Development and assessment of F1 hybrids in Romanesco cauliflower

Summary

In a trial of Romanesco cauliflower inbred lines, hybrids and controls, differences between mean performance of hybrids and their mid-parents demonstrated heterosis, with F₁ hybrids producing larger curds on larger plants with earlier maturity in most crosses. In F₁ hybrids, the small increases in curd depth, together with reduction in looseness and the overall slight improvement in curd quality, were attributed to the ability to harvest hybrid curds at earlier maturity than their inbred parents. The ability to increase the marketable yield is a prime benefit of F₁ hybrids in Romanesco cauliflowers. An effect of early test crossing was to improve seed production, both in inbred lines and hybrids. With a wider diversity of inbred lines, early testing generally would be advantageous and would also provide an opportunity to screen for inbred lines with strong self incompatibility as potential F₁ parents.     

Exploitation of heterosis through recurrent selection scheme applied in segregating generations of a tomato breeding program

This paper presents the efficiency of recurrent selection in the segregating generations of recycled lines, obtained via mass selection, in two tomato commercial single-cross hybrids, and the assessment of advanced lines in two farming systems at two different locations. In particular, in the F₃ and F₄ mass selection lines of the hybrids Iron and Sahara, half-sib (HS) selection was applied by crossing within the F₃ and F₄ plants. Two experiments were conducted, the first for evaluating the F₄ mass lines with the HS lines obtained by crossing in the F₃ generation, and the second for evaluating the F₅ mass lines with the HS lines obtained by crossing in the F₄ generation, and the second generation HS lines, which were selected from the first experiment. F₁ and F₄ generations were used as controls, respectively. The HS lines of cv. Sahara overyielded 18–56% the F₄ mass line, while Iron's HS lines presented greater uniformity in yield components and also outperformed qualitatively. The effectiveness of mass selection showed positive realized heritability only for fruit number of cv. Iron. In this study, where evaluation and selection was practiced in the absence of competition, the expected response in heterosis via HS depended on σ²_g. The differences of σ²_g of F₁ from mass and HS lines were positive for both hybrids, while when the control was the F₄ generation, mass lines showed a lower performance and some HS lines showed a higher performance. This means that HS lines have favorable alleles and heterosis. In this sense, Sahara's and Iron's HS lines increased 50.2 and 5.3% the charge of favorable alleles, respectively, compared to the corresponding control. The selected advanced lines were assessed in two farming systems at two different locations; the organic one, where two HS-lines, one from each hybrid, outyielded significantly the control; and the conventional one, where all lines performed equally to the control. The results assume the evidence that stable hybrids incorporate individual buffering into inbred line cultivars.     

耐热耐贮番茄品种改良

利用Lima品种作为父本与冬季栽培的番茄品种 (413、4 5 2、4 99、5 14和 5 6 0 )进行杂交 ,改良冬季栽培番茄品种的产量和品质 ,通过对杂交后代自交纯化 ,获得 4 5 2×Lima自交系产量最高 ,为 4 4 .2 9t·hm-2 ,比对照Lima和VF134 1 2增产 33.0 %和 31.6 % ,大部分自交系的果实硬度与对照相同 ;将耐热品种 6 6 7(CL5 915 2 0 6D4 2 5 0 )和 6 6 9(CL5 915 2 2 3D4 2 1 0 )与耐热的冬季栽培番茄品种进行杂交 ,然后自交并对其自交系的耐热性和果实品质进行选择 ,其中 5 0 2× 6 6 9、5 74× 6 6 7的自交系产量分别为 6 9.16和 6 6 .16t·hm-2 ,比对照Lima和VF134 1 2增产 18.2 %和 38.7% ,果实硬度与对照相同 ;将耐热品种L2 2和含突变基因 (nor1、nor2 )材料进行杂交和回交 ,对L2 2的货架期进行改良 ,其中BC2 和BC3 产量比L2 2高 4 %～ 9% ,果实在室温下保存 30d ,其完好率为 18%～...     

