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1.
Heterosis in rice over environments 总被引：2，自引：0，他引：2
Summary Ten CMS (A) lines and their maintainers (B) and seven restorers (R) were used to make 70 crosses (A/R) and 70 reciprocals (R/B) following line x tester design. The 140 crosses and 17 parents (10 B + 7 R lines) were evaluated in six environments created by three nitrogen fertility levels (0, 60, 120 kg N/ha) and two seasons wet (WS) and dry (DS). Hybrids (both A/R and R/B) were superior to their parents in yield. Hybrids flowered earlier and were taller than the parents. Substantial heterosis, heterobeltiosis and standard heterosis were observed in different environments. Extent of heterosis was higher in WS (stress environment) than in DS (favorable environment). Twenty four hybrids outyielded the standard check (IR46) significantly. Most of them were derived from crosses with parental lines: IR54752A/B, IR58057A/B, IR46 and IR54. For days to flowering, the overall mean heterosis, heterobeltiosis and standard heterosis were all negative values. Heterosis for plant height did not change the plant type of hybrids from semi-dwarf to tall because the parents possessed same dwarfing gene. With proper choice of parents hybrids possessing higher yield potential, early maturity and semi-dwarf plant type can be developed for the tropics. 相似文献
2.
为了分析转基因抗虫棉不育系的配合力和杂种优势。采用6×6NCⅡ交配设计,分析了6份转基因抗虫核不育系与6份陆地棉亲本杂交后,9个性状杂种F1的超父本优势、竞争优势和配合力。结果表明,籽棉产量超父本优势的平均值为19.44%,22个组合具正向的杂种优势;竞争优势的平均值为-8.36%,16个组合出现正向竞争优势。单株铃数的杂种优势最为明显。父本值与F1平均值的相关关系表明,8个性状F1代平均值与父本值的相关性达到极显著水平。经配合力分析,A1、A4、B1、B5等亲本的GCA较好;SCA效应显著的6个性状中,A1×B6、A3×B3等组合的SCA效应均为正值。 相似文献
3.
Cytoplasmic male sterility (CMS) is considered an efficient genetic tool in pearl millet hybrid breeding. Of the several CMS
sources available in pearl millet, A1 is the only CMS widely exploited to produce commercial hybrids in India. To explore the possibility of using alternate CMS
sources, we studied the cytoplasmic effects of different CMS sources on agronomic characters in pearl millet. Five CMS (A)
lines representing A1, A2, A3, A4 and A5 cytoplasms, their respective maintainer (B) lines and eight restorer (R) lines were used to generate 40 A × R and B × R experimental
crosses. The experimental material was evaluated at two different locations in India. Analysis of combining ability and heterosis
revealed that A4 and A5 cytoplasms had desirable effects for earliness. The A5 CMS was found to be particularly promising, as compared to other CMS sources for improving grain yield. The study also indicated
that the cytoplasmic effects on general combining ability (GCA) for various agronomic characters were largely non-significant.
However, cytoplasmic effects on specific combining ability and heterosis were found to be modulated by cytoplasmic-nuclear
interactions and influenced by the environmental conditions. The study also demonstrated the advantage of utilizing diverse
male-sterile and restorer combinations in maximizing the productivity as well as for genetic and cytoplasmic diversification
of hybrids in pearl millet. 相似文献
4.
5.
Paired A- and B-lines, cytoplasmic male-sterile (CMS)-lines and main-tainer lines, respectively, were crossed with R-lines (restorer) to produce A × R, R × B and B × R hybrids, which were used in 1993 and 1996 to predict the performance of three lypes of CMS cotton lines available in China. A significant difference in yield and yield components was revealed between paired A × R and B × R hybrids. This difference was greatly influenced by both CMS cytoplasm and the interaction between cytoplasm and nuclear genotypes. It is suggested that there are detrimental effects of CMS cytoplasm on yield and yield components. General combining ability of near-isogenic CMS lines was also affected by this negative effect. The detrimental effect was closely related to an increased number of immature seeds per boll, which might be caused by partial female sterility associated with CMS cytoplasm. The possibility of developing specific combinations of CMS Upland × Upland restorer hybrids that express enough heterosis for yield to overcome the detrimental effect of the CMS cytoplasm is discussed. 相似文献
6.
