Panicle erectness (PE) is one of the most important traits for high-yielding japonica cultivars. Although several cultivars with PE trait have been developed and released for commercial production in China, there is little information on the inheritance of PE traits in rice. In the present study, 69 widely cultivated japonica cultivars and a double haploid (DH) population derived from a cross between a PE cultivar (Wuyunjing 8) and a drooping panicle cultivar (Nongken 57) were utilized to elucidate the mechanisms of PE formation and to map PE associated genes. Our data suggested that panicle length (PL) and plant height (PH) significantly affected panicle curvature (PC), with shorter PL and PH resulting in smaller PC and consequently more erect. A putative major gene was identified on chromosome 9 by molecular markers and bulk segregant analysis in DH population. In order to finely map the major gene, all simple sequence repeats (SSR) markers on chromosome 9 as well as 100 newly developed sequence-tagged site (STS) markers were used to construct a linkage group for quantitative trait locus (QTL) mapping. A major QTL, qPE9-1, between STS marker H90 and SSR marker RM5652, was detected, and accounted for 41.72% of PC variation with pleiotropic effect on PH and PL. another QTL, qPE9-2, was also found to be adjacent to qPE9-1. In addition, we found that H90, the nearest marker to qPE9-1, used for genotyping 38 cultivars with extremely erect and drooping panicles, segregated in agreement with PC, suggesting the H90 product was possibly part of the qPE9-1 gene or closely related to it. These data demonstrated that H90 could be used for marker-aided selection for the PE trait in breeding and in the cloning of qPE9-1.
直立穗是高產(chǎn)粳稻品種最重要的性狀之一。盡管在中國有很多的直立穗品種被育成并被商業(yè)推廣，但是水稻直立穗性狀的遺傳研究還很少。本研究，利用69個廣泛種植的粳稻品種和一個來源于直立穗品種（武育粳8號）與彎穗品種（農(nóng)墾57）雜交的DH群體，來闡明直立穗形成的機制及直立穗基因的定位，數(shù)據(jù)顯示，穗長和株高顯著影響穗彎曲度，較短的穗長和較矮的株高導(dǎo)致較小的穗彎曲度，從而穗子更加直立。通過分子標(biāo)記和混合分離分析法，在DH群體中，在第9染色體鑒定到一個主效基因。為了精細(xì)定位該主效基因，第9染色體的所有SSR標(biāo)記和100個新發(fā)展的STS標(biāo)記被用于該QTL遺傳連鎖群的構(gòu)建。鑒定到一個主效QTL qPE9-1，位于STS標(biāo)記H90和SSR標(biāo)記RM5652之間，對穗彎曲度的表型貢獻(xiàn)值為41.72%，并且對株高和穗長具有多效性。另外還定位到一個與qPE9-1毗鄰的QTL，qPE9-2。此外，我們發(fā)現(xiàn)利用離qPE9-1最近的標(biāo)記H90對38個穗型非常直立和彎曲的水稻品種進(jìn)行基因型鑒定，該標(biāo)記的分離與穗彎曲度的分離一致。表明H90可能是qPE9-1基因的基因內(nèi)標(biāo)記或者與該基因緊密連鎖。上述數(shù)據(jù)表明H90能夠用于直立穗性狀的分子標(biāo)記輔助選擇和克隆qPE9-1。