甘蓝型油菜抗茎倒材料的筛选与候选基因挖掘

该研究采用茎秆抗折力指标评价了200份甘蓝型油菜种质资源抗茎倒伏能力,据此筛选出极端抗茎倒材料和不抗茎倒材料各1份,随后测定了2份材料成熟期茎秆的理化组分含量,并对2份极端抗茎倒差异材料蕾苔期、盛花期茎秆进行转录组测序分析,为甘蓝型油菜抗茎倒伏的遗传改良奠定基础。结果表明:(1)200份甘蓝型油菜种质资源的茎秆抗折力和茎粗均为正态分布,均属于数量遗传性状,并依据茎秆抗折力和农艺性状筛选出生育期相近,株型相似,茎秆粗度差异不显著,但茎秆抗折力差异显著的极端不抗茎倒材料GY172和抗茎倒材料GY199。(2)GY199的韧皮部比GY172更加致密,而GY172成熟期茎秆中的半纤维素、木质素、中性洗涤纤维及总可溶性糖含量均显著高于GY199,而其纤维素含量极显著低于GY199,即成熟期茎秆纤维素含量与这2个材料的茎秆抗折力呈正相关。(3)蕾苔期、盛花期茎秆转录组测序发现,碳代谢、碳固定、磷酸戊糖途径、氨基酸的生物合成、糖酵解/糖异生等途径的14个基因(BnaA10G0056100ZS、BnaC08G0455100ZS、BnaA08G0262400ZS、BnaC08G0239700ZS、BnaA07G0362300ZS、BnaC02G0081300ZS、BnaC04G0273000ZS等)以及纤维素合成相关的9个基因(BnaA05G0152200ZS、BnaA01G0411100ZS、BnaA03G0018900ZS、BnaA03G0037800ZS等)在抗茎倒材料GY199中显著上调表达,这些基因可能参与调控了茎秆强度性状,可作为油菜抗茎倒候选基因。     

水稻直立穗突变体抗倒伏性的遗传力分析

为研究直立穗突变体R1338和R334在抗倒伏特性方面的遗传力与配合力,选用弯曲穗型不育系川农1A、ABG15s和2个含有DEP1直立穗基因的直立穗不育系E69A、E102A,与蜀恢498及其直立穗突变体R1338、R334进行不完全双列杂交,比较F1基部各节的抗倒伏特性。发现F1基部各节抗折力与倒伏指数呈极显著负相关性,抗折力与茎节的直径和茎壁厚度呈极显著正相关;通过回归分析发现影响水稻基部节抗倒伏能力的主要影响因子为茎节的抗折力和弯曲力矩,抗折力越大、弯曲力矩越小其倒伏指数也就越低;2个直立穗突变体基部节倒伏指数的一般配合力效应值均低于野生型,其中R1338的倒伏指数的一般配合力效应值更低一些。因此利用直立穗亲本配组可以显著改良杂交后代的抗倒伏能力。     

一个新的水稻小粒矮秆基因的分子标记定位及效应分析

从水稻(Oryza safjva L．)半矮秆品种蜀恢I62中发现一份小粒矮秆突变体“I62d”。对I62d与4个半矮秆品种杂交F1和F2代的遗传分析表明,I62d的矮生性由一对隐性基因控制。以II-32B／162d F2代作定位群体,用分子标记将I62d突变基凶定位丁水稻第3染色体短臂,该基因与微卫星标记RM218和RMI57之间的遗传距离分别为3．5cM和10．0cM。同时,利用近等基因系分析了该基因的表型效应,结果表明它可使株高降为正常高度的1／4左右,籽粒降为正常大小的1／4左右,并使叶片显著缩短、加宽,结实率显著降低。我们认为162d突变基因是一个新的水稻小粒矮秆某因,暂命名为dI62(t）。     