An investigation was carried out to assess the efficiency of A2 cytoplasmic-nuclear male-sterility (CMS) system in comparison to the widely used A1 cytoplasm in terms of general combining ability (gca) effects of male-sterile (A-) lines and mean performance, specific combining ability (sca) effects and mid-parent heterosis of hybrids for days to 50% flowering, plant height and grain yield at International Crops
Research Institute for the Semi-Arid Tropics, Patancheru, Andhra Pradesh, India in 2001 and 2002 rainy seasons. The material
for the study consisted of six pairs of iso-nuclear, allo-plasmic (A1 and A2) A-lines and 36 iso-nuclear hybrids produced by crossing these A-lines with three dual restorer (R-) lines. The results revealed
that cytoplasm and its first-order interaction with year, R- and A-lines did not appear to contribute to variation in iso-nuclear
hybrids for plant height and grain yield. Cytoplasm had limited effect on gca effects of A-lines and on sca effects and mid-parent heterosis of iso-nuclear hybrids for days to 50% flowering, plant height and grain yield. The mean
days to 50% flowering, plant height and grain yield of A2 cytoplasm-based hybrids were comparable with those of widely used A1 cytoplasm-based hybrids. The relative frequency of the occurrence of the A1- and A2-based hybrids with significant sca effects and mid-parent heterosis indicated that A2 CMS system is as efficient as A1 with a slight edge over A1 for commercial exploitation. The implications of these results are discussed in relation to opportunities for broadening
not only cytoplasm base but also nuclear genetic base of both the hybrid parents. 相似文献
7.
Eight-parental diallel cross and SSR molecular markers were used to determine the combining ability of common wheat lines grown under well-watered (WW) and water-stress (WS) conditions. Analysis of variance of yield indicated highly significant differences among the progenies. General combining ability (GCA) determined most of the differences among the crosses. Specific combing ability (SCA) was also significant but less important. The estimates of GCA effects indicated that one line was the best general combiner for grain yield under drought. Neis genetic distance, measured using SSR markers, differed from 0.20 to 0.48 among the eight genotypes. The correlation of Neis genetic distance with SCA for grain yield and heterosis ranged from 0.4 to 0.5. These results indicate that the level of SCA and heterosis depends on the level of genetic diversity between the wheat genotypes examined. Microsatellite markers were effective in predicting the mean and the variance of SCA in various cultivars combinations. However, selection of crosses solely on microsatellite data would miss superior combinations. 相似文献
8.
M. Maris 《Euphytica》1989,41(1-2):163-182
Summary The main aim of the experiment was to study the behaviour of seven long-day adapted clones of Solanum tuberosum ssp. andigena (A) and three varieties of S. tuberosum ssp. tuberosum (T) in an incomplete diallel cross. The four groups of crosses, TxT, TxA, AxT and AxA, held 2, 12, 20 and 21 populations, respectively. Eleven of the intersubspecific crosses were exact reciprocals. Thirty random clones per population were grown as second clonal generation in an incomplete block design with four replications in plots of two plants per clone in 1980, the parents included in many plots. Data were recorded on ten characters.The results showed that group TxA gave the highest tuber yield and AxT the second highest. The F-values indicated highly significant genotypic effects for all characters in all populations. The mean genotypic coefficients of variation (GCV), were the highest for group AxA for all characters. The ANOVA, based on population means showed significant mean squares for general combining abilities (GCA) and for differences of reciprocalls for all characters; the specific combining ability (SCA) mean squares were significant only for date of emergence, plant height and haulm type. Almost all GCA effects of the parents were significant positive or negative. Several populations showed also significant SCA effects. The correlations between the GCA effects and the parental values were of about the same magnitude as the heritabilities; those between the population means and the midparental values were slightly lower.Compared to the midparental values, most populations showed significant positive heterosis for date of emergence, haulm type, number of tubers and under water weight; all populations had significant negative heterosis for mean tuber weight and nearly all for plant height and general impression. All populations from groups TxT and AxA had significant negative heterosis for tuber yield and so had 13 out of the 20 populations from group AxT, while seven of the 12 from group TxA showed significant positive and four significant negative heterosis. The average heterosis for tuber yield of group TxT was –11%, of TxA 3.4%, of AxT–9% and of AxA–18%. The highest mean tuber yields were obtained from crosses with a very high yielding A-parent as female, while the heterosis was negative. Though significant differences between the 11 reciprocals occurred for all characters, consistent differences occurred only for tuber yield. Averaged over the 11 crosses the TxA populations outyielded their exact reciprocals by 10.7%. For the highest tuber yields in A-T crosses, therefore, the tuberosum cytoplasm seems to be preferable. By contrast for a high male fertility the andigena cytoplasm is preferable. 相似文献
9.
