برآورد پارامترهاي ژنتيكي خصوصيات مرتبط با بذر و علوفه از طريق مطالعه جوامع پلي كراس علوفه اي- مرتعي Dactylis glomerata تحت شرايط عادي و تنش خشكي

چكيده انگليسي :

128 Estimation of genetic parameters of seed and forage yield related traits in orachard grass Dactylis glomerata polycross populations under normal and drought condition Behnam Hosseini Behnamhosseini @yahoo com Date of Submission septamber Department of Agronomy and Plant Breeding Isfahan University of Technology Isfahan Iran Degree M Sc Language Farsi Supervisors Mohammad Mahdi Majidi majidi@cc iut ac ir Aghafakhr Mirlohi mirlohi@cc iut ac ir Abstract Drought serves as one of the most important abiotics affecting crop growth and production The main objective of the present study was to evaluate genetic variation and estimate of genetic parameters for forage yield seed yield and associated traits in half sib families of Dacatalys glomerata under two moisture environments normal and drought conditions High genetic variation was observed among the families for most of the studied traits Results indicated that drought stress significantly affected all forage related traits except for leaf to stem ratio and all seed related traits except for seed number in panicle Physiological traits were also affected and except for chlorophyll a b and prolin they were all decreased under drought stress At first harvest the highest phenotypic coefficient of variation under stressed condition was observed for dry forage yield and for the second harvest under drought stress condition it was observed for dry forage yield and seed number per plant The highest broad sense heritabilities under normal non stress and drought conditions were related to crown diameter and flag leaf width in the second harvest respectively Narrow sense heritability for dry forage yield was for non stress and it was for stress conditions These values were and for seed yield under the two conditions respectively Based on dry forage yield genotypes and and based on seed yield genotypes and showed higher general combining ability Under non stress condition dry forage yield showed positive and significant correlation to chlorophyll a b and total chlorophyll Seed yield under non stress condition showed negative and significant correlation with prolin content According to regression analysis seed weight in panicle seed number in panicle and seed number in plant accounted for and of seed yield variation Path analysis for seed yield showed that under control condition seed weight per panicle and seed number per plant and under drought stress condition seed number and one thousand seed weight had the highest direct effect on seed yield Results of factor analysis under both moisture conditions indicated that six hidden factors were accounting for more than of total variation of all traits Cluster analysis showed that families were classified into two and three classes under non stress and stress conditions respectively Results of variance analysis on drought susceptibility and tolerance indices based on seed yield showed that there was no significant difference for SSI and TOL indices but in terms of dry forage yield there was significant variation for all indices suggesting that these indices can be used to select tolerant genotypes Based on principle component analysis of indices first and second components were nominated as production potential and tolerance and based on forage yield they were nominated as forage yield and drought stress sensitivity respectively Results of D graphs for seed yield and dry forage yield separately and STI index showed that families and in respect to seed yield and families and in respect to forage yield were located at A area which can be used to improve yield under both stress and normal environments Keywords Dactylis glomerata Half sib families genetic variation drought stressPDF created with pdfFactory trial version www pdffactory com

حسيني، بهنام

برآورد پارامترهاي ژنتيكي خصوصيات مرتبط با بذر و علوفه از طريق مطالعه جوامع پلي كراس علوفه اي- مرتعي Dactylis glomerata تحت شرايط عادي و تنش خشكي

علف باغ , فاميل نيمه خواهري , تنوع ژنتيكي و تنش خشكي