Estimation of the outcrossing rate for annual Asian wild rice under field conditions

Abstract

The Asian wild rice, Oryza rufipogon, has partial outcrossing behavior and shows high levels of genetic variation. To estimate an accurate outcrossing rate of annual form of O. rufipogon, two backcross lines (Lines R1 and R2) between Oryza sativa Nipponbare and O. rufipogon W630 were examined under field conditions. A chromosome survey confirmed that these lines had wild chromosomal segments at more than 92% of marker loci. As for the traits of glume, stamen and pistil, Line R1 showed similar floral morphology as that of O. rufipogon W630, whereas Line R2 had larger glumes. In 2005, 2006 and 2008, a total of 22 backcross plants were planted in the middle of wild rice plots. The successive progenies of each plant were examined using microsatellite markers that could clearly detect self-pollination and outcrossing. The outcrossing rates of Line R1 plants ranged from 4.04% to 25.50% with an average of 10.20%. This indicates that cross-pollination of wild rice is a chance event affected by many environmental factors. The outcrossing rates of Line R2 plants also varied, however, no significant difference was observed between the averages of Lines R1 and R2, suggesting that the glume sizes are not critical for outcrossing ability.

Estimating inbreeding coefficients from NGS data: Impact on genotype calling and allele frequency estimation

“…Among wild accessions the self-crossing rate is quite variable, although O. rufipogon tends to have lower rates than O. nivara: 50%-80% and 75%-95%, respectively (Morishima et al 1984;Oka 1988;Gao et al 2002;Phan et al 2012). As for the cultivated accessions, they are thought to be almost totally inbred with self-crossing rates close to 95%, although O. s. indica has been described as having slightly lower rates (Oka 1988 To assess the impact of explicitly assuming inbreeding on SFS estimation, we estimated it for each of the four rice species/ subspecies.…”

Identification of Quantitative Trait Loci Controlling Floral Morphology of Rice Using a Backcross Population between Common Cultivated Rice, <i>Oryza sativa</i> and Asian Wild Rice, <i>O. rufipogon</i>

“…This floral characteristic of wild rice enables it to increase outcrossing rate. In our previous study, outcrossing rate of W630 was estimated to be 10.2% [8]. This higher rate may be partly attributed to FLL, ANL, SGL, and SYL.…”

“…Generally, wild rice O. rufipogon exhibits outcrossing behaviour, while cultivated rice O. sativa has self-pollination behaviour [8]. This difference in pollination behaviour was likely mediated by the selection of the naturally occurring mutations during rice domestication.…”

Comparative Study of CaMsrB2 Gene Containing Drought‐Tolerant Transgenic Rice (Oryza sativa L.) and Non‐Transgenic Counterpart

“…The high level of outcross behaviour and genetic variations in the natural populations of wild rice may be attributed to the size variation in stamen and pistil (Phan et al. ).…”