Heterosis of Double Low Self-incompatibility in Oilseed Rape (Brassica napus L.)

66 F1 hybrids, produced by 3 double low self-incompatible lines and 22 varieties with a North Carolina Ⅱ (NCⅡ) crossing design, were tested for their heterosis in Wuhan, China during two growing seasons from 1999- 2001. The results showed that significant differences were found between F1s and their parents for yield per plant and seed oil content. Mid-parent heterosis of these two characters ranged from 5.50%-64.11% and from 1.55% -7.44% respectively. Heterosis for seed yield per plant was greater than that of seed oil content. For yield components, heterosis of total number of siliques per plant was the highest, followed by seed number per silique and 1 000 seeds weight. Significant genotype-by-year interaction was found for seed yield per plant. Results from correlation and combining ability analysis indicated that parental effects on its F1 hybrid depended on characters, seed yield per plant was affected by both additive and non-additive effects, and seed oil content was affected mainly by additive effect. When designing hybrid programme, parents might be selected by GCAs and variances of SCAs of parents for the characters affected by both additive and non-additive effects, and by the sum of GCAs of female and male parents for the characters mainly affected by additive effects.     

Genetic Analysis of Yield and Its Components of B. napus Hybrids Using Resynthesized Rapeseed Lines

Resynthesized rapeseeds obtained by crossing the diploid parents Brassica rapa and Brassica oleracea have significant potential in hybrid breeding because of their higher genetic basis compared with Brassica napus cultivars. In this study, an 8 × 8 complete diallel experiment using four B. napus cultivars （BN） and four resynthesized rapeseed lines （RS） as parents was designed to study heterosis and genetic inheritance for yield components. The results showed that heterosis for yield per plant, the number of pods per plant and number of seeds per pod were high, with means 32.77, 24.49 and 15.71%, respectively. Diallel analysis showed that both additive and dominant effects were significant for yield and yield components. All traits, except for 1 000-seed weight, were significant for bl mean squares and exhibited directional dominance. Dominant genes had positive effects on yield per plant, pods per plant and 1000-seed weight, and negative effects on seeds per pod （r=-0.86, -0.62, -0.41, and 0.47, respectively）. Narrow-sense heritability for yield per plant, pods per plant, and 1 000-seed weight and seeds per pod were 66, 31, 46 and 78% for the four traits, respectively. The Fl hybrids showed considerable yields compared to B. napus cultivars when B. napus cultivars and resynthesized rapeseeds were used as parents （NR hybrids）, with many more pods per plant and lower seeds per pod compared with the rapeseed cultivars, indicating that the resynthesized rapeseed may be applicable in current hybrid breeding programs.     

Differential Gene Expression Between Hybrids and Their Parents During the Four Crucial Stages of Cotton Growth and Development

The study aims to clarify the differential gene expression between cotton hybrids and their parents in order to better understand the molecular basis of cotton heterosis. The research focused on cotton heterotic and lower heterotic hybrids and their parents during the four crucial stages, which were analyzed using a differential display technique. The results indicated that there were both quantitative and qualitative differences in gene expression amongst them. The quantitative differences include over- and under-expression of parental genes and the dominant expression of highly-expressed parental genes in hybrids. In contrast, the qualitative differences are the following： （i） Bands were observed in both parents but not in the F1 hybrid （BPnF1）; （ii） bands occurred in either of the parents but not in the F1 hybrid （UPnF1）; （iii） bands presented only in the F1 hybrid but not in either of the parents （UF1nP）; and （iv） bands were detected in either of the parents and the F1 hybrid （UPF1）. Overall, the major differences of gene expression occurred in the qualitative level and four related differential patterns were observed. Furthermore, the amount of differential patterns during the flowering stage was relatively higher than those of other stages. At this juncture, both the amount of hybrid-specific expression patterns at flowering stage and the silenced expression patterns at boll-forming stage in highly heterotic hybrids were found higher than those in the lower heterotic ones. It was concluded that significant differences of gene expression in leaves were present between cotton hybrid and its parents during the whole growing stages. Hence, these differences might be responsible for the observed cotton heterosis.     

