Showing 3 results for Drought Tolerance
M. R. Jazayeri, A. M. Rezai,
Volume 10, Issue 3 (10-2006)
Abstract
This study was conducted at the Research Farm of Isfahan University of Technology in 2003 to evaluate drought tolerance potential of 20 oat (Avena sativa L.) genotypes including 14 cultivars released in Canada, two cultivars released in the United States of America and Switzerland and four Turkish breeding lines. A randomized complete block design with three replications was used in each irrigation treatment (i.e., irrigation after 70±3 and 130±3 mm evaporation from class A pan). Results of analysis of variance revealed significant differences among cultivars for all studied traits in both irrigation treatments, with the exception of plant height at heading stage and biological yield in stress condition. Stress condition significantly reduced all the traits. Also, the interaction of genotypes by irrigation treatments was significant for days to heading, grain and biological yields and 1000-grain weight. To evaluate drought tolerance of the studied cultivars, Rosielle and Hamblin tolerance index, mean productivity (MP), Fischer and Maurer stress susceptibility index and Fernandez geometric mean productivity and stress tolerance index were calculated based on yield data in stress and non- stress conditions. According to the obtained results, stress tolerance index seems to be the most effective index to identify tolerant genotypes. Rank correlations of stress tolerance index and grain yields in stress and non-stress conditions were 0.93 and 0.78, respectively. Based on this index, Boyer and Paisley were found to be the most tolerant cultivars.
Gh Dehghani, F Malek Shhi, B Alizadeh,
Volume 13, Issue 48 (7-2009)
Abstract
Canola (Brassica napus L.) as one of the oilseed crops has recently received lots of attention due to its suitable oil quality and high oil percentage. To evaluate the effect of water deficit stress on canola genotypes with regard to yield, drought tolerance quantitative indices and identify drought tolerant genotypes, an experiment was conducted in research farm of seed and plant improvement Institute (Karaj) using completely randomized block design with four replications, and 25 genotypes under two stress and non stress conditions. Genotypes were evaluated regarding drought tolerance. Drought tolerance quantitative indices include MP, GMP, STI, SSI and TOL. Result of variance analysis showed significant differences among genotypes as regards all indices and seed yield of genotypes in both conditions at 1% probability level. MP, GMP and STI indices were selected as the best indices for selection of tolerant genotypes in regard to analysis of correlation between seed yield in two stress and non stress conditions and drought tolerance indices. Results indicated that Genotype Vectra was the best genotype, because of its proper mean yield in both stress and non stress conditions. Multivariate biplot figure display showed that MP, GMP and STI indices had high correlation coefficient with each other, and tolerant genotypes were located near tolerance indices. Also results of three dimensional scatter plot and cluster analysis indicated that genotypes Modena, Jura, Eshydromel, Vectra, Dante, Zarfam, Esbetty and Olano were tolerant to drought stress, and genotypes Olpop, GKHelena, RG4504 and Olphi were sensitive genotypes.
M. Karimi Kakhaki , A. Sepehri,
Volume 13, Issue 50 (1-2010)
Abstract
In order to study the effect of deficit irrigation at reproductive growth stages on water use efficiency and drought tolerance of four sunflower cultivars, including Azargol, Allstar, Alison and Euroflor, an experiment was conducted during 2007 growing season at experimental field of Agricultural Faculty of Bu-Ali Sina University, Hamadan, Iran. The experiment was a split plot based on randomized complete block design with three replications. The irrigation levels included full irrigation, deficit irrigation at heading, deficit irrigation at flowering, deficit irrigation at seed filling, deficit irrigation at heading and seed filling and deficit irrigation at flowering and seed filling stages. The biological and economic yield (BY and EY), harvest index (HI), water used, water use efficiency (WUE) and water stress indexes were measured. The results indicated that the highest BY (11681.7 kg.ha-1), EY (4854.0 kg.ha-1) and HI (42%) were obtained from full irrigation treatment. The lowest negative effects in cultivars belonged to deficit irrigation at seed filling stage. Euroflor obtained the highest of these parameters with 10127.1 Kg.ha-1, 4081.5 Kg.ha-1 and 40% respectively. Highest WUE was related to twice cutoff of irrigation in flowering and seed formation stages and then without irrigation in seed formation stage by 1.09 and 0.96 Kg.m-3. Allstar and then Euroflor had highest WUE among sunflower cultivars by 1.01 and 0.94 Kg.m-3 respectively. Results also indicated that Euroflor was a tolerant cultivar and STI (Stress Tolerant Index) and GMP (Geometric Mean Productivity) were acceptable indexes for selection. Finally, deficit irrigation at seed formation stage had the lowest negative effect on yield and HI with suitable WUE. In addition, Euroflor showed the highest yield, drought tolerance and HI with suitable WUE.
