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1.
A. C. Zeven 《Euphytica》1970,19(1):33-39
Summary The distribution of the three different dominant genes for hybrid dwarfness in the Old World is given. It appears thatD
1 is found in southern Europe, Africa and Asia, whileD
3 is located in Europe.D
2 is common in all wheat-growing areas. The distribution ofD
1 coincides with that ofNe
1, while the distribution ofD
3 is probably similar to that ofNe
2.TheD
1-gene is still present inAegilops squarrosa. The sources ofD
2 andD
3 have not yet been determined with certainty. 相似文献
2.
J. G. Th. Hermsen 《Euphytica》1963,12(1):1-16
Hybrid necrosis is the premature gradual death of leaves and leaf sheaths in certain wheat hybrids. It is based on two complementary genes Ne
1 and Ne
2. Hitherto 89 Ne
1-carriers and 207 Ne
2-carriers from many countries are known (table 1 and 2). This corresponds with more than 18,000 different necrotic cross combinations.The degree of necrosis in the F1's varies greatly, due to multiple allelism of Ne
1 and Ne
2. Nine necrosis grades are described in table 3. Grades 6–8 are called severe necrosis (no seed is produced), 3–6 moderate necrosis (premature seed), 0–3 weak necrosis (normal seed). Most severely necrotic F1's could be brought to seed production by raising them under extra favourable conditions in a small growth-chamber. Growing moderately necrotic F1's in pots outside, at a high fertility level of the soil, resulted in a striking increase of the seed production.On the basis of the above mentioned data and results some practical advice is given to the breeders about the handling of necrotic crosses. In addition some ways to preclude hybrid necrosis are indicated, though the wheat breeder is advised against a systematic avoiding of necrosis because many combinations of excellent varieties then remain untried. 相似文献
3.
Variation of harvest index in several wheat crosses 总被引：2，自引：0，他引：2
G. M. Bhatt 《Euphytica》1976,25(1):41-50
Summary Harvest index was studied in F1 and F2 generations of eight wheat (Triticum aestivum L.) crosses and their reciprocals. The parental varieties involved in the crosses represented a fairly wide range of character expression for plant height, tillering potential, grain yield per plant and harvest index. Differences between reciprocal crosses were not evident for the expression of harvest index of the crosses under study. Means and degrees of dominance of F1 and F2 populations suggested partial dominance of high harvest index over low harvest index. The pattern of variation among F2 segregates was quantitative and the distribution was normal. The gene action governing the expression of harvest index was largely additive. Evidence was obtained for non-additive gene action in some crosses. There was complete absence of high parent heterosis for harvest index in the F1's but midparent heterosis was found to be present in all crosses. Estimates of heritability and genetic advance were moderate to high. Usefulness of selecting for harvest index as a measure of yield efficiency particularly in early generations is discussed. 相似文献
4.
Summary Inheritance pattern of seven dwarf mutants revealed each of them to be controlled by a single recessive gene. Tests for allelism indicated existence of two groups of dwarfs, group 1 comprising six mutants and group 2 a single dwarf. The dwarfs of group 1 were found to be allelic to D2 of the dwarf types already known in this crop and the dwarf of group 2 was allelic to D1 of these types.Botany Department, R.V.V.N. College, Dharanikota, India. 相似文献
5.
The dwarf safflower mutant ‘Enana’ has been developed from the cultivar ‘Rancho’ by chemical mutagenesis. The objective of the present research was to study the inheritance of plant height in crosses between ‘Enana’ and ‘Rancho’. Plants of both lines were reciprocally crossed and the F1, F2 and F3 generations were obtained. The evaluation of plant height in the F2 generation suggested the presence of a single locus controlling this trait. This was confirmed after the evaluation of 164 F2:3 lines, which revealed an F2 segregation fitting a 1:2:1 (dwarf: intermediate: standard) ratio. The locus was designated Dw. As the mutated allele was partly dominant over the wild‐type allele, the proposed genotype for ‘Rancho’ was dw dw, whereas that for ‘Enana’ was Dw Dw. Furthermore, a partial cytoplasmic effect on plant height was detected, with the heterozygote Dw dw being about 6 cm taller when ‘Rancho’ was used as female. 相似文献
6.
