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1.
In order to evaluate the effects of heterogeneity and heterozygosity on yield stability in faba beans, genotypes were generated with contrasting population structures, differing only in their levels of heterogeneity and heterozygosity. All entries were based on either eight or 36 inbred lines, respectively. The population structures tested consisted of pure stands of the inbred lines (1) and of their F1,-hybrids (2), blends of the inbred lines (3) and of their F1 hybrids (4), four-component synthetics in different Syngenerations (5), the open-pollinated source varieties (6) and 36 polycross progenies (7). Five different entry sets (= data sets), each covering several of the seven population structures listed, were grown during 1986 to 1991 in at least four different environments in Western Germany and tested for yield. Stability parameters, i.e., the regression coefficient and deviation from regression (EBERHART and RUSSELL 1966), and the ecovalence (WRICKE 1962), revealed that yield stability of the different population structures was improved by increasing heterozygosity as well as heterogeneity. But the impact of both factors of diversity on yield stability varied between the different data sets. Positive effects of both factors on yield stability seemed to be additively combined in the hybrid blends (data set I). The same proved to be partly true for the four different Syn-generations of the nine synthetics tested. Yield advantage of the different heterozygous variety structures over the homozygous ones in creased with increasing yield level at test sites, as indicated by regression coefficients larger than 1. 相似文献
2.
Heterosis and mixing effects in barley under drought stress 总被引：1，自引：0，他引：1
C. H. P. Einfeldt S. Ceccarelli S. Grando A. Gland-Zwerger H. H. Geiger 《Plant Breeding》2005,124(4):350-355
Yield stability is one of the main breeding objectives in breeding for stress environments, such as the semi‐arid areas of Syria. The objectives of this study were to measure the effects of heterogeneity and heterozygosity on yield and yield stability by comparing doubled haploid lines (DHL) in mixed vs. pure stand (influence of heterogeneity) and F2 populations vs. corresponding DHL mixtures (influence of heterozygosity). Six barley lines from two gene pools (LR = landraces, EL = experimental lines) were used to produce nine crosses (two LR × LR, three EL × EL, four LR × EL). The F2 generation and eight DHL per cross were produced from each cross. The six parental DHL, nine F2 populations, nine 8‐line mixtures and 72 DHL in pure stands were tested in five environments under drought stress in north Syria. The mean superiority of F2 populations over DHL mixtures for yield traits across environments and cross combinations ranged between 7.5 and 10%. The effect of heterogeneity was small throughout. For grain yield, harvest index, 1000‐grain weight and plant height significant interactions between heterozygosity levels and environments were observed. The effect of heterozygosity for grain yield increased substantially from ‐1.2% in the highest‐yielding environment to 45.6% in the most stressful environment. Interactions between levels of heterozygosity and cross combinations were significant for most traits. F2 populations were considerably more stable than DHL in pure stands, yet not as stable as DHL mixtures. It is concluded that heterozygosity is more important than heterogeneity in breeding for improved yield and yield stability under drought stress. 相似文献
3.
Summary The relative performance of synthetic varieties in faba beans (Vicia faba L.) as compared with line varieties is the result of the joint effect of several factors. Factors investigated in the present study were (1) effects of heterogeneity and (2) heterozygosity on agronomic performance, (3) genetic variance for the degree of cross-fertilization among inbred lines and (4) genetic variance among homozygous and heterozygous genotypes for yield. The evaluation was based on multilocational trials in Germany with 36 inbred lines and derived entries with contrasting population structure (levels of heterozygosity and heterogeneity). When inbred lines and F1-hybrids are included in the same mixture of genotypes, the resulting heterogeneity had a positive effect on yield. Relative mid-parent heterosis for yield was between 33% and 51%. The average degree of cross-fertilization was 53.5%, and its genetic standard deviation was 8.3%. The estimates for genetic standard deviation for yield among inbred lines were between 3.4 q/ha and 5.3 q/ha. The highest yielding synthetic variety is expected to outyield markedly the highest yielding line. 相似文献
4.
Genetic variation for resistance to low-temperature photoinhibition of photosynthesis in maize (Zea mays L.) 总被引：1，自引：0，他引：1
O. Dolstra S. R. Haalstra P. E. L. van der Putten A. H. C. M. Schapendonk 《Euphytica》1994,75(1-2):85-93
Summary In the partially allogamous faba bean, yield and yield stability can be improved significantly by heterozygosity and heterogeneity. The commercial production of hybrid varieties for the full exploitation of heterosis is still unfeasible. Hence, the breeding of synthetic varieties has repeatedly been recommended. The present study aimed at investigating whether and to what extent effects due to heterozygosity and heterogeneity occur in such varieties, particularly in relation to Syn-generation. A sample of 36 inbred lines (Vicia faba L. minor) was used to generate several entries of different population structure, e.g. blends of inbred lines (=Syn-0), experimental synthetics of generations Syn-1 to Syn-4 and polycross progenies. In 1986 to 1991 these entries were evaluated together with their parental lines grown in pure stands in six series of multi-locational field trials in West Germany. The yield of the synthetics increased with successive Syn-generations and asymptotically approached its maximum by as early as generations Syn-2 or Syn-3. The yield increase was mainly caused by heterozygosity. In two synthetics the yield increase corresponded to about one-half to two-thirds of the mid-parent heterosis. Effects due to heterogeneity were small and mostly non-significant. In one out of three expriments significant effects due to seed source were observed which, however, did not alter the yield increase with successive Syn-generations. Hence, Syn-generations Syn-2 or Syn-3 may be sold to the farmer. 相似文献
5.
选用来源于中国黄淮和美国的熟期组II~IV的8个大豆品种, 按Griffing方法II设计, 配成28个双列杂交组合, 包括8个亲本共计36份材料。选用300个SSR标记, 对8个大豆亲本进行全基因组扫描, 利用基于回归的单标记分析法, 对大豆杂种产量和分子标记进行相关性分析, 估计等位变异的效应和位点的基因型值, 剖析杂种组合的等位变异。结果表明, 300个SSR标记中有38个与杂种产量显著相关, 分布于17个连锁群上, 其中D1a和M等连锁群上较多, 有8个位于连锁定位的QTL区段内(±5 cM)。单个位点可分别解释杂种产量表型变异的11.95%~30.20%。杂种的位点构成中包括有增效显性杂合位点、增效加性纯合位点、减效加性纯合位点和减效显性杂合位点4部分, 其相对重要性依次递减。从38个显著相关的SSR标记位点中, 遴选出Satt449、Satt233和Satt631等9个优异标记基因位点, Satt449~A311、Satt233~A217和Satt631~A152等9个优异等位变异, 以及Satt449~A291/311、Satt233~A202/207和Satt631~A152/180等9个优异杂合基因型位点。这些结果为理解杂种优势的遗传构成和大豆杂种产量聚合育种提供了依据。 相似文献
6.
Summary Microspore embryogenesis technology allows plant breeders to efficiently generate homozygous micros-pore-derived breeding populations of oilseed rape (Brassica napus L.) without traditional generations of inbreeding. This study was conducted to compare the frequency distribution of microspore-derived population and single seed descent populations with respect to fatty acids of seed oil. Both microspore-derived populations and single seed descent populations were produced from each of three crosses made between selected parents containing contrasting amount of erucic, oleic, linoleic and linolenic acids. The fatty acid content of F3 plants derived lines (F5 seed) developed by single seed descent was compared to that of microspore-derived populations. The means, ranges and distribution pattern of seed fatty acid contents were similar in both populations for each fatty acid studied, although a few heterozygous lines were observed in the single seed descent populations. The results indicated that microspore-derived population form random, homozygous F1 plant derived gametic arrays for all fatty acids evaluated. Selection for altered fatty acid composition in microspore-derived and single seed descent homozygous populations should be equally efficient, in the absence of linkage of traits investigated. 相似文献
7.
玉米三交种郑三3号高产原因分析 总被引：2，自引：0，他引：2
用郑三3号的3个亲本自交系,组配成6个正反单交组合和6个以单交为母本的三交组合,进行产量比较和性状调查。结果表明,6个单交组合之间的产量差异不显著,6个三交组合之间的产量差异亦不显著,说明这3个自交系相互间的配合力都很高,这是郑三3号的产量达到了优良单交种产量水平的内在因素。 相似文献
8.
Twelve primary hexaploid triticale (X Triticosecale Wittmack), synthesized from, three lines of tetraploid wheat (Triticum durum L., T. turgidum L.) and four inbred lines of rye (Secale cereale L.), were used to produce 18 crosses with homozygous wheat and heterozygous rye genome and 12 crosses with heterozygous wheat and homozygous rye genome. Parents and crosses of triticale, wheat, and rye were tested for two years (rye for one year only) in two-replicate block designs with 1 m2-plots. Data were assessed for plant height, grain yield and for yield-related traits. Performance of triticale crosses was considerably lower than that of the wheat and rye crosses. The amount of heterosis varied greatly between years. Positive and mainly significant heterosis was revealed in triticale generations F1 and F2. The average values were closer to those in wheat than to those in rye. For most characters a high level of heterosis was retained in tnucalt1 generation F2. Heterozygosity of the wheat and rye genome both contributed to heterosis in triticale. However, gene action of the rye genome strongly depended on the homozygous wheat background: one wheat line almost completely suppressed and another greatly stimulated the heterotic effect of the rye genome. In the later case, the amount of heterosis was related to that in rye per se. Information from hybrid rye breeding may therefore be used when establishing gene pools for hybrid breeding in triticale. 相似文献
9.
A male sterile line with dominant gene (Ms) in cabbage (Brassica oleracea var. capitata) and its utilization for hybrid seed production 总被引：4，自引：0，他引：4
Zhiyuan Fang Peitian Sun Yumei Liu Limei Yang Xiaowu Wang Anfu Hou Chunsong Bian 《Euphytica》1997,97(3):265-268
A male sterile plant, 79-399-3, was identified from a spring cabbage line 79-399 in 1979. Light-microscopic studies with paraffin
section indicated that meiotic division stopped at the tetrad stage. The ratio of male sterile plants to fertile plants in
the progenies of test crosses was 1:1 in five experiments conducted in 1982 and 1991–1994. However, some male sterile plants
were sensitive and developed a very low number of viable pollen grains. When sensitive male sterile plants were selfed, the
progenies segregated into male sterile and fertile plants at a ratio of 3:1. The male sterile plants from selfing of sensitive
male sterile plants were propagated by tissue culture and crossed with different inbred lines. From the progenies of the crosses,
populations with 100% male sterile plants were observed. The results indicated that homozygous dominant male sterile (MsMs)
plants segregated from the selfed progenies. Populations with 100% male sterile plants and stable male sterility were developed
as male sterile lines. Several favorable combinations were also selected by crossing the male sterile lines with inbred lines
with high combining ability for desirable horticultural characters.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
10.
Haploid induction in onion via gynogenesis provides inbred lines that can be used in production of hybrid cultivars. Despite several successful reports, the gynogenic induction rate is still relatively low, ranging mainly from 0.5 to six embryos per 100 cultured flowers. In the present study, gynogenesis was induced in selfed progeny of three genetically homozygous and stable fertile doubled haploid lines previously obtained through in vitro gynogenesis. The aims were to acquire information on whether the gynogenic responsiveness of a particular heterozygous cultivar is correlated with higher or lower gynogenic capacity in the second cycle of gynogenesis, to evaluate the non-genetic component of the variability, and to monitor by random amplified polymorphic DNA (RAPD) analysis the onset of eventual gametoclonal variation induced during the gynogenic processes. The results from the gynogenic induction of 9708 flowers showed significant differences among three lines, one of them being extremely responsive, showing a mean yield of 118.3 haploid embryos per 100 cultured flowers (118.3%). The high embryo yield of this line was determined by the line's particular genotype. However, the induction rate of gynogenic embryos obtained within 24 genetically uniform donor plants of this responsive line varied from 67 to 196% and this variation can be attributed to uncontrolled environmental conditions. A total of 157 plants sampled from two lines and obtained through a first (RI) and a second (SCG) cycle of gynogenesis, was analysed by RAPDs. The single band profiles were compared either between or within the RI and SCG plants of each line. A total number of 4600 RAPD fragments were scored and no variation was found in the highly responsive line, while in the less responsive one, minor changes were detected for the presence/absence of two RAPD bands. These results indicate high genetic stability of onion homozygous lines passed through two cycles of gynogenesis. 相似文献
11.
Outcrossing Rates in Autumn and Spring-Sown Barley 总被引：1，自引：0，他引：1
H. Doll 《Plant Breeding》1987,98(4):339-341
Natural outcrossing is a potential cause of the admixtures which are often observed, especially in winter barley. Outcrossing was studied in yield trials with hap laid -derived homozygous offspring, lines from tour crosses between winter and spring barley varieties. Outcrosses were recognised by heterozygosity in storage protein loci Hor1 and Hor2 as revealed by electrophoresis. Outcrossing, was, on average, about 5% in lines sown in the autumn and less than 0.5% after spring sowing. Autumn-sown lines from one of the four crosses studied had about 10% outcrosses. 相似文献
12.
Organic farming requires cultivars that are specifically adapted to this low input cropping system. Hence, organic farmers
and scientists joined in a participatory breeding approach to develop region-specific genotypes of spring faba bean for organic
conditions in Germany. A set of 49 genotypes with contrasting degrees of heterozygosity and heterogeneity was used in field
trials across five locations in Germany during 3 years 2004, 2005 and 2006. The material involved 18 inbred lines, their 18
polycross progenies, one blend of inbred lines, one blend of polycross progenies, one blend of hybrids and ten checks. Inbred
lines are uniform, thus giving the option to be specifically adapted; whereas the polycross progenies and synthetics (Syn-1;
predicted from the inbred lines and polycross progenies performance) are partly heterogeneous and heterozygous, thus giving
the option to evolve. Agronomic performance was assessed and a “personal appreciation” score of the material was assigned
to each genotype by each partner. This personal appreciation was strongly influenced by biotic and abiotic constraints faced
by the crop in each location and by the expected grain yield of the genotypes. Uniformity was apparently appreciated by organic
farmers. In all locations, the highest yielding inbred line yielded slightly better than the predicted highest yielding synthetic.
However, this slight disadvantage of the synthetic is very likely to disappear if the synthetic (Syn-1) is propagated during
successive generations. 相似文献
13.
Maria-João Paulo Martin Boer Xueqing Huang Maarten Koornneef Fred van Eeuwijk 《Euphytica》2008,161(1-2):107-114
To improve QTL detection power for QTL main effects and interactions and QTL mapping resolution, new types of multi-founder
crossing populations are created in plants and animals. Some recent examples are complex intercrossed populations in mice
and Arabidopsis thaliana. For the latter, a set of eight accessions was intercrossed to produce four two-way hybrids that were subsequently intercrossed
again in a half diallel fashion leading to six subpopulations of four-way hybrids, each subpopulation containing 100 individuals.
Within each subpopulation, individuals were inbred for four generations via single seed descent. QTL mapping in the complex
crosses requires new statistical tools. We present a first sketch of a QTL mapping methodology for the complex cross in Arabidopsis
based on mixed model analyses. As experimental data were not yet available, we illustrate our methodology on simulated but
realistic data. 相似文献
14.
Populations of F6 recombinant inbred lines, generated by single seed descent from a half diallel among eight bread wheat lines adapted to the
East African highlands, were used to identify those crosses that were more likely to produce cultivars which combined resistance
to yellow rust with improved yield. Crosses having the most resistant line as one parent offered the best prospect of success,
particularly those which produced F1hybrids exhibiting better parent heterosis. For plot grain yield there was a highly significant correlation between the observed
and predicted rankings of the recombinant inbred line populations for the proportion of individual lines equalling or surpassing
the target value. For yellow rust severity, however, this correlation was non-significant when a target value of zero was
used. Adopting a slightly less stringent target of 0.25, coupled with the omission of two aberrant populations, increased
this correlation significantly. The plant breeding implications of these results are discussed.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
15.
Summary In diallel crosses of Io plants of pointed headed cabbage a significant sca variance for head weight and a significant gca variance for earliness was found.In a diallel set of inbred lines the sca variance for plant weight decreased when plants were harvested later, while the gca variance increased. By means of the Hayman-Jinks analysis clear overdominance but no epistatic effects could be recorded.Double crosses and mass propagated single crosses were inferior compared with single crosses and proved to be not attractive for horticultural practice.Already in a young plant stage differences in plant weight between inbred and hybrid plants were noted in favour of the latter. During the growth period this difference increased. Single crosses produced relatively fewer outer leaves than double crosses and inbred lines. 相似文献
16.
Summary The mean aim of this study was to identify an effective method of predicting cross-potential in respect of yield improvement of the cowpea (Vigna unguiculata (L.) Walp.) through hybridization and subsequent selection.Three prediction tests based on data collected from experiments with ten cowpea lines and the F1 and F2 generations of all possible crosses between these lines were evaluated. The three prediction tests were based on: i Yields of prospective parents. ii. General combining abilities estimated from F1 and parental data iii. Frequencies of superior plants in F2 populationsEach of the three procedures was used to identify the crosses with the lowest or highest yield potential, i.e. those crosses most likely to produce the greatest number of lines with yields higher or lower than those of either parent. Crosses selected on the basis of these criteria were evaluated in the following growing season on the basis of biometrical analysis of F2 and backcross populations and the performance of the respective F3 and F4 generations.Six different crosses were selected from the 45 tested on the basis of the three prediction tests. Analyses of F2 and backeross populations from each cross provided estimates of [d] the difference in parental means and 1/2D the additive genetic component which, in turn, were used to predict the frequency of transgressive inbred lines obtained by single-seed descent from the F2. Both crosses selected on the basis of F2 data were expected to produce a much higher frequency of transgressive lines than those selected on the basis of parental yields. The high potential cross selected on the basis of general combining ability was expected to produce a higher frequency of transgressive lines than the corresponding low yield potential cross. Replicated trails of F3 bulks of the selected crosses showed that high yield potential crosses were significantly higher yielding than low yield potential crosses for all prediction criteria. In a trial with 22F4 lines of each of the two crosses selected on the basis of parental yields and frequency of high yielding F2 plants, the high yield potential cross in each case had a greater mean and variance for seed yield than the corresponding low yield potential cross.It was concluded that parental yields provide a sound basis for an initial screening of prospective parents. This screening should identify a high yielding line which can be crossed with a number of contrasting lines to produce F2 populations for the final screening phase. 相似文献
17.
Root characteristics of maize inbred lines and single crosses in controlled environments and in field trials
Shoot and root dry matter yield and root surface of eight maize inbred lines and eight single crosses were investigated in nutrient solutions with low and high nitrogen content. In a seedling test root length was determined, and in field trials the vertical root-pull resistance, kernel yield, lodging resistance and root dry matter in soil cores were measured.
Nitrogen concentration had a positive effect on root growth in nutrient solution as well as under field conditions. For all root traits there exist a significant genotypic variation. No interactions occurred between genotype and nitrogen supply. Root dry matter in nutrient solution, vertical root-pull resistance, and lodging resistance were positively correlated among one another. No correlation was observed between root weight in nutrient solution and root weight under field conditions. 相似文献
Shoot and root dry matter yield and root surface of eight maize inbred lines and eight single crosses were investigated in nutrient solutions with low and high nitrogen content. In a seedling test root length was determined, and in field trials the vertical root-pull resistance, kernel yield, lodging resistance and root dry matter in soil cores were measured.
Nitrogen concentration had a positive effect on root growth in nutrient solution as well as under field conditions. For all root traits there exist a significant genotypic variation. No interactions occurred between genotype and nitrogen supply. Root dry matter in nutrient solution, vertical root-pull resistance, and lodging resistance were positively correlated among one another. No correlation was observed between root weight in nutrient solution and root weight under field conditions. 相似文献
18.
源于陕A群、陕B群玉米自交系在不同密度条件下配合力分析 总被引：1，自引：0，他引：1
采用NC-II遗传设计,以郑58、昌7-2为测验种,与17份高密度条件下筛选的玉米自交系组配成34份杂交组合,2014—2015年分别于陕西杨凌、长武、榆林进行3种密度(45 000、67 500和90 000株hm–2)配合力分析试验。采用PROC VARCOMP分析不同密度条件下产量及耐密性相关性状的遗传效应,采用频率直方分布图研究不同密度条件下产量及耐密性相关性状一般配合力(GCA)平均数的变化规律,利用AMMI评价玉米自交系与杂交组合的稳定性。结果表明,产量、倒伏率、茎秆强度主要受加性遗传效应控制,空秆率主要受非加性遗传效应控制。加性遗传效应对产量及耐密性相关性状的贡献率随种植密度的增加呈上升趋势。玉米自交系产量、空秆率、倒伏率、茎秆强度的一般配合力频率均属于正态分布,随着种植密度的增加,产量GCA的平均值提高了0.28,空秆率GCA平均值降低了0.21,倒伏率GCA平均值降低了0.03,茎秆强度GCA平均值增加了0.02。玉米杂交组合产量与玉米自交系产量GCA密切相关(r=0.877**,r=0.811**,r=0.672**)。随着种植密度的增加,表现稳定的玉米自交系及杂交组合的数量呈上升趋势。因此,强化逆境选择压力,实施高密度选择策略,是增强玉米自交系耐密性和抗倒性,提升一般配合力,实现产量增益的有效措施。 相似文献
19.
DNA marker-assisted selection was employed to select Xa-21 bacterial blight resistance and waxy (Wx) genes. Genotypes with both genes were selected from four F2 populations involving indica × indica, indica × intermediate and japonica × indica crosses. With the assistance of PCR marker,
13 true breeding lines carrying Xa-21 were identified from F2 generation of IRBB 21 × G 11353 cross. Similarly ten, eleven and fifty two plants having Xa-21 gene were isolated from G 3005-4-1 × IRBB 21, IRBB 21 × HJX 74 and IRBB 21 × SY 2crosses respectively. The lines with Wx gene in both homozygous and heterozygous state were also scored from the above crosses. Twenty plants having both Xa-21 and
Wx loci in homozygous state were identified. DNA-based progeny testing was conducted to ensure the selection of homozygous lines
for Xa-21 and Wx genes. Finally,twenty true breeding lines with high amylose content and Xa-21 gene were isolated from four crosses. These homozygous lines are phenotypically superior and resistant to Chinese race 5
of the bacterial blight pathogen. Fifty-six germplasm sources were surveyed for PCR polymorphism in order to facilitate future
PCR-based marker assisted transfer of bacterial blight resistance genes xa-5, xa-13 and Xa-21 to any desired varietal background which will be useful for selection of parents in breeding programmes.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
20.
R. I. H. McKenzie R. J. Lamb T. Aung I. L. Wise P. Barker O. O. Olfert R. I. McIntosh 《Plant Breeding》2002,121(5):383-388
Inheritance of resistance to a wheat midge, Sitodiplosis mosellana (Géhin), was investigated in spring wheats derived from nine resistant winter wheat cultivars. F1 hybrids were obtained from crosses between resistant winter wheats and susceptible spring wheats, and used to generate doubled haploid populations. These populations segregated in a ratio of 1:1 resistant to susceptible, indicating that a single gene confers the resistance. The F2 progeny from an intercross among spring wheats derived from the nine resistance sources did not segregate for resistance. Therefore, the same gene confers resistance in all nine sources of resistance, although other genes probably affect expression because the level of resistance varied among lines. Heterozygous plants from five crosses between diverse susceptible and resistant spring wheat parents all showed intermediate levels of response, indicating that resistance is partly dominant. Susceptible plants were reliably discriminated from heterozygous or homozygous resistant ones in laboratory tests, based on the survival and development of wheat midge larvae on one or two spikes. This powerful resistance gene, designated Sm1, is simply inherited and can be incorporated readily into breeding programmes for spring or winter wheat. However, the use of this gene by itself may lead to the evolution of a virulent population, once a resistant cultivar is widely grown. 相似文献