摘要:

AbstractIn several plant species, genetic maps have recently been developed for restriction fragment length polymorphisms (RFLPs). Together with isozymes, they offer alternative solutions to many breeding problems. This review deals with the current and potential uses of molecular markers in breeding for oligogenic resistance traits.In the first part, segregation analyses and analyses of near‐isogenic lines are collated with respect to the mapping of resistance genes. Also, various types of populations are compared for the amount of information obtained in segregation analyses. In the second part, theoretical and numerical results are presented dealing with the number of individuals required for marker‐facilitated selection of a resistance gene in a backcross program. Both the use of a single marker and a marker bracket are considered and the influence of the following parameters is investigated: (a) recombination frequency between the resistance gene and marker(s), (b) size of backcross families, (c) number of backcross generations, and (d) number of carriers of the resistance gene to be recovered in the final backcross generation. The results provide information with regard to the optimum design of marker‐facilitated selection programs and the required expenditures compared to direct selection of the resistance trait. In the third part, applications of molecular markers are discussed with respect to (1) advantages of marker‐facilitated selection for resistance genes under a variety of special circumstances, (2) pyramiding of resistance genes, (3) selection against the genetic background of a donor parent, and (4) their use as a starting point for chromosome

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1990.tb00396.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractMale sterileBrassica napusL. plants were found in breeding material which was used for the development of yellow‐seeded oilseed rape. The genetic studies indicated that the male sterility was conditioned by the presence of maintamer genes in the nuclear backgrounds of two newly resynthesizedB. napuslines, No7076 and No7406, in combination with a male sterility‐inducing cytoplasm (S) which is frequently found in cultivated forms ofB. napus.Test crosses withnapmaintainer and restorer lines support the conclusion that the observed male sterility is ofnaptype. Furthermore, the Eco RI restriction pattern of mitochondrial DNA of the (S) cytoplasm was identical to that of thenapcytoplasm. Hence, we conclude that we have uncovered a new source of maintainer lines for thenapsystem which couldpotentiallylead to the production of a better maintainer/restorer system for use in hybrid oilseed rape breeding programmes. However, more work is needed to reduce the glucosinolate content of the maintainer lines and to determine the factors controlling the phenotypic expression of the sys

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1990.tb00397.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractEmbryo rescue techniques were used to obtain hybrids betweenSinapis albaL. (white mustard) andBrassica napusL. (oilseed rape) with the goal of improving the disease tolerance of oilseed rape. Hybrid plants with 31 or 43 chromosomes were only recovered, whenS. alba, was used as the female parent. One hybrid was obtained from the crossS. albaL. cv. ‘Kirby’×B. napusL. cv. ‘Topas’, while 26 hybrids were obtained, when variousS. albaL. cultivars were pollinated with the rapid cyclingB. napusline CrGC 5006. All F1, hybrid plants were male sterile; however, the first generation backcross toB. napusL., also obtained by embryo rescue, produced plants with 50 chromosomes and 61–84 % pollen viability. Second backcross generation seed was produced by normal sexual crossing. Preliminary cytological analyses of pollen mother cells of hybrid plants suggests the possibility of genetic exchange between the t

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1990.tb00398.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractThe influence of telomeric heterochromatin on early embryo and endosperm development and the production of aberrant endosperm nuclei were investigated using eight triticale (×TritocmecaleWittmack) lines homozygous for the presence or absence ol blocks of telomeric heterochromatin from rye chromosome arms 1RL, 2RS, (SRS, and 7RL. The loss of heterochromatin from two chromosomes (6R, 7R) produced a significantly lower percentage of aberrant endosperm nuclei than did the loss from one chromosome (6R). Deletion of a third block had a significant additional effect in only one of four lines. The differences between lines for rales of embryo and endosperm development were significant even within a karyotypc, presumably because of genetic variation. The onset of cellularization of the endosperm tended to obscure the detection of aberrancy, and since it evidently occurred at different times in different lines, may have been largely responsible for the apparent reduction in aberrant nuclei in lines with less heterochromatin

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1990.tb00399.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractHomozygous doubled‐haploid plantlets derived from anther culture of wheat (Triticum aestivumL.) and triticale (×Triticosecale Wittmack) are useful breeding materials. However, efficiency of an‐drogenesis needs improvement. We used media (basic components, are the same as 85DI2) each containing one of the seven auxins [2,4,5‐trichlorophenoxyacetic acid (2,4,5–T),P‐chloraphenoxyacetic acid (pCPA), 3,6‐dichloro‐o‐anisic acid (dicamba), 4‐amino‐3,5,6‐trichloropicolinic acid (picloram), indole‐3‐butrytic acid (IBA), indole‐3‐acctic acid (IAA), and 2,4‐dichlorophenoxyacetic acid (2,4‐D) as a control] in combination with 6‐furturyl‐aminopurine (kinetin). In addition, each of the four cytokinins [6‐benzylaminopurine (6‐HA), 2‐isopenlylnyl adenine (2‐ip), 6‐(4‐hydroxy‐3‐meihylbut‐2‐enylamino) purinc (zeatin), and kinetin as a control]was tested in combination with 1‐naphthalene acetic acid (NAA). Anthers containing microsporcs at miduninucleatc stage from live wheat cultivars (Angus, Centurk, Chris, K.itt, and Pavon 76) and two octoploid trilicale lines (T81, T82) were tested mainly for callus induction and polyhaploid production on each of the 11 media. The cultivar × medium interaction was not significant, When averaged over all growth regulators, Pavon was (he best cultivar which produced 14.4 % calli and 23 % polyhaploid plantlets. Averaged over all cultivars, the medium containing 2, 4‐U produced the highest calli (13.9 %). Undifferentiated calli were regenerated on

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1990.tb00400.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractSeed dormancy is a domestication barrier in certainCupheaspecies. Between and within species variation has been observed for seed dormancy in agronomically promisingCupheaspecies, e.g.,C. laminuligeraKoehne and C lanceolata Ait. In tins note, we report on progress made in reducing seed dormancy through recurrent mass selection in theC. lanceolatapopulation LN43 and LN78. The germination percentages of unselected LA12 and LN43 populations increased from 0.0 % to greater than 95.0 % following an after‐ripening period of 20 weeks. We observed no germination percentage differences between unselected and selected LN43 populations following two cycles of selection. In contrast, there were highly significant differences between the unselected and selected populations of LA12 following two cycles of selection. The germination percentages of cycle zero (C0) and cycle two (C2) populations after‐ripened 10 weeks were 10.7 and 92.7 %, respectively. After one cycle of selection in the C. Lanceolata population LN78, the germination percentage of seed after‐ripened 10 weeks had increased from 1.3 % for the Copopulation to 28.7 % for the C0population. In summary, mass selection greatly reduced seed dormancy in LA12 and LN78, but had no effect in

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1990.tb00401.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractTriticum sharonensewas hybridized with autotetra‐ploidT. speltoides, T. longissimumandT. bicorne.Meiotic analysis of these hybrids showed thatT. sharonenseis almost equally related to bothT. speltoidcsandT. longissimum, while it is comparatively distant fromT. bicorne.Therefore, this study does not support treatingT. sharonenseas a subspeies or variety ofT. lottgissimu

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1990.tb00402.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractHomozygous lines from six Syrian and two Jordanian landrace populations were tested under highly productive growing conditions in Tel Hadia (1982/83), under drought stress in Breda (1983/84), and under dryland salinity stress in Hegla (1982/83/84) in Syria. Mean grain yield levels ranged between 260 kg/ha and 4850 kg/ha. Under drought and salinity stress, the majority of the landrace lines out‐yielded the best cheeks significantly. In Tel Hadia the check cultivars mostly outyielded the landrace lines, but not always significantly. In all environments the harvest index of the landrace lines was near the optimum for barley. They expressed intermediate plant height and time to flowering, high lodging susceptibility under favorable growing conditions, high protein content, and a wide range of yield component combinations.In the stress environments highly significant genetic variation among the landrace lines was found. The heritabilities for gram yield were high in these trials. The correlations between performance under stress and under favorable growing conditions were poor. Therefore, the largest gains for variety improvement for the Syrian steppe area are expected from direct selection under stress conditions.Unique responses in proline accumulation and germination patterns in saline solution indicated specific adaptation in this material. These landraces, thus, are a useful source of breeding material, which also widens the genetic base of the present breeding progra

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1990.tb00403.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractThe segregation of isozyme markers has been examined in the green and albino androgentic progenies of two plants ofLolium perenne.Overall the pooled data for the lociPG1/2andGOT/2does not deviate from expectation, but there is considerable heterogeneity between families and between green and albino plants. Specific alleles predominate in the different progeny sets. The results may be accounted for by possible linked loci affecting anther culture response or of linked lethal genes.

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1990.tb00404.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractSix stability statistics: (bi, s2di, , , and ) were estimated for maize, wheat and sorghum in different environments by using three statistical models. The significant linear portion of genotype × environment interaction for maize indicates different hybrids responded differently to environments, whereas the non‐significant genotype × environment interaction (linear) were found for wheat and sorghum suggest that all genotypes responded similarly as the environments change. However, the highly significant pooled deviations (deviation from regression) for all three crops make yield predictions from the model less reliable. When regression coefficients (bi) were non‐significant, s2di, became an important statistic in estimating stability. It appears that the regression coefficient, bi, was best used to estimate genotypic adaptability, whereas s2di, for stability. Maize and sorghum had negative correlations between the mean yield and stability statistics, s2di, , and , suggesting that high yield and stability are not mutually exclusive in the range of environments used in this study; however, such correlations did not occur in wheat. Thus, maize and sorghum hybrids with high yield potential and high stability could be identified and selected. Correlations between mean yield and bi, or , were positive and significant for maize and sorghum but were non‐significant for wheat, indicating that such relationships may be species specific. Under a given set of testing environments, the stability ranking associated with each maize hybrid is correlated to and depends on other hybrids included in the a

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1990.tb00405.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY