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Accueil du site → Doctorat → Chine → 2013 → Evaluation of Drought Tolerance Index, Selection of Drought Tolerant Varieties and Association Analysis of Important Traits with SSR Markers in Chinese Winter Bread Wheat

Northwest University of Science and Technology (2013)

Evaluation of Drought Tolerance Index, Selection of Drought Tolerant Varieties and Association Analysis of Important Traits with SSR Markers in Chinese Winter Bread Wheat

Chen Xiao Jie

Titre : Evaluation of Drought Tolerance Index, Selection of Drought Tolerant Varieties and Association Analysis of Important Traits with SSR Markers in Chinese Winter Bread Wheat

Auteur : Chen Xiao Jie

Grade : Doctoral Dissertation 2013

Université : Northwest University of Science and Technology

Résumé partiel
Wheat (Triticum aestivum L.) is one of the first plants cultivated by mankind ; it has beenextensively planted worldwide owing to its adaptation to a wide range of climates. Wheat isthe third most-produced cereal crop after maize and rice in China ; it is mainly planted insemi-humid and semi-arid regions. The arid and semiarid area covers about half of the totalland area in China ; and periodic drought, seasonal drought or temporary drought oftenoccurred in semi-humid area, even wet area ; drought stress has been one of the mostimportant abiotic constraints greatly limiting wheat production. Therefore, the study ofdrought resistance indicators, the excavation of drought tolerance germplasms, QTL mappingfor important traits, exploitation of allelic variations and maker-assisted selection (MAS) inwheat breeding will play an important role in increasing crop production study. This studyregards90broadly representative Chinese winter wheat accessions as research objects,through normal and drought treatment experiments for two years, screening drought tolerancegermplasms, evaluating drought tolerance of different traits ; second, the study regards12bredvarieties as research objects, through normal and drought treatment experiment, analysing therelationships among carbon isotope discrimination, grain yield, photosynthetic traits, stomataldensity of flag leaf, ash content and mineral elements ; analysing the genetic variation andbroad sense heritability of the investigated traits for90accessions ; to estimate the geneticdiversity, population structure and linkage disequilibrium in Chinese winter wheat with269SSR loci distributed over all21chromosomes ; to analyze the association loci with mainagronomic, physiological and root traits using269SSR loci distributed over all21chromosomes. The main results are included as follows:1. Through normal and drought treatment experiments for two years,5accessions withhighly drought tolerance were screened according to the membership function value ofdrought tolerance (MFVD), which combined the drought-tolerant coefficient (DC) of14traitsthat could be easily estimated ; these5accessions could be used as materials for droughttolerance improvement in wheat breeding. The analysis, consistency of traits variation todrought stress, indicated that there was a very strong consistency variation between transpiration rate (E) and stomatal conductance (Gs) to drought stress, also a very strongconsistency variation between biological yield per plant (BYPP) and grain yield per plant(GYPP) ; there were strong consistency variations among plant height (PH), spike length (SL),spikelet number (SN), grain number per spike (GMPS), biological yield per plant (BYPP) andgrain yield per plant (GYPP) under drought stress. The multi-regression analysis was donebetween the membership function value of drought tolerance (MFVD) and thedrought-tolerant coefficient (DC) of each trait. The results revealed that DC of GYPP, E (orGs), PH, UIL and SL could explain more than91%of the total variations in MFVD.Therefore, those five variables could be used as a combination to screen wheat germplasm orlines for drought tolerance in wheat breeding program.2. Through normal and drought treatment experiments in the2011-2012growing seasons,using12bred varieties as materials, the relationship among carbon isotope discrimination,grain yield, photosynthetic traits, stomatal density of flag leaf, ash content and mineralelements was studied. The mean values of8traits, including photosynthetic rate (Pn), carbonisotope discrimination (Δ13C), stomatal conductance (Gs), SPAD value of the flag leafchlorophyll content (SPAD), grain yield (GY), ash content (AC), K content (K) and Mncontent (Mn), significantly decreased under water stressed (WS) condition compared with thewell-watered (WW)(at least P <0.01) ; on the contrary, Fe content (Fe) significantly increased(P<0.01) under WS. Results of correlation analysis showed that Δ13C was positivelycorrelated with GY under two water conditions (WS and WW) ; Δ13C was significantlypositively correlated with Ci/Ca under WS (P<0.05), while Δ13C showed significantlynegative correlation with stomatal density of lower epidermis (SDLE) under WW (P<0.05).There were significant positive correlations among Gs, Ci, E and Ci/Ca with each other undertwo water conditions (at least P <0.05) ; AC was positively correlated with Fe, Zn, Mn and Kcontents under two water conditions ; there were positive correlations among Fe, Zn, Mn andK contents with each other under two water conditions

Mots clés : Chinese winter wheat Drought tolerance Genetic variation Geneticdiversity Association analysis

Présentation (Dissertation topics)

Page publiée le 2 septembre 2014, mise à jour le 10 janvier 2018