اثر شوری آب آبیاری بر عملکرد و کارآیی مصرف آب سه رقم پنبه (Gossypium hirsutum L.)

To investigate the effect of different levels of salinity on yield of three cultivars of cotton, an experiment was performed for two years (2008-2009) as split plot, based on randomized complete blocks design with four replications, at Rudasht Agricultural Research Station, Isfahan Province, Iran. To prepare the salinity levels, mixtures of well water, Zayandehrud river water and drainage water were used. The main plots were different salinity levels (4, 7, 10 and 13 dS/m) and subplots were three cultivars of cotton (B557, Tabladila, and Delta Pine 16 (control)). The results showed that with increasing salinity level, the performance of all three cotton cultivars was decreased. The highest yield (4602 kg/ha) was related to the Delta Pine 16 cultivar, which was obtained at salinity level of 4 dS/m. With increasing the salinity level from 4 to 7, 10 and 13 dS/m, the percent reduction in water productivity index in Tabladila, Delta Pine 16 and B557 cultivars was (25.5, 63.7 and 175), (22.6, 58 and 189) and (26, 65.5 and 196), respectively. At all levels of salinity, water productivity index was highest in Tabladila cultivar (0.424, 0.338, 0.259 and 0.154 kg/m3 in salinities of 4, 7, 10 and 13 dS/m, respectively). In summary, the results showed that in salinity levels of 4 and 7 dS/m, the Delta Pine 16 cultivar is recommendable due to higher yield. But in salinity level of 10 dS/m, the Tabladila cultivar had significantly higher yield than the other two cultivars. From the viewpoint of resistance to salinity, the B557 cultivar couldn’t compete with Tabladila and Delta Pine 16 cultivars.