QTL MAPPING OF WHEAT DOUBLED HAPLOIDS FOR CHLOROPHYLL CONTENT AND CHLOROPHYLL FLUORESCENCE KINETICS UNDER DROUGHT STRESS IMPOSED AT ANTHESIS STAGE

摘要

Drought stress is one of the major environmental constraints to crop plants including wheat worldwide. Synthetichexaploid can act as a vehicle for improving crop tolerance against biotic and abiotic stresses. Doubled haploid populationconsisting of one hundred and forty individuals derived from cross of Opata and SH223 was used in the present study toidentify genomic regions associated with various quantitative attributes of physiological nature. Doubled haploid mappingpopulation was phenotyped for chlorophyll content and chlorophyll fluorescence kinetics under control and drought stressimposed at anthesis stage. Genotyping of population was accomplished by utilizing two hundred and sixty one polymorphicGaterslaben wheat microsatellites and Beltsville agriculture research center simple sequence repeats. Linkage map of doubledhaploid population comprising of 19 linkage groups and covering map length of two thousands six hundred and twenty six(2626) cM was constructed using map maker software. Major and minor QTLs associated with quantitative traits wereidentified using QGene software. Major QTL for chlorophyll content (QTc.wwc-1B-S11) of doubled haploid mappingpopulation under anthesis drought stress was mapped on chromosome 1B and explained 10.09 percent of phenotypic variationat LOD score of 5.5. Seven major and minor QTLs for PCFK of doubled haploids were identified on chromosome 1B, 7A and7D under control and drought stress at anthesis stage. The identified QTLs are of prime importance for high resolution mappingin synthetic hexaploid wheat. Genomic synteny of doubled haploids was observed with rice chromosome 2, 4, 7 and maizechromosome 7 owing to occurrence of orthologous QTLs for chlorophyll content and chlorophyll fluorescence respectively.