For a better understanding of the inheritance of seed yield traits in Quinoa (Chenopodium quinoa) Willd., a half-diallelic crossing experiment with six diverse but uniform breeding lines was conducted. True hybrid plants
were detected by means of differences in panicle colour in 14 out of the 15 crosses performed. The agronomic performance of
14 F2 populations and six parental lines was evaluated in field trials on fertile clay soil. General and specific combining ability
of the lines (GCA and SCA) were estimated. Highly significant differences in GCA effects were found between the lines for
plant height at maturity, early flowering, early maturity, seed yield and thousand seed weight. Significant SCA effects were
only found for plant height at maturity. However, SCA effects were rather small and accounted for 7% of the total variance.
The finding of large GCA effects and low SCA effects suggests that best selection results could be expected from crosses between
the agronomic best performing genotypes.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
10.
陆地棉优异种质间的杂种优势和配合力分析 总被引：22，自引：6，他引：22
采用 NC 交配设计 ,对包括转基因抗虫棉、常规棉、柱头外露种质系、彩色棉等 1 0份陆地棉优异亲本交配后 ,杂种 F1的 1 0个性状的杂种优势和配合力进行了分析。结果表明 ,皮棉产量超高优势的平均值为 - 2 .91 % ,1 0个组合具正向的杂种优势 ;中亲优势的平均值为 2 2 .45 % ,2 1个组合均具有正向的中亲优势 ;竞争优势的平均值为 -1 4.2 1 % ,4个组合出现正向竞争优势。其它产量性状中单株铃数的杂种优势最为明显。纤维品质性状 ,2 .5 %跨长的优势明显 ,麦克隆值的负向优势明显。高亲值、中亲值和低亲值与 F1平均值的相关关系表明 ,多数性状 F1代平均值与中亲值和低亲值相关性密切。配合力上 ,新棉 33B、680 2、94AP1 4、96- 67、 99- 1 6和 99- 5 5表现较显著的GCA效应 ;SCA效应显著的 7个性状中 ,A1 B3、A4B1、A5 B3等组合有 6个性状的 SCA效应值为正。 相似文献
11.
Combining ability information is necessary for selection of suitable advanced lines for hybridization and identification of promising hybrids for development of improved varieties. A number of 14 maize (Zea mays L.) inbred lines and 91 related crosses were evaluated over two years, 2008 and 2009, in a temperate-zone of Iran. The objectives of the study were to identify the best general and specific combiners, heterosis and type of gene actions responsible for agronomic traits. Except for grain yield and growing degree day to milky, significant general (GCA) and specific (SCA) combining ability were observed for all traits. The Baker ratio for plant height (0.15), ear height (0.26), growing degree day to milky stage (0.04), and grain yield (0.002) showed the predominance of non-additive gene effects in the expression of these traits. The heterosis observed for grain yield, grain number, pollination period, ear and plant height was considerably higher than that observed for other traits. The correlations (r) of F1 means and SCA effects were positive and significantly higher than that of r (F1, mid-parents) and r (F1, heterosis) for all the traits except cob percent, growing degree days to silking, and physiological maturity. MO17, K3547/5, and K3615/2 had negative GCA effects for growing degree day to milky stage and maturity. Among hybrids, MO17 × K3653/2, B73 × K3651/2, and K3545/6 × K3493/1 with positive SCAs for pollination period and grain yield had also negative SCA effects for degree day to silking and milky stages. Therefore, the use of these inbred lines and hybrids increases the response to selection for increasing grain yield and early maturity in maize. 相似文献
12.
