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1.
The germplasm for modern sugarcane cultivars (Saccharum spp. hybrids)has been derived principally from S. officinarum (2n = 80), and S. spontaneum (2n = 40 to 128). Diploid gamete formation has been significant in developing cultivated sugarcane, but the cytological basis
for the processes involved is not clearly understood. This research investigated microsporogenesis in nine clones of Saccharum spp. Hybrids and in S. officinarum and S. spontaneum. Diploid gamete formation occurred in all 11 lines, but was least frequent in S. spontaneum and S. officinarum which produced 0.5% and 0.8%2n gametes, respectively. In the hybrid lines, 2n gametes were formed infrequencies ranging from
0.9% to 4.4%. Cytological evidence was obtained for dyad and triad formation during microsporogenesis. Detailed analysis of
chromosome behaviour at meiosis indicated that 2n male gamete formation is probably attributable to the absence of cytokinesis
rather than a combination of asynchrony and non-disjunction. The clones were ranked on the basis of the frequencies with which
they formed 4 × 1n microspores and the data were analysed using χ 2 tests for homogeneity. These established that theSaccharum spp. hybrids could be designated as either ‘high’ or ‘low’ frequency haploid gamete producers. Conversely, the latter group,
which formed diploid gametes most frequently (2.2%–4.4%), can be described as high frequency diploid gamete producers. The
identification of clones most frequently forming diploid gametes may facilitate the more rapid recovery of desirable sugarcane
genotypes because such clones could be selected for preferential use in clonal improvement.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
2.
Genetic relationships between attributes in sugarcane clones closely related to Saccharum spontaneum 总被引:1,自引:0,他引:1
Phillip Jackson 《Euphytica》1994,79(1-2):101-108
Summary
Saccharum spontaneum is being used in sugarcane breeding programs in attempt to improve characteristics such as ratooning ability and stress tolerance. A population of F1 (Saccharum officinarum or commercial variety x S. spontaneum) and F1 x F1 sugarcane clones was evaluated for sugar yield and a range of yield components in a plant and two ratoon crops. The aim was to determine genetic correlations between attributes in clones with a large component of S. spontaneum, that could be used to help derive appropriate selection indices in such populations.There were close associations between the same attributes measured in different crop-years and the associations between different attributes were generally similar across crop-years. Stalk number and fibre content were positively correlated, as were stalk weight and CCS. The latter two attributes (which are low in S. spontaneum but high in S. officinarum) were negatively correlated with the former two (high in S. spontaneum, low in S. officinarum). Sugar yield was more closely associated with stalk weight and CCS than with stalk number but became more closely associated with stalk number with successive ratoon crops.CCS was positively correlated (rg=0.55) with cane yield in the plant crop but showed a small negative correlation with cane yield (rg=–0.20) in the second ratoon crop. CCS (measured in any crop) also had a negative correlation with cane yield in the ratoon crops expressed as a percentage of plant cane yield. This suggests that CCS is negatively correlated with levels of traits contributing to ratooning ability. Intensive selection among such populations for CCS without consideration of ratooning performance may reduce the frequency of favourable specific ratooning characteristics.Abbreviations CCS
commercial cane sugar 相似文献
3.
Relationships among ancestral species of sugarcane revealed with RFLP using single copy maize nuclear probes 总被引:10,自引:0,他引:10
Y. H. Lu A. D'Hont D. I. T. Walker P. S. Rao P. Feldmann J. C. Glaszmann 《Euphytica》1994,78(1-2):7-18
Summary DNA restriction fragment length polymorphism (RFLP) analysis was performed on 50 wild and old cultivated sugarcane accessions. Ninety-four maize low copy nuclear DNA sequences of known chromosomal position were screened for hybridization to digested sugarcane genomic DNA blots. Seventy-five (80%) gave very strong hybridization signals and usually yielded many bands and detected profuse polymorphism. Twenty-nine probes and 36 probe/enzyme combinations were selected on the basis of the scorability of the banding profiles. A total of 1110 fragments were separately identified among the 50 genotypes. Multivariate analyses of the data allowed the separation of the three basic species, Saccharum spontaneum, S. robustum and S. officinarum, showed that S. spontaneum had structure which could be related to the geographic origin of the clones and supported current hypotheses on the origin of secondary species S. barberi and S. sinense. The use of more probes did not improve the resolution between the various species examined but identified a few key polymorphisms which were not accounted for by current phylogenetic hypotheses and can guide future analyses. RFLPs in sugarcane will be useful essentially for depicting the genomic constitution of modern varieties of interspecific origin. 相似文献
4.
Framework genetic linkage maps of two progenitor species of cultivated sugarcane, Saccharum officinarum ‘La Striped’ (2n = 80) and S. spontaneum ‘SES 147B’ (2n = 64) were constructed using amplified fragment length polymorphism (AFLP), sequence related amplified polymorphism (SRAP),
and target region amplification polymorphism (TRAP) markers. The mapping population was comprised of 100 F1 progeny derived from the interspecific cross. A total of 344 polymorphic markers were generated from the female (S. officinarum) parent, out of which 247 (72%) were single-dose (segregating in a 1:1 ratio) and 33 (9%) were double-dose (segregating in
a 3.3:1 ratio) markers. Sixty-four (19%) markers deviated from Mendelian segregation ratios. In the S. spontaneum genome, out of a total of 306 markers, 221 (72%) were single-dose, 43 (14%) were double-dose, and 42 markers (14%) deviated
from Mendelian segregation ratios. Linkage maps with Kosambi map distances were constructed using a LOD score ≥5.0 and a recombination
threshold of 0.45. In Saccharum officinarum, 146 markers were linked to form 49 linkage groups (LG) spanning 1732 cM whereas, in S. spontaneum, 121 markers were linked to form 45 LG spanning 1491 cM. The estimated genome size of S. officinarum ‘La Striped’ was 2448 cM whereas that of S. spontaneum ‘SES 147B’ was 3232 cM. Based on the two maps, genome coverage was 69% in S. officinarum and 46% in S. spontaneum. The S. officinarum parent ‘La Striped’ behaved like an auto-allopolyploid whereas S. spontaneum ‘SES 147B’ behaved like a true autopolyploid. Although a large disparity exists between the two genomes, the existence of
simple duplex markers, which are heterozygous in both parents and segregate 3:1 in the progeny, indicates that pairing and
recombination can occur between the two genomes. The study also revealed that, compared with AFLP, the SRAP and TRAP markers
appear less effective at generating a large number of genome-wide markers for linkage mapping in sugarcane. However, SRAP
and TRAP markers can be useful for QTL mapping because of their ability to target gene-rich regions of the genome, which is
a focus of our future research. 相似文献
5.
G. Bremer 《Euphytica》1961,10(1):59-78
In this article a survey is given on sugar cane breeding, as it was performed in Java during a period of about fifty years. When in the eighties of the nineteenth century sugar cane was heavily affected by the sereh disease it was Soltwedel, the first director of the Sugar Experiment Station Midden Java, who tried to obtain sereh resistant cane varieties by species hybridization, until his early death intervened. The first species hybrids were obtained in 1893 by Wakker, who crossed noble sugar cane, Saccharum officinarum, with Kassoer, considered by him as a wild species. In later years it appeared from morphological investigations by Jeswiet (1916) and from cytological investigations by Bremer (1921) that Kassoer is to be considered as a spontaneous hybrid between S. officinarum and S. spontaneum, the wild glagah. In 1895 Kobus imported the Indian sugar cane Chunnee in Java. Chunnee, not belonging to S. officinarum, was crossed with noble sugar cane (for the first time) in 1897. From this cross many clones were obtained which appeared to be resistant against the sereh disease but were highly susceptible to mosaic. The continued crossing between noble sugar cane and Kassoer, however, was very successful. Many clones were obtained, which as commercial varieties, showed a high degree of resistance against sereh disease and mosaic and moreover gave a much higher sugar production than the susceptible varieties of noble sugar cane.The following terms are introduced: first, second and third nobilisation of the wild S. spontaneum. Kassoer cane itself is a product of the first nobilisation, the direct cross between noble sugar cane and wild cane. The back cross between Kassoer and noble sugar cane is called the second nobilisation. When cane varieties belonging to the second nobilisation are crossed again with noble sugar cane, the third nobilisation of S. spontaneum is said to take place. The well-known sugar cane variety 2878 P.O.J. belongs to the third nobilisation.In all clones investigated Saccharum officinarum has 2n=80 chromosomes. Within S. spontaneum types occur which in chromosome number vary from 2n=48 to 2n=128. The Java glagah has 2n=112 chromosomes.Clones of the first glagah nobilisation S. officinarum (n=40) x S. spontaneum (n=56) did not have 2n=40+56 chromosomes, but 2n=40+40+56=136 chromosomes.In relation to the taxonomy of Saccharum many other cytological details are given. Within S. officinarum the basic chromosome number x=10. About S. spontaneum opinions are divided. The author supposes that x=6,8 and 10 are basic numbers of S. spontaneum. 相似文献
6.
