摘要:

AbstractThe germplasm of the potato (S. tuberosumssp.tuberosum) has been modified since the beginning of this century by breeders who introgressed important agronomic traits, for example disease resistance genes, from several wild and cultivatedSolanumspecies of the Americas. In this paper we show that the Rflpanalysis of potato‐breeding material can be used to detect chromosomal regions descended from more‐distantly relatedSolanumspecies. The Rflppatterns of individuals of tenSolanumspecies, ten breeding lines ofS. tuberosumssp.tuberosumand the cultivated variety ‘Bintje’ were analyzed. Rflpdata for each of eight single loci of known genomic position were used for the computation of locus‐specific phenograms by distance matrix methods. Several of the potato‐breeding lines deviated clearly from the clustered speciesS. tuberosum, S. stenotomumandS. canasensefor one or more of the loci considered. These deviations indicated the presence of “exotic” germplasm at a particular locus. The possibility of detecting such germplasm has implications for mapping the agronomic traits for which the wild species were introgressed and which may still be linked to “foreign” c

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1991.tb00498.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractNineteen commercial hexaploid wheat varieties were crossed with the maize F1hybrid ‘Seneca 60’. Fertilization frequencies ranged from 32.1 % to 47.5 % of pollinated florets (mean 39.5 %) in the 14 winter wheat varieties and from 40.7 % to 51.4 % (mean 47.8 %) in the five spring wheat varieties. In some cases only an endosperm was formed and the frequencies of embryo formation were therefore slightly lower, being 28.2 % to 45.9 % (mean 36.4 %) for winter wheats and 39.8 % to 48.6 % (mean 45.1 %) for spring wheats. Mean values were significantly higher in the spring wheats but no significant variation was found between varieties within the spring or winter categories. In the five spring wheats the mean yield of embryos, and hence the potential yield of haploid plants, was 3.4‐fold higher than with the tetraploidHordeum bulbosumclone PB179. For the 14 winter wheats the figure was 10.9‐fold higher. These differences were highly significant (p<0.001) in all varieties. A single 2,4‐D treatment given to spikes one day after pollination with maize enabled embryos to be recovered from all 19 varieties. A total of 311 embryos were recovered from 950 florets (an average of 7.3 embryos per spike) of which 191 germinated, giving an average yield of one haploid plant for every 5.0 florets pollinated (4.4 haploid plants p

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1991.tb00499.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractPrevious studies have indicated a relationship between genome size and cold tolerance in plants. Many species adapted to growth in cool environments have large genome sizes. These studies are based on interspecific DNA content variation. In this study, the nuclear DNA content of eight maize populations was determined. These populations were obtained from the University of Nebraska and represent populations selected for cold tolerance and their respective unselected original populations. Intraspecific DNA content variation was observed between the selected and unselected populations. Upon assessing the data based solely on cold tolerance, no clear relationship between genome size and cold tolerance was apparent. When both freeze tolerance and cold tolerance were considered, populations which were cold tolerant and exhibited a certain degree of freeze tolerance were observed to have significantly larger genomes relative to the unselected populations. Thus, it appears that the relationship between intraspecific genome size variation and cold tolerance is similar to the relationship between interspecific genome size variation and growth at cooler temperatures in plants.

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1991.tb00500.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractThe quantitative‐genetic basis of sprouting resistance in winter rye (Secale cerealeL.) was investigated in order to facilitate breeding for improved baking quality. Crosses within and between the Petkus and Carsten gene pools were tested along with the parental lines over two locations, two years, and two harvest dates. Heritabilities of approximately 0.6 were found for falling number (FN), a‐amylase activity, dormancy, and amylograph curve characters. FN showed moderate heterosis that reached 35%. High genetic variation for FN was observed in most genetic materials, and error variances were generally small. Considerable genotype × year interactions occurred. Genotypes with high FN showed more instability for FN over environments. General combining ability was the main source of genetic variation for FN (80%) and was correlated with line per se performance in the Carsten gene pool (r = 0.66). FN showed moderate to strong correlations with slowness of development, but only loose ones or none with other agronomic traits. We conclude that improving sprouting resistance by selecting for FN should be highly effective and would not cause unfavourable side effects with regard to yielding perform

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1991.tb00501.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractChloroplast (cp) and mitochondrial (mt) DNA restriction profiles of a cytoplasmic male sterile (CMS) line ofBrassica junceaand its maintainer line were compared and found to be markedly different. Comparison of cpDNA restriction profiles of fifty different species of genusBrassicaand some allied genera showed that the cpDNA profiles of CMS lines were similar to that ofB. tournefortiifor twenty different restriction endonucleases. This CMS system is thus not of spontaneous origin as reported earlier, but is alloplasmic in nature. Comparison of restriction profiles of mtDNA ofB. tournefortiiand CMS lines revealed some differences which might either be due to changes in DNA pattern during the transfer, or, due to the cytoplasm coming from aB. tournefortiiline different from the one used in this study.

