Do, Jung Hwa (2007-12). Quantitative trait loci(qtl) analysis of yield components and heat tolerance in wheat (Triticum aestivum). Doctoral Dissertation. Thesis uri icon

abstract

  • This study was conducted to identify and map QTLs for yield components and heat tolerance of wheat in response to two kinds of heat treatment (short term-and long term-heat treatment) during seed formation in a set of 62 RILs derived from a cross of '7C' (heat resistant variety) and 'Seri M82' (heat susceptible variety) in environmentally controlled growth rooms and field. Phenotypic variations of yield components (kernel number, kernel weight, spike number and grain filling duration) were evaluated as indicators of heat tolerance / susceptibility. Most of the phenotypic variations of yield components exhibited a normally distributed pattern in response to heat stress treatments. This suggests that the yield component responses to high temperature stress are likely quantitatively inherited. A transgressive segregation pattern compared to the two parents was observed in several yield traits. This suggests that genetic variation from optimal recombination from the two parents have occurred in the progeny population. The Pearson correlation coefficients revealed significant correlations between yield components. This suggests the probability of co-segregation of genes controlling each yield components. The ANOVA also revealed a significant genotype x environment effect on individual yield components in response to reproductive stage high temperature stress. The heritability of the individual yield components was low (0.42 to 25%, 0.1~ 2% for heat tolerance). One hundred two polymorphic SSRs markers among 323 SSRs markers tested were used to construct a linkage coverage and average interval distance of 1860.2 cM and 18.2 cM/marker, respectively. Eighty-one QTLs for yield components and 68 QTLs for heat tolerance were detected with high LOD values (2.50~8.35 for yield components, 2.51~ 9.37 for heat tolerance) and that explained significant phenotypic variations (7~40% for individual QTL for yield components, 2~40 % for individual heat tolerance QTLs) from seven individual environments and the four individual heat stress environments, respectively. Specifically the regions between wmc48 and wmc89, and between wmc622 and wmc332 on the chromosome 4A and 6A, respectively possessed QTLs for both yield components and heat tolerance from various environments.
  • This study was conducted to identify and map QTLs for yield components and
    heat tolerance of wheat in response to two kinds of heat treatment (short term-and long
    term-heat treatment) during seed formation in a set of 62 RILs derived from a cross of
    '7C' (heat resistant variety) and 'Seri M82' (heat susceptible variety) in environmentally
    controlled growth rooms and field. Phenotypic variations of yield components (kernel
    number, kernel weight, spike number and grain filling duration) were evaluated as
    indicators of heat tolerance / susceptibility. Most of the phenotypic variations of yield
    components exhibited a normally distributed pattern in response to heat stress treatments.
    This suggests that the yield component responses to high temperature stress are likely
    quantitatively inherited. A transgressive segregation pattern compared to the two parents
    was observed in several yield traits. This suggests that genetic variation from optimal
    recombination from the two parents have occurred in the progeny population. The
    Pearson correlation coefficients revealed significant correlations between yield
    components. This suggests the probability of co-segregation of genes controlling each
    yield components. The ANOVA also revealed a significant genotype x environment effect on individual yield components in response to reproductive stage high temperature
    stress. The heritability of the individual yield components was low (0.42 to 25%, 0.1~
    2% for heat tolerance). One hundred two polymorphic SSRs markers among 323 SSRs
    markers tested were used to construct a linkage coverage and average interval distance
    of 1860.2 cM and 18.2 cM/marker, respectively. Eighty-one QTLs for yield components
    and 68 QTLs for heat tolerance were detected with high LOD values (2.50~8.35 for
    yield components, 2.51~ 9.37 for heat tolerance) and that explained significant
    phenotypic variations (7~40% for individual QTL for yield components, 2~40 % for
    individual heat tolerance QTLs) from seven individual environments and the four
    individual heat stress environments, respectively. Specifically the regions between
    wmc48 and wmc89, and between wmc622 and wmc332 on the chromosome 4A and 6A,
    respectively possessed QTLs for both yield components and heat tolerance from various
    environments.

publication date

  • December 2007