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.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-2580 |
| Date | 15 May 2009 |
| Creators | Do, Jung Hwa |
| Contributors | Hays, Dirk B. |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Dissertation, text |
| Format | electronic, application/pdf, born digital |
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