Heterosis and Combining Ability for Major Yield Traits of a New Wheat Germplasm Shannong 0095 Derived from Thinopyrum intermedium

The wheatgrass, Thinopyrum intermedium （Host） Barkworth ＆ DR Dewey, shows many beneficial characteristics, such as big spikes and high resistance to many diseases. To transfer the beneficial genes of this species, many wheat- Thinopyrum intermedium alien chromosome lines were developed. Of them, Shannong 0095 （SN0095）, a disomic substitution, has long spikes and flag-leaves, and thus may be an important genetic resource for wheat yield improvement. In order to realize its heterosis and combining ability on major yield traits, a 7 ×7 complete diallel design was made according to Griffing＇s Method-1. The results showed that heterosis for spike length （SPL）, flag-leaf area （FLA）, number of spikes per plant （NSP）, number of spikelets per spike （NSL）, kernels per spike （KPS）, 1 000-kernel weight （TKW） and grain yield per plant （GYP） existed in all the crosses by SN0095, but heterobeltiosis occurred only for KPS, TKW, and GYP. The relative mid-parent heterosis （RMH） and relative high-parent heterosis （RHH） for GYP, which valued as high as 35.32 and 29.92% respectively, were the highest among all the traits mearsured. Though additive and non-additive gene effects and cytoplasmic effects （or cytoplasmic-nuclear interaction effects） were found in governing all the traits measured above, additive gene action played a predominant role. The results also showed that SN0095 was the best-general combiner for SPL and FLA, and high-general combiner for NSP amongst all the parents. Estimates of specific combining ability （SCA） showed that SN0095 could also make high-SCA combinations for GYP, such as SN0095 × Jimai 19 （JMI9）. SN0095 could be a unique and important parent in hybrid wheat breeding programs.     

Studies on Breeding and Application of Thermo- sensitive Genic Male Sterile Line 402S in Brassica napus：Ⅱ. Evaluation of Heterosis and Combining Ability

Augmented randomized complete block test was conducted to evaluate the heterosis of 80 hybrid combinations from TGMS line 402S and its original parent Xiangyou 91S, and the combining ability of 40 testcrossing lines. The results of identification test showed that among 47 combinations yielding over the control Xiangyou 15, 17 ones with 402S and 3 ones with Xiangyou 91S overyidded more than 20%, reaching the significant level of 1% ; and arrrmg 51 combinations yielding over their corresponding higher yield parents, 18 ones with 402S and 9 ones with Xiangyou 91S overyielded at 5 % or 1% significant level. The test for the GCA effect of all parents indicated that 402S possessed a stronger combining ability than Xiangyou 91S on yield, siliquae of main inflorescence, total siliquae per plant, seed yield of single plant and 1000- seed weight. 10 testcrossing lines with high GCA were picked out for next testcrosses. Amnng 8 agronomic traits, total siliquae per plant and seed yield of single plant were regarded as the key selecting indexes accccding to the correlation analysis between yield and the agronomic traits on heterosis and on the GCA effect of all parents.     

A Preliminary Study on the Relationship Between the Indica-Japonica RAPD Differentiation of Parents and Heterosis in Dian Type Hybrid Rice

The relationship between the indica-japonica differentiation of parents and heterosis of hybridin rice was studied with 10 sterile lines, 10 maintainer lines of the sterile lines, 38 restorer lines of Dian typehybrid rice and 40 hybrids derived from the sterile lines and restorer lines. The results indicated that there wasa parabolic correlation between the indica-japonica differentiation of parents detected by RAPD markers andheterosis of hybrid rice. When certain indica-japonica differentiation of parents exists, the percentage of com-binations with positve heterosis and the mean heterosis of hybrids were high. But that didn‘t mean too muchdifference of parents could lead to stronger hetesosis, that meant overdiffernt parents seldom bring positve het-erotic hybrids. Suitable difference of percent of indica alleles of parents of stronger heterotic hybrid was 12 -16%.     

