烤烟杂种优势及其相关性分析

研究了7个烤烟杂交组合F1代的农艺性状、经济性状及TMV抗性的杂种优势,分析了各性状与亲本间的相关性.结果表明,烤烟杂种优势以单位面积产量最为突出,7个组合的单位面积产量均超过中亲值,优势幅度在6.6%～50.40%之间,有6个组合超过了大值亲本,优势幅度在8.34%～43.78%之间.各性状都有表现超中亲或超高亲的组合,不同性状表现杂优组合比例不同,TMV抗性的高亲优势最强,占71.42%.亲本对杂种一代各性状有不同程度的影响,F1各组合的有效叶数、茎围、单位面积产量、产值几个性状与大值亲本、小值亲本、中亲值、双亲之差无显著相关;自然株高与亲本相关性较大,上等烟比例、TMV抗性优势大小与双亲之差为负相关.     

不同生态型大豆杂种后代早熟高产性研究

用不同生态来源的6个早熟大豆品种进行完全双列杂交,研究F_1、F_2单株产量等性状的亲子关系、杂种优势,配合力、M·S·g/M·S·s值、遗传力、相关系数。结果表明,早熟大豆杂种F_1、F_2单株产量等性状介于双亲之间,与双亲值、中亲值密切相关;F_2出现超亲分离,分离幅度、杂种优势、特殊配合力效应与双亲生态差异有关,单株粒重与鼓粒—成熟期密切相关,与开花—鼓粒期相关不显著,因此缩短开花—鼓粒期是提高大豆杂种后代早熟高产性的关键。     

应用遣传距离预测爆裂玉米杂种优势

根据80个爆裂玉米自交系数量性状的表现估算了它们之间的遗传距离及它们之间随机组配的67个杂交组合F_1代小区产量、爆粒率和膨胀倍数的杂种优势。相关和回归分析表明,F_1代产量的成分照优势与其双亲之间的遗传距离呈显著的二次曲线关系,而F_1代品质特性爆粒率和膨胀倍数的对照优势与其双亲之间的遗传距离无确定性关系。因此,可以根据亲本间数量性状的综合遗传差异——遗传距离预测爆裂玉米杂种一代产量优势。     

棉花亲本与杂种优势试验

对杂交棉优势组合与亲代间优势关系进行分析,揭示F1变化趋势。F1与两亲本相比,生育期与早熟亲本一致,株高、果枝数超过高值亲本,果枝始节位、第1果枝高度接近两亲本均值;抗病能力超过感病亲本,但低于抗病亲本;铃重极显著高于双亲,子、皮棉产量均表现出明显的正向中亲优势和超亲优势;纤维长度和成熟度指数与高值亲本P2相同,其余性状数值都接近于中亲值。本研究强调了种质创新、选择在杂优利用中的重要作用。     

两种类型蓖麻杂交种杂种优势的分析

为进一步了解蓖麻表型性状杂种优势表现特点及与亲本相应性状的关系.选用两种基因类型有明显差异的中高秆和矮杆蓖麻杂交组合的亲本CS-R6(♀)、CS-R181(♂)和CS-R63(♀)、CS-R268(♂)和它们的杂交种CS-R6.181F_1、CS-R6.181F_2、CS-R63.268F_1为研究材料.通过田间试验,测定了地上部干物质积累及在营养体和生殖体中分配速率和成熟期13个表型性状的杂种优势表现.结果表明:两种类型杂交组合的生育特点及杂种优势表现上有明显差别,CS-R6.181F_1属于生殖型为主、体质型为辅的杂种优势类型;而CS-R63.268F_1属于生殖型的杂种优势类型;中高秆杂交种CS-R6.181F_1收获期13个地上部主要性状杂种优势均表现为超高亲优势;而矮秆杂交种CS-R63.268F_1只是在籽粒产量、皮壳率和粗脂肪含量等7个性状表现为超高亲优势,百粒重等3个性状表现为超中亲优势,而营养体3个性状均表现超低亲优势,CS-R63.268F_1综合了母、父本突出的优良特性,生育期趋向父本,是适合密植和机械化栽培的杂交种;蓖麻杂种优势从杂种F_2开始出现衰退,不再适合在生产中应用.     

