TITLE:
Identification of Quantitative Trait Loci Controlling Floral Morphology of Rice Using a Backcross Population between Common Cultivated Rice, Oryza sativa and Asian Wild Rice, O. rufipogon
AUTHORS:
Ryo Ishikawa, Takafumi Watabe, Ryo Nishioka, Pham Thien Thanh, Takashige Ishii
KEYWORDS:
Rice, Oryza sativa, O. rufipogon, Floral Morphology, Domestication
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.8 No.4,
March
20,
2017
ABSTRACT: Differences
in floral morphologies affect pollination behaviour in many flowering plants.
In the genus Oryza, several
differences in the size of floral organs are known. In this study, we focused
on the differences in the size of floral organs between common cultivated rice, Oryza sativa L. and its wild ancestor, O. rufipogon. We compared floral morphologies between cultivated
rice O. sativa cv. Nipponbare and O. rufipogon W630. We first evaluated temporal changes in filament and anther lengths. W630
had longer filaments with rapid elongation within
15 min after spikelet opening. W630 also had longer anthers than Nipponbare, and size of anther was consistent throughout all time examined. We also analysed other six floral traits, and found
that W630 had higher stigma and style
length, as well as lemma and palea length, but lower lemma and palea width. Quantitative trait locus (QTL)
analysis was performed to identify the loci controlling these floral traits, using backcross recombinant inbred lines
derived from a cross between Nipponbare and W630. A total of 11 significant
QTLs were identified. Of these, two pairs of QTLs
for lemma and palea length and one pair for lemma and palea width overlapped, suggesting that common genetic factors may be the reason for
the differences in these traits. In addition, we performed QTL analysis for grain
size, and found that QTLs for
grain size coincided with those for lemma and palea size, indicating that grain size is partly controlled by glume
capacity. The QTLs identified in this study will be informative for understanding genetic
changes associated with rice domestication.