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991.
992.
Y. H. Lee 《Euphytica》1991,54(3):251-254
Summary Ten Aranda cultivars commercially grown in Singapore were selected to study their genomic constitutions and flower characteristics. Cytological evidence and breeding records of these cultivars showed that they are of three genomic classes. Four of them are diploid with AV genomes (one Arachnis and one Vanda genome), another four are triploid with AVV genomes and the remaining two are tetraploid with AVVV genomes. Sizes of flowers as well as of sepals and petals generally show significant increases from diploid to tetraploid. This trend reflects the increasing influence of Vanda resulting from additional one and two Vanda genomes in triploid and tetraploid respectively as compared to diploid cultivars. Among the three genomic classes, diploid cultivars generally bear less flowers per spray than those of triploid and tetraploid although exceptions may occur. There is no clear trend in the length of inflorescences although diploid cultivars tend to have less compact spray with flowers more distantly spaced out. 相似文献
993.
Identification of triploid Citrus by isozyme analysis 总被引:3,自引:0,他引:3
Summary Seedlessness is a desirable horticultural attribute in Citrus and is positively associated with triploidy. The conventional cytological method for triploid identification is a laborious technique involving the preparation of root tips for chromosomal analysis. Digital densitometry of isozymes, however, offers the possibility of distinguishing triploid Citrus from large populations of seedlings both quickly and cheaply. Where there are no gene dosage regulation effects, greater band density should be evident in the allozyme contributed by the diploid gamete for a heterozygous locus. The isozymes of 4 enzymes; malate dehydrogenase, 6-phosphogluconate dehydrogenase, shikimate dehydrogenase, and phosphoglucose isomerase, were investigated with polyacrylamide gel electrophoresis. Band densities of these isozymes for triploid Citrus, their diploid siblings and diploid progenitors were measured using a digital densitometer. Of the 4 enzymes investigated only allozymes for shikimate dehydrogenase exhibited consistent differences over a wide range of Citrus cultivars. Greater band density was evident in the allozyme contributed by the diploid gamete. The band density ratio between allozymes for triploid Citrus was close to 0.5, while for diploid Citrus band density ratios were close to 1.0. This effect is due to the extra protein coded by the additional gene dose and was not observed in diploids. Shikimate dehydrogenase proved to be an accurate molecular marker for distinguishing between diploid and triploid Citrus for heterozygous progeny.Abbreviations PAGE
Polyacrylamide gel electrophoresis
- MDH
malate dehydrogenase
- 6PGD
6-phosphogluconate dehydrogenase
- SkDH
shikimate dehydrogenase
- PGI
phosphoglucose isomerase 相似文献
994.
Ram C. Sharma G. Ortiz-Ferrara J. Crossa M. R. Bhatta M. A. Sufian J. Shoran A. K. Joshi R. Chand Gyanendra Singh R. Ortiz 《Euphytica》2007,157(3):457-464
Improving the level and stability of grain yield is the primary objective of wheat breeding programs in the Eastern Gangetic
Plains (EGP) of South Asia. A regional wheat trial, the Eastern Gangetic Plains Yield Trial (EGPYT), was initiated by CIMMYT
in collaboration with national wheat research programs in Bangladesh, Nepal, and India in 1999–2000 to identify wheat genotypes
with high and stable grain yield, disease resistance, and superior agronomic traits for the EGP region. A set of 21 wheat
experimental genotypes selected from a regional wheat screening nursery in South Asia, three improved widely grown cultivars
(Kanchan, PBW343 and Bhrikuti), and one long-term cultivar (Sonalika) were tested at 9–11 sites in six wheat growing seasons
(2000–2005) in the EGP. The 21 experimental genotypes were different in each year, whereas the four check cultivars were common.
In each year, one or more of the experimental genotypes showed high and stable grain yield and acceptable maturity, plant
height, and disease resistance compared to the check cultivars. Three improved cultivars have already been commercially released
in the region through EGPYT and many germplasm lines have been used in the breeding programs as parents. Identification of
wheat genotypes with high-grain yield in individual sites and high and stable yield across the EGP region underlines their
value for regional wheat breeding programs attempting to improve grain yield and agronomic performance. 相似文献
995.