Determination and Difference Analysis of DNA Methylation Content Both in Blood and Muscle Tissue of Pigs

In this experiment, DNA samples from parental lines Large White, Landrace, and Meishan pigs, and their hybrids Large White × Landrace, Landrace × Large White, Large White × Meishan, and Meishan × Large White pigs were used for the determination of DNA methylation content in both blood and muscle tissue. The differences about DNA methylation content between parental lines and their hybrids were analyzed. These will offer theoretical support from molecular level for heterosis. High performance liquid chromatography （HPLC） was firstly used to detect DNA methylation content. The average DNA methylation content in 163 DNA samples of muscle tissue was 16.92%, whereas, the average DNA methylation content in 182 samples of blood was 6.49%, the difference between which was especially prominent （P 〈 0.01）. In blood, the methylation content was lower than 10%, with the highest level of 9.93% in Landrace x Large White and the lowest of 2.97% in Landrace. The difference between Large White and Landrace was highly significant （P 〈 0.01）, but not significant between Large White and Meishan; and the differences between reciprocal cross hybrids in both hybrid systems were significant （P 〈 0.05）. In muscle tissue, the differences in methylation content among three parents were not significant （P 〉0.05）; and the differences between reciprocal cross hybrids in both hybrid systems were not significant （P 〉 0.05）, but between different hybrid systems, the hybrids had a significant difference （P 〈0.05）. The average methylation content in muscle samples was higher than that in blood samples, and the methylation in different tissues was different.     

QTL Analysis of Major Agronomic Traits in Soybean

Soybean is a main crop, and most agronomic traits of soybean are quantitative; therefore, there is vely important studying and applying value to locating these traits. A F2：10 RIL population containing 154 lines, derived from the cross between Charleston as female and Dongnong 594 as male parent, were used in this experiment. A genetic linkage map was constructed with 164 SSR primers, which were screened with the two parents and amplified on the 154 lines. 12 agronomic traits different between the two parents were investigated, and QTLs of all the traits were analyzed using the software Windows QTL Cartographer V2.0. The agronomic traits included quality traits： protein content, oil content, and content of protein and oil; yield traits： pods per plant, seed weight per plant, and 100 seeds weight; and other agronomic traits： plant height, days to maturity, branches, nod number in main stem, average leaf length, and average leaf width. The results showed that 68 QTLs in total were found for the 12 agronomic traits. The number of QTLs per trait varied from 3 for the average leaf width to 11 for 100 seeds weight and plant height, and was 5.8 on average. Good accordance was seen in many QTLs between the results of this study and the results obtained by other similar studies; therefore, these QTLs may be valuable for molecular marker assistant selection in soybean. In this study, 68 major QTLs of 12 important traits of soybean were analyzed.     

基于体细胞组织培养的甘蓝型油菜核三系保持系绵7MB-1亲本繁殖与F_1制种(英文)

[Objective] The aim was to study the reproduction of the three-line genic male sterile (GMS) line parent Mian 7MB-1 (B.Napus L.) and the seed production of F1 through somatic tissue culture. [Method] Through hybridization, a new breeding material Mian 7MB-1 in three-line genic temporary maintainer line propagated by tissue culture was used to improve the sterile plant rate of rapeseed in dual-purpose recessive GMS line, such as Mian 7AB type, S45AB type, and etc. And then the variety comparative test was performed. [Result] In order to avoid some fertility restoration phenomena occurring during the process of self-reproduction, Mian 7AB was propagated in bulk with somatic tissue culture of temporary maintainer line plant stem. The propagated temporary maintainer line seedlings were applied to the breeding and seed production of net room male sterile line parent, promoting the sterile plant rate of the male sterile line parent to 91.7%-93.5%. The male sterile line parents per hectare were enough for the seed production of hybrid F1 in 7 500-15 000 hm2. [Conclusion] Compared with the original dual-purpose GMS line, the seed production ultilizing male sterile line with high sterile plant rate greatly reduced the labor, significantly improved the seed yield, ensuring the seed quality and forming a perfect breeding and seed production system.     

Hybrid rice achievements,development and prospect in China

This article reviews the history and progress of hybrid rice development. Hybrid rice research was initiated back in 1964, and commercialized in 1976. Three-line and two-line system hybrid rice were developed in 1974 and 1995, respectively. Research on super hybrid rice, which was first launched by Ministry of Agriculture, China in 1996, is discussed, and the great progress of super hybrid rice had been achieved with a new yield record by 15.4 t ha–1 in the 6.84 ha demonstration location in Xupu, Hunan Province, China in 2014. And the mechanism of heterosis, the techniques of hybrid seed production and the modern field managements in hybrid rice over the past decades are also discussed. Additionally, this article dealt with the intellectual property protection(IPR) and development of hybrid rice seed industry in China. Major factors that constrain hybrid rice development are analyzed and possible solutions to this problems are proposed. Finally, the authors present methods to further increase production yield, and propose an improvement for breeding super high-yielding hybrid rice based on these methods.     