不同养分和水分管理模式对水稻抗倒伏能力的影响

大田试验下,通过对水稻茎秆基部物理性状、形态特征和硅、钾含量的测定和比较,系统研究了不同养分和水分管理模式对水稻茎秆抗倒伏能力的影响．结果表明,有机无机肥配施,特别是秸秆与化肥配施(CS)养分模式可明显提高水稻植侏茎秆粗度、茎壁厚度和茎重,从而有效提高了基部茎秆的抗折力(RS)和明显降低了水稻的倒伏指数(LI),秸秆与化肥配施(CS)养分模式对水稻抗倒伏能力的效果在干湿交替(AWD)和控水模式(DRA)下表现更为明显。有机无机肥配施,特别是秸秆与化肥配施(CS)的养分模式在干湿交替(AWD)和控水模式(DRA)下更有助于提高水稻茎秆的硅、钾含量、相关分析表明,水稻基部茎秆茎壁厚度、茎重和抗折力与茎秆硅、钾含量存在显著(P<0．05)或极显著正相关(P<0．01)。     

Improvement of lodging resistance with QTLs for stem diameter in rice (Oryza sativa L.)

Varietal differences among ten rice cultivars showed that stem diameter is a key factor in lodging resistance (measured in terms of pushing resistance). Two near-isogenic lines (NILs) were selected from a series of chromosome segment substitution lines developed between cultivars Nipponbar and Kasalath, one containing a single stem diameter QTL (sdm8; NIL114), and another with four stem diameter QTLs (sdm1, sdm7, sdm8, sdm12; NIL28). Compared with the Nipponbare control, stem diameters were larger in NIL114 and NIL28 by about 7 and 39%, respectively. Pushing resistance in NIL28 was significantly greater than in Nipponbare, but NIL114 was similar to Nipponbare. The two NILs had greater weight of lower stem and culm wall thickness than Nipponbare. NIL28 had higher plant height, which is a negative effect on lodging resistance, than Nipponbare. The non-structural carbohydrate contents of NIL stems were higher than that of Nipponbare, whereas the silicon contents were lower in the NILs, and cellulose contents were lower only in NIL28. The basal internodes of the two NILs were significantly stiffer than those of Nipponbare. These results suggest that increasing stem diameter in rice breeding programs would improve lodging resistance, although the combination of multiple QTLs would be necessary to produce thicker stems with higher pushing resistance, whereas the higher plant height could also result from the combination of multiple QTLs.     

Midday photoinhibition of two newly developed super-rice hybrids

Super-rice hybrids are two-line hybrid rice cultivars with 15 to 20 % higher yields than the raditional three-line hybrid rice cultivars. Response of photosynthetic functions to midday photoinhibition was compared between seedlings of the traditional hybrid rice (Oryza sativa L.) Shanyou63 and two super-rice hybrids, Hua-an3 and Liangyoupeijiu. Under strong midday sunlight, in comparison with Shanyou63, the two super-rice hybrids were less photoinhibited, as indicated by the lower loss of the net photosynthetic rate (P _N), the quantum yield of photosystem 2 (Φ_PS2), and the maximum and effective quantum yield of PS2 photochemistry (F_v/F_m and F_v′/F_m′). They also had a much higher transpiration rate. Hence the super-rice hybrids could protect themselves against midday photoinhibition at the cost of water. The photoprotective de-epoxidized xanthophyll cycle components, antheraxanthin (A) and zeaxanthin (Z), were accumulated more in Hua-an3 and Liangyoupeijiu than in Shanyou63, but the size of xanthophyll cycle pool of the seedlings was not affected by midday photoinhibition. Compared to Shanyou63, the super-rice hybrids were better photoprotected under natural high irradiance stress and the accumulation of Z and A, not the size of the xanthophyll pool protected the rice hybrids against photoinhibition.     

