ارزيابي تحمل به خشكي در توده هاي اسپرس

چكيده انگليسي :

Evaluation of Drought Tolerance in Sainfoin Accessions Onobrychis Viciifolia Scop Amin Veisipour a veisipour@ag iut ac ir Date of Submission 03 10 2010 Department of Agronomy and Plant Breeding Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisors s Name and Email address Mohammad Mahdi Majidi majidi@cc iut ac ir Abstract This investigation was conducted to study drought tolerance in different populations of sainfoin using morphological and physiological traits Twenty five cultivars were evaluated for 4 harvest according a split plot design with three replication under non stress and stress moisture environments Results indicated that water stress decreased genetic variation for most of the traits In both moisture conditions the coefficients of genetic variation for forage yield was highest and for the percentage of dry matter number of days to flowering and chlorophyll content was lowest Broad sense heritability was found high for proline content 87 plant height 87 leaf relative water percentage 83 and panicle length 82 The results showed that drought stress significantly increased the percentage of leaf leaf to stem ratio and the proline content while forage yield yield components and other studied attributes considerably decreased Significant differences were observed between sainfoin cultivars for all traits with the exception of chlorophyll ratio a b and carotenoids content Among studied accessions Kabootarabad Fereidunshahr and Khansar in non stress condition and Kabootarabad Fereidunshahr and Janat Abad in moisture stress condition had the highest forage yield Based on leaf to stem ratio cultivars Arak and Aqadash Semirom in non stress condition and Arak Khansar Aqadash Semirom and Juyfort Fereidunshahr in stress condition performed the better quality The highest dry matter yield reduction caused by water stress 33 percent and the highest increase in leaf to stem ratio 67 percent occurred in the forth cut Significant interaction were observed between plant genotype and harvest and also cut and environment Although proline content was increased more than six times under drought stress condition it did not have any association with forage yield and drought tolerance indices Results indicated that the Stress Tolerance Index STI and Geometric Mean Productivity GMP are effective selection criteria for identification of tolerant genotypes Based on STI index cultivar Fereidunshahr was the most tolerant cultivar and Arak Khansar Borujen Semirom and Prly were the most sensitive cultivars Results of biplot analysis based on the two first principle components showed that cultivar Fereidunshahr Khorram Abad Jannat Abad Damaneh and Isfahan had the highest yield potential and the less sensitivity to drought stress Stepwise regression analysis in non stress condition showed that the percentage of stem percentage of dry matter yield and number of stems per meter square justified the majority of dry matter yield variation Under stress condition the percentage of stem percentage of dry matter yield and plant height were the most components of forage yield Factor analysis revealed 5 factors which justified 90 and 87 percent of the total variation in normal and stress conditions respectively These factors were named forage production yield components reproductive factor phonological factor and photosynthesis respectively for normal condition Similarly under moister stress the five factors were named as yield components photosynthesis reproductive factor proline content and percentage of dry matter yield respectively Based on separate cluster analysis for the two moister conditions genotypes with most genetic distance were identified to be used in the further breeding programs Keywords Sainfoin Drought Tolerance index Yield Stepwise regression Factor analysis and Cluster analysis

ويسي پور، امين

ارزيابي تحمل به خشكي در توده هاي اسپرس

شاخص تحمل , عملكرد علوفه , رگرسيون مرحله اي , تحليل عاملي و تجزيه خوشه اي