本文对54个芝麻杂交组合,10个性状的杂种优势与配合力效应关系研究表明:芝麻杂种优势普遍存在,而且超显性优势较强,其优势顺序依次为单株产量>单株蒴数>果轴长>株高,其它性状优势较小.各性状的杂种优势与其特殊配合力效应均呈显著的正相关.杂种优势主要由其特殊配合力效应提供.但某些组合的特殊配合力效应很小,甚至为负值,其杂种优势表现也很明显,这主要是由于亲本一般配合力效应中包括很大部分杂种优势效应.因此,在选配强优组合时,除了考虑组合的特殊配合力效应外,亲本的优势效应也是不可忽视的. 相似文献
13.
标记型柱头外露种质系与陆地棉亲本间杂种优势与配合力分析 总被引：12，自引：1，他引：11
采用ＮＣⅡ遗传交配设计,对５份标记型柱头外露种质系和３份陆地棉亲本交配后,杂种Ｆ１的１１个性状的杂种优势和配合力进行了分析。结果表明,主要产量性状霜前皮棉产量,超高优势的幅度为－２８．８８％～１３．１７％,平均为－３．０６％,６个组合具正向的杂种优势;中亲优势的幅度为１８．１４％～８０．１２％,平均为５３．０８％,１５个组合均具有正向的中亲优势;竞争优势的幅度为－１５．３２％～４６．４３％,平均为１１．２７％,１０个组合具有正向的竞争优势。其它产量性状中单株铃数的杂种优势最为明显。纤维品质性状,２．５％跨长和比强度的优势明显,麦克隆值的负向优势明显。高亲值、中亲值和低亲值与Ｆ１平均值的相关关系表明,多数产量性状Ｆ１代平均值与高亲值相关性密切,因此在组合筛选时应注意对常规亲本的选择。配合力上,ＧＣＡ效应显著的性状,中棉所１９和石３２１分别在产量、品质性状方面表现较优,９６－１、９６－６７、９６－３３等３份标记型柱头外露种质系表现较优;ＳＣＡ效应显著的８个性状中,Ａ１Ｂ２８个性状的ＳＣＡ效应值均为正,Ａ２Ｂ２和Ａ４Ｂ１均有７个性状的ＳＣＡ效应为正。文中对标记型柱头外露种质及亲本选配等问题进行了讨论。 相似文献
14.
Summary Nuclear and cytoplasmic genes from 10 diverse Avena sterilis L. accessions were introgressed into four Corn Belt oat (A. sativa L.) cultivars. Grain and straw yield, harvest index, heading date, height, unit straw weight, and vegetative growth index were evaluated in the BC2 generation of 76 cytoplasmic isopopulations. Means of all seven traits in the BC2 of Tippecanoe matings were greater than Tippecanoe due to introgression of A. sterilis germplasm, whereas means of all seven traits in BC2 populations of Ogle were inferior to those of Ogle. BC2 populations of matings involving CI 9170 and CI 9268 were variable, with some trait means being greater than those of the recurrent parents and some being lower.The phenomena of nuclear-cytoplasmic interaction effects and nuclear-cytoplasmic heterosis also were investigated. In matings where significant differences were present between cytoplasmic isopopulations, those with A. sterilis cytoplasm usually were superior, but no trait exhibited a consistent cytoplasmic effect across all matings. These results suggest that all seven traits were influenced by nuclear-cytoplasmic interactions. Nuclear-cytoplasmic heterosis for grain yield was present in two of 38 isopopulations with A. sterilis cytoplasm; both were from matings involving Tippecanoe. Nuclear-cytoplasmic heterosis for each of the remaining traits was observed in four to eight of the 38 isopopulations with A. sterilis cytoplasm. 相似文献
15.
