Validation and Characterization of Ghd7.1, a Major Quantitative Trait Locus with Pleiotropic Effects on Spikelets per Panicle, Plant Height, and Heading Date in Rice (Oryza sativa L.)

Abstract

A quantitative trait locus (QTL) that affects heading date (HD) and the number of spikelets per panicle (SPP) was previously identified in a small region on chromosome 7 in rice (Oryza sativa L.). In order to further characterize the QTL region, near isogenic lines (NILs) were quickly obtained by self-crossing recombinant inbred line 189, which is heterozygous in the vicinity of the target region. The pleiotropic effects of QTL Ghd7.1 on plant height (PH), SPP, and HD, were validated using an NIL-F2 population. Ghd7.1 explained 50.2%, 45.3%, and 76.9% of phenotypic variation in PH, SPP, and HD, respectively. Ghd7.1 was precisely mapped to a 357-kb region on the basis of analysis of the progeny of the NIL-F2 population. Day-length treatment confirmed that Ghd7.1 is sensitive to photoperiod, with long days delaying heading up to 12.5 d. Identification of panicle initiation and development for the pair of NILs showed that Ghd7.1 elongated the photoperiod-sensitive phase more than 10 d, but did not change the basic vegetative phase and the reproductive growth phase. These findings indicated that Ghd7.1 regulates SPP by controlling the rate of panicle differentiation rather than the duration of panicle development.

Effects ofHd2in the presence of the photoperiod-insensitive functional allele ofHd1in rice

“…In the Nipponbare/Kasalath cross, it delayed flowering under LDs and promoted flowering under SDs (Yano et al, 2000). In the Zhenshan97/Teqing and the Kita-ake/PA64S crosses, Hd2 delayed heading under LDs and had little effect under SDs (Liu et al, 2013; Yan et al, 2013; Gao et al, 2014). In our studies, photoperiod response of Hd2 disappeared when the functional allele Hd1 ZS97 showed no response to photoperiod in the background of ZS97, although the functional Hd1 ZS97 and Hd2 MY46 alleles continue to affect heading date by promoting and suppressing flowering, respectively, irrespective of the day-length conditions.…”

“…In the last few years, an increasing number of genes/QTL for HD were reported to have pleiotropic effect on yield traits (Xue et al, 2008; Wei et al, 2010; Endo-Higashi and Izawa, 2011; Yan et al, 2011, 2013; Zhang et al, 2012; Liu et al, 2013; Zhao et al, 2013; Chen et al, 2014). However, most of them are involved in photoperiod response, contributing to yield enhancement accompanied with long growth duration under LDs (Xue et al, 2008; Wei et al, 2010; Endo-Higashi and Izawa, 2011; Yan et al, 2011, 2013; Liu et al, 2013).…”

Identification of a CONSTANS homologous gene with distinct diurnal expression patterns in varied photoperiods in ramie (Boehmeria nivea L. Gaud)

“…In rice, at least four genes involved in flowering regulation have been shown to have a pleiotropic role in regulating plant height and grain yield (Xue et al, 2008;Yan et al, 2011Yan et al, , 2013Gao et al, 2013;Liu et al, 2013b). Interestingly, all of these genes were commonly involved in flowering-regulated pathway of Ehd1-Hd3a.…”

Genome-Wide Association Studies Reveal that Diverse Heading Date Genes Respond to Short and Long Day Lengths between Indica and Japonica Rice

“…Approximately 25 days were required for rice to complete panicle development from the growth phase transition to heading (Vergara et al, 1966; Chang et al, 1969; Liu et al, 2013). In Wuhan, the day length decreased from 13.5 h after August 6, thus the accessions that completed heading prior to August 30 initiated the transition from a vegetative to a reproductive phase under LD.…”