溫一博，陳淑婷，徐正進(jìn)，孫健，徐銓

、和組合應(yīng)用調(diào)控水稻穗部性狀

1沈陽農(nóng)業(yè)大學(xué)林學(xué)院，沈陽 110866；2沈陽農(nóng)業(yè)大學(xué)水稻研究所，沈陽 110866

【】水稻是重要的糧食作物，為全球超過一半的人口提供主食。穗部性狀是影響水稻產(chǎn)量的主要因素，挖掘調(diào)控穗部性狀的優(yōu)異基因組合，為提高水稻產(chǎn)量提供聚合育種策略。【】以彎穗型秈稻品種R99和直立穗型粳稻品種SN265構(gòu)建的151個(gè)重組自交系為試材，應(yīng)用Illumina測(cè)序平臺(tái)對(duì)重組自交系和雙親進(jìn)行全基因組重測(cè)序。結(jié)合表型數(shù)據(jù)與遺傳圖譜，對(duì)每穗粒數(shù)、一次枝梗著粒數(shù)、二次枝梗著粒數(shù)和粒型進(jìn)行QTL分析，篩選QTL區(qū)間內(nèi)的候選基因，應(yīng)用基于三代測(cè)序組裝的SN265和R99高質(zhì)量基因組進(jìn)行候選基因預(yù)測(cè)和序列比對(duì)，在重組自交系中篩選產(chǎn)量性狀表現(xiàn)最好的基因組合，并在SN265遺傳背景下應(yīng)用CRISPR基因編輯技術(shù)對(duì)目標(biāo)位點(diǎn)進(jìn)行基因編輯?！尽縍99每穗粒數(shù)和二次枝梗著粒數(shù)顯著多于SN265，SN265的一次枝梗著粒數(shù)顯著高于R99，R99粒型細(xì)長(zhǎng)，SN265粒型短圓。每個(gè)重組自交系平均測(cè)序深度為6.25×，R99和SN265的測(cè)序深度分別為30×和32×。獲得1 456 445個(gè)高質(zhì)量的SNP，利用劃bin策略進(jìn)行圖譜構(gòu)建，得到一個(gè)包含3 569個(gè)bins，平均長(zhǎng)度為58.17 kb的遺傳圖。QTL分析在第9染色體檢測(cè)到一個(gè)同時(shí)調(diào)控每穗粒數(shù)、一次枝梗著粒數(shù)和二次枝梗著粒數(shù)的QTL，在第1染色體鑒定到一個(gè)調(diào)控每穗粒數(shù)和二次枝梗著粒數(shù)的QTL，在第5染色體鑒定到一個(gè)調(diào)控粒型的QTL。候選基因預(yù)測(cè)和序列比對(duì)發(fā)現(xiàn)第9染色體的同時(shí)調(diào)控水稻一次和二次枝梗著粒數(shù)，第1染色體的主要調(diào)控水稻二次枝梗著粒數(shù)，第5染色體的主要調(diào)控粒型。在151個(gè)重組自交系中，對(duì)、和的不同組合進(jìn)行分類并調(diào)查產(chǎn)量構(gòu)成因素，發(fā)現(xiàn)Gn1a/DEP1/qSW5等位基因組合產(chǎn)量表現(xiàn)最好，Gn1a/DEP1/qSW5產(chǎn)量表現(xiàn)最差。對(duì)SN265的位點(diǎn)進(jìn)行分子設(shè)計(jì)育種，獲得2個(gè)獨(dú)立的CRISPR基因編輯株系，通過調(diào)查其產(chǎn)量構(gòu)成因素，發(fā)現(xiàn)基因編輯植株穗長(zhǎng)顯著變長(zhǎng)，每穗粒數(shù)顯著增加，進(jìn)而顯著增加單株產(chǎn)量?！尽拷沂玖?、和對(duì)每穗粒數(shù)和粒型的影響，明確了Gn1a/DEP1/qSW5為重組自交系中最佳基因組合，通過改良SN265的位點(diǎn)進(jìn)一步提高了其單株產(chǎn)量。

水稻；高密度遺傳圖譜；每穗粒數(shù)；粒型；基因編輯

0 引言

【研究意義】水稻（L.）是重要的糧食作物，約為世界一半人口提供主糧，在全球糧食安全中也發(fā)揮重要作用[1]。水稻產(chǎn)量是一個(gè)復(fù)雜性狀，主要由穗部性狀控制。在過去的40年中，中國(guó)水稻的增產(chǎn)主要通過提高每穗粒數(shù)來實(shí)現(xiàn)[1]，因此，剖析調(diào)控穗部性狀的遺傳機(jī)制對(duì)育種家提高水稻產(chǎn)量具有重要的意義。【前人研究進(jìn)展】水稻的圓錐狀花序由穗軸、枝梗、籽粒組成，且籽粒著生在枝梗上，枝梗著生于穗軸上。水稻穗的發(fā)育過程是復(fù)雜的，包括小穗分化、發(fā)育和退化等一系列生理過程。在生殖生長(zhǎng)期，水稻莖尖分生組織轉(zhuǎn)變?yōu)榛ㄐ蚍稚M織，分化為一次枝梗分生組織，二次枝梗分生組織在一次枝梗上相繼產(chǎn)生，進(jìn)一步分化為小穗分枝分生組織和側(cè)穗分生組織。在同一時(shí)期，一次枝梗分生組織頂部分化為末端小穗分生組織[2-3]。這些分枝及其分化的穗狀分生組織最終形成水稻穗的基本結(jié)構(gòu)，決定每穗粒數(shù)。許多參與穗分枝形成的基因已被克隆，如、、/（/）、（）、（）、（）、等參與頂端分生組織分化形成花序分生組織，進(jìn)而形成一次枝梗和二次枝梗分生組織的分化過程[4-7]；/（/）、（）、（）等參與枝梗分生組織到小穗分生組織的分化過程[8-11]；/與（）調(diào)控小穗分生組織到穎花分生組織的分化[12-16]。水稻粒形是穗部性狀的重要組成部分，屬于受多基因控制的數(shù)量性狀，單個(gè)基因的效應(yīng)值通常較小，受環(huán)境影響較大[17]。目前，已報(bào)道的粒形相關(guān)QTL位點(diǎn)約600個(gè)，隨著水稻基因組測(cè)序和功能基因組研究的深入，已成功克隆近百個(gè)粒形相關(guān)基因[18-21]。這些基因通過多種途徑調(diào)控水稻粒形，主要包括轉(zhuǎn)錄因子調(diào)控（如、、和[16, 22-31]）、泛素途徑（如、和[27-28, 32-33]）、G蛋白途徑（如、和[34-36]），以及激素水平控制粒形途徑（如、、、和）等?！颈狙芯壳腥朦c(diǎn)】數(shù)十年來，中國(guó)科學(xué)家在水稻穗部性狀遺傳基礎(chǔ)、調(diào)控基因的定位與功能研究等方面取得了卓越成績(jī)，但由于材料背景的限制，單一的雜交組合僅能鑒定到少數(shù)穗部性狀相關(guān)QTL，單個(gè)QTL貢獻(xiàn)率因試驗(yàn)材料和研究方法的不同往往表現(xiàn)出巨大差異。目前對(duì)穗部性狀的研究還主要集中于單個(gè)功能基因的解析和應(yīng)用，對(duì)每穗粒數(shù)和粒形調(diào)控基因的組合應(yīng)用研究較少。【擬解決的關(guān)鍵問題】本研究以穗型和粒型差異顯著的雙親所構(gòu)建的重組自交系為試材，對(duì)每穗粒數(shù)、一次枝梗著粒數(shù)、二次枝梗著粒數(shù)和粒型進(jìn)行QTL分析和候選基因功能鑒定，評(píng)價(jià)不同基因組合的產(chǎn)量構(gòu)成因素，并對(duì)超級(jí)稻品種SN265進(jìn)行分子設(shè)計(jì)基因編輯育種，為水稻優(yōu)勢(shì)等位基因聚合育種提供重要種質(zhì)和基因資源。

1 材料與方法

1.1 供試水稻材料

R99為典型的彎穗型秈稻品種，SN265為中國(guó)第一個(gè)直立大穗型粳型超級(jí)稻品種。以SN265和R99為雙親配制雜交組合，采用單粒傳法套袋自交12代，獲得包含151個(gè)株系的穩(wěn)定遺傳重組自交系。親本和重組自交系于2021年春季種植于沈陽農(nóng)業(yè)大學(xué)水稻所試驗(yàn)田（123°E，41°N），每個(gè)株系按照3行×6株規(guī)模種植一小區(qū)，株行距均為20 cm，單苗插植，常規(guī)栽培管理。

1.2 表型考察

抽穗后45 d，每小區(qū)取中部5株收獲，充分曬干后，考察單株穗數(shù)。取長(zhǎng)勢(shì)均勻的5穗，統(tǒng)計(jì)一次枝梗著粒數(shù)、二次枝梗著粒數(shù)、每穗粒數(shù)和結(jié)實(shí)率。隨機(jī)取500粒飽滿籽粒稱重統(tǒng)計(jì)千粒重。最后以Microsoft Excel 2016計(jì)算各材料每株的各性狀平均值、標(biāo)準(zhǔn)差，并對(duì)各性狀進(jìn)行兩尾等方差檢驗(yàn)，使用GraphPad Prism 8進(jìn)行作圖。

1.3 全基因組測(cè)序和遺傳圖譜構(gòu)建

選取插秧后3周齡植株的幼嫩葉片，采用CTAB法提取DNA，送北京百邁克生物科技有限公司進(jìn)行高通量測(cè)序分析。參照Li等[37]報(bào)道的重測(cè)序手段，采用“滑動(dòng)窗口”法構(gòu)建R99和SN265的重組自交系群體的遺傳圖譜。利用劃bin策略得到3 569個(gè)bins，平均長(zhǎng)度為58.17 kb的遺傳圖譜。采用R/qtl的CIM方法進(jìn)行QTL定位，采用mqmpermutation命令進(jìn)行排列組合1 000次的LOD閾值（=0.05）確定，當(dāng)實(shí)際求得的LOD值大于LOD閾值時(shí)，就認(rèn)為該區(qū)段存在1個(gè)QTL，其置信區(qū)間為L(zhǎng)OD峰值向下1個(gè)LOD值單位的區(qū)間[38]。

1.4 CRISPR/Cas9基因編輯

以超級(jí)稻品種SN265為遺傳背景材料進(jìn)行CRISPR基因編輯。通過華南農(nóng)業(yè)大學(xué)亞熱帶農(nóng)業(yè)生物資源保護(hù)與利用國(guó)家重點(diǎn)實(shí)驗(yàn)室劉耀光院士團(tuán)隊(duì)開發(fā)的基因編輯工具包CRISPR-GE（http://skl.scau.edu. cn/）進(jìn)行靶位點(diǎn)的設(shè)計(jì)，應(yīng)用BLAST比對(duì)日本晴參考基因組確認(rèn)靶點(diǎn)的特異性（https://rapdb.dna. affrc.go.jp/tools/blast）?；蚓庉嫲悬c(diǎn)序列和引物合成，以及測(cè)序服務(wù)均由華大基因完成。參照Li等[37]方法構(gòu)建基因編輯載體以及基因編輯植株的遺傳轉(zhuǎn)化和篩選。

2 結(jié)果

2.1 雙親穗部性狀差異顯著

R99穗型松散，SN265穗型緊湊。R99每穗粒數(shù)顯著多于SN265。進(jìn)一步調(diào)查一次枝梗和二次枝梗，發(fā)現(xiàn)SN265的一次枝梗著粒數(shù)顯著多于R99，而R99的二次枝梗著粒數(shù)顯著多于SN265。此外，R99和SN265的粒型也存在顯著差異，R99籽粒細(xì)長(zhǎng)，籽粒長(zhǎng)寬比超過2.5，而SN265的籽粒較為短圓，籽粒長(zhǎng)寬比約為2（圖1）。

2.2 遺傳圖譜構(gòu)建與QTL分析

應(yīng)用Illumina測(cè)序平臺(tái)對(duì)R99和SN265為親本構(gòu)建的重組自交系和雙親進(jìn)行全基因組重測(cè)序，每個(gè)重組自交系平均測(cè)序深度為6.25×，R99和SN265的測(cè)序深度為30×和32×。得到1 456 445個(gè)高質(zhì)量的SNP，利用劃bin策略進(jìn)行圖譜構(gòu)建，得到3 569個(gè)bins，平均長(zhǎng)度為58.17 kb的遺傳圖譜[37]。利用R/qtl軟件對(duì)重組自交系群體的每穗粒數(shù)、一次枝梗著粒數(shù)、二次枝梗著粒數(shù)和粒型進(jìn)行QTL分析。獲得2個(gè)控制每穗粒數(shù)的QTL，分布在第1和第9染色體，其LOD值分別為7.8和12.6，表型貢獻(xiàn)率分別為16.8%和28.1%。隨后，把每穗粒數(shù)拆分成一次枝梗著粒數(shù)和二次枝梗著粒數(shù)分別進(jìn)行QTL分析。結(jié)果顯示，第9染色體的QTL同時(shí)控制一次枝梗著粒數(shù)和二次枝梗著粒數(shù)，而第1染色體的QTL只調(diào)控二次枝梗著粒數(shù)。在第5染色體檢測(cè)到一個(gè)LOD值為18.5，貢獻(xiàn)率為42.1%的主效粒型QTL（圖2）。

2.3 候選基因序列比對(duì)

通過數(shù)據(jù)庫(kù)比對(duì)發(fā)現(xiàn)第1染色體上調(diào)控每穗粒數(shù)和二次枝梗著粒數(shù)的QTL與已報(bào)道的編碼細(xì)胞分裂素降解酶位置重合[6]，第9染色體控制每穗粒數(shù)、一次枝梗著粒數(shù)和二次枝梗著粒數(shù)的QTL與已經(jīng)報(bào)道的G蛋白伽馬亞基位置重合[7]，第5染色體控制粒型的QTL與已報(bào)道的油菜素內(nèi)酯信號(hào)傳導(dǎo)的新型正調(diào)因子位置重合[33, 39-40]。應(yīng)用基于三代測(cè)序組裝的SN265和R99高質(zhì)量基因組[37, 41]，比對(duì)雙親、和的基因序列發(fā)現(xiàn)，與R99相比，SN265在位點(diǎn)上游5 kb存在一個(gè)1 212 bp的缺失，該1 212 bp缺失通過調(diào)控的表達(dá)量進(jìn)而調(diào)控籽粒大小[33]。SN265在的3′端有一段637 bp的序列被12 bp序列所替換，使蛋白缺失了C端的Cys富集區(qū)域，該突變能促進(jìn)細(xì)胞分裂，降低穗頸節(jié)長(zhǎng)度并使稻穗變密、枝梗數(shù)增加、每穗籽粒數(shù)增多，從而促進(jìn)水稻增產(chǎn)。SN265在和位點(diǎn)均為優(yōu)勢(shì)等位基因，而R99在位點(diǎn)的第1個(gè)外顯子處6 bp的插入和2個(gè)SNP（C/G和G/A），以及第4個(gè)外顯子處的1個(gè)SNP（G/T），導(dǎo)致其蛋白產(chǎn)物與粳稻品種產(chǎn)生差異，引起花序分裂組織中細(xì)胞分裂素的積累，因而增加每穗粒數(shù)，最終導(dǎo)致產(chǎn)量提高（圖3）。

A：株型；B：穗型；C：粒型；D：每穗粒數(shù)；E：一次枝梗著粒數(shù)；F：二次枝梗著粒數(shù)；G：籽粒長(zhǎng)寬比。*：P＜0.05

2.4 不同DEP1、Gn1a和qSW5組合的產(chǎn)量表現(xiàn)

為了闡明、和的不同基因組合對(duì)水稻產(chǎn)量表現(xiàn)的影響，根據(jù)3個(gè)基因的等位基因型，將151個(gè)重組自交系分為8個(gè)類型（圖4）。通過比對(duì)其每穗粒數(shù)、千粒重和單株產(chǎn)量，發(fā)現(xiàn)Gn1a/DEP1等位基因的組合每穗粒數(shù)表現(xiàn)最佳，Gn1a/DEP1和Gn1a/DEP1次之，Gn1a/DEP1組合的每穗粒數(shù)最少。千粒重主要受基因型調(diào)控，含有qSW5的4種類型千粒重普遍顯著高于含有qSW5等位基因4種類型。總之，Gn1a/DEP1/qSW5因每穗粒數(shù)和千粒重的優(yōu)勢(shì)體現(xiàn)出最好的產(chǎn)量表現(xiàn)，Gn1a/DEP1/qSW5則因?yàn)槊克肓?shù)和千粒重的劣勢(shì)產(chǎn)量表現(xiàn)最差（圖4）。

+：R99基因型；-：SN265基因型。不同字母表示差異顯著（P＜0.05）。下同

2.5 CRISPR/Cas9基因編輯聚合優(yōu)勢(shì)基因型

基于2.4結(jié)果，Gn1a/DEP1/qSW5有最好的產(chǎn)量表現(xiàn)，而超級(jí)稻品種SN265的基因型僅與Gn1a/DEP1/qSW5在位點(diǎn)上存在差別，在粳稻中花11遺傳背景下對(duì)進(jìn)行Knock-out突變，可以顯著增加每穗粒數(shù)[42-43]。因此，對(duì)SN265進(jìn)行基因設(shè)計(jì)育種，在的第一個(gè)外顯子設(shè)計(jì)PAM序列，進(jìn)行基因編輯，在T0篩選陽性植株，在T1進(jìn)行測(cè)序，鑒定到CR-1和CR-2 2個(gè)純合突變株系，分別缺失了1和2 bp，造成移碼突變（圖5）。2個(gè)基因編輯突變體穗長(zhǎng)較SN265穗長(zhǎng)顯著增長(zhǎng)，每穗粒數(shù)顯著增加（圖5）?；蚓庉嬛仓昱cSN265的結(jié)實(shí)率、穗數(shù)和千粒重差異不顯著，因?yàn)槊克肓?shù)的增加，基因編輯植株的單株產(chǎn)量顯著高于SN265（圖5）。綜上，Gn1a/DEP1/qSW5基因編輯植株較SN265體現(xiàn)出更好的單株產(chǎn)量表現(xiàn)。

A：CRISPR基因編輯的PAM序列和突變體序列；B：SN265和基因編輯植株的穗型；C：SN265和基因編輯植株的穗長(zhǎng)；D：SN265和基因編輯植株的每穗粒數(shù)；E：SN265和基因編輯植株的結(jié)實(shí)率；F：SN265和基因編輯植株的穗數(shù)；G：SN265和基因編輯植株的千粒重；H：SN265和基因編輯植株的單株產(chǎn)量

3 討論

3.1 優(yōu)異等位基因聚合

水稻育種實(shí)踐表明增加每穗粒數(shù)是提高水稻產(chǎn)量的最有效途徑之一。近幾十年來，水稻每穗粒數(shù)的研究取得了很大進(jìn)展，已成功克隆了多個(gè)影響每穗粒數(shù)的基因，這些影響每穗粒數(shù)的基因可以作為育種家的潛在種質(zhì)資源。分子標(biāo)記輔助選擇是基因聚合的有效工具[44]，如的3型等位基因和OsSPL14等位基因通過重復(fù)回交聚合，顯著增加每穗粒數(shù)[45]。和的聚合可以通過增加每穗粒數(shù)來提高水稻產(chǎn)量[46]。因?yàn)橐恍┛刂泼克肓?shù)的基因在水稻中產(chǎn)生其他不良影響，例如延遲水稻抽穗[47]，使得水稻籽粒變小[9]，減少分蘗數(shù)[31, 48]，直立穗型等位基因有降低千粒重的趨勢(shì)[49-50]。如何平衡這些性狀與每穗粒數(shù)之間的關(guān)系仍然是育種中亟待解決的問題。本研究發(fā)現(xiàn)同時(shí)調(diào)控水稻一次枝梗著粒數(shù)和二次枝梗著粒數(shù)，主要調(diào)控二次枝梗著粒數(shù)，qSW5等位基因通過增加粒寬提高千粒重，可減輕所引起的千粒重降低，、和優(yōu)勢(shì)等位基因的組合應(yīng)用可以獲得最優(yōu)的產(chǎn)量表現(xiàn)。

3.2 水稻分子設(shè)計(jì)育種

分子設(shè)計(jì)育種技術(shù)體系不斷實(shí)踐與完善對(duì)促進(jìn)作物育種技術(shù)發(fā)展有重要作用，近年來越來越多的水稻產(chǎn)量構(gòu)成因素調(diào)控基因被克隆，其分子調(diào)控網(wǎng)絡(luò)也被深入解析，加上CRISPR基因編輯技術(shù)的廣泛應(yīng)用，分子設(shè)計(jì)育種開始應(yīng)用到水稻生產(chǎn)實(shí)踐當(dāng)中[51-52]，以為核心的理想株型設(shè)計(jì)育種[53]，以為核心的品質(zhì)改良設(shè)計(jì)育種都已初見成效[54]。本研究針對(duì)中國(guó)第一個(gè)直立大穗型超級(jí)稻品種，根據(jù)試驗(yàn)結(jié)果嘗試對(duì)其位點(diǎn)進(jìn)行基因編輯以期進(jìn)一步增加SN265的每穗粒數(shù)。本研究證實(shí)了SN265的編輯植株每穗粒數(shù)顯著增加，顯著提高了其單株產(chǎn)量。但是水稻作為群體作物，單株產(chǎn)量的提高并不能保證其單位面積產(chǎn)量增產(chǎn)。超級(jí)稻SN265的直立穗型有助于改善群體受光結(jié)構(gòu)，適應(yīng)高密度密植[55]，其編輯植株穗長(zhǎng)增加，是否會(huì)削弱其對(duì)高密度栽培的適應(yīng)能力還需進(jìn)一步研究，與其配套的栽培技術(shù)也將是今后研究的方向之一。在水稻種質(zhì)資源中發(fā)現(xiàn)有利基因或等位基因并在不同遺傳背景下對(duì)其功能進(jìn)行評(píng)估，以及通過分子標(biāo)記輔助選擇和基因編輯技術(shù)闡明這些有利等位基因之間的遺傳互作及其對(duì)產(chǎn)量的聚合效應(yīng)是今后水稻分子設(shè)計(jì)育種的兩項(xiàng)主要任務(wù)。

4 結(jié)論

闡明了、和對(duì)一次枝梗著粒數(shù)、二次枝梗著粒數(shù)和粒型的影響，發(fā)現(xiàn)了Gn1a/DEP1/qSW5為重組自交系中最佳基因組合，通過改良SN265的位點(diǎn)增加每穗粒數(shù)，從而進(jìn)一步提高了其單株產(chǎn)量。

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Combination of,, andregulates the panicle architecture in rice

1College of forestry, Shenyang Agricultural University, Shenyang 110866;2Rice research institute of Shenyang Agricultural University, Shenyang 110866

【】Rice is an important food crop, providing staple food for more than half of the world’s population. Panicle traits are the main factors affecting rice yield. Discover the elite haplotype of the panicle regulation gene, and provide important germplasm and gene resources for pyramiding breeding. 【】In this study, recombinant inbred lines (RILs) derived from a cross between SN265 and R99 were re-sequenced through high-throughput sequencing. QTL analysis and candidate gene identification were conducted on the grain number on the primary branch, the grain number on the secondary branch, and the grain shape. The sequences of candidate genes were compared using the long-read sequence assemblies of SN265 and R99. The combination of candidate genes that can maximize grain yield was selected among RILs. Finally, the super rice variety SN265 was improved using CRISPR/Cas9 gene editing technology. 【】The R99 had significantly more grain number per panicle and grain number on the secondary branch, whereas SN265 had significantly more grain number on the primary branch. The grain of R99 is slender, and the grain of SN265 is short and round. The RILs were sequenced with approximately 6.25-fold depth. For parent lines, 30.0-fold depth and 32.0-fold depth data were generated for R99 and SN265, respectively. Subsequently, a bin map was constructed by 1456445 high-quality SNPs. The genetic map containing 3 569 recombinant blocks, with an average length of 58.17 kb. The QTL analysis detected a QTL on Chr.9 for grain number per panicle and grain number on both primary and secondary branch, a QTL on Chr.1 for grain number per panicle and grain number on the secondary branch, a QTL on Chr.5 for grain shape. The candidate gene prediction and sequence comparison showed thatregulated the grain number on both primary and secondary branches of rice,mainly regulated the grain number on secondary branches of rice, andmainly regulated the grain shape. The yield of the combination ofGn1a/DEP1/qSW5alleles showed an advantage in yield performance among the RILs. We further conducted a molecular design breeding to SN265 by knocking out thelocus using CRISPR/Ca9 gene editing technology, and the grain number per panicle of the transgenic plants increased significantly compared to that of SN265. 【】This study used RILs derived from a XI/GJ cross and high-throughput sequencing technology to conduct QTL analysis of rice panicle traits, revealed the effects of,andon grain number per panicle and grain shape, and clarified thatGn1a/DEP1/qSW5was the best gene combination in RILs. The yield per plant was further improved by knocking out thelocus of SN265. This study provided important germplasm and gene resources for pyramiding breeding with elite alleles.

rice; high density genetic map; grain number; grain shape; gene editing

2022-10-21；

2022-11-14

國(guó)家自然科學(xué)基金（32071982）

溫一博，E-mail：wenyibo@syau.edu.cn。通信作者徐銓，E-mail：kobexu34@syau.edu.cn。通信作者孫健，E-mail：sunjian811119@syau.edu.cn

（責(zé)任編輯 李莉）