G. Spangenberg Z. Y. Wang G. Legris P. Montavon T. Takamizo R. Pérez-Vicente M. P. Vallés J. Nagel I. Potrykus 《Euphytica》1955,85(1-3):235-245
Summary Intergeneric symmetric and asymmetric somatic hybrids have been obtained by fusion of metabolically inactivated protoplasts from embryogenic suspension cultures of tall fescue (Festuca arundinacea Schreb.) and unirradiated or 10–500 Gy-irradiated protoplasts from non-morphogenic cell suspensions of Italian ryegrass (Lolium multiflorum Lam.). Genotypically and phenotypically different somatic hybrid Festulolium mature flowering plants were regenerated.Species-specific sequences from F. arundinacea and L. multiflorum being dispersed and evenly-represented in the corresponding genomes were isolated and used for the molecular characterization of the nuclear make-up of the intergeneric, somatic Festulolium plants recovered. The irradiation of Italian ryegrass protoplasts with 250 Gy X-rays prior to fusogenic treatment favoured the unidirectional elimination of most or part of the donor chromosomes. Irradiation of L. multiflorum protoplasts with 500 Gy produced highly asymmetric (over 80% donor genome elimination) nuclear hybrids and clones showing a complete loss of donor chromosomes.The RFLP analysis of the organellar composition in symmetric and asymmetric tall fescue (+) Italian ryegrass regenerants confirmed their somatic hybrid character and revealed a bias towards recipient-type organelles when extensive donor nuclear genome elimination had occurred.Approaches aimed at improving persistence of ryegrasses based on asymmetric somatic hybridization with largely sexually-incompatible grass species (F. rubra and Alopecurus pratensis), and at transferring the cytoplasmic male sterility trait by intra- and inter-specific hybridization in L. multiflorum and L. perenne, have been undertaken.Abbreviations cpDNA
chloroplast DNA
- CMS
cytoplasmic male sterility
- 2,4-D
2,4-dichlorophenoxy-acetic acid
- IOA
iodoacetamide
- mtDNA
mitochondrial DNA
- RFLP
restriction fragment length polymorphism 相似文献
7.
Ronald Eijlander Wendy ter Laak Jan G.Th. Hermsen M.S. Ramanna Evert Jacobsen 《Euphytica》2000,115(2):127-139
Diploid Solanum tuberosum (tbr), 2n=2x=24,can be crossed with S. verrucosum (ver) only when the latter is used as a pistillate parent but not reciprocally. This conforms to the phenomenon of unilateral
incompatibility (UI) where a self-compatible species, like ver (SC) cannot be used as a male parent to cross with a self-incompatible (SI) parent like tbr. Even if ver × tbr hybrids are made, the F1 hybrids possess cytoplasmic male sterility and thus hinder genetic analysis of crossing barriers.
