Comparative analysis on grain quality and yield of different panicle weight indica-japonica hybrid rice(Oryza sativa L.) cultivars

Indica-japonica hybrid rice(Oryza sativa L.) cultivars showed high yield potential and poor tasting quality when compared with common japonica rice cultivars. Large panicle is a prominent factor of high yield for indica-japonica hybrid rice cultivars, and the panicle weight varies greatly among different indica-japonica hybrid rice cultivars. It is important to research on yield and grain quality of different panicle weight indica-japonica hybrid rice cultivars. In this study, two different panicle types indica-japonica hybrid cultivars were used to research on the relation of yield and grain quality. The yields of two heavy panicle weights indica-japonica hybrid cultivars were significantly higher than that of two medium panicle weight rice cultivars. The cooking and eating quality and starch properties of different panicle type cultivars were evaluated. Yongyou 6715(medium panicle) and Yongyou 1852(heavy panicle) got the relatively higher cooking and eating quality. Rice cultivars with medium panicle weight had more large starch granules and higher relative crystallinity than cultivars with heavy panicle weight. Transition temperature and retrogradation enthalpy(ΔHret) of medium panicle type cultivars were significantly higher than that of heavy panicle type cultivars. There was no significant difference in amylose content among different panicle type cultivars. Protein content of heavy panicle type cultivar was higher than that of medium panicle type cultivar, and protein content is the main factor affect cooking and eating quality in this study. The cultivar Yongyou 6715 got the highest taste value with the lowest protein content. Thus, it is suggested that the emphasis on improving rice cooking and eating quality of indica-japonica hybrid rice cultivars is how to reduce the protein content in rice grain. According to the results of this study, medium panicle type with high grain weight is the desired panicle type for high quality indica-japonica hybrid rice breeding.     

Postulation of Seedling Resistance Genes in 20 Wheat Cultivars to Yellow Rust （ Puccinia striiformis f. sp. triticl）

The gene postulation, cluster analysis and pedigree analysis of 20 wheat cultivars to 28 physiological races of yellow rust （Puccinia striiformis） were conducted under greenhouse conditions, The spectrum of their resistance were compared each other. None of the 20 cultivars were resistant to all the test pathogens. The cultivars containing resistance genes Yr5 and Yr24 were not find and genes Yr8, Yrl9 and Yr27 could not be postulated from cultivars tested due to the susceptibility to all isolates used. A total of 6 probale seedling yellow rust resistance genes or gene combinations （Yrl, Yr2, Yr2 ＋ YrHVII, Yr3 ＋ unknown, Yr3 ＋ Yr4, YrAlba） were postulated in the wheat cultivars （Atou, Flanders, Maris Huntsman, Bouquet, Holdfast, Elite Lepeuple, and Vilmorin 27）. The gene combination Yr2＋YrHVII with the highest frequency （35%） was present in 7 cultivars. The Yr genes present in some wheat cultivars could not be postulated because of non-matching virulence combinations with any of known genes. Cluster result showed that Yr2 and Yr3 are the most important genes in the cultivars. The 13 cultivars are believed to have the pedigree of Noe, which was selected from South Russian wheat. These results will be useful for wheat breeding and provide information about genetic control of wheat yellow rust.     

Effect of Preplant Fertilizer on Agronomic and Physiological Traits of Soybean Cultivars from Different Breeding Programs

Understanding the changes in agronomic and physiological traits associated with yield genetic gain is important for soybean production and future breeding strategy. The objective of this study was to compare the older and modern cultivars to learn whether the yield improvements depend on preplant fertilizer or the plant productivity improvement, A set of older cultivars, with their modern counterparts derived from breeding programs in Liaoning and Ohio were evaluated for their agronomic and physiological traits under different fertilizer levels from 2004 to 2006. There was no improvement of response to N and P preplant fertilizer for genotypes. After more than 70 yr breeding, soybean breeders made some improvements in agronomic and physiological traits that contribute to yield increase. When compared to older cultivar, modern Liaoning and Ohio cultivars were shorter and more resistance to lodging, had greater leaf density, higher harvest index, more leaf area per plant, and greater photosynthetic rate, transpiration rate and stomatal conductance at the beginning of seed development. Ohio cultivars were more resistant to lodging as if selected for easy harvest by combine, even under high N and P preplant fertilizer level, which resulted in Ohio cultivars with higher and stable yield productivity.     

Study of the Adult-Plant Resistance at Different Growth Stages to Stripe Rust in Wheat

Components of resistance were investigated for five adult-plant resistant (APR) wheat (Triticum aestivum) cultivars at six growth stages and two temperatures in the greenhouse, and disease progress in a field trial. Chinese cultivar Chuanyu 12 displayed high to intermediate infection type (IT) in the greenhouse but was highly resistant in the field. Weebill showed an intermediate IT in the greenhouse and also in the field. Chpaio, Tukuru and Saar, known to carry combinations of Yr18 and 2-3 additional minor genes, were highly resistant in both experiments. Greenhouse experiments indicated that the lower IT of APR cultivars initiated at tillering stage. Latent periods (LP) for APR cultivars were generally longer as the growth stage progressed. We conclude that APR to stripe rust can be best characterized in field trials although significant correlations are seen between field severity and IT and LP measured in the greenhouse.     

The Source of Genes Related to Rice Grain Starch Synthesis Among Cultivated Varieties and Its Contribution to Quality

The property of starch in rice grain endosperm is a very important determinant for rice quality, and it is essential to understand the genetic effect of the genes related to starch synthesis in high-yielding rice varieties for rice quality improvement. The physicochemical properties （e.g., amylose content, gel consistency, and RVA profile） were assessed on 53 rice varieties, including certain typical indica/japonica landraces and certain high-yielding modern varieties. And molecular markers for Sbel, Sbe3 developed on the basis of sequence diversities between the rice subspecies indica and japonica, together with PCR-Acc I marker for Wx gene were used to investigate the genotypes of 53 rice cultivars. The result showed that the developed molecular markers for Wx, Sbel, Sbe3 could distinguish indica or japonica alleles at three loci. Among all the 53 rice cultivars, six genotypes were observed when Sbel, Sbe3, and Wx loci were considered together, while the genotypes of WxiSbelJSbe3i and WxiSbelJSbe3J were absent. In order to explore the genetic effects of the three genes, especially for starch branching enzyme genes, ANOVA and multiple comparison analysis were conducted. The results showed that rice cultivars with different genotypes exhibited different phenotypes, including amylose content, gel consistency and certain RVA characteristics, and the significant differences among the six genotypes were observed. It was concluded that these three genes had randomly recombined during the process of the rice variety development. And the genetic effects of indica and japonica alleles at three gene loci were different, of which, Wx gene plays a major role in determining the starch properties, followed by Sbel and Sbe3, and the genetic effects of Sbel and Sbe3 in different backgrounds （Wx~, WxJ） are different. The results have provided a clue for rice good quality variety development, and the molecular markers will benefit to the improvement in quality of rice.     

Effects of different mechanical direct seeding methods on grain yield and lodging resistance of early indica rice in South China

Direct seeding of rice has become a main planting method due to the low labor input and high economic benefit in South China. Dry direct seeding(DDS) has been widely used for single-season rice planting establishment. However, few studies have examined the performance of early-season indica rice under mechanical dry direct seeding. A two-year field experiment was conducted with two indica rice cultivars(i.e., Zhongjiazao 17 and Zhuliangyou 819) to study lodging characteristics and grain yield formation under DDS, flooded direct seeding(FDS) and wet direct seeding(WDS) patterns. The results showed that the annual grain yield in DDS was higher by 14.42–26.34% for cultivar ZLY819 and 6.64–24.58% for cultivar ZJZ17 than in WDS and FDS, respectively, and these increases were mainly attributed to the improvement of the panicles. The DDS pattern significantly increased the seedling emergence rate of early indica rice cultivars, and increased total dry weight and crop growth rate. Meanwhile, shorter basal internodes, better stem diameter and stem wall thickness and lower lodging index were found in DDS in contrast to FDS and WDS. In particular, DDS improved the stem lodging resistance. Our results suggested that the appropriate direct seeding method was beneficial for improving the grain yield and lodging resistance of early indica rice.     

Molecular Screening and Resistance Evaluation of American Wheat Cultivars to Chinese Stripe Rust Races

Stripe rust, caused by Puccinia striiformis f. sp. tritici, is one of the major diseases of wheat in China. In order to asses the resistance levels and existing Yr genes among 59 wheat cultivars （lines） from the Pacific Northwest （PNW） of the United States, to provide resistance resources for genetic improvement of wheat stripe rust resistance in China, 59 wheat cultivars （lines） from PNW of the United States were infected by 3 mixed races of predominant Chinese stripe rust races CRY31, CRY32, and CRY33 to evaluate their resistance at seedling and adult plant stages, and screened with molecular markers tightly linked to currently effective all-stage resistance genes YrlO, Yrl5 and adult plant resistance genes Yrl8, Yr39. Of 59 American cultivars （lines）, five cultivars （lines）, Expresso, 02W50076, ACS52610, WA008012, and WA00801833, had all-stage resistance, showing resistance to mixed races of CRY31, CRY32, and CRY33 at both seedling and adult plant stages. 33 cultivars （lines） had adult plant resistance, only showing resistance to stripe rust at adult stage. Based on the molecular screening, none of the 59 PNW cultivars （lines） had the polymorphic bands of linked markers to YrlO. There were 12, 33 and 29 cultivars （lines） which bad polymorphic bands of linked markers to Yr15, Yr18 and Yr39, accounting for 20, 55 and 49% of the 59 PNW cultivars （lines）, respectively. All these results suggested that Yr15, Yr18 and Yr39 were widespread among PNW cultivars （cultivars） and could be utilized in Chinese wheat stripe rust resistance breeding.     

Screening of Drought Resistance Identification Indexes for Rice (Oryza sativa L.) Cultivars in Ningxia

The morphological characters, physiological characters, yield traits and yield per plant of total 49 rice cultivars from Ningxia were investigated under conditions of water stress and non-water stress so as to determine the relationship between each trait and yield per plant under water stress and the relationship between each relative character and drought resistance coefficient under water stress and non-water stress. The correlation, grey correlation, stepwise regression and path analyses showed that the til er number per plant, plant height, grain density, effective panicle number per plant and grain number per pan-icle, total 5 traits, were significantly correlated with the drought resistance of rice, and they could be used to identify the drought resistance of rice in Ningxia. In addition, the drought resistance of rice was graded qualitatively according to the subordinate function value of corresponding drought resistance coefficient. The results showed that among the 49 rice cultivars from Ningxia, 6 rice cultivars were highly drought resistant, and 9 rice cultivars were moderately drought resistant, suggesting that the evalua-tion method was feasible and effective.     

Genetics and Molecular Mapping of a High-Temperature Resistance Gene to Stripe Rust in Seeding-Stage in Winter Wheat Cultivar Lantian 1

Stripe rust, caused by Puccinia striiformis Westend. f. sp. tritici (Pst), is a severe foliar disease of common wheat (Triticum aestivum L.) in the world. Resistance is the best approach to control the disease. The winter wheat cultivar Lantian 1 has high-temperature resistance to stripe rust. To determing the gene(s) for the stripe rust resistance, Lantian 1 was crossed with Mingxian 169 (M169). Seedlings of the parents, and F 1 , F 2 and F 2-3 progenies were tested with races CYR32 of Pst under controlled greenhouse conditions. Lantian 1 has a single partially dominant gene conferred resistance to race CYR32, designated as YrLT1. Simple sequence repeat (SSR) techniques were used to identify molecular markers linked to YrLT1. A linkage group of five SSR markers was constructed for YrLT1 using 166 F 2 plants. Based on the SSR marker consensus map and the position on wheat chromosome, the resistance gene was assigned on chromosome 2DL. Amplification of a set of nulli-tetrasomic Chinese Spring lines with SSR marker Xwmc797 confirmed that the resistance gene was located on the long arm of chromosome 2D. Because of its chromosomal location and the high-temperature resistance, this gene is different from previously described genes. The molecular map spanned 29.9 cM, and the genetic distance of two close markers Xbarc228 and Xcfd16 to resistance gene locus was 4.0 and 5.7 cM, respectively. The polymorphism rates of the flanking markers in 46 wheat lines were 2.1 and 2.1%, respectively; and the two markers in combination could distinguish the alleles at the resistance locus in 97.9% of tested genotypes. This new gene and flanking markers should be useful in developing wheat cultivars with high level and possible durable resistance to stripe rust.     

稻瘿蚊多抗性材料的聚合与创新

抗源的发掘和利用是创新抗稻瘿蚊育种材料的有效途径,笔者在广西品种资源中发现了新的抗性品种GX—M001,经与抗蚊青占等位性测定,初步认为其与抗蚊青占基因（GM6）不等位,可能是一个新的抗性基因。为此,笔者选用GX—M001抗源与抗蚊青占等抗性品种杂交,培育出新的多抗创新材料。     

水稻新品种多抗性的综合鉴定及其在生产上的应用研究

选育和利用多抗性品种是防治水稻白叶枯病和稻飞虱等多种病虫害最经济有效的措施。自1982年起,协作组筛选测定了近5000份品质资源,已选育出一批高产、抗病、抗虫的新品系,如扬稻1号,2号,262,665等。特别是在1982和1987年,江淮流域曾两次发生白叶枯病和稻飞虱的猖獗流行,凡病区种植扬稻2号等抗病品种的地区,病害虫害极轻,确保丰收,深受农户欢迎,目前这些新品种的种植面积已超过2000万亩,在长江流域稻区的抗病高产活动中发挥了重要的作用。     

Application of the New Gene Gm6 Against Rice Gall Midge in Resistance Breeding Through PCR-Based Marker Aided Selection

The research results of marker aided selection (MAS) for resistant varieties and lines against rice gall midge Orseolia oryzae Wood-Mason successfully in 1999-2002 were reported in the present paper. The molecular markers linked to the gene Gm6 against rice gall midge were used to select and breed the resistant varieties and lines. The RAPD marker OPM06 was used to verify the existence actually of gene Gm6 in ten developed varieties resistant to gall midge such as Duokang1, Duokang2, Kangwen2, Kangwen3, Kangwen5, Duokangzaozhan, Kangwenqinzhan, which were derived from Daqiuqi. For resistance breeding through PCRbased marker aided selection (MAS), the polymorphisms in the resistant and susceptible parents were identified by RG476/AluⅠ and RG476/ScaⅠ respectively. The RAPD marker OPM06 (1.4 kb) was used to identify 15 new resistance lines from F3 lines of Fengyinzhan1/Daqiuqi in 1999. 21 and 7 resistance lines were selected from F4 and F6 lines of KWQZ/Gui99 (restored line of hybrid rice) using RG476/AluⅠin 2000-2001 respectively. The Gm6 gene was transferred into the restored line of hybrid rice. In 2001-2002, RG214/HhaⅠ and G214/ScaⅠ were used for selecting 11 and 5 resistance lines from F3 lines of KWQZ/IR56 and AXZ/KWQZ successfully. The application of the resistance gene through PCR-based marker aided selection is a new and effective approach in resistance breeding.     

葡萄品种抗霜霉病不同鉴定方法的比较和相关性分析

[目的]选择适宜的接种方法是品种抗病性鉴定能否成功及鉴定结果是否可靠的重要因素之一.研究通过对葡萄品种抗霜霉病不同鉴定方法的比较和相关性分析,旨在寻找一种简单、快速的鉴定方法,为品种抗病性鉴定和霜霉病菌致病性分化研究奠定基础.[方法]采用室内离体叶片接种鉴定、田间叶片接种鉴定和自然条件下发病鉴定三种方法对15个抗病性不同的葡萄品种进行抗霜霉病鉴定,鉴定结果用DPS软件进 行相关性分析,并对三种方法的可行性进行比较.[结果]三种鉴定方法的结果基本一致,其相关系数均在095以上,从中初步筛选出对霜霉病高抗、抗病、感病和高感的品种,为品种抗病性鉴定和霜霉病菌致病性分化研究奠定了基础.[结论]室内离体叶片接种鉴定方法简单,快速,环境条件易控制,其结果可以反映葡萄品种对霜霉病的抗感程度.     

水稻OsBBR1基因的白叶枯病抗性研究

水稻Y73是疣粒野生稻和栽培稻‘大粒香’经不对称体细胞杂交产生的后代,它对水稻白叶枯病表现为高抗。Y73在接种白叶枯病菌株P10 (PXO124) 后,一个NBS-LRR类基因的表达量显著上调。为了研究该基因的水稻白叶枯病抗性,采用RT-PCR技术从Y73中克隆了该基因的CDS片段 (2 631 bp),将该基因命名为OsBBR1(Bacterial Blight Resistance-related gene 1),并且利用pCAMBIA1300双元载体分别构建了OsBBR1基因超表达及干涉载体,采用农杆菌介导的转基因方法获得了转基因水稻植株。接菌试验显示,抑制OsBBR1基因的表达,能减弱抗病材料Y73的抗性;而提高OsBBR1基因的表达水平,则能增强感病材料的耐病性。结果表明OsBBR1基因与水稻白叶枯病抗性直接相关。此外,OsBBR1基因亚细胞定位结果还显示,OsBBR1编码产物主要定位于水稻细胞膜和细胞核,表明该基因很可能与信号转导和下游基因转录密切相关。     

