Developmental Genetics Analysis for Plant Height in indica Hybrid Rice Across Environments

The developmental genetics of plant height was analyzed from two groups of three-line indica hybrid rice at two environmental conditions based on the NCII design, using the additive-dominant developmental genetics models and the statistic methods. The results showed that the rice genotypes and environmental conditions could both affect plant height, and the effects of environment on plant height decreased gradually with plant development. Additive and dominant effects both governed the performance of plant height at all developmental stages. However, the degrees of effect varied among the rice genotypes. Moreover, the interaction between environments and genotypes also affected plant height. The genetic effects differed at most developmental stages. Furthermore, the expressJon of additive effect was more active than that of dominant effect. Conditional interaction effects with environment also influenced plant height during genetic development, especially at the eady stage. Mid-parent heterosis （HMP） increased gradually with the developmental stage of plant height, and maximized at the latest stage, whereas the heterosis over the better parent （HBP） showed small differences among the genotypes, and kept stable at the later stage, with positive numeric value. At most developmental stages, conditional HMP was positively significant, while conditional HBP was negatively significant. All above results suggest that HMP and HBP have some new expressions in all developmental periods and the levels and directions are quite different.

Genetic dissection of the developmental behavior of plant height in rice under different water supply conditions

Plant height （PH） is one of the most important agronomic traits of rice, as it directly affects the lodging resistance and the high yield potential. Meanwhile, PH is often constrained by water supply over the entire growth period. In this study, a recombinant inbred line （RIL） derived from Xiaobaijingzi and Kongyu 131 strains grown under drought stress and with normal irrigation over 2 yr （2013 and 2014）, respectively （regarded as four environments）, was used to dissect the genetic basis of PH by developmental dynamics QTL analysis combined with QTL^environment interactions. QTLs with net effects excluding the accumulated effects were detected to explore the relationship between genexgene interactions and genexenvironment interactions in specific growth period. A total of 26 additive QTLs （A-QTLs） and 37 epistatic QTLs （E-QTLs） associated with PH were detected by unconditional and conditional mapping over seven growth periods, qPH-2-3, qPH-4-3, qPH-6-1, qPH-7-1, and qPH-12-5 could be detected by both unconditional and conditional analyses, qPH-4-3 and qPH-7-5 were detected in four stages （periods） to be sequentially expressed QTLs controlling PH continuous variation. QTLs with additive effects （A-QTLs） were mostly expressed in the period $3iS2 （the time interval from stages 2 to 3）, and QTLxenvironment interactions performed actively in the first three stages （periods） which could be an important developmental period for rice to undergo external morphogenesis during drought stress. Several QTLs showed high adaptability for drought stress and many QTLs were closely related to the environments such as qPH-3-5, qPH-2-2 and qPH-6-1. 72.5% of the QTLs with a and aa effects detected by conditional analysis were under drought stress, and the PVE of QTLs detected by conditional analysis under drought stress were also much higher than that under normal irrigation. We infer that environments would influence the detection results and sequential expression of genes was highly influenced by environments as well. Many QTLs （qPH-1-2, qPH-3-5, qPH-4-1, qPH-2-3） coincident with previously identified drought resistance genes. The result of this study is helpful to elucidating the genetic mechanism and regulatory network underlying the development of PH in rice and providing references to marker assisted selection.

Identification of QTLs for Plant Height and Its Components by Using Single Segment Substitution Lines in Rice (Oryza sativa)

QTLs for plant height and its components on the substituted segments of fifty-two single segment substitution lines （SSSLs） in rice were identified through t-test （P〈0.001） for comparison between each SSSL and recipient parent Huajingxian 74. On the 14 substituted segments, 24 QTLs were detected, 10 for plant height, 2 for panicle length, 4 for length of the first internode from the top, 5 for length of the second internode from the top and 3 for length of the third internode from the top, respectively. All these QTLs were distributed on nine rice chromosomes except chromosomes 5, 9 and 11. The additive effect ranged from -4.08 to 3.98 cm, and the additive effect percentages varied from -19.35% to 10.43%.

