摘要:

AbstractThe linkage relationship between eighteen isozyme loci and the morphological markers hypocotyl colour (R‐r), monogerm character (M‐m), pollen fertility (X) and stem fasciation (Verb.) are tested. Three linkage groups could be set up, involving all morphological marker loci and eight of the isozyme loci.Est‐2,R‐r,Fdp‐2,Got2andIcd‐1belong to linkage group I, linkage group II includes the lociFas‐fas M‐m, Est‐3andAco‐1, linkage group III contains the lociX,Mdh‐1andEst‐5.When analysing the inheritance of isozymes and RFLPs, deviations are usually found in some lines from the expected frequencies of a 3 : 1 or 1 : 2 : 1 segregation at single marker loci. In many cases these data can still be used for the estimation of recombination values with linked loci under the control of selection. Procedures to estimate linkage in such cases are given and applied to experiment

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1992.tb00106.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThe enzyme‐linked immunosorbent assay (ELISA) was used to determine the concentration of barley yellow dwarf virus (BYDV) in leaves of spring wheatTriticum aestivumL. cv. ‘Fukuhokomugi’,Leymus angustus(Trin.) Pilger (Altai wild rye) and their F1hybrids inoculated at the 2‐ to 3‐leaf stage. The BYDV isolate “Cloutier” (serotype PAV) was used. The results showed thatL. angustusconfers immunity or strong resistance to the virus. Significant multiplication of the virus occurred in ‘Fukuhokomugi’ which expressed an intermediate level of tolerance to the disease under field conditions. The F1haploid hybrids of ‘Fukuhokomugi’×L. angustusexpressed a level of resistance almost equal to that of their wild parent, with a low concentration of virus appearing 16 days after inoculation and no more afterwards. The discovery of BYDV resistance inL. angustusand the expression of this character in the F1hybrids provide new opportunities for the enlargement of the gene pool for BY

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1992.tb00107.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThe mutagenic effects of gamma radiation and sodium azide (SA) immersion of explants on culturability and frequency of somaclonal variation in indica rice were investigated. The results showed that young inflorescence and mature embryo were satisfactory explants both for in vitro culture and for mutagenesis. 1 kR gamma rays applied to immature embryos and exposure of calli derived from mature seeds at the dose range of 250—500 R led to a higher rate of callusing and plantlet regeneration, 0.5—1 kR would be the appropriate exposure for young inflorescence to produce a better culture response and higher variability, and 2.5—5.0 kR the optimal dose range for mature embryos. Immersion of mature seed in 2—4 mM sodium azide solution is a concentration level to induce these effects in indica rice. Application of optimal gamma exposure and chemical mutagen to rice explants enhanced the somaclonal variation frequency and provided a large number of variants useful for rice b

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1992.tb00108.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThe aim of the investigation was to see if the partial resistance of three sister‐lines is determined by identical genes. The sister‐lines were selected from a cross between a susceptible line and a partially resistant line. These lines and the susceptible parent line were crossed in all directions. The downy‐mildew resistance of the different combinations was investigated in the F1, F3and F4generations. The resistance of the sister‐lines is not determined by the same genes. The moderate resistance of line X309 is recessive and might be determined by a single gene. The more resistant line X282 carry at least one resistance gene that shows dominance in crosses with X309. Line X311 carries, in addition to the resistance in X309, some resistance gene or genes with an intermediate

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1992.tb00109.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractAccording to our previous investigations, resistance toPhytophthora capsidinCapsicum annuum genotypes, ‘Line 29’, ‘PI201232’, ‘PI201234’ and Serrano Criollo de Morelos 334 (‘SCM334’), seems to be controlled by three genes. In order to determine the genie relationships between these four sources of resistance, three experiments were conducted which included the four genotypes, their F1s, F2s, F3s and BC1generations together with the susceptible pepper genotype ‘Morron INI A 224’. Inoculations were made, when plants had 4—6 leaves, by irrigating the culture substrate with a zoospore suspension ofP. capsiciisolate ‘Bl’. Though the four genotypes showed percentages of resistance close to a 100%, none of them actually reached this level in the three experiments. ‘SCM334’ was the most resistant genotype, transmitting a high level of resistance to its F1, F2and BQ generations. ‘Line 29’ was more resistant than ‘PI201232’ and ‘PI201234’. However, the F1F2and BQ generations of these three lines showed similar degrees of resistance. The four genotypes seem to have one of the three genes postulated for their resistance in common. All genes displayed a similar level of resistance, except the specific genes of ‘SCM334’, the effect of which was slightly higher. Several working pro

