finally explore significant genetic variation among these populations for future breeding. 11 population of this species, collected from different locations of Iran, were selected based on amount of seed availability and viability. Seeds were planted in plastic pots in a greenhouse and then transplanted to field in Kohne-Kan research station (Bojnoord). The project was conducted in randomized complete block design with 3 replicates, under complete irrigation. ANOVAS showed significant differences among populations for all traits except total tiller number/plant, panicle weight and seed width. Maximum plant height and leaf length were significantly correlated (P0.05) with dry forage yield/plant. Positive significant correlation existed between seed yield and all it&rsquos components except of 1000-seed weight. Results of principal components analyses showed that the first, second and third principal components, on average, explained 61.5, 20.61 and 13.20% of total variations in the 11 populations, respectively. Eigenvalues showed the highest positive values for total and fertile tiller number/plant in the first and for total floret number/panicle, dry forage yield/plant and fertility index in the second principal component. Cluster analyses separated the populations into 4, 3 and 4 groups based on vegetative, reproductive and all traits, respectively. Generally, results indicated that population no. 30 and 64 were the strongest and no. 51 was the weakest populations for most traits. Correlation between seed yield and dry forage yield was positive and nonsignificant that is of interest for seed and forage production simultaneously.