Mining Applicable Elite Alleles of Growth Duration, Plant Height and Panicle Number per Plant by Conditional QTL Mapping in Japonica Rice

Unconditional and conditional QTL mapping were conducted for growth duration (GD), plant height (PH) and effective panicle number per plant (PN) using a recombinant inbred line (RIL) population derived from a cross between two japonica rice varieties Xiushui 79 and C Bao. The RIL population consisted of 254 lines was planted in two environments, Nanjing and Sihong, Jiangsu Province, China. Results showed that additive effects were major in all of QTLs for GD, PH and PN detected by the two methods, and the epistatic effects explained a small proportion of phenotypic variation. No interactions were detected between additive QTL and environment, and between epistatic QTL pairs and environment. After growth duration was adjusted to an identical level, RM80-160bp was detected as an applicable elite allele for PN, with an additive effect of 0.71. When effective panicle number per plant was adjusted to an identical level, RM448-240bp was detected as an applicable elite allele for GD, with an additive effect of 4.64. After plant height was adjusted to an identical level, RM80-160bp was detected as an applicable elite allele for PN, with an additive effect of 0.62, and RM448-240bp was detected as an applicable elite allele for GD, with an additive effect of 3.89. These applicable elite alleles could be used to improve target traits without influencing the other two traits.

水稻Ⅲ类过氧化物酶基因IPH1调控水稻株高

过氧化物酶(peroxidase, PRX)是过氧化物酶体的标志酶,能够保护细胞免受氧化损伤和解除H2O_(2)的毒害作用,还可以增强自然杀伤细胞的活性,调节细胞的增殖、分化和凋亡等.其中Ⅲ类过氧化物酶(CⅢPRXs)是植物中特有的过氧化物酶家族,通过清除活性氧(ROS)在植物免疫中发挥重要作用,然而CⅢPRXs在水稻株型建立中的功能尚不清楚.通过基因编辑技术CRISPR/Cas9获得CⅢPRXs基因(LOC_Os12g09460)两种不同形式的敲除突变体iph1-1,iph1-2.iph1突变体的株高显著高于野生型,除倒1节节长(即第5节)外,其他节节长均显著或极显著长于野生型.农艺性状考察表明,穗长及结实率等主要性状差异无统计学意义;通过RT-qPCR技术进行的表达模式分析表明,IPH1在根、茎、叶、鞘、穗中均表达,并在茎和鞘中表达相对较高;亚细胞定位分析表明,IPH1蛋白主要定位于过氧化物酶体中.进一步通过生理分析,发现突变体中过氧化物酶活性显著降低,同时H2O_(2)质量分数显著增加.这些结果初步证实了IPH1能够通过过氧化氢途径调控水稻株高的形成,可为丰富株高调控网络提供有利的基因资源,进一步为株型相关生物育种奠定基础.

Effect of Dominant Semi-Dwarf Gene on Plant Height and Its Related Traits and Sensitivity to Gibberellic Acid in Rice

Six pairs of tall and dwarf near-isogenic lines derived from a dominant semi-dwarf mutant （Y98149） were selected to study height expression and sensitivity to gibberellic acid （GA3）. The lengths of the 4-5th internode, the 3rd, 2nd, 1st internodes from the top and the panicle length in the six dwarf near isogenic lines were 97.2%, 53.3%, 65.1%, 61.9% and 94.7% of those in the six tall ones, respectively, indicating that the dominant semi-dwarfing gene significantly inhibited the internode elongation. Moreover, Y98149 （mutant type） was more sensitive to GA3 than Y98148 （wild type）, and had a lower GA3 concentration in plant, about 78% of Y98148.

