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1.
The GCAs are new tetraploid interspecific hybrids developed in Madagascar from Coffea eugenioides, C. canephora and C. arabica. Selected GCA having genotype UF1023 contained 0.37% DW caffeine and no detectable theobromine in green beans. Low caffeine accumulation in GCA plants is due mainly to the low biosynthetic activity of purine alkaloids, possibly the extremely weak N-methyltransferase reactions in caffeine biosynthesis. No significant catabolic activity of caffeine was found in GCA-UF1023, in common with almost all coffee plants including C. arabica.  相似文献   

2.
Summary Various wild relatives of pigeonpea,Cajanus cajan, namely some species ofAtylosia andRhynchosia, possess desirable characteristics that could be utilized for effecting genetic improvement of this crop. In total 73 cross combinations among two cultivars ofC. cajan and one accession each of eightAtylosia species and one ofRhynchosia were attempted. Twelve hybrids were obtained. Seven of these were analysed for F1 fertility and their utility for agronomic improvement of theC. cajan. Fertility behaviour of the different F1 hybrids varied and indicated that potential of gene transfer between the two genera,Atylosia andCajanus, was as good as within the genusAtylosia. From F2 and F3 families ofC. cajan × A. scarabaeoides andC. cajan × A. albicans, plants were selected with greater physiological efficiency and agronomic superiority. The prospects of transferring pod borer resistance and higher seed protein content from someAtylosia species to pigeonpea are discussed.  相似文献   

3.
Summary Crosses between a wild species C. chacoense and three cultivated species of chili pepper viz. C. annuum, C. frutescens and C. chinense yielded hybrids when C. chacoense was the seed parent but the reciprocal crosses were unsuccessful. C. chacoense × C. annuum F1 hybrids were partly fertile and therefore an F2 population could be raised; the other two F1 hybrids were totally sterile. Chromosome pairing in the F1 plants resulted largely in bivalents and a few multivalents and univalents. The genomes of the four species share large homologies and the role of chromosome structural changes in genome differentiation is suggested. Hybrid sterility is the major reproductive isolation mechanism.  相似文献   

4.
S.288 an offspring of a putative spontaneous interspecific hybrid between tetraploid Coffea Arabica (2n = 4x = 44) and diploid C. liberica(2n = 2x = 22) and 17 arabica coffee introgression lines (representing F2 and F4) derived from the cross S.288 x Kent arabica were evaluated for introgression of C. liberica genetic material. In all, 36 AFLP primer combinations were used in the analysis. The AFLP profiles of introgressed lines were compared to five accessions each of C. arabica and C. liberica. A total of 137 polymorphic bands were scored among the 29 accessions analysed. The introgressed genotypes exhibited 102 marker bands consisting of 65 additional bands and 37missing bands associated with introgression of C. liberica genetic material. C. liberica accessions of EA group (C. liberica var liberica of Guinean origin) seemed to be the likely progenitor in the origin of natural hybrid. Analysis of genetic relationships in the introgressed lines suggested that introgression was limited to few fragments. Segregation and wide variation in number of marker fragments in the F2 and F4progenies were attributed to chromosome recombinations. The differences in the level of introgression between introgressed parent, F2 and F4 groups was not pronounced. Therefore the alien genetic material appeared to be fixed and there was no elimination or counter-selection over generations, from introgressed parent to F4.In C. arabica accessions, only 35 polymorphic bands were seen confirming the low genetic diversity. On the contrary, although representing a small amount of alien genome introgression, the Liberica-introgressed genotypes provided notable genetic diversity. Considering the fact that the diploid species of Coffea constitute a valuable source of genetic diversity, the potential implications of variability generated by Liberica-introgressed genotypes in C. arabica breeding are discussed. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