Exceptionally, however, some diploid genotypes of tbr (SI) can be used as pistillate parents to cross with ver, and such exceptional tbr clones are called `acceptors'. Repeated backcrossing of acceptors to ver have resulted in male fertile genotypes that possess tbr cytoplasm and ver nucleus. These genotypes were used for the genetic analysis of `acceptance' and UI in thse experiments. It was found that
acceptance of ver-pollen by tbr-pistils is based on a dominant gene A that expresses only in the absence of an inhibitor I. In the F1 hybrids, only the S-allele of tbr was expressedbut not that of ver. Concomitant with this observation, it was shown that ver does not produce style-specific S-glycoproteins that are responsible for self-incompatible reaction in diploid potato. Although the the F1 populations were SC, they segregated into SC and SI genotypes giving skewed segregation ratios for this trait. Because of
this as well as the disappearance and re-appearance of SC trait in the offspring generations, it was necessary to postulate
a more complex interaction between A and I. Models are presented in order to explain acceptance, non-acceptance and the expression of UI. It is concluded that at least
four different loci are involved in the expression of UI.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
8.
Sreedhar Alwala Collins A. Kimbeng John C. Veremis Kenneth A. Gravois 《Euphytica》2009,167(1):127-142
The cultivated sugarcane (Saccharum spp. hybrids, 2n = 100–130) is one crop for which interspecific hybridization involving wild germplasm has provided a major breakthrough in
its improvement. Few clones were used in the initial hybridization event leading to a narrow genetic base for continued cultivar
development. Molecular breeding would facilitate the identification and introgression of novel alleles/genes from the wild
germplasm into cultivated sugarcane. We report the identification of molecular markers associated with sugar-related traits
using an F1 population derived from a cross between S. officinarum ‘Louisiana Striped’ × S. spontaneum ‘SES 147B’, the two major progenitor species of cultivated sugarcane. Genetic linkage maps of the S. officinarum and S. spontaneum parents were produced using the AFLP, SRAP and TRAP molecular marker techniques. The mapping population was evaluated for
sugar-related traits namely, Brix (B) and pol (P) at the early (E) and late (L) plant growing season in the plant cane (04)
and first ratoon (05) crops (04EB, 04LB, 04LP, 05EB and 05EP). For S. officinarum, combined across all the traits, a total of 30 putative QTLs was observed with LOD scores ranging from 2.51 to 7.48. The
phenotypic variation (adj. R2) explained by all QTLs per trait ranged from 22.1% (04LP) to 48.4% (04EB). For S. spontaneum, a total of 11 putative QTLs was observed with LOD scores ranging from 2.62 to 4.70 and adj. R2 ranging from 9.3% (04LP) to 43.0% (04LB). Nine digenic interactions (iQTL) were observed in S. officinarum whereas only three were observed in S. spontaneum. About half of the QTLs contributed by both progenitor species were associated with effects on the trait that was contrary
to expectations based on the phenotype of the parent contributing the allele. Quantitative trait loci and their associated
effects were consistent across crop-years and growing seasons with very few QTLs being unique to the early season. When the
data were reanalyzed using the non-parametric discriminant analysis (DA) approach, significant marker-trait associations were
detected for markers that were either identical to or in the vicinity of markers previously identified using the traditional
QTL approach. Discriminant analysis also pointed to previously unidentified markers some of which remained unlinked on the
map. These preliminary results suggest that DA could be used as a complementary approach to traditional QTL analysis in a
crop like sugarcane for which saturated linkage maps are unavailable or difficult to obtain. 相似文献
9.
Heterosis and heritability in crosses among Asian and Ethiopian parents of hot pepper genotypes 总被引:1,自引:1,他引:0
Hot pepper is the most important worldwide grown and consumed spice and vegetable crop. Though hybrid breeding has been proposed
for genetic improvement in the crop, but there is lack of information on heterosis in crosses among crop genotypes in Ethiopia.
