Fig 1.
Breeding scheme for the development of the chromosome segment substitution lines (CSSLs).
The CSSLs were developed from the weedy rice accession PSRR-1 in the rice cultivar ‘Bengal’ background. MAS: Marker assisted selection.
Fig 2.
Graphical genotypes of the 74 chromosome segment substitution lines (CSSLs) of the donor U.S. weedy rice accession PSRR-1.
The CSSLs are arranged vertically in order of their substituted chromosome segments. The regions in black represent homozygous regions for PSRR-1 alleles; the light blue regions indicate regions homozygous for recurrent parent Bengal alleles. The white regions are heterozygous segments.
Fig 3.
Frequency distribution of introgressed homozygous (black) and heterozygous segments (grey) in the weedy rice CSSL population.
Fig 4.
Frequency distribution of the donor segment length (% of the rice genome) in the weedy rice CSSL population.
Table 1.
Mean values for the agronomic and domestication traits in the parents, RILs, and CSSLs.
Fig 5.
Frequency distribution for seven agronomic and two domestication traits in the weedy rice CSSL population.
Mean phenotypic values of both parental lines are indicated by arrows. (A) Plant height; (B) panicle length; (C) flag leaf length; (D) flag leaf width; (E) breaking tensile strength; (F) germination% (arcsine transformed); (G) grain length; (H) grain width; (I) thousand grain width (I).
Table 2.
Quantitative trait loci for five agronomic traits detected in the RIL population developed from the cross Bengal x PSRR-1 using a composite interval mapping procedure.
Table 3.
Quantitative trait loci for seven agronomic traits detected in the RIL population developed from the cross Cypress x PSRR-1 using a composite interval mapping procedure.
Fig 6.
Chromosomal location of introgressed weedy rice segments and quantitative trait loci for seven agronomic and two domestication traits in weedy rice CSSLs.
The linkage map developed in a recombinant inbred line (RIL) population from the cross between Bengal and PSRR-1 [21] was used to determine the substituted segments and coverage of rice genome in each CSSL. The bars to the right side of chromosomes indicate the substituted weedy rice chromosome segments in the CSSLs. The presence of a QTL is inferred when there is a significant difference between the means of each CSSL and the recurrent parent at p<0.01 using the Dunnett’s test. When multiple CSSLs with overlapping chromosome segments are significantly different from the recurrent parent for the trait values, the QTL location was narrowed down to smaller region using substitution mapping [17]. Bars with a red border indicate the PSRR-1 alleles responsible for increased trait values.
Fig 7.
Chromosome segment substitution lines (CSSLs) that are significantly different for various agronomic traits compared to the recurrent parent Bengal’ at p < 0.01.
(A) plant height; (B) plant length; (C) flag leaf length; (D) flag leaf width; (E) grain length; (F) grain width; (G) thousand grain weight. Bars indicate the mean values of traits±standard error. Data from the CSSLs with overlapping chromosome segments were used to narrow down the QTL regions for traits using substitution mapping [17].
Fig 8.
Chromosome segment substitution lines (CSSLs) that are significantly different for breaking tensile strength (A) and germination % (Arcsine transformed) (B) compared to the recurrent parent Bengal’ at p<0.01.
Bars indicate the mean values of traits ± standard error. Data from the CSSLs with overlapping chromosome segments were used to narrow down the QTL regions for traits using substitution mapping [17].