Karim Sorkheh Behrouz Shiran T. M. Gradziel B. K. Epperson Pedro Martínez-Gómez E. Asadi 《Euphytica》2007,156(3):327-344
Amplified fragment length polymorphism (AFLP) analysis is a rapid and efficient method for producing DNA fingerprints and
molecular characterization. Our objectives were to: estimate genetic similarities (GS), marker indices, and polymorphic information
contents (PICs) for AFLP markers in almond cultivars; assess the genetic diversity of almond cultivars and wild species, using
GS estimated from AFLP fingerprints and molecular characterization; and facilitate the use of markers in inter-specific introgression
and cultivar improvement. The genetic diversity of 45 almond cultivars from Iran, Europe, and America, were studied assaying
19 primer combinations. In addition, several agronomic traits were evaluated, including flowering and maturity times, self-incompatibility,
and kernel and fruit properties. Out of the 813 polymerase chain reaction fragments that were scored, 781 (96.23%) were polymorphic.
GS ranged from 0.5 to 0.96, marker indices ranged from 51.37 to 78.79, and PICs ranged from 0.56 to 0.86. Results allowed
the unique molecular identification of all assayed genotypes. However, the correlation between genetic similarity clustering
as based on AFLP and clustering for agronomic traits was low. Cluster analysis based on AFLP data clearly differentiated the
genotypes and wild species according to their origin and pedigree, whereas, cluster analysis based on agronomic data differentiated
according the pomological characterization. Our results showed the great genetic diversity of the almond cultivars and their
interest for almond breeding. 相似文献
996.
No information is available on the effects of different biomass yield environments on selection efficiency in switchgrass
(Panicum virgatum L.) breeding improvement. This study was conducted to assess the effects of high- and low-biomass yield environments (HYE
and LYE, respectively) on recurrent selection for general combining ability (RSGCA) in a lowland population of switchgrass
(NL-94). The top 14 of 65 NL-94 C0 parent plants were selected based on biomass yield of half-sib (HS) progeny tested for one post-establishment year under HYE
and LYE conditions. Nine of the 14 C0 parent plants were the same based on HS performance under HYE and LYE. Selected plants were intercrossed to produce NL-94
HYE and NL-94 LYE C1 populations. One hundred and twenty-five HS C1 progeny families (60 NL-94 HYE and 65 NL-94 LYE) were evaluated for biomass yield for 3 years (2002–2004) under HYE and LYE
conditions. The HYE produced about 2.5 times higher biomass yields than the LYE in both C0 and C1 HS progeny tests. Estimated additive genetic variance and predicted gains from selection (ΔG) were high in the C1 populations indicating that RSGCA should achieve higher biomass yields. Mean biomass yields of C1 HS families originating from the LYE protocol were significantly higher than those of families originating from the HYE protocol
in both HYE and LYE performance tests, suggesting greater selection response under LYE in the C0 population. The estimates of narrow-sense heritability (
) and ΔG from the C1 populations indicate that positive response to selection for biomass yield is possible in subsequent cycles of selection
under either HYE or LYE, with a possible small advantage for HYE. 相似文献
997.
Tartary buckwheat (Fagopyrum tataricum) is a highly nutritious crop that is widely grown in Asia, but the flour contains a large portion of the hull if it is ground
with industrial processing since the hull is very hard to remove as it adheres to the testa layer of the groat. Rice-Tartary,
a particular type of Tartary buckwheat, has seeds with a loose hull and the presence of splits on the sides of the seeds that
make dehulling easily. The present study reports on the first attempt of crop improvement in Tartary buckwheat breeding through
hybridization. Hybrids were obtained by hybridization of crosses between Tartary buckwheat and Rice-Tartary. Additional crosses
were made among selected progenies of these crosses. Based on progeny analysis of the F1, F2, and F3, the character of Rice-Tartary, as exhibited as the presence of splits on the sides of the seeds, is controlled by one gene
which is homozygous recessive. A Tartary buckwheat breeding program has been conducted for 6 years based on these crosses.