5.
T. Yabuya 《Euphytica》1987,36(2):381-387
Summary Anthocyanins of colchicine-induced amphidiploids of I. laevigata × I. ensata were analyzed by the HPLC procedure and compared with those of parental species and F1 hybrids of I. laevigata × I. ensata. The amphidiploids were characterized by seventeen anthocyanins, and exhibited all anthocyanins of the parental species and the F1 hybrids. Malvidin 3RGac5G and petunidin 3RGac5G in anthocyanins detected were major pigments in the amphidiploids, which exhibited strongly the malvidin 3RGac5G-petunidin 3RGac5G type of I. ensata rather than the petunidin 3RGac5G-malvidin 3RGac5G type of I. laevigata. Moreover, a higher degree of anthocyanin content was observed in the amphidiploids and the F1 hybrids. Namely, the anthocyanin content of the amphidiploids and the F1 hybrids were 2.81 and 2.45 times as much as that of the mid-parent. This implies that there is a complementary effect on anthocyanin synthesis of parental genes in them. Finally, the utility of the amphidiploids was discussed.Contribution from the Laboratory of Plant Breeding, Faculty of Agriculture, Miyazaki Univ., No. 64.  相似文献   

6.
Yoshito Asano 《Euphytica》1982,31(1):121-128
Summary Meiotic observations in PMCs were made in eight kinds of interspecific hybrids in Lilium. Three hybrids, 6134-S × L. cernuum. L. regale × L. leichtlinii maximowiczii and L. auratum platyphyllum × L. henryi showed respectively the mean chromosome association frequencies of 1.4II, 0.8II and 1.5II per cell at MI which were the lowest values hitherto reported in Lilium hybrids. In L. longiflorum × L. henryi, 33.3° of the cells had 1 or 2 multivalents of three to five chromosomes in addition to uni- and bivalents. 12° bivalents and 12 univalents were invariably observed in the triploid hybrid L. longiflorum × L. cernuum. The hybrids between the species belonging to the different sections of the genus generally showed high pollen sterility, with some exceptions. A more or less remote genomic homology was found between the different sections in Lilium.  相似文献   

7.
Summary F1 hybrids of triazine resistant Brassica napus and triazine susceptible B. oleracea were morphologically intermediate to the parent species. Of 49 hybrids examined, 44 had 28 chromosomes, two had 37, one had 38 and two had 56. The 38-chromosome plant was thought to be a matromorph, the others, A1C1C (28), A1C1CC (37) or A1A1C1C1CC (56) type hybrids. Pollen stainability averaged 9.0% in the sesquidiploid, 32.0% in the tetraploids and 89.5% in the hexaploids. All the interspecific hybrids were resistant to 1.0×10-4 mol L-1 atrazine. The sesquidiploid hybrids produced gametes with chromosome numbers ranging from 9 to 17 and the tetraploid hybrid gametes had chromosome numbers from 15 to 22. Most hybrids produced self-seed. The partial fertility of these hybrids may permit their backcrossing to one or both parents.  相似文献   

8.
Summary The production, vigour, and fertility of F1 hybrids between nine African species of the genus Cucumis L. were studied as a measure of the relationships between the species. Hybrid plants were obtained from 29 out of the 72 possible cross combinations. Two F1 hybrids died as seedlings, and 27 hybrids were raised to maturity. Pollen production and stainability varied greatly amongst these hybrids, as did fruit and seed set following self pollination and backcrossing with either parental species. The fruit shape of the hybrids was always intermediate between that of both parental species.Two species appeared to be closely related: C. prophetarum L. and C. anguria var. longipes A. Meeuse. Most other species produced highly to moderately fertile F1 hybrids with at least one other species. C. metuliferus Naud. produced only sterile hybrids with C. zeyheri Sond. 2x. The results sustain the recent taxonomic classification of the genus (Jeffrey, 1980).  相似文献   