Genetic divergence among inbred lines in Cucurbita moschata from China

Knowledge of genetic divergence among inbred lines is essential for cross breeding. The objectives of this study were to (1) analyze the level and character of genetic diversity in C. moschata accessions, and (2) classify the genetic divergence among inbred lines in C. moschata to assist in selection of parent genotypes for genetic improvement. Twenty agronomic characters were investigated and rich diversities were demonstrated among 39 inbred lines of C. moschata from China. Various degree correlations among these characters made it possible to summarize the diversities of the twenty characters into 3 major principal components: leaf, fruit and flesh quality factor. Forty-one inbred lines of pumpkin were clustered into four groups based on principal component data, which is more distinct for classification that based on the original data of the 20 characters. However, parent inbred lines whose hybrids displayed significant heterosis in fruit weight, soluble solid and fruit shape were located in different clusters or sub-clusters based on standardized original data. It was suggested that genotypes in the same clusters may represent members of one heterotic group.     

The inheritance of two novel subgynoecious genes in cucumber (Cucumis sativus L.)

Cucumber (Cucumis sativus L.), which is a vegetable crop, has served as the model system for sex expression in flowering plants, and the inheritance of sex expression in cucumber is well documented. However, the genetics of subgynoecism expression in cucumber had rarely been described. In this study, we investigated the inheritance of subgynoecious traits in cucumber plants with the inbred cucumber lines of subgynoecious (C. sativus L. var sativus cv 97-17 and S-2-98) as the materials. Genetic analysis had showed the two subgynoecious inbred lines were controlled by one pair of recessive gene and one pair of incompletely dominant gene, which were designated presently as mod-F2 and Mod-F1, respectively. Furthermore, the mod-F2 and Mod-F1 loci, which enhance the intensity of femaleness, also inherited independently with F and M genes.     

茄子抗病导入系的抗青枯病性及GISH鉴定

利用栽培茄与野生茄(Solanumtorvum)的种间杂种为供体,以两个栽培茄的自交系为轮回亲本进行多代回交,得到2个导入系"BILR-1","BILR-2"。经过抗青枯病及GISH鉴定,表明所得两个导入系对青枯病有很强的抗性,且它们含有野生茄(Solanumtorvum)的遗传物质,成功把野生茄(Solanumtorvum)的抗青枯病性状转到栽培茄子中。所得抗病导入系的染色体数量为24条,它们可以作为一种新的抗源未来在茄子抗病育种中加以应用。     

黄瓜耐弱光性的多元统计分析

 利用遮阳网模拟弱光条件, 调查18份黄瓜自交系苗期生长发育和生理生化指标, 采用多元统计分析方法评价黄瓜品系耐弱光性强弱。结果表明, 参试品系的13个指标在品系间存在显著差异, 利用因子分析将这些指标综合成5个主因子, 累计贡献率达85.62%。对旋转后的因子得分进行聚类分析, 供试品系可分为4类: 耐弱光材料M₂₂、M₄₃、M_a9; 较耐弱光材料M₈、M₁₁、M₃、M₄、M₃₄; 弱光中度敏感材料M₁₂、M₂₁、M₁₄、M₂、M_a1、M₂₈和弱光敏感材料M₁₀、M₄₄、M₃₂、M₃₆。经过弱光处理后耐弱光指数较大、光合速率降低幅度较小的品系耐弱光性强, 应结合耐弱光指数与光合、生长等因子综合进行黄瓜耐弱光性鉴定。     

西瓜杂种优势育种与杂交亲本选配

西瓜育种包括自交系选育和杂种优势利用2个主要内容。对西瓜自交系选育与杂优品种选配的异同点进行了阐述,分析了影响西瓜杂种优势的4个主要因素,提出了明确目标性状、亲本的质量性状及其对数、亲本优良目标数量性状累加、选用一般配合力高的亲本等杂交亲本的选配原则。     

Genetic diversity of ash gourd [Benincasa hispida (Thunb.) Cogn.] inbred lines based on RAPD and ISSR markers and their hybrid performance

Ten inbred lines of ash gourd [Benincasa hispida (Thunb.) Cogn.] were crossed to produce 45 F₁ hybrids (without reciprocal) which were evaluated along with the parents for 20 growth- and yield-related traits, in a replicated field trial. High level of heterosis was observed among the hybrids for most of the traits examined, including yield. These inbred lines were analysed by using 42 RAPD primers those produced 282 DNA marker bands. A total of 130 RAPD markers were obtained with a mean of 3.1 per primer, which in combination discriminated all the inbreds from each other. Pair-wise genetic distance measurements ranged from 0.07 to 0.31, suggesting a wide genetic diversity for these inbreds. These inberds were also analysed with five ISSR primers of which four were informative. Twenty-six ISSR marker bands were generated of which 11 were polymorphic with an average of 2.80 per primers. The percentage of polymorphic bands produced were higher in ISSR markers (>80%) than generated through RAPD markers (46%). Although the results indicated significant positive correlations of genetic distance with hybrid performance and heterosis, the RAPD based genetic distance measures and use of limited ISSR markers in this present study could not effectively predict hybrid performance in this crop. The genetic variation among ash gourd inbred lines examined, herein, defined a marker array (combined ISSR and RAPD) for the development of a standard reference for further genetic analyses, and the selection of potential parents for predicting hybrid performance and heterosis.     

结球甘蓝抗寒性配合力分析及优良抗寒组合选育

通过自交分离和抗寒性鉴定,选育出经济性状优良的结球甘蓝抗寒自交系逾30份,以其中6份抗寒性有一定差异的自交系为试材,按照Griffing双列杂交方法Ⅳ进行甘蓝抗寒性配合力及遗传力分析。结果表明：甘蓝抗寒性遗传符合加性-显性模型,以加性效应为主,随着寒害程度的增加其加性效应所占比重增加|一般配合力方差在总遗传方差中所占比重较大,一般配合力/特殊配合力的均方比大于7,且差异达极显著水平,因此在甘蓝抗寒育种中应重视早期世代的选择。结合配合力测定结果及田间经济性状调查结果,初步明确两个优良抗寒越冬甘蓝新组合。     

籽用南瓜新品种银辉2号的选育

银辉2号是由从欧洲引入籽用南瓜白板类型专用品种玛丽单株套袋自交选育出的自交系95-23和地方品种虎林面瓜自交系进行杂交,然后在后代分离群体中通过系统选择育成的籽用南瓜新品种。植株生长势强,主茎有少量分枝,第1雌花着生于第6～8节,坐瓜节位为第10～12节,生育期115 d（天）左右,老熟瓜为灰色,瓜形扁圆。单瓜质量4～6 kg,3～5个心室,单瓜产籽300～350粒,百粒质量35～40 g,瓜籽雪白色,籽宽1.2 cm以上,籽长2.16 cm。每667 m²产瓜籽75～100 kg。较抗病毒病和白粉病。     

节瓜果皮颜色遗传规律的研究

用2个果皮青绿色自交系桂优1号毛节瓜、环江节瓜和1个果皮深绿色自交系七星节瓜作亲本,通过正、反交及回交组配,对其杂交组合(桂优1号毛节瓜×七星节瓜、环江节瓜×七星节瓜)的F1、F2、BC1和BC2各世代的果色进行统计.结果表明:F1果色表现一致,无论正、反交均表现为深绿色;F2果色无论正、反交都分离出深绿色和青绿色两种果色,且分离比率接近3:1;BC1(以深绿色的自交系作父本进行回交)果实颜色均表现为深绿色,BC2(以青绿色的自交系作父本进行回交)果实颜色则表现出深绿色和青绿色的分离,分离比率接近1:1.根据经典遗传学原理对节瓜果皮颜色的遗传效应进行了研究,初步推断出:节瓜果实的深绿色与青绿色受一对核基因控制,深绿色对青绿色为显性.     