Twelve genotypes (nine Asian and three Ethiopian parents) of hot pepper were crossed in 2003 cropping season in a half-diallel
fashion to fit Griffing’s fixed effect model analysis. An open field experiment was conducted in 2004/2005 to investigate
heterosis for fourteen traits in 66 F1 hybrids grown together with their 12 selfed parents. Highly significant genotypic differences were observed for all the traits
except for leaf area. Variance component due to specific combining ability (dominance) were larger than that due to general
combining ability (additive) for each of the studied traits with few exceptions. Broad sense heritability (H
b2) for fruit traits were more than 60% and with wide gap from narrow sense heritability (h
n2) for most of the important traits like number of fruit per plant (H
b2 = 88.3% and h
n2 = 46.0%), days to maturity (H
b2 = 87.2% and h
n2 = 23.1%) and dry fruit yield per plant (H
b2 = 72.6% and h
n2 = 14.6%). Maximum heterosis over mid-parent and better-parent, and economic superiority of hybrid over standard check were
recorded, respectively for dry fruit yield per plant (163.8, 161.8 and 92.1%), number of fruits per plant (104.4, 79.6 and
136.4%) and days to maturity (−29.8, −31.5 and −23.6%). These observations suggested a possibility of utilizing dominance
genetic potentiality available in diverse genotypes of the crop by heterosis breeding for improving hot pepper to the extent
of better economic return compared to the current commercial cultivar under production in the country. Low narrow sense versus
very high broad sense heritability for days to maturity and dry fruit yield per plant could be a sign for achievability of
earliness and high fruit yield using heterosis in hot pepper. The maximum heterobeltiosis were recorded either from F1s obtained from Ethiopian and Asian crosses or from within Asian crosses, suggesting the possibility of maximizing heterosis
by considering genetically diverse parental genotypes. The manifestation of highest heterosis in hybrids from among Asian
lines indicated existence of genetic diversity among Asian genotypes and the potentiality for improvement of hot pepper using
genotypes from different regions of the world along with elite inbred lines from local cultivars. 相似文献
10.
Most potato transgenic research has focused on development of resistance to pathogens and modification of potato physiology.
Many transgenes, particularly those conferring pathogen resistance, could substantially lower potato production costs in developing
countries. However, transgenes have not been reported in sexually propagated 4x-2x potato hybrids commonly grown in developing countries. Two transgenes,the Bacillus thuringiensis cry3Aa endotoxin protein gene and the PVY°coat protein gene, were engineered intodiploid and tetraploid potato using Agrobacterium tumefaciens-mediated transformation. Cry3Aa was produced at high levels in several lines while the PVY° coat protein was not expressed.
Diplandroid and tetraploid genotypes were crossed to produce transgenic 4x-2x hybrids. Genetic transformation had no discernable effect on fertility ofthe primary transformants, germination of4x-2x seed derived from the transformants and agronomic performance(tuber set, average tuber weight and total tuber yield) of the
4x-2xhybrids. The transgenic 4x-2xhybrids produced non-viable pollen and could only be crossed as female parents. Results suggest that transgenes, such ascry3Aa, could be expressed in 4x-2x hybrids to lower costs of production with no significant effect on plant phenotype.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
11.
Tomato mosaic virus (ToMV) is a limiting factor for the success of pepino (Solarium muricatum) as a new crop. The effects of ToMV infection on total and marketable yield, fruit weight, length/width ratio and soluble
solids content (SSC) have been studied in two commercial clones (`Sweet Long' and `Sweet Round'). ToMV infection depressed
total yield in infected plants of `Sweet Long' (43.1%), while it had no effect on this trait in `Sweet Round' . Marketable
yield was dramatically reduced by ToMV infection in both clones, 94% in `Sweet Long' and 100% in `Sweet Round'. Infected plants
of clone `Sweet Long' had a lower weight than healthy plants. Although no differences in fruit weight were detected in `Sweet
Round' between ToMV infected and healthy plants, many fruits from infected plants showed deformities. Changes in fruit length/width
ratio and SSC as a result of ToMV infection were not relevant, but fruit quality was lower in infected fruits, most of which
had corky-like flesh. Forty-two clones from cultivated (S. muricatum), wild (S. caripense and S. tabanoense) and interspecific hybrids were tested for ToMV resistance. All but seven clones (four from S. muricatum and three from interspecific hybrids S. muricatum × S. caripense) were susceptible. Non-susceptible clones showed variable degrees of resistance and developed hypersensitive local lesions.