Advanced lines with easy dehull and yield potential are at the stage of ready for yield trials. Production of easy dehulling
Tartary buckwheat in the future could boost Canada’s domestic and international markets. 相似文献
998.
Robert F. Park Henriette Goyeau Friedrich G. Felsenstein Pavel Bartoš Friedrich J. Zeller 《Euphytica》2001,122(1):113-127
Pathogenicity data from surveys of Puccinia triticina (formerly P. recondita f. sp. tritici) conducted in western Europe in 1995 were analysed to compare the structure of regional populations of the pathogen. Many
of the populations differed in phenotypic diversity and pathotypic composition, even though they occurred within a single
epidemiological unit, suggesting that local factors may influence the establishment and propagation of individual pathotypes
in the regional populations. Neighbouring regions were more similar than distant regions, and all regions shared at least
one pathotype, except populations in northern Italy and Scotland. A high degree of similarity was found between populations
in northern France and Great Britain, providing strong evidence of free movement of inoculum between these regions. Resistance
genes were postulated for a selection of 91 wheat cultivars, representing those most commonly grown in western Europe in 1995.
Thirteen cultivars lacked detectable seedling resistance genes and the remaining 78 possessed from one to three resistance
genes; those detected were Lr1, Lr3a, Lr10, Lr13, Lr14a, Lr17b, Lr20, Lr26 and Lr37. The most commonly detected resistance gene was Lr13, which was present singly or in combination with other resistance genes in 48 cultivars (53%). The gene Lr14a was detected in 18 cultivars, Lr26 was present in 16 cultivars. The role of host selection in the composition of the regional populations of P. triticina in western Europe in 1995 was difficult to assess on the basis of the results obtained, since virulence data were not available
for Lr13 and Lr14a.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
999.
Two wide hybrids, Diplotaxis erucoides (2n = 14) × Brassica rapa (2n = 20) and B. maurorum (2n = 20) × B. rapa, were developed using the sequential ovary–ovule culture. Reciprocal crosses failed, possibly as a consequence of strong
unilateral incompatibility. The F
1 hybrids in each combination were completely male sterile and morphologically intermediate to the respective parents. DNA
marker polymorphism and chromosome counts confirmed their hybrid nature. High frequency of bivalents in the F
1 and the presence of trivalents/quadrivalents in the derived amphiploids suggested genomic duplications and homoeology of the
parental genomes. Up to three homoeologous pairs between the D. erucoides (DeDe) and B. rapa (AA) genomes, and one between B. maurorum (BmBm) and B. rapa genomes were observed. Successful synthesis of the F
1 hybrids and amphiploids of B. rapa with D. erucoides and B. maurorum, and allosyndetic chromosome pairing are expected to permit introgressions of desirable loci into the cultivated Brassica
germplasm, especially for resistance to Alternaria
brassicae and Albugo candida. 相似文献
1000.
Raquel Sánchez-Pérez Encarnación Ortega Henri Duval Pedro Martínez-Gómez Federico Dicenta 《Euphytica》2007,155(3):381-391
The inheritance of 16 important agronomic traits and its relationship were studied for four years in a population of 167 almond
[P. dulcis (Mill.) D.A. Webb] seedlings obtained from a cross between the French selection ‘R1000’ (‘Tardy Nonpareil’ × ‘Tuono’) and
the Spanish cultivar ‘Desmayo Largueta’. For some traits (blooming and leafing date) descendants segregated between the value
of both progenitors, meanwhile for others the mean of the offspring was lower (bloom density, productivity and ripening date)
or higher (in-shell/kernel ratio and double kernels). As expected, kernel bitterness and self-incompatibility behaved as monogenic
traits. Some important correlations between traits were detected. The implications of the transmission and the correlation
of these traits in the breeding programmes are discussed. 相似文献