甘蓝自交系背景选择标记的建立

为了快速、准确识别不同甘蓝自交系的遗传背景,提高回交育种效率,利用36对多态性EST-SSR引物对8个甘蓝变种的101份自交系进行扩增,应用NTSYSpc2.11a进行遗传背景分析表明,不同甘蓝变种种内平均遗传相似系数都大于0.55,变种间遗传相似系数为0.45 ~ 0.59,101份自交系在遗传相似系数0.62处基本可聚为8个类群。在此基础上,选出23份具有代表性的自交系材料,增加筛选获得多态性稳定的50对EST-SSR引物,初步建立了一套包含86对引物的甘蓝背景选择标记,并应用于甘蓝自交亲和性的回交选择。     

Linkage map saturation,construction, and comparison in four populations of Prunus

Summary

One of the objectives of the ISAFRUIT Project was to perform genetic analyses in four populations of Prunus, two of peach (P. persica) and two of apricot (P. armeniaca), in order to identify major genes and quantitative trait loci (QTLs) for characters related to fruit quality. This required the construction of saturated marker maps in each of these populations. Marker maps were available for an intra-specific peach × peach F₂, a BC₂ peach × P. davidiana (using peach as the recurrent parent), and an apricot × apricot F₁. We have further saturated these maps mainly with SSR (simple sequence repeat) markers. A new map, constructed uniquely from SSRs was prepared for a fourth apricot × apricot F₁ population. Using anchor markers, we compared these four maps with the reference Prunus map, constructed using an almond × peach F₂ population. As previously observed, conservation of synteny and co-linearity were the general rule, providing additional evidence of the high level of similarity between all Prunus genomes. Comparisons of genetic distances between the maps suggested that those involving similar genomes had higher levels of recombination than those with more distant genomes, particularly the inter-specific crosses.     

西瓜系谱法选育后代群体大小及选择指标的 研究

运用作物杂交育种基本理论，研究总结出西瓜自交系系谱法选育的F₂ 代材料群体大小、中前
期选择的技术指标、依据中前期保留比例确定移植密度以及F₃ 代种植材料份数、F₃ 代每份材料群体大小等；
对传统的西瓜系谱选育技术进行了改进，将西瓜自交系选育代数缩短2～3 代，加速了西瓜育种进程，降
低了育种成本。     

大白菜显性核复等位基因雄性不育恢复基因Msf的SSR标记

 为筛选大白菜核复等位基因遗传的雄性不育恢复基因Msf的SSR标记,用基因型为MsfMs的雄性不育两用系‘AB01’的可育株自交,得到恢复基因型纯合个体MsfMsf。再用其与基因型为msms的自交系‘a20’杂交和连续回交,获得BC4分离群体。筛选了104对SSR引物,获得3个与雄性不育恢复基因Msf连锁的SSR标记syau_m13、syau_m14和BRMS-040。经群体验证和连锁分析,Msf基因位于R07连锁群上,3个标记位于Msf基因的同一侧,距Msf基因的遗传距离分别为6.7、6.7和8.6 cM。     

Studies on the variability,inheritance, and inter-relationships of mineral macro-nutrients and micro-nutrients in strawberry (Fragariaananassa Duch.)