Ruizhen Qin Yang Qiu Zhijun Cheng Xueyan Shan Xiuping Guo Huqu Zhai Jianmin Wan 《Euphytica》2008,160(3):379-387
This study was to determine the agronomic and genetic characteristics of a novel rice dominant dwarf mutant 986083D (japonica) and its potential in breeding. 986083D derived from the anther culture of an autotetraploid indica/japonica hybrid and its progeny segregated into normal and dwarf plants. Homozygous and heterozygous 986083D plants looked similar
phenotypically, showing shortened stature, erect leaves, more tillers and poor fertility. The segregation ratio of dwarf to
normal plants fit the expected 3:1 by χ2-test in 77 out of 88 tested lines. Crosses between homozygous 986083D and eight other rice varieties had uniform semi-dwarf
F1 plants. The F1 plants from crosses between heterozygous 986083D and five other varieties had normal and semi-dwarf plants close to the expected
ratio of 1:1. The reduction of plant height in F1 plants ranged from 40.0 to 53.5% in a subtropical environment and from 37.5 to 48.2% in a temperate environment. 986083D
showed moderate sensitivity to exogenously applied GA3 in terms of elongation of shoots and induction of α-amylase activity in the endosperm. Linkage analysis showed that the dominant
dwarf gene (designated as Dx) in 986083D was not allelic to D53. Dx was roughly mapped to the short arm of chromosome 8. All results showed that 986083D was a novel mutant controlled by single
dominant gene, providing a valuable material in rice breeding.
Ruizhen Qin, Yang Qiu contributed equally to this work. 相似文献
7.
Inheritance of resistance to dieback, caused by Pythium aphanider‐matum, in periwinkle (Catharanthus roseus) was studied using a dieback‐resistant dwarf mutant, Dw, with a green stem, and a susceptible accession, OR, with a purple stem. Plants of parental F1, F2 and backcross generations were evaluated for resistance to dieback in a randomized complete block design with four replications, in a field plot that had been continuously planted with periwinkle in previous years and where dieback severity was high. Resistance to dieback was evaluated on two dates, i.e. when distinct differences between plants of the parental strains were noticed. From both quantitative and qualitative analyses of data, resistance to dieback appeared to be governed by a single gene (with a broad‐sense heritability of 0.85 and 0.79, depending on the date of evaluation), and was inherited independently of genes governing dwarfness and stem pigmentation. 相似文献
8.
The distribution and allelic expressivity of hybrid necrosis genes (Ne
1 and Ne
2) were studied in 21 winter (mostly exotic) and 43 spring type elite wheat genotypes, by crossing them with two known testers,
C 306 (Ne
1-carrier) and HD 2380 (Ne
2-carrier).Ne
1 gene was present in one north-west Himalayan winter wheat landrace, Shoure Local, but absent in the other winter as well
as spring wheats. Ne
2 gene was prevalent to a much lower extent in the exotic winter wheat germplasm (31.57%) as compared to the recently developed
Indian and Mexican spring wheat semidwarfs (69.80%). This may suggest that breeders have tried to preclude hybrid necrosis
by selecting for non-carrier genotypes in the development of exotic winter wheats in contrast to the situation in spring wheats.
Based on the degree of expression of hybrid necrosis genes in the F1 hybrids, the carrier genotypes were characterized with respect to the allelic strength of the hybrid necrosis genes. The
27 non-carrier genotypes of the two ecotypes identified in the present study have a greater potential use in future hybridization
programmes so as to overcome the problem of hybrid necrosis.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
9.
Accessions of Beta macrocarpa Guss., collected on the Canary Islands, were tetraploid (2n = 36). Three of these accessions were studied in detail. The plants were rather uniform in their morphological appearance, both within and between accessions, and were annual and fully self-compatible. Meiosis was completely diploidised, suggesting an alloploid nature of the tetraploid species. Crosses with diploid B. vulgaris yielded triploid hybrids which were sterile or nearly so; a few descendants of such hybrids were highly aneuploid. Crosses between tetraploid B. macrocarpa and autotetraploid cytotypes of B. vulgaris showed variable results, only part of these crosses yielded tetraploid hybrids. The tetraploid hybrids exhibited somewhat higher fertility than the triploids. An F2 generation showed partial hybrid dwarfness, partial fertility and segregation for carliness and coloration of the hypocotyl. All hybrids had multivalents at meiosis (averages: 2.5—5.4 multivalents per pollen mother cell), indicating suppression of the diploidised meiosis. The possibilities of application of the diploidised meiosis in breeding sugar beet are discussed. 相似文献
10.
Summary The origin and nature of the diploid cultivated potato species S. ajanhuiri Juz. et Buk. was studied. Several lines of evidence indicate that S. ajanhuiri might be derived from natural crosses between primitive cultivars of the diploid species S. stenotomum and the wild species S. megistacrolobum. Morphological comparisons were made between S. stenotomum x S. megistacrolobum F1 hybrids and naturally occurring S. ajanhuiri to investigate this hypothesis. Comparisons were also made between S. ajanhuiri x S. stenotomum crosses and the F2 generation of the first-mentioned cross.Crosses between the two major groups of S. ajanhuiri cultivars, Ajawiri and Yari, showed not only genetic breakdown but also a wide range of phenotypic variation similar to those of artificial F2 families of S. stenotomum x S. megistacrolobum. Furthermore, there was strong evidence showing that the Yari group of S. ajanhuiri could almost certainly be an F1
S. stenotomum x S. megistacrolobum hybrid, whereas the Ajawiri group could be a backcross of an F1 hybrid to S. stenotomum. These results added further support to the hypothesis of a hybrid origin of S. ajanhuiri, as well as indicating its putative parents. It is suggested that this hybridogenic taxon be retained at the species level under the name Solanum x ajanhuiri. 相似文献
11.
In a self-fertilised crop like lentil, the identification of transgressive segregants for economically important trait such
as seed yield is an important aspect of any practical breeding programme. The prediction of expected transgressive segregants
in F1 generation obtained as a ratio of additive genic effect [d] and additive variance (D) i.e. [d]/√D was studied in 28 crosses of lentil generated in a diallel fashion involving four parents each of macrosperma (exotic) and microsperma (Indian) types, respectively, resulting in three hybridization groups. The seed material advanced to F2, F3 and F4 generations through single seed descent method was evaluated to determine the observed transgressive segregants for seed yield/plant.
The observed frequency of crosses showing more than 20% transgressive segregants in F2 to F4 generations were exhibited in 9(32%) crosses, of which 7(77%) crosses were of macrosperma × microsperma type. Genotypes Precoz and HPL-5 of the exotic group (macrosperma) produced maximum number of transgressive segregants with the genotypes L-259, L-4145 and PL-406 of the Indian origin (microsperma). Goodness of fit (non-significant χ2 value) in F2 generation was observed for 19(68%) crosses of the total genepool, out of which 9(56%) crosses each in F3 and F4 generation belonged to the macrosperma × microsperma group, depicting it as the gene pool of paramount importance to obtain maximum transgressive segregants, therefore establishing
the efficacy of the method used. 相似文献
12.
Summary Variation in pigment content of the flour of bread wheats (Triticum aestivum L.) was studied in the progenies of F1 and F2 of three crosses and their reciprocals. Reciprocal differences in pigment content were observed in the F1 and F2 means. Low pigment content was found to be partially dominant or over dominant in the crosses studied. There was evidence of substantial mid-parent F1 heterosis in all crosses and betterparent F1 heterosis in three crosses. In the F2, heritability estimates were moderate to high. The F2 frequency distributions were not normal. Estimation of effective factor pairs indicated the presence of one or two major gene pairs involved in the expression of pigment content in the flour. Action of modifiers was also assumed in one cross and its reciprocal. A factorial approach to metrical character suggested that the F2 segregation ratios of low pigment content to high pigment content were 3:1, 15:1, 13:3 and 9:7 for the different crosses. Utilization of the findings in a wheat breeding program is briefly discussed. 相似文献
13.
K. Moore 《Euphytica》1969,18(2):190-203
Summary Crosses between certain normal varieties of wheat (T. aestivum) produce grass-dwarfs in the F1 or F2 generations. Grass-dwarfs are defined as short grass-like plants which do not become reproductive when grown in an 8-hour photoperiod at a maximum temperature of 21°C. This phenotype is not related to either the winter or semi-dwarf habits of wheat. At least three major dominant genes D1 D2 and D3 interact to produce the grass-dwarf phenotype.The interaction of these genes has been studied using monosomic lines. The results indicate that D
1 and D
2 interact by complementation, D
2 being effective only in the homo- and hemizygous condition, but not when heterozygous. D
3 probably has an additive interaction with D
1 and D
2. Evidence for the existence of multiple alleles at these three loci is discussed.Data from F2 and F3 segregation studies is presented and details of procedure which must be observed if accurate segregation ratios are to be obtained. The data obtained support the hypothesis proposed for the inheritance of the grass-dwarf phenotype. 相似文献
14.
Graham J. Scoles 《Euphytica》1985,34(1):207-211
Summary An inbred line of rye (Secale cereale L.) has been found to carry a gene for hybrid necrosis. This gene was detected in crosses with a highly crossable wheat (Triticum aestivum L.) genotype which carries the gene Ne2. This appears to be the first report of a gene for hybrid necrosis being present in the rye genome. 相似文献
15.
