The effect of in planta TIBA and proline treatment on somatic embryogenesis of sugar beet (Beta vulgaris L.)

The effect of in planta TIBA and L-proline onin vitro seedlings and cell culture of sugar beet was investigated. Sterilized seeds were grownin vitro on 1/2 MS medium supplemented with 0 or3 mg/l TIBA. Calli obtained on young leaves cultured on MS medium containing 1 mg/l BAP, were used for the initiation of cell suspension cultures using MS basal composition supplemented with 0 or 50 mM proline. Aliquots of 1 ml from cell suspension culture were inoculated onto the first somatic embryo induction MS medium containing TIBA 0.5 mg/l, BAP 1.0 mg/l, and proline at 0 or 50 mM. After three weeks of culture, embryogenic calli were transferred to the second embryo induction medium supplemented with NAA and BAP at 0.2 and 0.5 mg/l, respectively. The frequency of somatic embryos of calli obtained from in plantaTIBA together with proline treatments on average was20 which was higher than that of the other treatments. This revised version was published online in July 2006 with corrections to the Cover Date.     

Cytoplasmic male sterility,resistance to gall mite and mildew,and season of leafing out in black currants

Summary Cytoplasmic male sterility (cms) is described in the F₁ hybrids Ribes × carrierei (R. glutinosum albidum × R. nigrum) and R. sanguineum × R. nigrum. In backcrosses to R. nigrum, progenies with R. glutinosum cytoplasm were either all male sterile, or segregated for full male fertility (F) and complete (S) and partial (I) male sterility. Ratios of F:I+S suggested that two linked genes controlled cms, F plants being dominant for one (Rf ₁) and recessive for the other (Rf ₂).Segregation for cms in relation to three linded genes, Ce (resistance to the gall mite, Cecidophyopsis ribes), Sph ₃(resistance to American gooseberry mildew, Sphaerotheca mors-uvae) and Lf ₁(one of two dominant additive genes controlling early season leafing out) indicated that Rf ₁and Rf ₂were in this linkage group. The gene order and approximate crossover values appeared to be: % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXafv3ySLgzGmvETj2BSbqef0uAJj3BZ9Mz0bYu% H52CGmvzYLMzaerbd9wDYLwzYbItLDharqqr1ngBPrgifHhDYfgasa% acOqpw0xe9v8qqaqFD0xXdHaVhbbf9v8qqaqFr0xc9pk0xbba9q8Wq% Ffea0-yr0RYxir-Jbba9q8aq0-yq-He9q8qqQ8frFve9Fve9Ff0dme% aabaqaciGacaGaamqadaabaeaafaaakeaacaWGdbGaamyzamaamaaa% baGaaiiiaiaacccacaGGWaGaaiOlaiaacgdacaGG0aGaaiiiaiaacc% caaaGaaiiiaiaacccacaGGGaGaamOuaiaadAgaliaaigdakmaamaaa% baGaaiiiaiaacccacaGGGaGaaiiiaiaaccdacaGGUaGaaiOmaiaacs% dacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaaaacaWGsbGaamOzaSGa% aGOmaOWaaWaaaeaacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaiaacc% cacaGGGaGaaiiiaiaacccaaaGaamitaiaadAgaliaaigdakmaamaaa% baGaaiiiaiaacccacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaiaacc% cacaGGGaGaaiiiaiaacccacaGGGaaaaiaadofacaWGWbGaamiAaSGa% aG4maaaa!6E4D!\[Ce\underline { 0.14 } Rf1\underline { 0.24 } Rf2\underline { } Lf1\underline { } Sph3\]. Crossover values of 0.36 for Ce-Lf ₁, and 0.15 for Lf ₁-Sph ₃were estimated from the relative mean differences in season of leafing out between seedlings dominant and recessive for Ce and Sph ₃.It is suggested that competitive disadvantage of lf ₁-carrying gametes and/or zygotes at low temperatures may be implicated in the almost invariable deficit of plants dominant for the closely linked mildew resistance allele Sph ₃. Poor performance of lf ₁- (and possibly lf ₂-) carrying gametes and young zygotes during periods of low temperature at flowering might also account for the liability of some late season cultivars and selections to premature fruit drop (running off).     

Crossability and cytology of hybrid progenies in the cross between Brassica campestris and three wild relatives of B. oleracea,B. bourgeaui,B. cretica and B. montana

Summary Crossability and cytology were examined in F₁, F₂, B₁ and hybridsplants of F₁ hybrids of Brassica campestris and three wild relatives of B. oleracea, B. bourgeaui, B. cretica and B. montana, respectively. The F₂ plants were obtained after self-and open pollination of the F₁ hybrids. The B₁ and hybrid plants were produced after the F₁ hybrids backcrosses with B. campestris and crossed with B. napus, respectively. After crossing the F₁ hybrids, many seeds of the F₂, B₁ and hybrid plants were harvested. Multivalent formation was high in the chromsome configuration for the PMCs of F₂, B₁ and hybrid plants, suggesting that crossing over might occur between them. Many different types of aneuploids were obtained in the progenies of the F₂, B₁ and hybrid plants. It is suggested that different types of normal egg cells may be produced by one-by-one or little-by-little chromosome addition. The possibility is discussed of gene transfer from B. bourgeaui, B. cretica and B. montana, to cultivated plants, B. campestris and B. napus.     