Among these clones the most promising as sources of variation for resistance to ToMV are those belonging to the cultivated
species. Although no immunity was found, plants from these clones remained asymptomatic and absorbance values resulting from
the DAS-ELISA tests in these plants were always lower than those of the susceptible control (cv. `Sweet Round'). These sources
of resistance may be of great utility in developing commercial clones resistant to this severe disease affecting pepino.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
12.
Summary Two tetraploid and two diploid clones of Hordeum bulbosum were screened for resistance to five isolates of powdery mildew which are virulent on cultivated barley. All were resistant and this resistance was also expressed in hybrids with H. vulgare. The tetraploid genotypes were also resistant to isolates of yellow rust and brown rust. These results show that H. bulbosum contains useful genes for resistance to these diseases and that there is a potential to transfer these into cultivated barley. 相似文献
13.
K. S. Shankarappa Sriharsha K. T. Rangaswamy D. S. Aswathanarayana H. A. Prameela R. S. Kulkarni V. Muniyappa A. Mohan Rao M. N. Maruthi 《Euphytica》2008,164(2):531-539
Resistance to tomato leaf curl virus disease (ToLCVD) in tomato (Solanum lycopersicum) is scarce but was developed recently in three open pollinated (OP) varieties (Sankranthi, Nandi and Vybhav), which are now
available for cultivation in South India. Hybrids with superior yield capabilities, however, are a preferred choice of cultivation
by farmers but hybrids are highly susceptible to ToLCVD. In order to develop virus resistant tomato hybrids, the three OPs
were crossed with 12 tomato genotypes with superior agronomic characteristics. From the crosses, 20 hybrids were selected
(named BLRH-1 to BLRH-20, Bangalore leaf curl virus-resistant hybrid) and evaluated for their resistance to ToLCVD at the University of Agricultural Sciences, Bengaluru, South India, both through
whitefly-mediated inoculations in the glasshouse and natural infection in the field during summer 2005. Their growth and fruit
yield parameters were compared against the popularly grown hybrids and OPs. Differences occurred between hybrids in disease
incidence, spread, symptom severity and fruit yield. Of the 20 hybrids evaluated, 11 were found resistant to ToLCVD in the
field, but only three (BLRH-3, BLRH-9 and BLRH-16) remained resistant when challenged with high virus inoculum pressure in
the glasshouse through whitefly-mediated inoculations. None of the six commercially available hybrids tested was found resistant
to ToLCVD. An examination of the extent of heterosis in resistant hybrids for both quantitative and qualitative characters
over the popularly grown hybrid, US-618, indicated a major improvement in virus resistance, yield and fruit quality. All the
twenty hybrids yielded significantly more than US-618, and of these, BLRH-3 and BLRH-16 were considered the best with yields
over ca. 60 t/ha and resistant to virus both in the glasshouse and field. 相似文献
14.
The genus Kalanchoe is currently divided into section Kalanchoe and section Bryophyllum, and there has been no successful report on the production
of inter-sectional hybrids. Therefore, reciprocal crosses were made between Kalanchoe spathulata (sect. Kalanchoe) and K. laxiflora (sect. Bryophyllum) in order to obtain basic information on the reproductive barriers between these two sections. The seeds
were aseptically germinated in vitro and the plants were grown in greenhouse till flowering. When K. spathulata was used as a maternal donor, 39 out of 80 plants showed intermediate characteristics between K. spathulata and K. laxiflora. In contrast, no plants were obtained in the reverse crosses. Hybridity of these plants was confirmed by flow cytometric
analysis, chromosome numbers and RAPD analysis. Bulbil formation on the leaf margin as one of the conspicuous characteristics
of K. laxiflora was not observed in the hybrids. Some of the hybrid lines showed some pollen fertility, but failed to yield viable seeds
by self-pollination or backcross-pollination. Successful production of the inter-sectional hybrid between the two species
suggests that they are not so distantly related as considered previously. 相似文献
15.