The aim of this study was to determine the direction and magnitude of change in morphological and agronomical characters of spring barley ( Hordeum vulgare L.) in Germany over a period of 80 years and to assess the value of various strategies for further crop improvement. Old and new two-rowed cultivars, eight in each case, were tested together with their F2 intra-group diallel crosses in a field trial at Braunschweig-Völkenrode in 1994. New parents and their crosses showed a higher dry matter grain and total biomass yield, a lower plant height, and a higher harvest index as compared to the respective old germplasm. The annual genetic gain in grain yield was estimated at 0.15%. The superior grain yield of the new germplasm was attributable to the higher number of ears per plant and the larger kernel weight. The F2 mid-parent heterosis in grain yield was 7.6 and 7.2 % for the old and new crosses, respectively. The differences between the two types of crosses were nonsignificant except for the higher heterosis for plant height in the new crosses. General combining ability effects were significant for all characters in both types of crosses, whereas specific combining ability effects were significant in a few cases only. In the new crosses, a significant positive correlation was found between grain yield and straw yield (r = 0.52), whereas no such association was observed between grain yield and harvest index. For further gain in grain yield, improvement of the straw yield is more promising than increasing harvest index. 相似文献
16.
西南骨干玉米自交系主要农艺性状和产量正反交杂优效应分析 总被引：2，自引：1，他引：1
为了比较玉米自交系主要农艺性状和产量的正反交杂优效应,以9份西南地区骨干玉米自交系组配的72份单交种为材料,采用随机区组试验,对自交系及其正反交杂种F1代主要农艺性状和产量进行比较研究。结果表明,正反交效应对不同玉米自交系杂种F1代主要农艺性状和产量的影响不同;T检测表明,大多数玉米自交系正反交杂种F1代主要农艺性状和产量差异不显著。玉米自交系海9-21、5003、478正反交杂种F1代在穗粗、百粒重、单穗粒重、穗下茎节强度及穗位高等性状上差异显著或极显著。由此得出,不同自交系正反交杂种F1代在主要农艺性状和产量上具有不同的杂种优势,其中穗位高/株高具有负向杂种优势。由于玉米穗位高/株高具有负向杂种优势,即杂种F1代穗位高/株高值较自交系有所降低,因此在自交系选育时,不宜对亲本材料过分追求低的穗位高/株高。 相似文献
17.
Heterosis is an important way to improve yield and quality for many crops. Hybrid rice and hybrid maize contributed to enhanced productivity which is essential to supply enough food for the increasing world population. The success of hybrid rice in China has led to a continuous interest in hybrid wheat, even when most research on hybrid wheat has been discontinued in other countries for various reasons including low heterosis and high seed production costs. The Timopheevii cytoplasmic male sterile system is ideal for producing hybrid wheat seeds when fertility restoration lines with strong fertility restoration ability are available. To develop PCR-based molecular markers for use in marker-assisted selection of fertility restorer lines, two F2 populations derived from crosses R18/ND36 and R9034/ND36 were used to map fertility restoration genes in the two elite fertility restorer lines (R-lines) R18 and R9034. Over 678 SSR markers were analyzed, and markers closely linked to fertility restoration genes were identified. Using SSR markers, a major fertility restoration gene, Rf3, was located on the 1B chromosome in both populations. This gene was partially dominant in conferring fertility restoration in the two restorer lines. SSR markers Xbarc207, Xgwm131, and Xbarc61 are close to this gene. These markers may be useful in marker-assisted selection of new restorer lines with T. timopheevii cytoplasm. Two minor QTL conferring fertility restoration were also identified on chromosomes 5A (in R18) and 7D (in R9034) in two R-lines. 相似文献
18.
A study was made on the quantitative inheritance of seven characters viz., flowering time, plant height, leaf length, leaf width, number of curable leaves, green weight and cured weight for two crosses of flue-cured tobacco Chatham x Delcrest and 232 x Hicks. Six genetic populations P1, P2, F1, F2, B1 and B2 were observed in each cross.Small and significant values of heterosis were observed for almost all the characters for the two crosses. Significant average inbreeding depression was found for all the characters in both the crosses.Significant additive and dominant effects were found for the various characters in the cross Chatham x Delcrest in which the dominance gene effects were high. While in 232 x Hicks cross, additive gene effects contributed much in controlling the characters studied.Significant epistatic effects were found for leaf length and number of leaves in the cross Chatham x Delcrest, flowering time and plant height in 232 x Hicks by 2 test. Indications of exploiting these above two characters in plant breeding were revealed by these studies and a systematic approach in planning for such exploitation would be possible by further investigations. 相似文献
19.
矮秆超大穗小麦亲本与多抗丰产小麦主要农艺性状的配合力评价及遗传分析 总被引：1，自引：1，他引：0
为了进一步挖掘矮秆超大穗小麦亲本在遗传育种中的应用潜力,为小麦高产、超高产育种选择优良亲本和最优杂交组合提供理论依据,选用5个矮秆超大穗小麦品种（系）作为父本,8个多抗丰产小麦品种（系）作为母本,按NCII遗传交配设计,采用8×5不完全双列杂交法,配制了40个杂交组合,对小麦亲本及杂种F1的株高、主穗长、单株穗数、结实小穗数、主穗粒数、主穗产量、单株产量、千粒重8个性状进行了考察,并在基因型方差分析显著的基础上进行了配合力评价及遗传力分析。结果表明：父本中A1、A3、A4是综合性状优良的亲本,其多数性状的一般配合力均较高,特别是穗长、主穗粒数、结实小穗数、主穗产量、单株产量的一般配合力高,而株高的一般配合力效应值较低,是很理想的矮秆超大穗多粒亲本材料。母本中B5、B6单株穗数一般配合力较高,株高的一般配合力效应值较低,可作小麦高产杂交育种的矮秆多穗型亲本使用。结合特殊配合力效应分析：组合B5×A3单株穗数、主穗产量、单株产量、千粒重特殊配合力效应最高,株高特殊配合力效应较低,可作为的矮秆、多穗、粒重高且高产的重点杂交组合。B2×A4主穗长、单株产量、单株穗数特殊配合力效应都较高,而株高特殊配合力效应低,可作为矮秆大穗高产的重点杂交组合。遗传力分析表明：单株产量、千粒重、主穗长、主穗产量皆在70%以上,表明这4个性状的广义遗传力较大,受环境影响较小,而狭义遗传力的分析除主穗长、主穗粒数、主穗产量、株高大于50%,其余4个性状均低于50%,说明受环境影响大,不宜早期选择,应该适当推迟选择的代数。 相似文献
20.
Analysis of embryo, endosperm, cytoplasmic and maternal effects for heterosis of protein and lysine content in indica hybrid rice 总被引：1，自引：0，他引：1
The heterosis controlled by genetic main effects and genotype × environment (GE) interaction effects for protein content and lysine content traits of indica hybrid rice, Oryza sativa L., was studied by using a genetic model for quantitative traits of triploid endosperm. The experiment was conducted over 2 years in a factorial design that included nine cytoplasmic male-sterile lines as females and five restorer lines as males. It was revealed that heterosis of protein content and lysine content were simultaneously controlled by genetic main effects and GE interaction effects. Maternal general heterosis and maternal interaction heterosis were observed. Embryo heterosis or cytoplasm heterosis for lysine content and endosperm heterosis for protein content were more important in general heterosis. Embryo interaction heterosis and cytoplasm interaction heterosis were more important for protein content, but endosperm heterosis was only important for lysine content in GE interaction heterosis. It was shown that some indica hybrid crosses had significant positive heterosis for protein content. Negative heterosis for lysine content was observed in most hybrid crosses. 相似文献