Heterosis for Seed Yield,0il Content and Other Characters in Rapeseed(Brassica napus L.)

Nine inbred lines of rapeseed(Brassica napus L.)used as male were crossed to five recessive genetic male sterile(RGMS)lines used as female to produce 45 single crosses.The crosses,their parents and a check hybrid were tested at two locations during 2007 to 2008 for testing the performance and heterosis of hybrids for seed yield and other characters.Results showed that variationsfor seed yield,oil content,days to flowering and days to maturity were significant.Mean squares for hybrids were significant for allcharacters.High heterosis(-4.5%-88.3%),heterobeltiosis(-15.6%-81.1%)and standard heterosis(-34.8%-33.1%)were found forthe seed yield.The highest heterosis and heterobcltiosis were found in the cross QH303-4A×1190.The highest standard heterosiswas found in the Cross Qianyou8A×Q034.Both positive and negative heterosis of single crosses were demcted for the oil content.Small heterosis was found for days to flowering and days to maturity.Among parents,Ⅲ188,Ⅲ224,and Q034 were proved to be thesuperior for seed yield when used as parents in most of the hybrid combinations.2365,Ⅲ1224,and QH303-4AB were good for high oilcontent breeding.Ⅲ176,2313 and Qianyou3AB were good for the early hybrid breeding.Total 11 hybrids yielded higher than 2 500kg·hm-2 and also gave significantly positive heterosis,heterobeltiosis and standard heterosis.Among them,10 crosses gave higher oilcontent than that of check.These crosses Can be used in the future breeding program for the seed yield and the oil content.Two crossesincluding Qianyou3A×Ⅲ224 and Qianyou3A×2313 can be used for the early breeding program.     

甘蓝型油菜雄性不育系性状关联性分析

[目的]评估甘蓝型油菜雄性不育系性状间的关系。[方法]采用半双列杂交方法,利用10个甘蓝型油菜隐性细胞核雄性不育系为材料配制了45个杂交组合。45的杂交组合和10个亲本材料于2007-2008年在贵阳种植并用于评估。[结果]植株高度、株有效角果数、初花期和成熟期与产量成显著正相关,相关系数分别为0.644,0.583,0.281和0.341;每角粒数与种子大小（千粒重）成显著负相关（-0.533）。株有效角数、每角粒数、千粒重和植株高度对产量的直接通径系数分别为0.5562、0.4074、0.4813和0.4017。[结论]株有效角数、每角粒数、千粒重和植株高度与种子产量成正相关,并对产量有较高的直接贡献。其它性状包括株分枝数、初花期、成熟期和含油量对产量的贡献较低。     

e-杂交稻株形及产量构成

以协青早 e A(2 ) (含有 eui2基因 )、协青早 A、 -3 2 e A(1 ) (含有 eui1基因 )及 -3 2 A为母本 ,以明恢 63、明恢 86、皖恢5 7及密阳 46为父本 ,按 p×q模式配置了 1 6个杂交组合 ,研究了 e-杂交稻的株型、产量构成 .结果表明 ,e-杂交稻具有与原杂交稻相近的株叶形态、生育期及产量水平 ;但因含有 eui基因 ,具有其特有的生物学特性 ,植株生长较繁茂 ,各个生育期的植株高度略有增加 ,分蘖数、有效穗数、穗粒数略减少 ,结实率略降低 ,千粒重增加 .统计分析表明 ,e-杂交稻与原杂交稻各性状间的差异都不显著 .构成产量的 4个要素对原杂交稻产量的直接效应为 :穗粒数 >有效穗数 >千粒重 >结实率 ,而 e-杂交稻直接效应为 :穗粒数 >结实率 >有效穗数 >千粒重     

Analysis on Combining Ability for Characters of Male Sterile Lines in Rapeseed （ Brassica napus L.）

The male sterile line is very important in the hybrid breeding program of rapeseed. This study was conducted to evaluate the combining ability of many characters of male sterile lines in Brassica napus...     