黄瓜早熟性状配合力测定及其相关性分析

南京农业大学园艺学院曹清河等以黄瓜4个高代自交系为亲本，按部分双列杂交法配制6个组合，利用软件QGA Station对与早熟有关的7个性状的配合力及相关性进行研究．结果表明，4429适合作为提高早期产量及早期采瓜数的亲本；CC3适合作为降低第1雌花节位和减少侧枝数的选育亲本。     

玉米早熟性的相关和遗传研究

以包含11个早熟自交系的共24个自交系及由它们配成的含有正、反交组合的116个单交组合(1991年)和122个单交组合(1992年)为材料,研究了玉米早熟性及产量与有关性状的相关性、早熟性的遗传特点。结果为单交组合生育期与其小区产量呈正相关,但也有个别组合表现既早熟又较高产的,单交组合生育期与其株高、单株叶数均呈正相关,单交组合单株籽粒产量与株高、行粒数、百粒重呈正相关,与穗行数基本无相关;杂交组合生育期多数介于双亲生育期之间,并稍偏晚熟亲本,早熟的显性度为0.22(1991年)和0.37(1992年),杂交组合F_1生育期与双亲生育期平均敷(x)之间存在显著正相关关系,回归方程为y=-10.9 1.17x;早熟性的正、反交组合之间不存显著差异。     

黄瓜早熟及丰产性与主要农艺性状的相关性分析

通过对黄瓜杂种一代苗期及成株33个性状的性状值、超中优势、超亲优势进行了全面系统地研究,分析了黄瓜丰产及早熟两个性状的主要构成因素及与其他性状间的相关性。结果表明,总瓜条数、单瓜重、主枝瓜重量、主枝单瓜重、主枝瓜条数、侧枝瓜条数、侧枝单瓜重、侧枝瓜重量、茎粗和生育天数等性状是决定总产量最为重要的因素并具有较强的杂种优势,无论在性状值、超亲还是超中优势中均达到极显著相关。前期产量主要决定于第一雌花节位和雌花节率及主侧枝瓜条数和瓜重、株高、叶面积等性状,达到显著水平,其中第一雌花节位和雌花节率在性状值、超亲和超中优势中都呈极显著相关性,说明这两个性状是决定黄瓜早熟性的决定性的因素并具有较强的杂种优势。根据试验结果分析了在黄瓜育种和生产过程中为达到早熟高产目的应当注意的几个主要问题。     

玉米光合生产率遗传的研究

通过对46个杂种及21亲本自交系光合生产率的测定结果表明:F_1平均光合生产率优势为16.4%.用高光合生产率亲本作母本时,F_1光合生产率优势超亲8.8%,反交F_1光合生产率优势超亲0.9%;母本光合生产率遗传力,大于父本光合生产率遗传力11倍.低光合生产率亲本的光合生产率遗传力大于高光合生产率亲本光合生产率的遗传力1.6倍.低光合生产率亲本作母本的连应遗传力达到42.1%.因此,以组配高光合生产率×低光合生产率的的组合为佳.     