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1991.tb00502.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractBy interspecific hybridization within the genusBrassica, trigenomic haploids were produced and back‐crossed four times withB. napus, variety ‘Andor’. From this material, monosomic B‐genome chromosome addition lines were selected with the extra chromosome derived from three different B‐genome sources, i.e.,B. nigra(BB),B. carinata(BBCC), andB. juncea(AABB). After selfing and/or microspore culture, disomic addition lines were obtained. Meiotic behavior was studied of the trigenomic hybrids, the pentaploid BC1plants, and the monosomic addition lines. The addition lines were shown to possess cytological stability and good

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1991.tb00503.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractThe quantity of N2fixed in common bean (Phaseolus vulgarisL.) is a quantitatively inherited trait that shows sufficient genetic variability for improvement through breeding, but there is little information on gain from selection for15N‐determined N2fixation ability. The objective was to determine whether intrapopulation recombination and selection could be used to improve N2fixation. Four agronomically acceptable lines were selected, based on their acetylene reduction‐determined N2fixation ability, from an inbred backcross (IB) line population created from a cross between the high N2‐fixing donor parent ‘Puebla 152’ and a commercial, low N2‐fixing recurrent parent ‘Sanilac’. These four IB lines were intercrossed, advanced to the F3, and the six resulting F3populations with 25 F3families per population were evaluated for N2fixation in a low‐N field using15N‐depleted (NH4)2SO4. The six F3population means differed significantly and were superior to ‘Sanilac’ for N2fixation ability and yield, indicating significant improvement over ‘Sanilac’. Four F3population means were similar to ‘Puebla 152’, indicating selection advance towards high N2fixation while retaining favorable agronomic characteristics. Fifty percent of the F3families were superior to ‘Sanilac’ for N2fixation and one family exceeded ‘Puebla 152’, indicating that intrapopulation recombination produced

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1991.tb00504.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractPopulations of 64 taxa ofTrifoliumwere assessed for nitrogen fixation and dry matter production with and without added mineral nitrogen. The number of rhizobia per gram of compost capable of inducing nodulation was tested in 7 species and ranged from 3 to 114, showing interspecific variation for nodulation with indigenous rhizobia. In a sample of 8 species, nitrogen fixation was assessed by acetylene reduction and nodule scoring. There was a good correlation (84 %, P ≤ 0.01) between the two methods, and therefore nodule score was used as a measure of nitrogen fixation in the main assessment. There were large differences between populations in terms of shoot and root dry weight, the shoot: root ratio and nodule score. Added nitrate had a significant effect on all characters, increasing shoot dry weight and the shoot: root ratio and decreasing root dry weight and the nodule score. Results showed the importance of assessing legume germplasm with and without added nitrate in locations where suitable rhizobia for the nodulation of exotic species might not be presen

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1991.tb00505.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractGenetic Variability for Some Brewing Quality Characters in Barley Malting and brewing quality of six different barley genotypes and their F1 hybrids were investigated in a diallel cross programme. Plants were grown in pots in a randomized block design with four replications. General and specific combining abilities were determined for 1000 grain weight, percentage of proteins of the grain, percentage of water uptake, and, after micromalting, for β‐glucanase and α‐amylase activities. Significant general and specific combining abilities were observed for all the traits studied. 1000 grain weight, percentage of proteins and water uptake have been found to be essentially controlled by genetic additive effects, while enzymatic activities of malt have been found to be mostly controlled by dominance effects. ‘Karl’ has interesting characteristics for all traits and general combining abilities, except for 1000 grain weight, and has been introduced in a three‐way cross programme with ‘Plaisant’ and ‘Clarine’, also showing interesting values for malting quali

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1991.tb00506.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractSeveral methods for determining yield reduction resulting fromSeptoria nodorumblotch have appeared in the literature during the past decade. These methods varied from the measurement of effects of disease on components of yield to calculation of area of symptoms on certain leaves at different growth stages. We analyzed data from a uniform group of wheat entries in the USDA Septoria nursery that had been grown in seven locations in North America and Europe during the years 1982–1987. Symptom severity and height of symptom on the plant were compared to kernel number and kernel weight. Location, year‐within‐location and genotype were also considered. In the context of this study, we concluded that location, and year‐within‐location are the most important factors determining yield reduction (as measured by relative kernel weight). Selection directly for components of yield is quite effective, but selection by means of disease symptoms is often not correlated with yield. We also conclude that specific methods for relating symptoms to yield reduction that are applicable to a particular location are probably useful and appropriate for that loca

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1991.tb00507.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY