2015 Cilt 9 Sayı 26

Permanent URI for this collectionhttps://hdl.handle.net/11452/31801

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Browsing by Subject "Drought stress"

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    Evaluation of drought tolerance in some kentucky bluegrass (Poa pratensis) cultivars
    (Uludağ Üniversitesi, 2015-10-08) Sadeghi, Leila; Arab, Mostafa; Etemadi, Nematollah; Yazdani, Navid
    Drought stress is a major factor limiting the growth of turfgrasses and it has become a problem for turf management, as water availability for irrigation in urban areas is declining. Finding drought-tolerant turfgrasses will facilitate turf management for areas with limited water. This study was conducted to determine the morphological and physiological responses of five Kentucky bluegrass cultivars to drought stress. Treated cultivars were ‘Nutop’, ‘Merion’, ‘Georgetown’, ‘Crusade’ and ‘Barcelona’. A split-split design based on the completely randomized block in three replications was considered. Treatments were irrigated after 30, 50, 70, 90, 110, and 130 millimeter evaporation from class A pan. Drought stresses significantly reduced turf quality, relative water content (RWC), shoot lengths, shoot and root dry weights and number of days to complete leaf wilting, but increased electrolyte leakage (EL) and number of days to recover complete green canopy after re-watering. Under drought stress, ‘Nutop’ had higher RWC, shoot dry and fresh weights and shoot lengths than other cultivars. ‘Merion’ had faster recovery from drought stress and higher root weight. Overall, among five cultivars, ‘Nutop’ and ‘Georgetown’ were least and most affected by drought stress, respectively.
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    Water stress and plant within row spacing effects on safflower yield in competition with wild oat
    (Uludağ Üniversitesi, 2015-10-08) Naderi, Ruhollah; Kazemeini, Seyed Abdolreza; Noroozi, Majid
    A Two-year field experiment was carried out in 2009 and 2010 at Agricultural College of Shiraz University, Iran to evaluate the effects of different water stress and plant within row spacing on safflower yield and photosynthetic characteristics in weedy conditions. Results showed that drought stress at 75 % FC (field capacity) caused a reduction of 15 % in seed yield but this treatment had no significant difference with well watered. Yield reduction of 31 % was also observed at 50 % FC. The greatest seed yield was also found at plant within row spacing of 5 cm (302.6 ±23 kg m-2 ). The yield reduction caused by weed competition was 57%. Compared to well water, at 75 % FC and 50 % FC Photosynthesis rate of safflower reduced 26.18 and 65.49 %, respectively. Weeds competition reduced safflower photosynthesis rate significantly about 25 %. Transpiration in weedy plots was also significantly lower than that of weed free plots (33%). Compared to well-watered, water stress at 75 % and 50 % FC reduced wild oat biomass by 29 % and 43 %, respectively. Increasing within row spacing from 5 cm to 10 cm and 20 cm caused an increase in wild oat biomass by 30% and 40%, respectively.