Effects Of Viability And Vigour Of Seed On Establishment And Grain Yield Of Wheat Cultivars In Field Conditions

In order to evaluate the effects of seed quality on establishment and growth of seedling of wheat cultivars in field conditions, two years experiment (2000 and 2001) was conducted at Ramin Agricultural and Experimental Field in Ahvaz. In the first year, effects of water stress and different seed harvesting periods on seed quality of durum wheat cultivars (Chenaltar and Showamald) and bread wheat cultivar (Falat) were studied. To determine the quality of seeds, a part of seeds were tested in laboratory for germination and seedling growth, then percentage of germination, germination rate and seedling dry weight were determined. Based on the resultus of the first year, in the secand year seeds were planted in field to determine the effects of their quality on seedling establishment and grain yield. Experimental design was factorial based on RCBD. Emergence rates, percentage of stand establisment and grain yield for all treatments were recorded. Results showed that emergence rate, stand establisment and grain yield were significantly affected by wheat cultivars and seed quality. According to the results, Seed quality and wheat cultivars had influenced on stand establishment and early growth through the rate and percentage of seedling emergence. This effect was prolonged throughout the crop life cycle and ultimately influenced grain yield. Significant correlation of seedling emergence (%) with stand establisment and grain yield, indicated that increase in grain yield resulted from more matured seeds (harvested at 44 and 58 days after anthesis) compared with less matured seeds (harvested at 12, 18and 25 days after anthesis) was mainly due to higher stand establishment of more matured seed. Also results showed that seedling growth had the highest correlation with percentage and rate of emergence, stand establishment and grain yield. Therefore, seedling growth test is recommended as an appropriate test to evaluate the seed vigour of wheat cultivars.