9.
Summary Three non-tuberous Solanum species of series Etuberosa-S. brevidens (brd), S. etuberosum (etb) and S. fernandezianum (frn)-upon selfing displayed compatible berry set but seed set varied and on an average was below normal. Also in crosses between species berry set was unhampered (apart from the crosses with short-styled frn as pollen plant), but the interspecific hybrid plants showed various degrees of sterility and a low average seed set upon selfing. Cytological investigations revealed that in pure species-plants semi-sterility regularly occurred and was invariably associated with multivalent associations (up to decavalents). This may account for the decreased seed set found after selfing and intercrossing. Meiosis in F1-hybrids was even more irregular, 75% of the pmc's showing multivalents involving from 4 to as many as 22 chromosomes in various complicated configurations in which even numbers of chromosomes were predominant. However, anaphase I separation was numerically balanced in more than 75% of the cells. Pollen stainability was very low in the hybrids.It is concluded that heterozygous translocations occur within each species and that the genomes of the species are differentiated by means of gross structural changes. In view of this and of the high chromosome pairing affinity the genome symbols E 1, E 2 and E 3 are proposed for etb, brd and frn, respectively.Crossability of the Etuberosa species with tuberous S. pinnatisectum (pnt) was slightly more successful (average 2.7 seeds/berry) than that of Etuberosa species hybrids with S. pinnatisectum (average 1.7 seed/berry). In the hybrids studied-etb × pnt, frn × pnt and (brd × etb) × pnt-a high frequency of univalents was the rule (range 6–16 per cell). In addition rod bivalents (4–8 per cell) and a low frequency of trivalents occurred (0–3 in the biparental hybrids and 1–4 in the trispecific hybrid).Utilization of the valuable characters of Etuberosa for potato breeding is dependent on the degree of gene exchange between Etuberosa chromosomes and chromosomes of tuberous species. In the diploid hybrids such exchange, though limited, may take place through bivalents and trivalents. As shown in this article such diploid hybrids are non-crossable because of complete male and female sterility. Only after doubling the number of chromosomes the hybrids are fertile and can be used for further crosses.  相似文献   

10.
Summary Doubling the chromosome number of sterile F1 hybrids of S. etuberosum × S. pinnatisectum resulted in fertile allotetraploid hybrids (code 4x-EP) with nearly normal chromosome pairing at meiosis. Many seeds were obtained from selfing and sibbing, but seed set varied considerably. The 4x-EP hybrids were successfully crosses as females with S. stoloniferum and S. polytrichon and as males with S. verrucosum. The crosses with S. stoloniferum and S. polytrichon were carried out reciprocally and unilateral incompatibility was detected. Crosses of 4x-EP hybrids as males onto S. phureja and S. tuberosum cv. Gineke produced parthenocarpic berries only. Nearly 1700 flowers of colchicine-doubled S. pinnatisectum × S. bulbocastanum and the trispecific hybrid (S. acaule × S. bulbocastanum) × S. phureja did not yield a single berry after pollination with a pollen mixture from 20 4x-EP plants.It is concluded that the use of the bridging species S. pinnatisectum and either S. stoloniferum, S. polytrichon or S. verrucosum may enable gene transfer from the non-tuberous Etuberosa species to potato cultivars.  相似文献   

11.
Interspecific hybrids from cross incompatible relatives of sweetpotato   总被引：1，自引：0，他引：1  
Summary Hybrids were obtained from Ipomoea interspecific crosses through ovule culture. The hybridity of the progeny obtained from I. triloba × IitI. trifida and (I. triloba × I. lacunosa) × I. batatas (4x) crosses was established by comparisons of floral morphology and analyses of peroxidase and esterase isozymes. The hybrids displayed the inflorescence type and sepal shape and texture of their male parents, while corolla size and anther and nectary color tended to be intermediate to their parents. The isozyme banding patterns of the hybrids contained bands present in the patterns of each of their parents. Pollen grain viability, measured by aceto-carmine stainability, was 44.1%, 92.3% and 82.4%, respectively, for the I. triloba × I. trifida hybrid and the (I. triloba × I. lacunosa) × I. batatas (4x) hybrids, H1 and H2. A controlled pollination study revealed that the I. triloba × I. trifida, and the (I. triloba × I. lacunosa) × I. batatas (4x) hybrids, H1 and H2 were partially self fertile with 6%, 70% and 13%, respectively, of the pollinated flowers producing viable seed. Success in backcrossing and sib-mating varied with the cross combination.  相似文献   