Intergeneric hybrid between Brassica napus and Diplotaxis harra through ovary culture and the cytogenetic analysis of their progenies

Brassica napus (2n = 38) and Diplotaxis harra (2n = 26) were used to investigate gene transfer from D. harra to B. napus. Intergeneric F₁ hybrids (dihaploid 2n = 32 chromosomes) were obtained through ovary culture. The chromosome associations in the first meiotic division was (0–2)_III + (2–10)_II + (12–28)_I. Many seeds were harvested in the F₁ hybrid after backcrossing with B. napus, and from open pollination of the F₁ hybrid. Somatic chromosome numbers of BC₁ and hybrid plants varied from 2n = 26 to 52. In the first meiotic division, high frequencies of bivalent association and relatively low pollen fertility were observed. BC₂ plants generated from the BC₁ plants with 2n = 38 chromosomes, 69.6% showed 2n = 38 chromosomes. Many aneuploids with addition and deletion of chromosomes were also obtained. A bridge plant between B. napus and D. harra with 2n = 32 chromosomes should be valuable material for the breeding of brassica crops.     

Production of intergeneric hybrids between Brassica juncea and Diplotaxis virgata through ovary culture, and the cytology and crossability of their progenies

The cytogenetic study was investigated in the intergeneric F₁ hybrid, F₂and backcross progenies (BC₁). The plants used were Brassica juncea(2n=36) and Diplotaxis virgata(2n=18). Three intergeneric F₁ hybrids between two species were produced through ovary culture. They showed 36 chromosomes. It might consist one genome of B. juncea and two genomes of D. virgata. The morphology of the leaves resembled that of B. juncea. The color of the petals was yellow that was like in D. virgata. The size of the petal was similar to that of B. juncea. The mean pollen fertility was15.3% and the chromosome associations in the first meiotic division were(0–1)_IV+(0–2)_III+(8–12)_II+(12–20)_I. Many F₂ and BC₁seeds were harvested after open pollination and backcross of the F₁ hybrids withB. juncea, respectively. The F₂seedlings showed different chromosome constitutions and the range was from 28 to54 chromosomes. Most seedlings had 38chromosomes followed by 36, 40 and 54. The BC₁ seedlings also showed different chromosome constitutions and the range was from 29 to 62. Most seedlings had both 40and 54 chromosomes followed by 36, 46 and52. In the first meiotic division of F₂ and BC₁ plants, a high frequency of bivalent associations was observed in all the various kinds of somatic chromosomes. Many F₃ and BC₂ seeds were obtained by self-pollination and open pollination of both F₂ and BC₁ plants, and by backcrossing both F₂ and BC₁plants with B. juncea, respectively,especially, three type progeny with 36, 40or 54 chromosomes. The somatic chromosomes of the F₃ and BC₂ plants were further investigated. The bridge plants between B. juncea and D. virgata with 36 chromosomes may be utilized for breeding of other Brassica crops as well as B. juncea. This revised version was published online in July 2006 with corrections to the Cover Date.     

A self-fertile trigeneric hybrid in the Triticeae involving Triticum,Hordeum, and Secale

Summary A self-fertile trigeneric hybrid in the Triticeae involving species from the Hordeum, Triticum and Secale genera has been produced. The trigeneric hybrid was obtained by crossing octoploid triticale (x Triticosecale Wittmack) with octoploid tritordeum (H. chilense × T. aestivum amphiploid). The trigeneric hybrid presented a genome constitution AABBDDRH^ch and 2n=8X=56 chromosomes. The cytogenetical analyses showed no chromosome instability nor homeologous pairing between Hordeum and Secale chromosomes. In the F₂ generation the chromosome number ranged from 42 to 52. Within this range, the plants with smaller numbers of chromosomes were more frequent. A preferential transmission of rye chromosomes could be inferred.     

Potato Virus Y Resistance Gene, Ry chc, Mapped to the Distal End of Potato Chromosome 9

Summary A Japanese leading cultivar ‘Konafubuki’ has an extreme resistance gene Ry _chc to Potato virus Y (PVY) in a simplex fashion. To reduce complexity of the highly heterozygous autotetraploid genome and map the Ry _chc gene, haploid plants were parthenogenetically induced from ‘Konafubuki’. The ratio of 7 resistant: 5 susceptible haploids confirmed the single dominant, simplex genotype of ‘Konafubuki’. A selected resistant haploid 98H20-5 was crossed with a susceptible diploid, resulting in 119 F ₁ plants. Using RFLP and RAPD markers, Ry _chc was mapped to the most distal end of the chromosome 9 where the recovery of recombinant genotypes was extremely reduced in this mapping population possibly due to the linked inferiority factor. The location of Ry _chc is different from those of the other extreme resistance genes to PVY, but possibly resides in one of resistance gene clusters.     