Summary

Strawberry (Fragaria ananassa Duch.) is a rich source of minerals, vitamins, and anti-oxidants, and has a unique flavour and aroma. However, there is little information on the genetic variability and inheritance of mineral elements in strawberry. This is important as it can influence the selection of better genotypes and suitable breeding approaches for improvements in the nutritional quality of fruit. The objectives of the present study were, therefore, to estimate the variability, inheritance, and inter-relationships of mineral elements, to identify mineral-rich and productive genotypes, and to suggest suitable breeding approaches. A significant genotypic mean square for all the minerals studied indicated sufficient variation among genotypes. Our results also indicated that the effect of genotype on the mineral content of fruit was stronger than that of environment. Six genotypes, namely ‘Ofra’, ‘Sweet Charlie’, ‘Elista’, ‘Festival’, ‘Camarosa’, and ‘Douglas’ were found to have higher mineral contents as well as better fruit yields, and therefore could be useful in further breeding programmes. N, K, Ca, Mg, Fe, Mn, Zn, and Cu contents, together with fruit yield, could be improved by selection and hybridisation as these traits showed high heritability (> 80%) and high genetic advance as a percentage of the mean (> 40%), while recurrent selection was suitable for increasing P contents, which showed moderate heritability (> 79.81%) and low genetic advance as a percentage of the mean (> 33.86%). Moreover, Mg and N contents could be used as reliable tools with which to identify the most productive and mineral-rich genotypes, as indicated by correlation and path analysis. Studies on such genetic estimates will increase our understanding of the inheritance of mineral contents and affect the design of crop improvement strategies.     

番茄砧木材料的筛选与青枯病抗性鉴定

通过广泛收集番茄品种资源,在番茄青枯病区进行自然筛选,采用系统育种方法获得多份6代以上稳定的相对抗青枯病的自交系材料。将其中8份材料进行青枯病菌接种试验,筛选出5份高抗番茄青枯病材料。将筛选出的5份材料在青枯病重灾区作重复对比试验,并与3个不同的接穗品种进行嫁接试验,进一步确定其高抗青枯病特性以及较强的嫁接亲和性与共生性。多项试验证明,筛选的5份材料完全可以作为番茄砧木材料或品种进一步研究利用或推广使用。     

结球甘蓝BoCBF1与BoCBF2基因的CAPS标记及其对耐寒性的影响

以两份具有不同耐寒性的甘蓝自交系341和21-3为试材,根据已有拟南芥CBF1基因序列及甘蓝基因组测序拼接出的Scaffold信息,获得了甘蓝BoCBF1和BoCBF2基因编码区的全长序列。经PCR产物直接测序发现BoCBF1基因在自交系341和21-3间的变异表现为4个单核苷酸多态性（SNP）,而BoCBF2基因则表现为16个SNP及1个18 bp碱基的插入缺失（InDel）。为简便快捷地鉴定两个自交系间BoCBF1和BoCBF2基因序列的变异,开发了BoCBF1和BoCBF2基因的CAPS标记,分别命名为BoCBF1-TaqαⅠ和BoCBF2-BstUⅠ。利用这两个CAPS标记对两个自交系、F1、F2群体的基因型与耐寒性进行相关性分析,发现这两个基因的变异与材料的耐寒性极显著相关,可用该标记进行甘蓝耐寒育种的分子标记辅助选择。     

全雌黄瓜单性结实性遗传分析

 采用植物数量性状主基因+多基因混合遗传模型对黄瓜强单性结实雌性系‘6401’ 与非单性结实自交系‘6429’、‘6426’杂交组合多世代群体的单性结实性进行联合分析,结果表明：全雌黄瓜单性结实性在不同遗传背景下遗传表现基本一致,单性结实性遗传均表现为不完全隐性基因遗传,符合E-1-1模型,受2对加性-显性-上位性主基因+加性-显性多基因控制。两组合第1主基因显性效应、主基因显性×显性互作效应以及多基因效应较大。‘6401×6429’组合的B₁、B₂、F₂群体（主基因+多基因）遗传率分别为51.36%、72.31%和76.78%;‘6401×6426’组合的B₁、B₂、F₂群体（主基因+多基因）遗传率分别为20.50%、75.39%和74.58%。强单性结实全雌黄瓜品种选育以双亲均为强单性结实为宜。