水稻不同生育期茎秆生化成分的变化及其与抗倒伏能力的关系

以抗倒伏品种‘南粳44’、‘武运粳7号’与不抗倒伏品系‘宁7412’为试验材料,通过对水稻不同生育期茎秆硅、钾、钙、镁含量及可溶性糖含量的测定,结合氮钾肥配比试验,研究了水稻不同生育期茎秆硅、钾、钙、镁含量及可溶性糖含量的变化及其与茎秆抗倒伏能力的关系。结果表明：水稻茎秆的硅、钙、镁含量及可溶性糖含量随生育进程呈上升趋势,而茎秆的钾含量呈现先降后升的趋势。在不同施肥水平条件下,水稻茎秆的硅、钾、钙、镁含量及可溶性糖含量存在一定的差异。抗倒伏品种‘南粳44’和‘武运粳7号’茎秆基部抗折力较强,施肥对水稻茎秆基部抗折力有一定的影响。水稻生殖生育期茎秆的硅含量、可溶性糖含量与茎秆基部抗折力呈极显著正相关（P〈0.01）,与水稻抗倒伏能力的强弱有一定的关系。     

Heterosis breeding in rice (Oryza sativa L.)

Summary Studies conducted at the International Rice Research Institute (IRRI) during 1980 and 1981 have shown up to 73% heterosis, 59% heterobeltiosis and 34% standard heterosis for yield in rice. The latter was estimated in comparison to commercial varieties: IR36 and IR42 (yield 4–5 t/ha in wet season trials and 7–8 t/ha in dry season trials). Generally speaking, absolute yield was lower and extent of standard heterosis was higher in wet season than in dry season with some exception. Yields up to 5.9 t/ha (22% standard heterosis) in the wet season and 10.4 t/ha (34% standard heterosis) in the dry season were obtained. Most of the hybrids performed better in some season while some performed better in both seasons. Hybrids showed better lodging resistance although they were 5–10 cm taller. F₁ hybrids had significant positive correlations with the parental traits viz., yield (r = 0.446), tillering (r = 0.746), height (r = 0.810) and flowering (r = 0.843). Selection of parents among elite breeding lines on the basis of their per se yield performance, diverse origin and resistance to insects and diseases should give heterotic combination. Yield advantage of hybrids was due primarily to increase in number of spikelets per unit area even though tiller number was reduced. Grain weight was either the same or slightly higher. High yielding hybrids also showed significant heterosis and heterobeltiosis for total dry matter and harvest index. For commercial utilization of heterosis in rice, effective male sterility and fertility restoration systems are available and up to 45% natural outcrossing on male sterile lines has been observed. Consequently, F₁ rice hybrid have been successfully developed and used in China. Prospects of developing hybrid rice varieties elsewhere appear bright especially in countries that have organized seed production, certification and distribution programs and where hybrid seed can be produced at a reasonable cost.     

水稻茎秆形态结构特征和化学成分与抗倒伏关系综述

水稻茎秆形态结构特征和化学成分与其抗倒伏性能相关。本文对水稻茎秆高度、茎秆基部第1、2节间长度、茎秆粗细、茎壁厚度、厚壁组织(机械组织)数量和强度、维管束数量、细胞壁纤维素和木质素含量、细胞中碳水化合物积累的数量、硅与钾的含量以及茎秆抗倒伏相关的QTL等与水稻的抗倒伏性的相互关系进行了综述,为水稻抗倒伏优良品种性状的选育提供参考。     

小麦种质抗倒性的评价和抗倒性状的相关与通径分析

对９６份小麦种质资源的抗倒性进行了鉴定评价,筛选出高抗型材料９份,其中４份是丰源,表明抗倒性能够与丰产性状很好地协调结合。对抗倒性状的相关分析表明,在株高相差较大的情况下,株高和重心高度对抗倒性十分重要。但在对株高相差不大的情况下,茎秆的机械强度是主要决定因素,对于株高较高的材料,重心高度对抗倒性有较大影响;对于较矮的材料,基部第一节间长度则较为重要。通径分析结果进一步表明,茎秆机械强度对抗倒性的     

稻鸭共作下水稻植株的壮秆效应及生理特性

通过田间小区对比试验,分析了稻鸭共作下水稻植株的壮秆效应及其相关生理特性.结果表明：由于鸭子在稻田的活动使水稻植株形态发生了明显变化,植株碳水化合物含量、植株碳氮比、茎秆干物质输出率都明显增加,茎秆基部节间长度比对照缩短2.88%,茎粗增加64.90%,茎秆强度和抗倒伏指数也分别提高了11.78%和10.95%;稻鸭共作提高了水稻深层根系比例和根系活力,黑根比例降低了16.63%.因此,稻鸭共作对水稻植株有壮秆效应,提高了植株的抗逆性,有利于水稻稳产高产.     

套作大豆苗期茎秆纤维素合成代谢与抗倒性的关系

为从茎秆强度的角度研究套作大豆苗期对荫蔽胁迫的响应及耐荫抗倒机制,采用耐荫性不同的3个大豆材料,在玉米大豆套作和单作两种种植模式下,对茎秆的纤维素、可溶性糖、蔗糖、淀粉含量及蔗糖代谢中关键酶活性以及茎秆抗折力、抗倒伏指数等进行测定,研究它们与套作大豆苗期倒伏的关系.套作大豆苗期倒伏严重,茎秆抗折力、抗倒伏指数、纤维素、可溶性糖、蔗糖、淀粉含量和相关酶活性均显著低于单作.不同大豆材料受套作荫蔽影响程度不同,强耐荫性大豆南豆12茎秆抗折力降低幅度最小,在套作环境下其茎秆抗折力、抗倒伏指数大,纤维素、可溶性糖、蔗糖、淀粉含量高,酶活性强.相关分析表明： 套作大豆苗期茎秆糖含量均与抗折力呈极显著正相关,与倒伏率呈极显著负相关;蔗糖含量与蔗糖磷酸合酶(SPS)、蔗糖合酶(SS)、中性转化酶(NI)活性呈极显著正相关,与酸性转化酶(AI)活性相关性不显著;纤维素含量与SPS、SS呈极显著正相关,与NI呈显著正相关,与AI相关性不显著.套作环境下,强耐荫性大豆苗期茎秆中较高的SPS、SS活性是其维持高蔗糖和纤维素含量的酶学基础,而高纤维素含量有利于提高茎秆强度,进而增强其抗倒伏能力.本研究应用玉米大豆套作种植系统,从苗期抗倒角度,探明了光环境对不同基因型大豆茎秆纤维素代谢的影响机制,为下一步筛选耐荫抗倒大豆品种提供了理论依据.     

水稻茎秆解剖结构与抗倒伏能力关系的研究

利用石蜡切片法研究了抗倒伏水稻品种南粳44、武运粳7号与不抗倒伏水稻品系宁7412基部茎秆解剖结构及其与水稻抗倒伏能力的关系.结果表明:抗倒伏水稻品种南粳44和武运粳7号基部节间的维管束数目较多,维管束鞘较厚,细胞层数较多,细胞排列紧密、体积较小;而不抗倒伏水稻品系宁7412基部节间的维管束数目偏少,维管束鞘较薄,细胞层数较少,细胞体积大.从解剖结构还可看出,南粳44和武运粳7号茎秆内的贮藏物质明显多于宁7412.这些茎秆解剖结构的差异可用于区分不同水稻品种(系)的抗倒性强弱,可以作为抗倒伏水稻品种的选育指标和筛选依据,为水稻抗倒伏品种的选育提供了理论依据.     

Photosynthetic light and CO2 utilization and C4 traits of two novel super-rice hybrids

Characteristics of photosynthetic light and CO2 use efficiency from seedling to heading stage, and C4 pathway enzyme activities in both flag leaves and lemma were compared between two newly developed super-rice hybrids (Oryza sativa L.), Liangyoupeijiu and Hua-an 3, and a traditional rice hybrid, Shanyou 63. At seedling and tillering stages, Liangyoupeijiu and Hua-an 3 had higher net photosynthetic rates (Pn) and light saturated assimilation rates (Asat) than did Shanyou 63, at both normal (360 micromol mol(-1)) and doubled (720 micromol mol(-1)) CO2 concentrations. At the heading stage, the flag leaves of all three rice hybrids had similar Pn and Asat. However, the two super-rice hybrids had higher apparent quantum yield (AQY) and carboxylation efficiency (CE) during all three typical developmental stages, and higher quantum yield of CO2 fixation (PhiCO2) at the tillering and heading stages. In addition, Liangyoupeijiu showed significantly higher activities of the C(4) pathway enzymes in both flag leaves and lemmas than did Shanyou 63. As a result, flag leaves of the two super-rice hybrids had higher Pn at morning, noontime and late afternoon during the daily cycle. Since most of the grain yield of rice comes from the photosynthesis of flag leaves, the similar Asat and much higher AQY, CE and PhiCO2 at heading stage of the two super-rice hybrids indicates that higher photosynthetic efficiency rather than higher photosynthetic capacity may be the primary factor contributing to their higher grain yields.     

水稻籼粳交DH群体收获指数及源库性状的QTL分析

以 1个水稻籼粳交 (圭 6 30 0 2 4 2 8)来源的DH群体为材料 ,利用 1张含有 2 32个标记的RFLP连锁图谱和基于混合线性模型的定位软件QTLMapper1 0对水稻收获指数及生物量、籽粒产量、库容量和株高 5个性状进行QTL分析 ,共检测到 2 1个主效应QTLs和 9对上位性互作位点。其中 ,控制籽粒产量的 3个QTLs合计贡献率为 4 2 % ,LOD值为 7 10 ;这 3个QTLs或者与收获指数的QTL同位 ,或者与生物量的QTL同位 ,且加性效应的方向一致 ,从而揭示了“籽粒产量 =生物量×收获指数”的遗传基础所在。控制收获指数的 4个QTLs合计贡献率为 4 6 % ,LOD值为 10 3;控制生物量的 4个QTLs合计贡献率为 6 4 % ,LOD值为 14 0 9;收获指数的 4个QTLs与生物量的 4个QTLs均不同位。因此 ,通过基因重组 ,可能实现控制收获指数和生物量的增效基因的聚合 ,由此获得收获指数和生物量“双高”的基因型。检测到 5个株高QTLs,其合计贡献率为 6 4 % ,LOD值为 11 6 2 ;其中 ,有 3个效应较小的QTLs与生物量、库容量和 或籽粒产量QTLs同位 ,且同位QTLs的加性效应方向一致 ;未发现株高QTLs与收获指数QTLs的同位性。由此表明 ,株高与“源 流 库”概念中的“源”和“库”在遗传上有一定程度的关联 ,而与“流”无关联。此外还发现 ,在上述同位性QTL     

高产早籼稻群体动态结构的差异

1998年早季在广州研究了不同类型高产早籼稻群体动态结构差异,结果认为:两系法杂交稻高产新组合培矮64s/E32、培矮64s/9311、粤杂122,其幼穗第2次枝梗原基分化期以前的植株干物重、叶面积指数（LAI）比常规稻高产品种粤香占和特三矮2号表现出明显的生长优势。培矮64s/E32在5个供试材料中在始穗期的LAI最高,达7.81,干物重日增量最大,达8.76kg/亩·d;粤香占的每亩有效穗数最高,达23.3万穗/亩,收获指数是所有参试材料中唯一达到 0.6以上者。     

作物抗倒伏相关性状及其信号转导调控机理的研究进展

倒伏是影响作物品种选育和产业化推广的重要限制因子,会使作物籽粒与秸秆的产量和品质显著降低且易引发病虫害,不利于机械化收割使作物经济效益显著降低.株高、茎秆强度、壁厚、分蘖数、分蘖夹角等性状同作物茎秆抗倒伏特性密切相关.倒伏主要分为为根倒伏和茎倒伏,茎倒伏与茎秆特性相关,其中株高与分蘖数分别受赤霉素信号转导和独脚金内酯信...     