12.
Summary Atrazine resistant Brassica napus × B. oleracea F1 hybrids were backcrossed to both parental species. The backcrosses to B. napus produced seeds in both directions but results were much better when the F1 hybrid was the pollen parent. Backcrosses to B. oleracea failed completely but BC1s were rescued by embryo culture both from a tetraploid hybrid (2n = 4x = 37; A1C1CC) and sesquidiploid hybrids (2n = 3x = 8; A1C1C). Progeny of crosses between the tetraploid hybrid and B. oleracea had between 25 and 28 chromosomes. That of crosses between the sesquidiploid hybrid and B. oleracea had between 21 and 27. A few plants that had chromosome counts outside the expected range may have originated from either diploid parthenogenesis, unreduced gametes or spontaneous chromosome doubling during in vitro culture. Pollen stainability of the BC1s ranged from 0% to 91.5%. All the BC1s to B. oleracea were resistant to atrazine.  相似文献   

13.
Summary The possibilities to transfer important traits and in particular resistance to the beet cyst nematode (Heterodera schachtii, abbrev. BCN) from Raphanus sativus to Brassica napus were investigated. For these studies B. napus, R. sativus, the bridging hybrid ×Brassicoraphanus (Raparadish) as well as offspring of the cross ×Brassicoraphanus (Raparadish) ×B. napus were used. Reciprocal crosses between B. napus and R. sativus were unsuccessful, also with the use of embryo rescue. Crosses between ×Brassicoraphanus as female parent and B. napus resulted in a large number of F1 hybrids, whereas the reciprocal cross yielded mainly matromorphic plants. BC1, BC2 and BC3 plants were obtained from backcrosses with B. napus, which was used as the male parent. F1 hybrids and BC plants showed a large variation for morphology and male and female fertility. Cuttings of some F1 and BC1 plants, obtained from crosses involving resistant plants of ×Brassicoraphanus, were found to possess a level of resistance similar to that of the resistant parent. These results and indications for meiotic pairing between chromosomes of genome R with those of the genomes A and/or C suggest that introgression of the BCN-resistance of Raphanus into B. napus may be achieved.  相似文献   

14.
Summary Interspecific crosses were made to introduce the scent of flowers of C. purpurascens into C. persicum cultivars and ovule culture was used to rescue the abortive hybrid embryos. Cultivars of C. persicum diploid (CPD, 2n=2×=48) and C. persicum tetraploid (CPT, 2n=4×=96) were the pistillate parents and wild species of C. purpurascens (CP, 2n=34) were staminate parents. After pollination, crossed ovaries were collected periodically and examined using paraffin sections. Histological observations suggested that both hybrid ovules of CPD x CP and CPT x CP should be transferred to culture medium 35 days after pollination. Based up on this observation, crossed ovaries were collected 28 days after pollination and ovules with placenta were transferred to MS (1962) medium containing 3% sucrose. These ovules were cultured in the dark at 25° C. The hybrids (2n=41) derived from CPD x CP had the scent of C. purpurascens, whereas the hybrids (2n=65) derived from CPT x CP had the scent of C. persicum. Although both hybrids had complete genomes from the parents and produced a few viable pollen grains, they failed to yield viable seeds by self- and cross-pollination with fertile pollen grains of C. persicum cultivars.Abbreviations CPD C. persicum diploid - CPT C. persicum tetraploid - CP C. purpurascens  相似文献   

15.
Jens Weibull 《Euphytica》1987,36(2):571-576
Summary Twenty-seven accessions of Hordeum species and interspecific hybrids were screened in a growth chamber for resistance against the aphid Rhopalosiphum padi. Resistance measurement was based on the aphids' population growth during a 16-day period. The mean number of nymphs produced per female was only about 14% of that on the control cv. Tellus. H. bogdani was the most resistant accession. As a group, interspecific F1-hybrids with common barley (H. vulgare × H. sp.) held an intermediate position. Differences in resistance between hybrids as well as between species (H. jubatum and H. lechleri) were observed. The most resistant species were all diploids. No effects of the host plant on formation of alatae or on the within-plant distribution of aphids were found.  相似文献   