基于深度相机的水稻穗层高度检测研究

为实现水稻穗层高度检测,基于深度相机对水稻穗层高度计算方法开展研究,以期为水稻割台高度控制、收割机智能化提供技术支持。为选择一种适用于水稻穗层分割的颜色空间,分别在RGB、HSV、LAB和i1i2i3颜色空间中对成熟水稻图像进行3D可视化,通过观察水稻穗层像素分布分析其可分离性;在此基础上,基于多阈值分割法、小联通区域移除、图像腐蚀等方法对水稻穗层进行提取;提出一种基于深度相机的水稻穗层高度(包括穗层最高高度H_(hs)、最低高度H_(ls))计算方法,并分别在实验室及田间进行验证试验。结果表明:水稻穗层在HSV颜色空间中具有较好的可分离性,所采用的图像分割、处理方法可有效提取水稻穗层;水稻穗层高度计算方法的实验室测试结果显示,H_(hs)与H_(ls)的计算误差均小于1.5%,田间测试结果显示H_(hs)与H_(ls)的计算误差分别为1.6%和18.2%。

基于RVoG模型的双极化SAR水稻株高反演

水稻株高被广泛应用于物候监测、水稻健康评估及产量预测等领域,极化合成孔径雷达(Polarimetric Synthetic Aperture Radar,PolSAR)信号能穿透水稻冠层记录水稻垂直结构信息,有助于实现高分辨率、大范围水稻株高提取。该文提出一种适用于非干涉条件下PolSAR数据水稻株高反演方法:利用极化SAR分解技术分离冠层及地表散射信号,引入随机地体二层散射模型(Random Volume over Ground,RVoG)对分解得到的水稻冠层散射能量进行建模,从而建立水稻株高反演模型;最后,联合邻域同质像素并利用NSGA-Ⅱ遗传算法对模型进行解算。利用2019年13景Sentinel-1影像在西班牙地区进行试验,水稻株高反演精度达到0.1 m,R^(2)达0.96以上,证明新方法能较好地适用于非干涉条件下PolSAR数据水稻株高反演。

水稻籼粳中间型杂交组合若干性状的遗传效应分析

【目的】水稻籼粳亚种间杂交具有强大的杂种优势已成为当前水稻育种关注的焦点,本研究旨在为籼粳交水稻育种实践以及水稻关键性状的遗传研究提供理论依据。【方法】按照NC-II不完全双列杂交方式,选择14个亲本材料并配组48个杂交组合,采用植物数量性状的加性-显性遗传模型(A-D模型)分析生育期、株高与粒形相关性状等共计5个农艺性状的遗传效应、杂种优势及性状之间的相关性。【结果】籼粳亚种间杂交稻生育期、株高、粒长、粒宽及长宽比等的加性方差分量占遗传主效应比率(V_(A)/V_(P))比值分别为69.2%、 74.2%、 58.9%、66.0%和63.5%。广义遗传率(H^(2)B)和狭义遗传率(H^(2)N)的变幅分别为59.0%~99.6%和69.2%~98.9%,均达显著或极显著水平,主要受加性效应控制,且受环境影响小,在育种上早期选择有效。大多数的籼粳亚种间杂种一代的生育期、株高和粒形性状均呈负向中亲优势和负向超亲优势,杂交后代的生育期缩短、株高降低,长宽比介于双亲之间。籼粳亚种间杂交稻生育期是一个独立遗传的品种特性,株高与粒形具呈显著正相关。【结论】在籼粳交育种上应关注生育期、株高,粒形等性状间的协调,有效利用杂种优势,培育强优势亚种间杂交稻新组合。

留桩高度对水稻壮香优系列新品种再生稻的影响试验

对壮香优1205品种进行了留桩高度对再生稻出苗、生育和成穗的影响试验研究。结果显示,留桩高度与再生稻的出苗时间、生育期及成穗率均存在关联。高度越高的留桩,其再生稻的出苗更快、生育期短,且成穗率也相对较高。这一研究为全州县的水稻生产提供了科技支撑,有助于推进水稻产业的高质量发展。

不同基质对罗汉果组培苗炼苗的影响

为研究不同基质对罗汉果无糖组培苗的影响,试验以6种不同基质对罗汉果无糖组培苗进行移栽炼苗试验,比较不同育苗基质对罗汉果无糖组培苗移栽炼苗的影响。结果表明,处理3基质植株生长最快、叶片最大、根系发达,但部分品种出现不明原因失绿且补肥效果有限,不是罗汉果最适合基质。处理6为全价育苗基质(纯草炭土型)∶珍珠岩∶碳化稻壳=2∶1∶1,该基质种植的种苗生长速度仅次于处理3,且整个育苗期罗汉果生长健壮,根系发达,是试验中最适合罗汉果无糖苗移栽炼苗的基质。此基质在不同季节均适用,在冬季使用效果更加明显,添加碳化稻壳使基质疏松、透气、颜色变深,多吸收太阳热能,提高土温,更有利于根系生长。

Identification of New Resistance Loci Against Sheath Blight Disease in Rice Through Genome-Wide Association Study

Sheath blight(SB) caused by the soil borne pathogen Rhizoctonia solani is one of the most serious global rice diseases. Breeding resistant cultivar is the most economical and effective strategy to control the disease. However, no rice varieties are completely resistant to SB, and only a few reliable quantitative trait loci(QTLs) linked with SB resistance have been identified to date. In this study, we conducted a genome-wide association study(GWAS) of SB resistance using 299 varieties from the rice diversity panel 1(RDP1) that were genotyped using 44 000 high-density single nucleotide polymorphism(SNP) markers. Through artificial inoculation, we found that only 36.5% of the tested varieties displayed resistance or moderate resistance to SB. In particular, the aromatic and aus sub-populations displayed higher SB resistance than the tropical japonica(TRJ), indica and temperate japonica sub-populations. Seven varieties showed similar resistance levels to the resistant control YSBR1. GWAS identified at least 11 SNP loci significantly associated with SB resistance in the three independent trials, leading to the identification of two reliable QTLs, qSB-3 and qSB-6, on chromosomes 3 and 6. Using favorable alleles or haplotypes of significantly associated SNP loci, we estimated that both QTLs had obvious effects on reducing SB disease severity and can be used for enhancing SB resistance, especially in improving SB resistance of TRJ sub-population rice varieties. These results provided important information and genetic materials for developing SB resistant varieties through breeding.

丙酰芸苔素内酯施用浓度对水稻植株性状和产量的影响

为了明确丙酰芸苔素内酯对水稻植株性状和产量的作用,采用单因素拉丁方设计,试验因素为0.003%丙酰芸苔素内酯水剂施用浓度,设4个处理,处理A稀释500倍液,处理B稀释2 000倍液,处理C稀释3 000倍液,处理D稀释4 000倍液,设喷施等量清水空白对照(CK),每个处理5次重复。收获前调查记录植株相关性状和产量构成因子,每个重复单独收获脱粒烘干测产。结果表明,水稻移栽后,丙酰芸苔素内酯稀释2 000倍液叶面喷施2次,植株高度为100.9 cm,分蘖数为23.0,穗下节间、倒2节间和倒3节间的长度分别为22.3、19.7和16.4 cm,每穗总粒数、实粒数和千粒重分别为137.2粒、128.9粒和32.1 g,产量为7 362.7 kg/hm~2。因此,0.003%丙酰芸苔素内酯水剂稀释2 000倍液可增加水稻植株高度、节间长度、分蘖数和提高产量。

杂交水稻机械收获减少稻谷产量损失度的关键技术研究

为了降低机收水稻的产量损失,2019—2022年以杂交中稻品种川优6203、内6优1787、内6优107、天优华占为材料,分别设置施氮方式、机收前植株湿润状态、收割株高、排风力度等处理对机收稻谷损失率的影响试验,并利用集成的机收减损技术进行多点大区比较示范。结果表明,底肥∶穗肥∶粒肥=6∶2∶2施氮方式的稻谷损失率仅2.51%,显著低于底肥∶蘖肥∶穗肥=5∶3∶2、底肥∶蘖肥=7∶3这两种施氮方式。机收前每hm^(2)喷清水1500 kg和3000 kg,机收时稻谷损失率分别高达9.30%和16.39%,均显著高于不喷清水的处理(5.17%)。无论何种品种,水稻机收割茎处距穗顶长度80 cm左右时稻谷损失率最低。低风力与传统人力半自动收割这两种收割方式间稻谷产量差异不显著,均比中、高风力收割方式显著增产。集成以上最佳试验处理为核心的机收减损技术大区对比示范,平均稻谷损失量仅208.5 kg/hm^(2),比大面积现有机收技术减少稻谷损失367.5 kg/hm^(2),减损效果显著。

0.003%丙酰芸苔素内酯对水稻生长、 产量和品质影响

为了明确丙酰芸苔素内酯对水稻生长、产量和品质的作用,秧苗期采用单因素完全随机设计,试验因素为0.003%丙酰芸苔素内酯水剂施用次数,设2个处理,处理A:喷施1次,处理B:喷施2次,设喷施清水空白对照(CK)。大田期采用单因素随机区组设计,试验因素为丙酰芸苔素内酯稀释倍数,设稀释1000倍液,2000倍液,3000倍液和4000倍液4个处理和一个喷施清水空白对照(CK)。秧苗期调查记录地上鲜重、地下鲜重,株高、根长和总根数,大田期调查记录水稻株高、有效穗数、每穗总粒数、结实率、千粒重和产量,并测定淀粉含量。结果表明,水稻秧苗期用0.003%丙酰芸苔素内酯水剂常规用量稀释2000倍液喷施1次,可显著提高秧苗素质,地上鲜重3.4 g,地下鲜重1.7 g,株高36.7 cm,根长16.3 cm,总根数50.7条;0.003%丙酰芸苔素内酯水剂常规用量稀释2000倍液或3000倍液在水稻移栽后5和12 d各喷施1次,对水稻提质增产效果明显。因此,0.003%丙酰芸苔素内酯水剂合理控制使用浓度和适期可以促进水稻生长发育。

早熟籼稻低留桩机收再生丰产优质增效栽培技术

针对现有杂交中籼稻高留桩机收再生栽培模式存在头季机收碾压严重、再生季生长期短等导致再生季产量不高、品质差的问题,结合区域生态气候特点和生产实际,创建了以“品种选择、适期早播、氮肥优化管理、干湿交替灌溉、低留桩收割(10~15 cm)”等措施为核心的早熟籼稻低留桩机收再生栽培模式。与杂交中籼稻高留桩机收再生栽培模式相比,新模式将再生季生育期延长了20~30 d,将头季与再生季温光资源的分配率由7∶3提高至6∶4,实现再生稻高产优质与资源高效协同。

水稻和陆稻分化相关性状的QTL分析及水旱不同栽培条件下连续选择的影响

本研究以来自云南的地方品种Ch5-10和Ch6-11为亲本,后代用SSD方法而得到的RIL9群体为试验材料,对水、陆稻差异性状(始穗期、剑叶宽、株高等)进行了考察,并利用SSR分子标记构建遗传连锁图谱,进行了各性状的QTL定位;在自然和人工选择的过程中,栽培稻无论是形态上还是基因组上,都发生多种多样的变化。利用F 2群体(父、母本和前述的SSD群体相同)采用Bulk混合选择的方法,在F 4代开始进行水、旱田两种条件下种植,以模拟水陆稻的分化条件,经过5代的种植后繁殖成株系,分别得到CA、CB两个群体。对这两个群体的水陆稻差异性状(始穗期、最高分蘖数、有效分蘖数、剑叶宽、株高等)进行了考察。结果表明,利用SSD方法而得到的RIL9群体对始穗期、剑叶宽、株高等3个性状进行QTL分析,两年共检测到19个QTL,分别位于1,2,3,7,8,9,11号染色体上。其中株高qPH-1效应最大,贡献率为22%(2009年安徽),16%(2009年北京),16%(2010年北京),表现为来自亲本Ch5-10的等位基因增加株高;利用Bulk方法而得到的CA群体(经过水田筛选5代、289个株系)和CB群体(经过旱田筛选5代、332个株系),考察其最高分蘖数、有效分蘖数、始穗期、株高、剑叶宽等5个性状。2009年安徽和北京两地试验发现:两群体间除安徽始穗期和北京剑叶宽差异不显著外,其他性状差异均达到极显著水平。根据氯酸钾抗性和低温发芽力的QTL定位结果,选择qSLtr-2、qSLratio-2、qRL28-2-1和qRL28-4附近的标记RM166、RM5472、RI05751和RM5979,及未定位到QTL的标记RM259对CA群体和CB群体进行基因型分析,两群体间t测验结果表明,RM5472、RI05751和RM5979差异均达到极显著水平,RM259和RM166差异不显著。说明在人工模拟水、陆稻选择的条件下这2个群体有了明显的分化。

