Effect of plant density on the stomata morphological structure and forage yield in three species of forage yield vetch (Vicia sp.) under dry farming conditions of khorramabad

This experiment was conducted in the Agriculture College of the University of Lorestan in 2007. To study morphological structure of stomata and forage yield in three species of forage vetch (Vicia sp.), a factorial experiment on the basis of a complete randomized block design (RCBD) with three replications was performed. The experimental treatments were three plant densities (100, 150 and 200 seed per m2) and three species of vetch including broad leaf vetch (V. narbonensis L.), common vetch (V. sativa L.) and woolly pod vetch (V. dasycarpa L.) evaluated under dry farming conditions. The interaction of density and plant species significantly affected the number of upper stoma and forage yield (P= 0.01). So the maximum and minimum number of stomata (/mm2) in the upper level was related to woolly pod and common vetch, respectively, and for the densities of 200 and 150 plant/m2 was equal to 224 and 123.2, respectively. Other properties of stomata (stomata number in the other level, its length and width in the both level of upper and lower, was affected by palnt species. Also, the highest and the lowest forage yield was related to the broad leaf and woolly pod vetch, respectively, with plant density of 200 and 100 seed per m2 equal to 2268 and 724 kg yield per hectare. The differences in the leaf area index (LAI) was not related to the differences among the plant species density. Thus, under the semiarid climate of region (Khorramabad), the broad leaf and common vetch species are superior to the hairy vetch species for forage production.