高羊茅草坪草在阜阳市的适应性研究

[目的]筛选出最适应阜阳市建植的成坪速度快、抗性强等综合品质优良的高羊茅品种。[方法]以从美国引进的11个高羊茅草坪草品种为试材,在阜阳当地种植,观察各品种草坪草的密度、颜色、质地、均一性、抗热性、抗病性、耐旱性、抗寒性和耐践踏性等指标,并采用美国9分制评分标准对各供试品种的草坪坪用性状进行综合评价。[结果]11个引种的高羊茅品种中绝大多数的坪用价值较好;颜色大都为浓绿,密度大;多数品种出苗快,出苗齐,成坪速度快;多数品种耐践踏、抗病、耐热、抗旱;唯质地较为粗糙,均一性稍差。[结论]在11个品种中,Houndog6、Houndog5、Jaguar3和Coalnaduo颜色深绿、分蘖性强、适应性较强,景观品质较佳,可作为阜阳市冷季型草坪建坪的首选品种;其次CrossfireⅡ、Bingo、Oasis、Eldorado也是较为理想的高羊茅品种;只有Fawn、Aries、Triple表现略差,不适于阜阳市种植推广。     

抗稻瘿蚊新基因Gm6在分子标记抗性育种中的应用

 在发现与抗稻瘿蚊的基因Gm6紧密连锁的分子标记的基础上 ,应用分子标记辅助选育 (markeraidedse lection ,MAS)方法 ,成功地选育出抗稻瘿蚊的品系。首先用RAPDOPM0 6标记鉴别和确认大秋其及其衍生品系抗蚊青占、抗蚊 2号、抗蚊 3号、抗蚊 5号、多抗早占等 10个品系含有Gm6基因 ;分别用RG4 76 /AluI和RG4 76 /ScaI标记确定了育种亲本的多态性。 1999年用OPM0 6标记 ,从丰银占 /大秋其F3 家系中 ,鉴定出 15个抗稻瘿蚊的株系 ;2 0 0     

4个不同指天椒品种比较试验研究

[目的]筛选高产优质抗逆性好的指天椒品种。[方法]以从国外引进的4个指天椒品种为供试品种,对这些品种的物候期、植物学性状、商品性、抗逆性及丰产性进行比较分析。[结果]4个指天椒品种均表现商品性好、植株长势旺、抗逆性较好。4个品种中,艳红、GL-5和红香为相对早熟品种,红利为较迟熟品种;艳红的抗倒能力最强,其余3个品种的抗倒能力无明显差异;4个品种均不发生青枯病;鲜椒产量以艳红最高,达到22 725.0 kg/hm2,与其他品种差异极显著,GL-5次之,为19 380.0 kg/hm2;干椒产量以红利最高,达5 827.5 kg/hm2,艳红和红香次之,分别为5 344.5和5 454.0 kg/hm2。[结论]可根据指天椒的不同用途加以推广,艳红比较适合作为鲜椒品种加以推广,红利比较适合作为干椒品种加以推广。     

河北玉米新品种穿刺强度和压碎强度比较

[目的]比较河北玉米新品种的穿刺强度和压碎强度。[方法]采用随机区组设计,利用茎秆强度测定仪对河北12个品种进行茎皮穿刺强度和茎秆压碎强度研究。[结果]大喇叭口期不同品种间茎秆穿刺强度有一定差异,其中8号品种最强,而4号品种最弱;灌浆期不同品种抗折能力无差异;乳熟期9号品种穿刺强度最强,而7号品种最弱。12号品种的压碎强度最高、最抗压,而11号品种最低,抗压能力最差。测量茎秆穿刺强度适宜在抽雄期第6节间进行。参试的12个品种中,8号和9号品种的综合抗倒能力最强。[结论]该研究为筛选抗倒能力强的玉米品种提供了理论基础。     

籼稻品种对三个白叶枯病菌系的抗性遗传分析

分析和研究了全生育期表现抗病的5个籼稻品种二九丰、三黄占2号、川植5号、扬稻1号和83007对3个水稻白叶枯病菌系HB84-17、PXO16和T7174的抗性遗传,对这5个抗病品种分别与感病品种沈农1033或金刚30杂交的F_1、F_2和B_1F_1群体植株对供试3个菌系的抗性反应和分离世代植株抗感分离比例的分析结果表明:供试的5个籼稻抗病品种对菌系HB84-17和PXO61的抗性均由一对显性基因控制,对菌系T7174的抗性均由二对独立遗传的显性基因控制,其中一对能控制对这3个菌系的抗性,另一对只控制对菌系T7174的抗性而对菌系HB84-17和PXO61表现为感病。