早熟水稻品种的再生特性及留桩高度对产量的影响

再生稻是提高田间复种指数、增加水稻总产量的重要途径,为丰富早熟再生稻的研究内容,探究早熟水稻品种的再生特性以及适宜的留桩高度。本研究以两优336、双直一号、香53、香27为材料,其中两优336为对照,再生季设置5种留桩高度3~5 cm、8~13 cm、18~23 cm、28~33 cm、38~43 cm,考察与测定再生苗的生长发育能力和再生稻的产量。结果表明:不同水稻品种头季稻和再生稻生育期差异显著;相同品种的不同留桩高度处理下,再生稻的生育期和产量差异显著,留桩高度在一定程度上影响再生稻的生育期,生育期随留桩高度的增加表现出缩短趋势。在香53、香27、双直一号在留桩18~23 cm再生稻产量最高,两优336在留桩28~33 cm再生稻产量最高。

基于无人机多光谱遥感的水稻株高估测方法

针对数字表面模型计算水稻株高步骤繁琐、精度低的问题,提出了一种基于无人机多光谱植被指数的水稻株高估测模型。首先,在吉林省大安市水稻示范区采用无人机搭载一体式多光谱成像系统,获取地面采样距离为0.015 m的高清数字正射影像、数字表面模型和多光谱影像,并采集水稻实测株高;其次,基于多光谱影像数据提取反射率,计算了28种植被指数并根据他们与水稻株高的相关性进行优选,将优选后的植被指数与水稻株高利用不同的回归方法构建水稻株高估测模型并进行精度验证。结果表明:基于改良后冠层叶绿素含量指数MCCCI构建的幂函数水稻株高估测模型拟合效果最好,精度最高,R^(2)为0.876,RMSE为5.15 cm。所提出的无人机水稻株高估测方法为精准农业监测提供了新方向。

Mining Elite Alleles of Growth Duration and Productive Panicle Number per Plant by Association Mapping with Conditional Phenotypic Value in Japonica Rice

To provide genetic information and materials for breeding hybrid japonica rice with wide adaptability and strong competitive advantage of yield, elite alleles and their carrier varieties of growth duration （GD） and productive panicle number per plant （PN） were detected. A natural population composed of 94 japonica varieties was phenotyped for the GD, PN and plant height （PH） in two environments. The conditional phenotypic data were transferred by the linear model method in software QGAStation 1.0, and association mapping based on the unconditional and conditional phenotype values of GD and PN was analyzed by using general linear model in software TASSEL. A total of 34 simple sequence repeat （SSR） marker loci associated with GD and PN were detected in the two environments. Among them, 15 were associated with GD, and 19 were associated with PN. Four elite alleles of RM8095-120bp, RM7102-176bp, RM72-170bp and RM72-178bp were associated with GD, and their carrier varieties were Hongmangshajing, Nipponbare, Hongmangshajing and Nannongjing 62401, respectively. These elite alleles from the carrier varieties can shorten GD by 2.03-9.93 d when they were introduced into improved materials. RM72-182bp associated with PN was an elite allele, and its carrier variety was Xiaoqingzhong. It can increase PN by three when introduced into improved materials. Moreover, these elite alleles can be used to improve target traits without influencing another two traits.