Summary In an attempt to determine the transmission of androgenetic competence, 10 families resulting from intra- and interspecific hybrids including three reciprocal hybrids were examined in anther culture. Hybrid families were generated between competent clones of Solanum phureja and incompetent clones of S. phureja, S. microdontum and S. berthaultii. S. phureja clones PP5 and A95 (derived by androgenesis of a 2n microspore of PP5) were found to be consistently competent for androgenesis. Androgenetic competence was observed to segregate in all hybrid families with some highly responsive and some unresponsive genotypes in all families. A total of 9,465 cultured anthers have yielded 936 embryoids and 91 plants, including 29 monoploids. The cytoplasm of species lacking competence appeared to have greater influence on the expression of androgenesis in intraspecific than in interspecific hybrids. Expression of androgenesis varied among half-sib hybrid families indicating that competence for androgenesis was influenced by the parents lacking competence. The anther culture data on a backcross between a highly responsive hybrid and its unresponsive parent indicated that competence may be under control of a single dominant gene. 相似文献
16.
Summary A complete ancestral history of the recently developed and closely related South African commercial sugarcane varieties N11 and NCo376, which differ markedly in their response to sugarcane mosaic virus (SCMV), was elucidated from archival records. The genealogy spans seven generations, starting with early intraspecific crosses between varieties of Saccharum officinarum and interspecific crosses between S. officinarum and either S. spontaneum or S. barberi. In total, the genealogy comprises 38 different varieties. Genomic DNA samples from N11 and NCo376 respectively were screened for polymorphisms using the PCR-RAPD technique. Ten polymorphic fragments ranging in molecular size from 317 to 1263bp were identified from a total of 1159 loci amplified with 100 random decamer primers. Two of the 10 polymorphic fragments were shown to be consistently present in N11 (resistant) and absent in NCo376 (susceptible), while 8 showed the reverse occurrence. The primers producing the polymorphisms were used to screen genomic DNA samples from all 19 varieties representing the genealogy. Results have indicated that (1) specific PCR-RAPD generated polymorphic fragments can indeed be identified across the seven generations; (2) certain fragments are sufficiently definitive to be used as markers to trace parentage; (3) the validity of documented crosses and/or the authenticity of germplasm material may be questioned using this technique, and (4) there is the potential to subject the markers to linkage analysis once a full and accurate assessment of the SCMV resistance phenotype is obtained. 相似文献
17.
Anne-marie Wolters Evert Jacobsen Mary O'Connell Guusie Bonnema K. Sree Ramulu Hans de Jong Herman Schoenmakers Jelle Wijbrandi Maarten Koornneef 《Euphytica》1994,79(3):265-277
Protoplast fusion can be used to produce somatic hybrids of species that cannot be obtained by sexual hybridization. The possibility to introgress genes from Solanum species into the cultivated tomato species Lycopersicon esculentum, and to obtain novel cytoplasm-nucleus combinations (cybrids) was considered as an important strategy to extend the genetic variation available for tomato breeding. Somatic hybrids between L. esculentum and other Lycopersicon species, as well as between L. esculentum and Solanum or Nicotiana species, have been produced. Specific mutants, genotypes with antibiotic resistances, and metabolic inhibition by iodoacetate or iodoacetamide and irradiation were used for the selection of hybrids. In addition, the improvement of protoplast culture techniques and the use of the favourable tissue culture traits derived from species such as L. peruvianum, which have been introduced into tomato by classical breeding, allowed the efficient recovery of somatic hybrids. However, the occurrence of somatic incongruity in fusion combinations of L. esculentum and Solanum and even more in L. esculentum and Nicotiana, did not allow the production of true cybrids and/or fertile hybrids, indicating the importance of both cytoplasm-nucleus and nucleus-nucleus interactions in somatic incongruity. Another problem with fusions between distantly related species is the strongly reduced fertility of the hybrids and the very limited homoeologous recombination between chromosomes of the parental species. Partial genome transfer from donor to recipient through microprotoplast (+) protoplast fusion, and the production of monosomic or disomic chromosome addition lines, light overcome some of these problems. In symmetric somatic hybrids between L. esculentum and S. tuberosum the occurrence of limited somatic and meiotic recombination was demonstrated. Fertile progeny plants could be obtained, though at a low frequency, when embryo rescue was performed on a large scale after backcrossing hexaploid somatic tomato (+) potato hybrids with a tetraploid potato genotype. The potential value of genomic in situ hybridization (GISH) and RFLPs for the analysis of the genome/chromosome composition of the hybrids has been demonstrated for intergeneric somatic hybrids between Lycopersicon and Solanum.Abbreviations cpDNA
chloroplast DNA
- mtDNA
mitochondrial DNA 相似文献
18.
