Iranian Journal of Seed Research

Salinity is one of the most extensive environmental stresses and is a limiting factor for the growth and development of crops, such as rice. Then, an experiment based upon completely randomized design with four low levels (0, 7.5, 15, 22.5) and four high of salinity (75, 150, 225 and 300 mM) with control as the first factor and nine cultivars of rice (dollars, Hasan Saraii, Mousa Tarom, Kamfiruz, Lenjan Askari, Gharib, Domsiah Mamassani, 304, Champa Yasouj) as the second factor with three replications was conducted in 2012 in the Yasouj University. Results showed that Hasan Saraii had salinity tolerance with the most germination percentage, germination rate and shoot length at high salinity levels (more than 75 mM), and Domsiah Mamassani with the minimum of that traits had not any salinity tolerance. But in the low salinity (less than 22.5 mM), Hasan Saraii, Lenjan and Mousa Tarom had the highest percentage of germination. The maximum germination rate was due to Mousa Tarom and the maximum shoot length observed in Gharib variety. So it seems, if we would only consider the germination percentage, Hasan Saraii is the best variety and if the maximum germination percentage and rate are considered, the variety that would be considered is Mousa Tarom. Therefore, high salinity we should not just rely on the germination but the germination rate should also be noted and in lower salinity due to different cultivars germination percentage, germination rate and dry weight of root should be paid much more attention.

Salinity is one of the environmental stresses limiting rice cultivation. Evaluation of the tolerance and sensitivity of offsprings of segregated generations under salinity condition is one way of finding tolerant cultivars. In order to study the effects of salinity (80 mM NaCl) stress on the second generation offspring of crosses of three rice varieties (Dollars and Gharib with 304) and to compare them with their parents and their classification in terms of salinity stress, the first experiment was conducted, adopting a Completely Randomized Design with four replications (i.e., crossing parents with Yasouj and Kamfirooz varieties). In the second experiment, check cultivars and the second generation progeny were evaluated, using an augment with a completely randomized design. At the germination stage, the Dollar cultivar was sensitive to salinity stress because it had the lowest ratio of all traits except germination percentage. However, Gharib and Kamfirooz Cultivars were salt tolerant. In both crosses, second-generation offsprings showed genetic variations in terms of the traits measured. Broad-sense heritability values for Dollars×304 and Gharib×304 crosses for shoot height (5.98% and 96%), root length (8.90% and 86%) and shoot fresh weight (8.95% and 7.92%), were relatively high, indicating that we can select these traits based on their phenotypes. General irritability for the shoot and root length traits in the second generation offsprings of Dollar and 304 crosses was higher than that of the second generation progeny of 304 and Gharib crosses. Based on these results, we concluded that for the purpose of improving salt tolerance at germination stage, 304 and Dollars crosses are more useful in rice breeding programs.