Table 1.
Environmental settings for high temperature treatment in the indoor growth chamber.
Table 2.
Information on the selected linked molecular markers used for high temperature stress tolerance.
Fig 1.
(a) Maximum temperature during the hottest time (April-May) in 2014 at National Rice Research Institute (NRRI), Cuttack, India, (b) 59 germplasm lines (red bars) were selected from 240 genotypes in the field selection in 2014 dry season for high temperature stress tolerance based on spikelet fertility from 240 germplasm lines under field screening during the hottest period (April-May month) of 2014, dry season.
Table 3.
Details of SSR loci used for genotyping a set of 60 rice genotypes and their genetic diversity parameters.
Fig 2.
Genotype-by-trait biplot analysis of 60 genotypes for first two principal components.
The numbers in the figure represent the serial number of the genotypes enlisted in Table 2. DFF-days to 50% flowering; PH-Plant height (cm.); FLL- Flag leaf length (cm.); FLB-Flag leaf breadth; PN-Panicles/plant; PL-Panicle length; SF(N)-Spikelet fertility under normal condition; SF(S)-Spikelet fertility under stress condition SS(N)-Spikelet sterility under normal condition; SS(S)-Spikelet sterility under stress condition; PE(N)-Panicle exsertion under normal condition; PE(N)-Panicle exsertion under stress condition.
Table 4.
Comparison of 60 rice genotypes for panicle exesertion and spikelet fertility under normal and high temperature Stress condition.
Fig 3.
Unrooted tree using unweighted-neighbour joining method illustrating the genetic relationship among 60 genotypes based on 20 molecular markers colored on the basis of (A) individual clusters from origin point and (B) sub-populations obtained from structure analysis (SP1-red; SP2-blue and SP3-green). The numbers in the figure represent the serial number of the genotypes enlisted in Table 3.
Fig 4.
(a) Population structure of a panel of 60 genotypes based on 20 molecular markers (K = 3) and (b) Graph of estimated membership fraction for K = 3. The maximum of adhoc measure ΔK determined by structure harvester was found to be K = 3, which indicated that the entire population can be grouped into two sub-groups (SP1, SP2 and SP3).
Fig 5.
Population structure of a panel of 60 landraces and breeding lines arranged based on inferred ancestry.
The membership fractions, the genotypes with the probability of ≥ 80% were assigned to corresponding subgroups with others categorized as admixture.
Table 5.
Population structure group of accessions based on inferred ancestry values.
Table 6.
AMOVA between sub-populations and germplasm lines and fixation indices (GenAlEx 6.5 software).
Table 7.
Association of marker alleles with phenotypic traits under high temperature stress using GLM and MLM analysis in 60 rice genotypes.
Fig 6.
Quantile-Quantile (QQ) plot and distribution of marker-trait association from MLM analysis.