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1992.tb00110.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractForty‐one lettuce cultivars (butterhead type), carrying race‐specific resistance geneDm11 in combination with some others, were studied for field resistance toBremia lactucae. Significant differences in the level of field resistance were revealed. Most of the cultivars under study were highly susceptible under field conditions. There are evident relationships between combinations of race‐specific Dm genes and field resistance. The cultivars with gene combinationsDm2,Dm3 andDm11 are susceptible. A very high level of field resistance was detected in the cultivars with combination of genesDm5/8,Dm6 andDm16 (cvs. ‘Celia’, ‘Katanga’ and ‘Musette’). This is in close link with theirLactuca serriolaorigin and a high level of field resistan

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1992.tb00111.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThe occurrence of spontaneous polyploidy was quantified in the tamarillo (Cyphomandra betacea[Cav.] Sendt.), a diploid (2n = 2x = 24) solanaceous fruit crop cultivated in New Zealand. Polyploids of this species were recognized by their small, almost seedless fruit, these types occurring at a frequency of 0.24 % in seedling orchards. Parallel spindles were seen on rare occasions during meiotic anaphase II in diploid tamarillos and were the probable cause of spontaneous polyploidy in this crop. Pollen volume and viability, seed number per fruit, seed weight, fruit size, stomatal length and guard cell chloroplast number were measured in diploids and polyploids. The polyploids typically showed the manifestation of the gigas effect, with thicker leaves and larger flowers. Pollen volume, stomatal length and guard cell chloroplast number also increased with higher ploidy. Pollen viability was markedly lower in the polyploids compared to the diploids and in combination with post‐zygotic abnormalities caused a reduction in seed set and hence fruit size. Improvements in fertility and thus fruit size would be needed if the polyploids were to have commercial potentia

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1992.tb00112.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThe successful induction of tetraploids in the tamarillo (Cyphomandra, betacea[Cav.] Sendt.) by the application of colchicine to the germinating seed is described. Chimeric and solid tetraploids were produced although the proportion of the chimeric types could be minimized by optimizing the treatment time. There were reciprocal differences in all interploidy crosses, with triploids being ineffective in crosses when used as the paternal parent. The analysis of aniline blue stained gynoecia showed that incompatibilities in interploidy crosses occurred largely at the post‐zygotic stage of the reproductive process. Triploids and aneuploids were produced from interploidy crosses. The features of some aneuploids were described. Most aneuploids produced were primary trisomics (2n = 2x + 1 = 25) but some had 26 chromosomes and two others were hyperpolyploids. Pollen fertility in these plants varied from 10% to 90%. Morphological traits did not differ between the aneuploids or between the aneuploids and diploids. Fruit and seed size in the aneuploids were comparable to those of the diploids and were thus suitable for potential commercial exploitatio

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1992.tb00113.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThree oat (Avena salivaL.) populations (i.e., lines of descent), high grain yield (HG), high protein content (HP), and high protein yield per se (HGP), each developed by three cycles of S, recurrent selection, were evaluated for the effect of selection for groat‐protein yield upon other agronomic traits. Selections making up the HG line of descent had high protein yield primarily due to high grain yield, and those selected for HP had high protein yield due to both high protein content and high grain yield. Selection in HGP was on the basis of protein yield per se. Selection caused increases in bundle weight, harvest index, vegetative growth rate, and seed number in all lines of descent. Heading date, plant height, and seed weight were unaffected, whereas groat percentage and test weight were decreased in HP and HGP. Heritabilities were high for heading date, plant height, test weight, and seed weight, moderate for harvest index and bundle weight, and low for groat percentage. Genetic variability generally declined from CO to C3 for all traits.Groat‐protein yield and amount of protein per groat increased in all lines of descent. In HG, the increase in groat weight was due primarily to increases in the nonprotein fraction, with groat‐protein content actually decreasing. In HGP, groat weight increased due to increases in protein and nonprotein fractions, and groat protein content remained constant. In HP, groat weight and amount of nonprotein per groat decreased, thus increasing groat‐protein content.Three cycles of recurrent selection resulted in oat lines with groat‐protein yields significantly higher than the highest lines from CO. Utilization of index selection may be desirable to obtain populations of greater breed

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1992.tb00114.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThree crosses of cowpea (Vigna unguiculata[L.] Walp) were used to assess the effectiveness of two selection procedures in cowpea. The selection procedures were pedigree selection (PD) and single seed descent selection (SSD).Lines developed through each procedure were yield tested and selected at F6and F7for PD and SSD, respectively. The selected lines for both procedures were compared at F8for grain yield per plant (YLD), number of pods per plant (NPO), and pod development period (PDP), in two locations.Lines developed through both procedures differed more in their population means than in the performance of their top 10% or highest yielding lines. There was no consistent relationship between magnitude of genetic variability and percentage of superior lines obtained from each procedure. Both procedures have been effective in producing superior genotypes for yield and number of pods. The PD method produced superior transgressive segregants in two out of the three crosses for PDP. SSD allowed a more rapid generation than PD.

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1992.tb00115.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY