Developing rice lines possessing neutral alleles at sterility loci to improve the width of compatibility

To improve the width of compatibility for overcoming various sterilities in inter‐subspecific hybrid rice, some elite lines combining several sterility‐neutral genes were developed and the effects on mitigating various hybrid sterilities were tested. From Akihikari// IR36/Dular, neutral genes at ga11 and six sterility loci, S5, S7, S8, S9, S15 and S16, were combined and elite lines were obtained in their successive progeny. Four of the lines tested were confirmed to combine the neutral alleles S5‐n, S7‐n, S8‐n, S9‐n, S15‐n and S16‐n at the sterility loci and, among them, two harboured an additional gamete abortion‐neutral allele, ga11‐n. F₁s, which used the lines and various testers as parents, mitigated the spikelet sterilities by six sterility loci and gamete abortion by a gametophyte gene, ga11. These lines could be selectively used as parents or donors to increase the width of compatibility of rice varieties for improving fertility in inter‐subspecific hybrid rice breeding.     

两套水稻籼粳交DH群体的亲和性及其遗传分析

以两套水稻籼、 粳交DH群体为材料, 研究了籼、 粳程度及籼、 粳基因组的比例与亲和性 的关系, 结果 表明, 两套群体与籼、 粳测交F1小穗的育性与DH系的籼、 粳程度及基因组比例存在相 关, 但广亲和DH系(与籼和与粳测交F1小穗育性均大于70%)在籼、 粳程度及基因组比例 上的特异性不明显。 通过DH系与籼、 粳测交F1小穗育     

栽培稻的基因型差异程度和分类

本文利用来自一个籼/粳交(圭630/02428)的双单倍体(DH)系和由多种类型的籼、粳品种(系)组成的对照组,从分子水平上研究亚洲栽培稻的基因型差异。结果表明,栽培稻中存在两种主要的差异类型,即质的差异和量的差异。前者主要存在于籼、粳分化程度比较高的对照组中,85%以上的有关位点已经发生了籼或粳的分化趋向;后者主要存     

Wide compatibility in rice (Oryza sativa L.)

Summary Wide compatible varieties (WCVs) show normal spikelet fertility in crosses with Indica and Japonica rice varieties. Crosses of Indica and Japonica varieties frequently show high spikelet sterility which prevents exploitation of heterosis for grain yield. We screened 41 rice varieties for the wide compatibility trait by crossing each with three Indica and three Japonica testers. Varieties giving fertile F₁ hybrids with both groups of testers were classified as WCVs. Seven varieties viz., BPI-76 (Indica); N 22; Lambayeque-1 and Dular (Aus); Moroberekan, Palawan and Fossa HV (Japonicas), were identified as WCVs. The frequency of WCVs was higher among Aus and Japonicas. The wide compatibility trait in varieties: Dular and Moroberekan was controlled by a single dominant gene linked with the Est-2 and Amp-3 loci (mean recombination 32.0%). Est-2 and Amp-3 showed complete linkage. Pgi-2 was found to be linked with Est-2 and Amp-3 (mean recombination 16.1%). Est-2 and Amp-3, showed a tighter linkage with C ⁺ (mean recombination 4.1%). Pgi-2 showed a lower linkage with C ⁺ (mean recombination 17.3%). The recombination values between the WC gene in Dular and C ⁺ was much higher than those reported in Japan for the WC gene (S₅ ⁿ) from Ketan Nangka. It is possible that the WC gene from Dular is different from that in Ketan Nangka. Linkage intensities with the WC gene were not strong enough to be of use for indirect selection for the wide compatibility trait. A search for a more closely linked isozyme or DNA marker was proposed.     

Analysis of Vietnamese rice germplasm provides an insight into Japonica rice differentiation

Genetic differentiation among landraces of rice in northern Vietnam that lie in the centre of genetic diversity of Asian cultivated rice was analysed using DNA markers, and morphological and physiological traits to obtain an insight into the genetic differentiation of Asian rice. Principle coordinate analysis, based on nuclear RFLP data, divided Vietnamese rice varieties into three groups, designated A, B and C. Chloroplast DNA variation discriminated group A, which corresponded to the Indica rice varieties, from both groups B and C, which corresponded to the Japonica rice varieties. Physiological characteristics for Indica‐Japonica and tropical‐temperate Japonica discrimination suggested groups A and B consisted of typical Indica and Japonica varieties, respectively, while the characteristics of group C were distinct from those of the other two groups. This suggests that the genetic differences between groups B and C represent a new aspect of genetic variation that has not been previously reported in Japonica rice. Groups C and B corresponded with upland and lowland rice, respectively. Eight marker loci were associated with upland‐lowland differentiation in Japonica rice. Highlighted chromosomal regions might have been selected during the history of cultivation under different cultural conditions, and thus contain genes related to adaptation.     

Impact of Humidity on Temperature-Induced Grain Sterility in Rice (Oryza sativa L)

High temperature‐induced grain sterility in rice is becoming a serious problem in tropical rice‐growing ecosystems. We studied the mechanism of high temperature‐induced grain sterility of different rice (Oryza sativa L) cultivars at two relative humidity (RH) levels. Four varieties of Indica and Japonica rice were exposed to over 85 % RH and 60 % RH at 36/30 °C, 34/30 °C, 32/24 °C and 30/24 °C day/night air temperatures from late booting to maturity inside sunlit phytotrons. Increasing both air temperature and RH significantly increased spikelet sterility while high temperature‐induced sterility decreased significantly with decreasing RH. Neither Indica nor Japonica rice types were superior to the other in the response of their spikelets to increased air temperature and RH. Increased spikelet sterility was due to increased pollen grain sterility which reduced deposition of viable pollen grains on stigma. Reduction in sterility with decreased RH was more due to decreased spikelet temperature than to air temperature. Thus the impact of RH should be considered when interpreting the effect of high temperature on grain sterility. Spikelet fertility was curvilinearly related to spikelet temperature. Grain sterility increased when spikelet temperature increased over 30 °C while it became completely sterile at 36 °C. The ability of a variety to decrease its spikelet temperature with decreasing RH could be considered as avoidance while the variability in spikelet sterility among varieties at a given spikelet temperature could be considered as true tolerance.     

Morphological Classification of Traditional Philippine Upland Rice Cultivars in Upland Nurseries Using Cluster Analysis Methods for Recommendation, Breeding and Selection Purposes

Using eight morphological parameters with six cluster analysis methods, a set of 21 traditional and four improved Philippine upland rice cultivars (cvs) could be separated into five groups: (1) improved semi-dwarf plant type, (2) improved or 'moderately modified' (short) Indica plant type, (3) traditional tall Indica plant type, (4) traditional tall Japonica plant type and (5) traditional short Japonica plant type. The results emphasized the importance of the separation into Indica and Japonica plant types, but the cultivars could be classified more accurately using growth characteristics such as tillering ability, followed by plant height and leaf area parameters. The clusters containing Indica cvs consistently showed a higher tiller number per plant, a higher growth stage (DC classification) and narrower leaves than clusters with Japonica cvs. The parameters culm length, plant height, leaf area, leaf length and width were represented in subgroups with both long and short expression of the respective characteristic. Use of the existing variability of morphological traits within the group of traditional upland rice cvs should be beneficial in recommendation, breeding, selection and development of upland rice cvs for the different rice ecosystems as well as for the upland rice/rice blast pathosystem.     

上海地区水稻已知品种SSR指纹图谱库构建

用24对引物构建上海地区53份水稻品种的DNA指纹图谱,为当地水稻新品种保护、遗传资源评价及亲缘关系分析提供理论依据和技术支持。结果显示,实验中共检测出109条多态性片段,变幅2~9条,平均每对引物4.5417条多态性片段,有效等位基因数为70.8187,平均每个标记2.9508个;Shannon多样性指数(Ⅰ)平均值为1.1296,变幅0.4949~1.8402;多态性信息含量(PIC)平均值为0.5415,变幅0.2656~0.8001。用24个标记建立53份材料的DNA指纹图谱,这些字符串就构成了这53份材料的“身份证号码”,本实验中,各材料的分子身份证号码是唯一的;聚类分析表明,在遗传相似系数0.21处可以将53份材料分为2个类群,分别为粳稻组和籼稻组,但是组内遗传距离较近。由此可见,上海地区水稻品种的遗传多样性相对狭窄。     

Increased regeneration from NaCl-tolerant callus in rice

Summary NaCl-tolerant calli were selected from two Japonica and two Indica rice (Oryza sativa L.) cultivars on basal media containing 6,000, 9,000, 12,000 or 15,000 ppm NaCl. Frequency of callus formation decreased with the increase of NaCl in the medium, especially in Indica. About half of the calli of Japonica cultivars selected on NaCl-ammended media survived 20,000 ppm NaCl but none of the Indica callus survived. In Japonica, more plants were regenerated from calli selected on all concentrations of NaCl media than from NaCl-free medium. Concentration of Cl^- in callus increased dramatically with increased NaCl content but peroxidase activity decreased.     

水稻亲本遗传分化程度与籼粳杂种优势的关系

本文利用两套材料,即来自一个籼／粳交（圭６３０／０２４２８）的双单倍体（ＤＨ）系和另一组由多种类型的籼、粳组成的对照组,从分子水平上研究了水稻亲本的遗传分化程度。在此基础上探讨了亲本的遗传分化程度与籼粳杂种优势的关系。两套测交Ｆ１群体的结果一致表明,亲本遗传分化程度对穗数和千粒重的影响相对较小,但是对每穗结实粒数和结实率这两项体现育性的指标影响较大。当亲本遗传分化综合指数ＴＤｊ值为２０￣２５时,育     

水稻种子耐干性机理的研究

以籼稻C38、粳稻京21、杂交稻秋优3为材料,进行种子超干储藏特性的研究,进而探讨种子耐干性的机理。通过超干水稻种子生活力和活力的比较,发现籼稻C38耐干性较强。超干有利于保持种子抗氧化酶系统的完整性,因此超干能提高种子的耐储性。对超干种子可溶性糖含量与组分进行分析,结果表明随着种子含水量的降低,蔗糖含量增高,多糖和葡萄糖含量降低,籼稻C38的蔗糖含量明显低于粳稻京21和杂交稻秋优3。用热重仪测定的种子含水量与烘干法得到的数据相吻合,用差示热量扫描仪测定束缚水/自由水的比例和玻璃化转变温度Tg,发现籼稻C38的Tg高于粳稻京21和杂交稻秋优3,籼稻C38束缚水/自由水比例大于粳稻京21和杂交稻秋优3,而束缚水/自由水的比例与耐干性成正相关。由此表明,耐干性在不同的水稻品种间有明显的差异,籼稻C38的耐干性较强。     

Indica-Japonica differentiation of paddy rice and its relationship with heterosis

The Indica‐Japonica differentiation of three photoperiod‐sensitive and/or thermosensitive genetic male‐sterile rice (PGMS or TGMS, respectively) lines and 47 male parental lines from seven ecotypes were studied for their restriction fragment length polymorphism marker data to determine which ecotype crosses with the three PGMS and/or TGMS lines could lead to higher yield potential, and to estimate the relationship between the Indica‐Japonica differentiation of parents and heterosis in grain yield and its components. The results indicated that hybrids derived from ‘N422s’ and the early‐middle ripening Indica varieties from southern China, and hybrids between ‘Pei'ai64s’ and three Japonica ecotypes, including North‐eastern Japonica varieties, restoring lines of Japonica hybrid rice and north China Japonica varieties, showed the highest grain yields. There was less variation of yield among the F1s between ‘108s’ and the seven ecotypes than among the other F₁s. Highly significant positive correlations between heterosis of the F₁ yield and genetic distance of the parents were detected, although the correlation between F₁ yield performance and genetic distance did not reach a significant level. Considerable variation of correlation between heterosis and genetic distance was also detected in the Indica × Indica crosses and Indica × Japonica crosses. There was much higher correlation (r = 0.63) between the F₁ yield performance and the genetic distance of parents in the Indica × Indica crosses than in the others. It is proposed that a genetic distance of 0.4‐0.8 between the two parents of hybrid rice might be appropriate not only for F₁ performance, but also for heterosis.     

水稻粳型恢复系 C57的选育

1.粳恢 C57具有较高配合力,杂种一代具有较强优势,花粉量大,有利于提高异交结实率,是当前较好的广谱恢复系。2.籼粳杂交复交与配子利用的“架桥”制恢方法,在杂种一代提供利用部分籼核的机率,丰富了遗传基础,为间接利用籼粳杂种优势及其优良性状开辟了途径。3.粳恢 C57对杂种一代的株型、叶型、高产的“库”和“源”以及适应     

籼粳亚种间杂种育性相关基因座全基因组分析

利用一套以粳稻品种Asominori为遗传背景、籼稻品种IR24为染色体片段供体的覆盖全基因组的CSSL群体，研究了籼粳亚种间组合Asominori/IR24和02428/IR24杂种小穗低育性的遗传基础。结果发现，Asominori/IR24组合的育性主要受第5染色体上的2个育性位点S-24(t)和S-31(t)及第6染色体上的 S-5位点控制，其中S-31(t)为本研究发现的新育性位点，粳稻品种02428带有该位点的亲和性基因。02428/IR24组合的低育性主要受S-24(t)花粉育性位点的影响。育性基因的表达受遗传背景的影响，在粳稻遗传背景中，S-24(t)位点处在Sⁱ/S^j杂合基因型时可使杂种小穗育性下降70%左右，而S-31(t)和 S-5为杂种半不育位点。在籼粳全基因组杂合遗传背景中，当S-5ⁱ/S-5^j基因型置换成S-5ⁱ/S-5ⁱ基因型后，亚种间杂种小穗育性可平均提高22.5%，接近正常育性水平。在S-5ⁱ/S-5^j遗传背景中，S-24(t)和S-31(t)的Sⁱ/Sⁱ纯合基因型不能改善亚种间杂种的小穗育性。说明S-5位点是影响亚种间小穗育性的关键位点，在亚种间杂交稻育种中，必须首先克服S-5位点造成的育性障碍。提出了等位基因置换法克服水稻籼粳亚种间杂种小穗低育性的技术策略。     