甘蓝型油菜杂种优势和过氧化物酶的关系分析

对3个甘蓝型油菜杂交组合和亲本的农艺性状表现及其与过氧化物酶活性的关系进行了浅析,研究结果表明：杂种的产量性状,如单株粒重、单株有效角果数、有效分枝数、主花序有效角果数等,比其双亲有明显的优势;杂种花期的过氧化物酶活性高于双亲,与株高、有效分枝数、有效角果数、千粒重等性状具有显著的相关性;杂种的过氧化物酶同工酶谱表现为双亲的互补型。     

亚麻温敏雄性不育系F1、F2的优势分析

通过对以温敏亚麻雄性不育系1S为母本配制的6个杂交组合F1、F2代主要农艺性状和产量性状杂种优势的测定和分析,结果表明：不同杂交组合F1、F2代在株高和工艺长度上的平均优势均表现为负向超父本优势,而各产量性状上的平均优势均表现出很强的正向超父本优势;但与F1代相比,F2代平均优势明显下降。产量性状构成因素平均优势大小顺序为：单株产量＞单株果数＞千粒重＞每果粒数。不同组合间F1、F2代杂种优势表现差异较大,其中1S×黑亚15号组合产量性状的超父本优势最强,F1、F2代均表现出很强的杂种优势。     

Heterosis and heritability in crosses among Asian and Ethiopian parents of hot pepper genotypes

Hot pepper is the most important worldwide grown and consumed spice and vegetable crop. Though hybrid breeding has been proposed for genetic improvement in the crop, but there is lack of information on heterosis in crosses among crop genotypes in Ethiopia. Twelve genotypes (nine Asian and three Ethiopian parents) of hot pepper were crossed in 2003 cropping season in a half-diallel fashion to fit Griffing’s fixed effect model analysis. An open field experiment was conducted in 2004/2005 to investigate heterosis for fourteen traits in 66 F₁ hybrids grown together with their 12 selfed parents. Highly significant genotypic differences were observed for all the traits except for leaf area. Variance component due to specific combining ability (dominance) were larger than that due to general combining ability (additive) for each of the studied traits with few exceptions. Broad sense heritability (H _b²) for fruit traits were more than 60% and with wide gap from narrow sense heritability (h _n²) for most of the important traits like number of fruit per plant (H _b² = 88.3% and h _n² = 46.0%), days to maturity (H _b² = 87.2% and h _n² = 23.1%) and dry fruit yield per plant (H _b² = 72.6% and h _n² = 14.6%). Maximum heterosis over mid-parent and better-parent, and economic superiority of hybrid over standard check were recorded, respectively for dry fruit yield per plant (163.8, 161.8 and 92.1%), number of fruits per plant (104.4, 79.6 and 136.4%) and days to maturity (−29.8, −31.5 and −23.6%). These observations suggested a possibility of utilizing dominance genetic potentiality available in diverse genotypes of the crop by heterosis breeding for improving hot pepper to the extent of better economic return compared to the current commercial cultivar under production in the country. Low narrow sense versus very high broad sense heritability for days to maturity and dry fruit yield per plant could be a sign for achievability of earliness and high fruit yield using heterosis in hot pepper. The maximum heterobeltiosis were recorded either from F₁s obtained from Ethiopian and Asian crosses or from within Asian crosses, suggesting the possibility of maximizing heterosis by considering genetically diverse parental genotypes. The manifestation of highest heterosis in hybrids from among Asian lines indicated existence of genetic diversity among Asian genotypes and the potentiality for improvement of hot pepper using genotypes from different regions of the world along with elite inbred lines from local cultivars.     

Genetic analysis of rapeseed self-incompatibility lines reveals significant heterosis of different patterns for yield and oil content traits

Self‐incompatibility is one of the most effective approaches to utilizing heterosis in oilseed rape around the world. To evaluate the heterosis of double low self‐incompatibility, the possibility of combining seed yield and oil content, and the genetic effects of parents on their hybrid progenies, a 2‐year field trial using a 3 × 22 NC II mating design was conducted during the 1999‐2001 growing seasons in Wuhan, China. Significant differences in seed yield per plant and seed oil content were observed among the F1 hybrids and between F1 progenies and their parents. However, the heterosis for seed yield per plant was much greater than that for seed oil content. Mid‐parent heterosis and high‐parent heterosis of seed yield per plant ranged from 5.50 to 64.11% and from –2.81 to 46.02%, while those of seed oil content ranged from –1.55 to 7.44% and –3.61 to 6.55%, respectively. Non‐additive genetic effects were a major mechanism that accounted for the yield heterosis in addition to additive effects. In contrast, seed oil content heterosis was mainly dependent on an additive genetic effect. General combining ability (GCA) determined the stability of hybrid cultivars. In hybrid breeding, parental materials might be selected by the sum of GCAs and variances of special combining abilities (SCAs) of female and male parents for traits affected by both additive and non‐additive effects, and by the sum of GCAs of two parents for traits controlled mainly by additive effects. Primary branches and their siliques were the most important yield traits.     