Summary Selection indices at different stages of selection were estimated for a biparental mating population of sugarcane (Saccharum officinarum L.). At the seedling stage indices constructed from primary characters are better than selection for yield alone. At the clonal stage the superiority of index selection over direct selection was marginal. In the seedling stage, selection based on index can lead to better selection efficiency in succeeding clonal stages. This was confirmed by a sample study. 相似文献
19.
The purpose of the study was to evaluate the relationship between the genetic distances (GD) and phenotypic distances (PD)
of parents and the specific combining ability (SCA) and heterosis effects. The experiment comprised 18 parental genotypes
of wheat (Triticum aestivum L.) and 76 F2 hybrids, obtained after crossing in a line × tester scheme. Parents and hybrids were examined in a field experiment conducted
in a block design with three replications. SCA as well as mid-parent heterosis effects were estimated for selected morphological
and technological traits. PDs and GDs were investigated between pairs of parental genotypes. GD between parental genotypes
was evaluated by using randomly amplified polymorphic DNA markers. Heterosis was observed in all hybrids, and protein content
exhibited the highest heterosis among the seven examined traits. The relationship between PD and GD as well as the SCA and
mid-parent heterosis effects were evaluated using correlation coefficient. The correlation between PD, SCA and heterosis were
low and not significant for the examined traits, whereas the correlation between SCA, heterosis and GDs were significant for
protein content and rheological properties. The results indicate that GDs between parents can be used to predict performance
of hybrids for selected technological traits. 相似文献
20.
Twenty-one (near) pentaploid hybrids between sexually incompatible Solanum
commersonii [2x(1EBN)] and cultivated S. tuberosum [4x(4EBN)] were characterized for tuber traits and fertility. A number of genotypes resembled the S. tuberosum type in terms of stolon length and eye depth and produced tubers under long day conditions. Tuber yields were not as high
as expected, probably due to lack of adaptation of the S. commersonii genome to the environmental conditions in southern Italy (on average 325 g·pt−1 and 285 g·pt−1 in 2003 and in 2004, respectively). Compared to 2004, in the summer of 2003, characterized by extremely high temperatures,
hybrids gave a higher tuber yield than the S. tuberosum control, suggesting that in our environmental conditions the wild S. commersonii genome, rather than resulting in heterosis for tuber yield, provides better adaptation to harsh environments. Although aneuploidy
has often been associated with reduced fertility, several hybrids were fertile in crosses with S. tuberosum when used as female parents. In particular, the average berry set and number of seeds per berry were 38.2% and 31.8%, respectively.
Based on significant relationships between ploidy levels and all yield and fertility data measured, the presence of extra
chromosome affected the parameters considered: tuber yield in 2003 and 2004, percentage of fruit set, number of seeds per
berry and number of seeds per pollinated flower. Regression analysis also indicated that “Residuals” were significant for
all parameters measured. Therefore, additional factors (e.g. the genetic makeup of hybrids) may be key to fertility and yield. 相似文献