九个抗虫棉品系的杂种优势及其产量性状配合力分析

摘要：为了分析转Bt基因棉花蛋白高表达品系的杂种优势和配合力,采用NCII设计,利用4个生产上推广应用的棉花品种与9个转Bt基因棉花蛋白高表达品系进行杂交组配,对36个组合的F1产量性状的杂种优势和配合力进行分析,结果表明：大多数组合的竞争优势明显,皮棉和籽棉的产量均具有较大的竞争优势,两者分别为16.1%和6.8%,皮棉和籽棉的产量的竞争优势率分别达到83.3%和80.6%。产量性状的优势大小依次为衣分、铃重和单株铃数,分别为3.7%、2.0%和0.8%。对组合的配合力方差进行分析,结果显示：九个转基因抗虫棉品系各产量性状的一般配合力差异较大,对这些组合特殊配合力进行分析,发现有3个组合具有较高的特殊配合力。     

抗虫棉杂交种杂种优势及亲子相关分析

利用5个具有抗虫基因的棉花品种(系)作母本与6个非抗虫棉品种(系)作父本,采用NCⅡ交配设计进行杂交,研究抗虫杂交棉F1代产量与品质性状的杂种优势、性状相关和亲子相关。结果表明,整齐度和单铃重具有较强的中亲优势和竞争优势;2.5%跨长与整齐度、比强度和籽指之间极显著正相关;杂种一代大多性状不同程度的受到亲本的影响,亲子相关分析为利用亲本初步预测杂种一代性状表现、杂交制种亲本选择选配和性状改良提供理论依据。     

玉米自交系结实性和籽粒产量的配合力

用9个玉米自交系及其完全双利杂交的36个组合对玉米自交系结实性和籽粒产量的配合力进行了研究,结果表明,自交系结实性的一般配合力和特殊配合力均达到极显著差异。F_1的结实性与其亲本系呈极显著正相关(r=0.7008)。自交系籽粒产量的一般配合力差异不显著,所配组合的特殊配合力差异极显著。F_1的籽粒产量与亲本系结实性呈正相关(r=0.534),但未达显著水平。F_1的籽粒产量与结实性的相关也不显著(r=0.0155)。     

影响小麦提型不育系种子质量的遗传因素

根据Ｔ型不育系和恢复系,不育系和保持系的两套双列杂交试验以及川７Ａ和其它保持系的４套回交试验。对影响Ｔ型不育系种饱满度和发芽率的遗传因素进行了分析,发现不育系异交子粒的发育进程和充实程度主要取决于母体的基因型;而不育系种子的发芽率则受母体基因型和花粉供体基因型的共同影响。用川７Ｂ给其它不育系授粉得到的杂交种子,其发芽率明显地高于这些不育系与同型保持系杂交产生的种子;不育系种子的饱满度也因有了川７Ｂ     

水稻“野败”不育胞质对杂种一代的影响

用二个水稻“野败”胞质不育系和四个恢复系,配制五个不育系杂种及其相应的保持系杂种,包括三对正反交;比较它们的株高、抽穗期、最高分蘖数、穗数、成穗率、每穗粒数、每穗实粒数、结实率、千粒重和单株重。结果表明,不育系杂种比其相应的保持系杂种,除了抽穗期延迟和最高分蘖数增加外,其它性状的数值均下降,且都达到极显著差异水准;即野败不育胞质表现杂种优势负效应。杂种的减产与千粒重的降低呈显著正相关,与每穗粒数的减少呈正相关。但是,通过选育高产、恢复力强的恢复系,选择最优的组合,可以达到基本消除不育胞质负效应的育种目的。     

中国高粱细胞质对杂种一代的影响

采用中国高粱(麦茬)、迈罗及粒用草原1号三个不同细胞质的高粱雄性不育系,经过核置换,转育成为两套同核异质的6个高粱雄性不育系,并分别与同一个恢复系杂交得到两套共6个同核异质杂交种,以此为试材,观察了各个杂种一代的主要性状。结果表明,在生育天数、自交结实率、产量、千粒重、株高和叶片数等性状上,中国高粱细胞质与迈罗细胞质在相同的核背景下无显著差异。