16.
The expression of the “glanded-plant and glandless-seed” trait was assessed using High Performance Liquid Chromatography (HPLC) analysis methods in different Gossypium hybrids obtained by crossing Australian diploid cottons and various diploid and tetraploid species. Significant variation in the gossypol content in the seed was observed among the analyzed genotypes. HPLC data demonstrated that the gossypol synthesis repression mechanism in the Australian diploid species belonging to C and G genomes was dominant but did not confirm its preferential functioning against A genome species bearing GL2 locus. About 10% of the produced seeds had total gossypol content lower than the limit imposed by the World Health Organisation (600 ppm) for the use of cotton flour in food and feed. HPLC analysis of the terpenoids aldehyde (TA) contents in the aerial parts of the hybrids showed important qualitative and quantitative variability. This result could indicate a certain separation between pigment gland morphogenesis and terpenoid synthesis mechanisms in cotton.  相似文献   

17.
Summary Morphological and cytogenetical studies were carried out on the F1 and F2 hybrids and backcross derivatives of the interspecific cross Capsicum baccatum L. x C. frutescens L. The F1 and F2 hybrids displayed irregular meiosis with a maximum association of eight chromosomes in the former and one quadrivalent in the latter with the appropriate number of bivalents and univalents. It is inferred that C. baccatum differs from C. frutescens (yellow) by at least tow or three interchanges and from the white cultivar by a single interchange. Structural repatterning of chromosomes, erratic meiotic behaviour, genes for pollen sterility, segregational imbalances following intergenomic recombination are believed to be major factors causing sterility in the hybrids. The two species are sympatric and natural hybrids have not been realised.  相似文献   

18.
The mode of inheritance of chloroplast and mitochondrial DNA has been determined in intergeneric hybrids between C. papaya and four different Vasconcellea species by employing a restriction fragment length polymorphism analysis of a PCR-amplified chloroplast and mitochondrial DNA region. Artificial F1 hybrids were produced between a female specimen of C. papaya and male specimens of either V. parviflora, V. goudotiana, V. cundinamarcensis or V. quercifolia. The hybridization patterns of all hybrids correspond in all cases with that of the C. papaya mother, and are different from that of the paternal Vasconcellea species, thus indicating the maternal inheritance of cpDNA and mtDNA in intergeneric hybrids between C. papaya and wild relatives of the Vasconcellea genus.  相似文献   

19.
Reproductive fertility traits were studied in the reciprocal hybrids of the eggplant(Solanum melongena L.) and S. aethiopicum L. Gilo Group, and in synthetic amphidiploids to discover whether fertility in these reciprocal hybrids was restored by chromosome doubling. Isozyme and RAPD analyses confirmed hybridity of the hybrids and amphidiploids. Analyses of chloroplast and mitochondrial DNAs confirmed that the cytoplasm of each of the hybrids and amphidiploids was from the maternal parent. Pollen sterility of S. melongena × S. aethiopicum Gilo Group [F1 (Mel × Aet)] was restored by chromosome doubling, while the reciprocal hybrid S. aethiopicum Gilo Group ×S. melongena [F1 (Aet × Mel)]and its amphidiploid did not produce any pollen grains; their microspores degenerated without being released from tetrads. Hence the cytoplasm of S. aethiopicum Gilo Group seems to beresponsible for their pollen-non-formation type sterility of the hybrid. Both the F1 hybrids did not set any fruits by either selfing or backcrossing, while their amphidiploids set fruits after pollinating with pollen from the amphidiploid of F1 (Mel × Aet). Seeds obtained from both the amphidiploids germinated normally. Chromosome doubling has been effective in restoring fertility of the hybrids. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

20.
T. Yabuya 《Euphytica》1984,33(2):369-376
Summary Chromosome association at MI of PMCs in hybrids of I. laevigata x I. ensata was examined and compared with that of parental species. The mean chromosome association per cell in the parental species was 0.02I+11.99II for I. ensata (Kachô, 2n=24), 0.11I+15.94II and 0.15I+15.92II for I. laevigata (Yukidôrô and wild type, 2n=32), respectively. On the other hand, the mean chromosome association per cell in the hybrids (2n=28) was 20.22I+3.88II+0.0046IV for Yukidôrô × Kachô and 20.92I+3.54II for wild type × Kachô. Thus, the hybrids indicated a low homology between I. ensata and I. laevigata, and did not exhibit pollen and seed fertility. The utility of the hybrids was discussed.  相似文献   

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