水稻不同品种糙米含钙量的差异

采用盆栽土培法,研究了5个类型共89个水稻品种糙米含钙量的差异。结果表明,不同类型品种糙米含钙量差异显著。89个水稻品种糙米含钙量变化范围为44.5~245.5mg/kg。5种类型水稻糙米含钙量由高到低依次为：常规粳稻、杂交晚籼、常规晚籼、常规早籼、常规中籼。     

东北地区水稻种质资源遗传多样性分析

以能够代表东北地区水稻当前育种动态的区域试验品种(系)为试材,利用SSR标记分析了东北稻区水稻种质资源地区问和品种间的遗传多样性差异以及亲缘关系.结果表明,东北稻区整体的遗传多样性狭窄,明显低于国内其他稻区水平.在103个多态性位点上共检测到303个等位基因,平均每个位点只有2.94个,并且等位基因分布也极不均匀.不同染色体问的遗传多样性分析结果表明,Chr.6、Chr.9、Chr.11三条染色体的多态性位点分布较均匀且多态性信息含量也较多,整体遗传多样性丰富程度高于其他染色体.结果还发现,三个省份中黑龙江地区的品种整体纯合程度最高的,吉林次之,辽宁最低.东北三省水稻遗传多样丰富程度排序是:黑龙江>吉林>辽宁.通过遗传聚类分析显示,吉林与黑龙江的整体亲缘关系较近,相对地与辽宁较远.     

四引物分子标记鉴定水稻光合效率基因TAC1的不同基因型

水稻(Oryza sativa)的株型含株高、分蘖、穗型和叶型等性状,其表现与光合效率直接相关。一般地,籼稻(Oryza sativa ssp.xian)株型松散,而粳稻(Oryza sativa ssp.geng)更为紧凑。松散型的籼稻自身遮蔽少,通风好,植株光合效率高;紧凑株型的粳稻适应密植,通过提高单位面积植株数量提高总体光合效率。控制籼粳稻分蘖角度差异的主效基因是TAC1基因。相比TAC1xian,发生在tac1geng的3'非翻译区(3'UTR)的A→G突变导致mRNA稳定性下降,从而影响了粳稻的株型。2个等位基因分别属于单株高光效基因型和整体高光效基因型,处于杂合状态下还可互补,因此建立可精确选择TAC1等位基因的分子标记在育种实践中意义重大。本研究利用扩增受阻突变系统(amplification refractory mutation system,ARMS)的原理,开发出包含4条引物的共显性分子标记,鉴定TAC1的功能单核苷酸多态性(functional nucleotide polymorphism,FNP)。该分子标记命名为tac1fnp,同TAC1完全连锁,一次PCR反应即可精确区分2种等位基因及杂合基因,有助于水稻的高光效分子标记辅助选择育种。     

新麦草Psathyrostachys juncea遗传变异的细胞学和分子的分析

本文用染色体C分带、同功酶和RAPD技术分析了来自不同地理分布的新麦草不同材料的单株,观察其c带的多态性,即同源染色体的配对,相同材料的不同个体之间,同一地区不同材料之间,以及不同来源的材料之间的多态性。10个同功酶揭示了14个假定标记位点,其中11个显示了多态性(平均66.2％,每个位点具2.6个等位基因)。大量的等位变化发生在多数的多态位点上。在所用试材中有近90％的等位变化。在优化条件下,200个测试引物中有55.5％的材料间产生了多态性的RAPDs带型。在同一材料中和不同材料间分别有55.7％和47.8％的扩增片断是多态的。C—带、同功酶和RAPD分析结果是互相确证而高度一致的,为新麦草的遗传变异提供了模式。 新麦草具有抗旱、耐盐碱和抗黄矮病的特性,可以在小麦育种工作上加以利用。     

旱作对籼粳稻产量及相关性状的影响

研究了旱作对籼、粳亚种间产量及其相关性状的影响,并用逐步回归分析法建立亚种间水稻旱作的产量回归模型。研究表明,旱作在生育期、分蘖数、有效穗、穗长、株高、总粒数、结实率、千粒重等性状上对籼型品种的影响较粳型品种的影响大。在旱作条件下,粳型产量总体表现比籼型品种高。     

水稻广亲和与非广亲和品种蛋白质的比较研究

本文对水稻广亲和与非广亲和品种种子蛋白质组分进行了单向和双向电泳分析，获得了较清晰而稳定的结果。发现籼稻和粳稻亚种间电泳图谱有明显差异，而广亲和与非广亲和品种间蛋白组分未发现规律性的差异。又用SDS-PAGE方法比较了广亲和与非广亲和品种水稻叶片、花药的蛋白组分，未现4个广亲和品种水稻花药蛋白质中均有一条共