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The screening of genotypes that perform better in saline soils is important for food security as the arable land affected by this problem is increasing. To mimic the conditions found in saline fields, a saline soil‐based screening method was developed to distinguish genetic diversity in root growth responses and shoot growth rates of bread wheat (Triticum aestivum L.) cultivars, namely Roshan, Bam, Tabbasi, Mahooti, Shiraz, Qods, Falat, and Atrak. Soil‐filled polyvinyl chloride (PVC) tubes perfused with 50 to 200 mM NaCl and a standard nutrient solution was employed. A constant salt concentration was maintained throughout the soil profile in the PVC tubes. Genetic variation in root growth and leaf Na+ concentrations was observed between cultivars in response to salinity. Salinity decreased the relative growth rate, seminal and total root length, and the distance between root tip and the first lateral root but increased total branch roots. For most traits, the growth reductions due to salinity were higher in salt‐sensitive compared with salt‐tolerant cultivars. The seminal root length was reduced more than branch root length in all cultivars. Roshan and Tabbasi were identified as the most tolerant to salinity due to their longer seminal axile roots, shorter distance from the tip, higher distal branch root numbers, and higher branch root length compared to the other cultivars. A positive relationship between genetic variations in root growth response and relative growth rate indicates that root growth might be the key factor driving shoot growth and can be used as a criterion for screening salinity tolerance. Core Ideas Genetic variation was found in root growth traits and shoot growth rate in response to soil salinity. Salinity reduced shoot growth rate, seminal and total root length, but increased branch root length. A positive relationship was found between root growth response and shoot growth rate.

The aim of this study carried out in Shahid Chamran Ahwaz, University, in 2001-2002 to determine the effect of different forms of irrigation on the safflower (Carthamus tinctorius L.) yield and yield components. Information was needed on application time of irrigation water on cultivars of safflower (Carthamus tinctorius L.). Increasing competition for water supplies and rising costs of applying water make efficient irrigation important. Yield and water use of safflower were evaluated on silt loam soil. Deficit irrigation treatments; I1: normal irrigation, I2: cutoff irrigation in budding period, I3: cutoff irrigation in flowering period (blooming), I4: cutoff irrigation in maturity period, were examined in Randomized Complete Block Design (RCB) with three replications. In this field experiment irrigation regimes were the main plots and cvs (ARAK 28, ESFAHAN LOCALITY and FO2 cvs) were as sub plots. The plant height, the plant head number, the 1000 seed weight, and the seed yield were measured in this experiment. The different irrigation regimes had a significant effects (p < 0.05) on the seed, the crude oil yields (kg ha(-1)), seed number per boll, harvest index, total dry weight. The highest seed yield (2679 kg seed ha(-1) in cv. ESFAHAN Lo.) and the crude oil yield (855 kg oil ha(-1) in cv. ARAK) were obtained from the I1 irrigation regime. I3 gave the lowest seed yield (1499 kg seed ha(-1) in cv. FO2) and the crude oil yield (449 kg oil ha(-1) in cv. FO2). I1 gave the highest oil percentage (35% in ARAK cv.) and the lowest (27.4% in FO2 cv.) obtained in I4. The different between cvs were significant in number of boll per plant, number of seed per boll, the 1000 seed, high, number of branch per plant, seed yield (kg ha(-1)), crude oil yield and total dry weight.

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This study was conducted to investigate the effects of heat stress after anthesis on the performance of Photosystem II (PSII) and the enzymatic activity of catalase and ascorbate peroxidase. Two treatments-normal and heat stress-were conducted on four bread wheat cultivars from 7 days after anthesis until maturity. Heat stress led to an acceleration of chlorosis, reduced the efficiency of electron transfer and increased concentrations of malondialdehyde; however, the level of susceptibility varied depending on the cultivars. On the 10 th day of heat stress, reductions in fluorescence parameters, depending on the cultivar, were 6.9 to 18.9% for Fv/Fm, 9 to 21% for ΦPSII and 8.3 to 19.4% for F'v/F'm compared to normal conditions. Catalase activity increased after initial exposure to heat stress. However, after 10 days of treatment, catalase activity increased in the Chamran and Aflak cultivars by 32% and 45%, respectively, but it did not change in the Dez cultivar and decreased 22% in Darab2. Ascorbate peroxidase activity decreased in two treatments, while the amount of reduction in heat stress treatment was more than the normal treatment. The highest levels of enzymatic activity were observed in Chamran under heat stress conditions, whereas Darab2 and Dez showed the lowest activity of the enzymes. Chlorophyll fluorescence parameters and chlorophyll index had a significant negative correlation with the levels of malondialdehyde; however, they had a significant positive correlation with the antioxidant activity. ÖZETBu çalışmanın amacı çiçeklenme sonrası sıcaklık stresinin buğday çeşitlerinin fotosistem II (PSII) ile askorbat peroksidaz ve katalaz enzim aktivitelerine etkisini belirlemektir. Dört ekmeklik buğday çeşidine çiçeklenmeden 7 gün sonar Effects of Heat Stress after Anthesis on PSII Photochemical Efficiency and the Antioxidant Activity of Wheat Cultivars, Zmani et al Ta r ı m B i l i m l e r i D e r g i s i -J o u r n a l o f A g r i c u l t u r a l S c i e n c e s 24 (2018) 72-81