Relationship between heterosis and genetic distance based on morphological traits and AFLP markers in pepper

Genetic diversity is considered as one of the criteria for the selection of parents for hybrid breeding. The present study was undertaken to evaluate genetic divergence among seven pepper cultivars and to assess the relationship between heterosis and parental genetic distance. Twenty‐one F₁ hybrids and seven parents were evaluated for 15 morphological characters in a greenhouse and in the field. The parents were examined for DNA polymorphisms using six amplified fragment length polymorphism (AFLP) primer combinations. Cluster analysis using two genetic distance measures grouped the seven parents differently. Mid‐parent and high‐parent heterosis was observed for most characters. Most hybrids outperformed the parental lines for fruit yield, earliness and plant height. Morphological and AFLP‐based distance measurements were efficient enough to allocate pepper genotypes into heterotic groups. The correlations of morphological distances with mid‐parent heterosis were significant for days to flowering and maturity, suggesting earliness can be predicted from morphological distances of parental lines. However, the correlations of AFLP‐measured genetic distances with mid‐ and high‐parent heterosis were non‐significant for all characters, except for fruit diameter, and proved to be of no predictive value.     

高丹草遗传效应与杂种表现预测模型

以5个高粱不育系材料为母本, 18个优质苏丹草材料为父本, 按照遗传交配设计(NCII)配制成90个杂交组合。分别在内蒙呼市和包头两地, 利用与高丹草产量相关的QTL位点标记检测亲本间的遗传差异, 并将F₁的8个性状表型值对亲本材料进行标记位点的筛选, 建立标记效应和标记型值估算体系。估算特异性位点对性状表现的效应及杂种标记型值, 进而分析杂种标记型值与杂种表现的相关性, 应用逐步回归分析法建立8个性状杂种表现的预测模型, 并通过Jackknife抽样技术检测模型的精确度和稳定性。结果显示, 在分别考虑显性、加性作用下8个性状的标记型值与表型值的相关系数平均为0.65, 各性状的可决系数较大(0.51~0.88), 而且两地结果趋势一致, 表明该预测模型稳定性强, 精确度较高。该模型对高丹草的杂种表现预测以及亲本选配都具有一定的指导意义。     

Heterosis for yield and related characters in pea

Summary To determine the levels of heterosis in F1 hybrids, four current pea (Pisum sativum L.) cultivars from southern Australia were used as female parents and crossed with 18 introduced genotypes. The 22 parents, 72 F1 hybrids and, depending on the environment, either 54 or all 72 F2 families were grown in replicated plots in four environments. Grain yield, total dry matter, harvest index, branches per plant, pods per plant, seeds per pod, hundred seed weight, plant height, onset of flowering and flowering periods were evaluated. For both the F1 and F2 generation, heterosis was determined as the superiority over the mid-parent and also over the better parent. In addition, the superiority over the best commercial cultivar was calculated. Most hybrids were higher yielding than their mid-parent but were less stable in yield across environments. Four F1 hybrids were significantly higher yielding than the best parent, by up to 26%. There were significant correlations between F1 hybrid and mid-parent value for plant height, pods per plant and hundred seed weight but not for yield. Overall, grain yield heterosis was mainly due to more pods per plant in the hybrids. The level of heterosis for yield in a poor yielding environment was higher than that in a high yielding one. Both additive and non-additive gene effects were important in the expression of all studied traits. The average level of heterosis for grain yield and total dry matter in the F2 population was half of that in F1 hybrids. The low level of inbreeding depression from the F1 to the F2 generation suggested that epistatic gene action also contributed to the expression of grain yield. Some F2 populations maintained the high yield levels of the corresponding F1 hybrids.     

花生蛋白质、脂肪含量及其它农艺性状的配合力和遗传参数分析

三个高蛋白与三个高脂肪品种进行完全双列杂交,研究以籽仁重、蛋白质和脂肪含量为主的15个性状的配合力、遗传相关及杂种优势.结果表明:两种配合力的方差分析F值均达显著标准,但加性效应占主要优势,总配合力与杂种实际表现高度相关.郑71—3是高产高脂肪的理想亲本,奇科可作为高蛋白材料加以利用.在性状间相关中,蛋白与脂肪为显著负相关,但二者与籽仁产量呈弱的正、负相关,有利高产高油分和高产高蛋白品系的选育.花生杂种一代有明显优势,但营养生长性状、结实性状和脂肪含量趋向高亲,而出仁率、百仁重和蛋白含量趋向低亲.     

Prediction of heterosis using QTLs for yield traits in rapeseed (Brassica napus L.)

Three double low (erucic acid and glucosinolates) self-incompatible lines and 22 varieties from different origins were selected to produce 66 hybrids according to a NC II mating design. Field experiments for identification of hybrid performance and heterosis were conducted in two successive rapeseed growing seasons in Wuhan, China. After heterosis identifications, SI-1300 and Eagle were chosen to construct an F₂ segregating population. One hundred and eighty four F_2:3 lines were planted at Wuhan and Jingmen to test yield traits. F₂ plants and the 25 parents were analyzed using simultaneously AFLP (amplified fragment length polymorphism) and SSR (simple sequence repeat) markers. A total of 270 and 718 polymorphic loci were detected in the F₂ population and among the 25 parental lines, respectively. Of the 718 polymorphic loci, 178 were significantly correlated to yield traits. With the use of one-way ANOVA, 84 common QTLs were detected for 12 traits at two trial locations. Although the genetic distances based on general/specific heterozygosities and single-locus QTLs showed significant correlations with hybrid performance and heterosis for some yield traits, the determination coefficients were low. The results suggested that neither heterozygosities nor QTLs for yield traits were suitable to predict hybrid performance and heterosis in Brassica napus.     

Combining ability for yield,protein and oil of peanut lines from South American centers of diversity

Summary Ten peanut (Arachis hypogaea L.) lines, two from each of five centers of diversity in South America, and the F₂ generation of all possible crosses among them were used to characterize the variation for yield, fruit and seed traits and protein and oil content and to determine the breeding potential of the parents. Two of the parental lines belong to subspecies hypogaea and the other eight to subspecies fastigiata.Several crosses gave heterotic responses for yield. The parents of the crosses with significant heterosis generally came from different centers of diversity.Variation among both general and specific combining abilities was significant for all traits with the exception of the SCA estimate for protein percent. The component of variation for GCA was larger than the SCA component for all traits.A Spanish line and a Valencia-like intermediate line from the Guarani region had the highest GCA effects for fruit yield, seed yield and meat content and transmitted consistently their characteristics to their F₂ progeny. Some lines showed significant but small maternal effects for oil, protein and oil + protein percent. Differences between reciprocal crosses were significant for fruit length, fruit weight and oil + protein percent.A significant portion of the variation among crosses was explained by differences among parental lines within centers of diversity. This supports the fact that centers are founded because of the diversity of the peanuts grown there.The performance of parental lines per se was useful in predicting the performance of the lines in hybrid combination for all traits except fruit yield.Paper number 6141 of the Journal Series of the North Carolina Agricultural Research Service (USA). This work was partially supported by CSRS Research Agreement 701-15-51.