Genotyping of endosperms to determine seed dormancy genes regulating germination through embryonic, endospermic, or maternal tissues in rice.
Bottom Line: Many quantitative trait loci (QTL) have been identified for seed dormancy as measured by gross effects on reduced germination rate or delayed germination in crop or model plants.This research developed an endosperm genotype-based genetic approach to determine specific tissues through which a mapped QTL regulates germination using rice as a model.Using this approach, the seed dormancy loci SD12, SD1-2, and SD7-1 were determined to regulate germination through the embryo, endosperm, and maternal tissues, respectively; SD12 and SD1-2 acted additively on germination velocity in the offspring tissues; and SD12 also was associated with the preferential fertilization of male gametes in rice.
Affiliation: Plant Science Department, South Dakota State University, Brookings, South Dakota 57007 Xingyou.firstname.lastname@example.org.Show MeSH
Related in: MedlinePlus
Mentions: Two germination experiments were conducted for 14-(Ex. #1) or 35-(Ex. #2) DAR seeds derived from the dihybrid F1_SD7-1SD12 (Table 1). Germination rate for the 14-DAR seed samples was 29%, which was lower than those for the 10- and 14-DAR seed samples segregating only for SD7-1 (77%) and SD12 (36%), respectively. The reduced germination rate indicates that pyramiding of the dormancy-enhancing alleles at SD7-1 and SD12 lengthened the dormancy duration. Germinated seeds in Ex. #1 were genotyped for endosperms with the markers RID12 and SD12m13. In the germinated subpopulation, the joint frequency distribution for the two loci was dramatically biased in favor of the four genotypes homozygous (sd12sd12sd12) for the dormancy-reducing allele at SD12, the two (SD12SD12sd12 and SD12sd12sd12) groups of genotypes heterozygous for the SD12 locus were similar in frequency (Figure 4A), and allelic frequency distributions displayed two patterns, i.e., Fsd12 varied from 0.74 to 0.68 whereas Fsd7-1 was constant around 0.5 during the germination period (Figure 4B), which were similar to those observed in the germinated subpopulations segregating only for the SD7-1 or SD12 locus (Figure 2, A and C). These results indicate that SD12 played a major role in regulating germinability through the embryo, not endosperm tissue in the digenic system.
Affiliation: Plant Science Department, South Dakota State University, Brookings, South Dakota 57007 Xingyou.email@example.com.