Inheritance of black leaf mold resistance in tomato 总被引：1，自引：0，他引：1
Summary Inheritance of black leaf mold (BLM) (caused by Pseudocercospora fuligena) resistance was studied in four crosses involving two resistant Lycopersicon accessions (PI134417, L. hirsutum and PI254655, L. esculentum) and four susceptible Asian Vegetable Research and Development Center tomato lines (CLN657BC1F2-267-0-3-12-7, CL143-0-10-3-0-1-10, CLN698BC1F2-358-4-13 and CL5915-93D4-1-0-3). For each cross, six generations, i.e. P1, P2, F1, F2, BC1F1 and BC1F2 were evaluated following inoculations with isolate Pf-2 of P. fuligena. Chi-square analyses of the data based on the ratio of resistant to susceptible plants in the F2 in three of four crosses gave a good fit to a segregation ratio of 1 R : 15 S, and BC1F2 data in three of four crosses gave an acceptable fit to the segregation ratio of 1 R : 63 S. The results indicate that resistance to BLM may be conditioned by two recessive genes acting epistatically in both PI134417 and PI254655. 相似文献
16.
Nobumichi Inomata 《Euphytica》1993,69(1-2):7-17
Summary Crossability and cytology were examined in F1, F2, B1 and hybridsplants of F1 hybrids of Brassica campestris and three wild relatives of B. oleracea, B. bourgeaui, B. cretica and B. montana, respectively. The F2 plants were obtained after self-and open pollination of the F1 hybrids. The B1 and hybrid plants were produced after the F1 hybrids backcrosses with B. campestris and crossed with B. napus, respectively. After crossing the F1 hybrids, many seeds of the F2, B1 and hybrid plants were harvested. Multivalent formation was high in the chromsome configuration for the PMCs of F2, B1 and hybrid plants, suggesting that crossing over might occur between them. Many different types of aneuploids were obtained in the progenies of the F2, B1 and hybrid plants. It is suggested that different types of normal egg cells may be produced by one-by-one or little-by-little chromosome addition. The possibility is discussed of gene transfer from B. bourgeaui, B. cretica and B. montana, to cultivated plants, B. campestris and B. napus. 相似文献
17.
F. Pohlheim 《Plant Breeding》1986,97(1):93-96
In reciprocal crosses between Pelargonium zonale and Pelargonium inquinans uniformly green, uniformly bleached and variegated plants occurred among the F1 progeny. The effect has been described as hybrid variegation and also as hybrid bleaching. Because of the differences among the reciprocal crosses, it is assumed that the zonale-plastids undergo normal development in hybrids, while the plastids of Pelargonium inquinans do not develop normally due to their interaction with the nucleus of the hybrid. Using the results obtained in the experiments, the development of zonale-hybrids from Pelargonium is discussed. 相似文献
18.
Summary Inheritance studies on the stem termination in pigeon pea using F1, F2 and F3 generations of two crosses between determinate and indeterminate lines suggested that two dominant genes with epistatic (inhibitory) interaction of one of them control the interminate growth habit. The gene symbols D. idid and ddIdId have been designated to the parental plants with determinate and indeterminate growth habits, respectively. The gene IdId was epistatic (inhibitory) to the gene D giving a ratio of 13 indeterminate: 3 determinate inthe F2's observed. F3 segregation supported the proposed model on the mode of inheritance. 相似文献
19.
A. C. Zeven 《Euphytica》1976,25(1):255-276
Summary The seventh supplement of the genotype hybrid necrosis in Triticum is presented. This list contains 414 Ne
1-, 179 Ne
2- and 662 non-carriers. The total number of varieties tested is 4629 viz. 1298 (28.0%) Ne-, 1031 (22.3%) Ne
2- and 2300 (49.7%) non-carriers.The various aspects reported in literature and those studied by me are discussed.The geographical distribution of Ne-genes and their alleles indicates two Ne
1
w
-areas, one Ne
1
m
-area, probably two Ne
2
ms.s
-areas and four non-carrier-areas. 相似文献
20.
A. E. Zeilinga 《Euphytica》1962,11(2):126-136
The production of Begonia semperflorens varieties has recently concentrated on the F1 types, because of their free-flowering habit, uniformity and reduced sensitivity to adverse conditions. As many of the F1 varieties are sterile, it was supposed that a differential ploidy in the species was present. The following is a study of the varietal development of the species since its introduction in 1828 and of the chromosome numbers of the different varieties. In a series of crosses it was proved that the triploids resulted from tetraploid x diploid crosses, which are sterile. At the same time it could be observed that the heterosis effect, which is most manifest in the triploids, results in a better response to adverse conditions. The inheritance of dwarfness, which is an important feature of the species, was studied. 相似文献