Characterising the morphological characters and carbohydrate metabolism of oat culms and their association with lodging resistance

• Lodging resistance can be improved by enhancing the mechanical strength of culms, and culm carbohydrates could improve this mechanical strength. Culm carbohydrates can regulate development of the culm and affect its toughness.
• The present study determines the relationship between lodging and carbohydrate content in oat culms. Field experiments were conducted in alpine regions in 2017 and 2018 using three oat varieties with different lodging resistance. Lodging‐related morphological characteristics were directly determined and culm carbohydrate content and enzyme activity related to cellulose synthesis and sucrose metabolism were evaluated with ultraviolet spectrophotometry.
• Results showed that the lower the gravity height or the lower ratio of gravity height to plant height, the stronger the lodging resistance of the varieties. Higher culm nonstructural (NSC) and structural (SC) carbohydrate content contributed to the ability of culms to resist lodging, especially the content of cellulose and sucrose. PCA showed that sucrose metabolism and SC content were closely related to lodging resistance. Correlation analysis showed that the lodging index (LI) was significantly negatively correlated with NSC. Sucrose content was highly and significantly positively correlated with NSC. Additionally, the activities of sucrose phosphate synthase (SPS) and sucrose synthase (SS) were highly and significantly positively correlated with sucrose and cellulose content.
• The relationship between field characters and oat lodging, as well as the regulatory mechanism of carbohydrate content on lodging resistance of the culm are discussed.

     

QTLs linked to leaf epicuticular wax,physio-morphological and plant production traits under drought stress in rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.)

Drought stress is the major constraint to rice (Oryza sativa L.) production and yield stability in rainfed ecosystems. Identifying genomic regions contributing to drought resistance will help to develop rice cultivars suitable for rainfed regions through marker-assisted breeding. Quantitative trait loci (QTLs) linked to leaf epicuticular wax, physio-morphological and plant production traits under water stress and irrigated conditions were mapped in a doubled haploid (DH) line population from the cross CT9993-5-10-1-M/IR62266-42-6-2. The DH lines were subjected to water stress during anthesis. The DH lines showed significant variation for epicuticular wax (EW), physio-morphological and plant production traits under stress and irrigated conditions. A total of 19 QTLs were identified for the various traits under drought stress and irrigated conditions in the field, which individually explained 9.6%–65.6% of the phenotypic variation. A region EM15_10-ME8_4-R1394A-G2132 on chromosome 8 was identified for leaf EW and rate of water loss i.e., time taken to reach 70% RWC from excised leaves in rice lines subjected to drought stress. A large effect QTL (65.6%) was detected on chromosome 2 for harvest index under stress. QTLs identified for EW, rate of water loss from excised leaves and harvest index under stress in this study co-located with QTLs linked to shoot and root-related drought resistance traits in these rice lines and might be useful for rainfed rice improvement.     

不同小麦品种茎秆特性及其与抗倒性的关系

以黄淮麦区优良品种矮抗58、周麦18、豫麦49、百农418为研究对象,采用田间试验与实验室分析相结合的方法,对不同小麦品种在不同生育时期的抗倒伏性状进行研究.结果表明: 茎秆机械强度在开花期至花后20 d处于较高水平,在花后30 d明显下降;倒伏指数在开花期最小,花后30 d最大,其余两个时期处于中间水平.相关分析表明,开花期机械强度与重心高度呈显著负相关,与纤维素、木质素含量呈显著正相关,倒伏指数与节长、株高、重心高度呈显著正相关,与纤维素、木质素含量呈显著负相关;花后10 d和花后20 d机械强度与节长、株高、重心高度呈显著负相关,与茎粗、纤维素、半纤维素、木质素含量呈显著正相关,倒伏指数这段时期正好与之相反;花后30 d机械强度与株高、重心高度呈显著负相关,倒伏指数与株高、重心高度呈显著正相关,与木质素含量呈显著负相关.因此,明确各个生育时期与抗倒性相关的茎秆特性,可为黄淮麦区高产抗倒性品种的选育提供依据.