Mapping Co, a gene controlling the columnar phenotype of apple, with molecular markers

The columnar phenotype is a very valuable genetic resource for apple breeding because of its compact growth form determined by the dominant gene Co. Using bulked segregant analysis combined with several DNA molecular marker techniques to screen the F₁ progeny of Spur Fuji × Telamon (heterozygous for Co), 9 new DNA markers (6 RAPD, 1 AFLP and 2 SSRs) linked to the Co gene were identified. A total of 500 10-mer random primers, 56 pairs of selective AFLP primers and 8 SSR primer pairs were screened. One RAPD marker S1142₆₈₂, and the AFLP marker, E-ACT/M-CTA₃₄₆, were converted into SCAR markers designated SCAR₆₈₂ and SCAR₂₁₆, respectively. These markers will enable early selection in progenies where Co is difficult to identify. The Co gene was located between the SSR markers CH03d11 and COL on linkage group 10 of the apple genetic linkage map. Finally, a local genetic map of the region around the Co gene was constructed by linkage analysis of the nine new markers and three markers developed earlier.     

The importance of wild potato species resistant to the potato cyst nematode,Globodera pallida,pathotypes P4A and P5A,in potato breeding. I. Resistance studies

Summary Seven wild diploid potato species, Series Tuberosa, representing 1023 clones were screened for resistance to the potato cyst nematode, Globodera pallida. Over 25% of the clones were resistant to pathotype P₄A and almost 30% were resistant to pathotype P₅A. The resistance in hybrid progenies of these and other resistant species with cultivated potatoes was evaluated, and over 2200 seedlings were screened. High frequencies of resistance (>50%) to P₄A were found in progenies with Solanum leptophyes, S. vernei, S. gourlayi and S. capsicibaccatum, whereas resistance to P₅A was found in these species as well as S. sparsipilum. The importance of nematode resistant wild species for potato breeding is discussed.     

A biosystematic study of the origin of the cultivated diploid potato,Solanum x Ajanhuiri Juz. et Buk.

Summary The origin and nature of the diploid cultivated potato species S. ajanhuiri Juz. et Buk. was studied. Several lines of evidence indicate that S. ajanhuiri might be derived from natural crosses between primitive cultivars of the diploid species S. stenotomum and the wild species S. megistacrolobum. Morphological comparisons were made between S. stenotomum x S. megistacrolobum F₁ hybrids and naturally occurring S. ajanhuiri to investigate this hypothesis. Comparisons were also made between S. ajanhuiri x S. stenotomum crosses and the F₂ generation of the first-mentioned cross.Crosses between the two major groups of S. ajanhuiri cultivars, Ajawiri and Yari, showed not only genetic breakdown but also a wide range of phenotypic variation similar to those of artificial F₂ families of S. stenotomum x S. megistacrolobum. Furthermore, there was strong evidence showing that the Yari group of S. ajanhuiri could almost certainly be an F₁ S. stenotomum x S. megistacrolobum hybrid, whereas the Ajawiri group could be a backcross of an F₁ hybrid to S. stenotomum. These results added further support to the hypothesis of a hybrid origin of S. ajanhuiri, as well as indicating its putative parents. It is suggested that this hybridogenic taxon be retained at the species level under the name Solanum x ajanhuiri.     

Trichomes on leaves of Lycopersicon hirsutum,L. esculentum and their hybrids

Summary Density of certain types of trichomes were characterized on leaflets of Lycopersicon hirsutum, L. esculentum and their hybrids. Trichome density covaried with leaflet development, and depending on the species and type of trichome, density also covaried with leaflet surface. Type IV trichomes were not observed on leaflets of L. esculentum and Type V trichomes were not observed on leaflets of L. hirsutum. Type IV and V trichomes were present on F₁ hybrids and densities of these two types of trichomes segregated in the F₂ population. When corrected for differences of leaflet size between L. hirsutum and L. esculentum, densities of Type VI trichomes were more similar between species than uncorrected densities. There was little difference in Type VI density among F₂ individuals. The appearance, lipid and phenol staining properties, and native fluorescence of the multicellular tip of the Type VI trichome differed between L. hirsutum and L. esculentum. F₁ hybrids were intermediate for these characters and these characters segregated in the F₂ generation.The investigation reported in the paper (84-10-94) is in connection with a project of the Kentucky Agricultural Experiment Station and is published with the approval of the Director. This material is based upon work supported, in part, by the U.S. Department of Agriculture, Agreement No. 59-2213-1-1-717-0 (Competitive Research Grants Program).     

Introgression of Cajanus platycarpus genome into cultivated pigeonpea, C. cajan

Summary Cajanus platycarpus, an incompatible wild species from the tertiary gene pool of pigeonpea (C. cajan (L.) Millspaugh), has many desirable characteristics for the improvement of cultivated varieties. To necessitate such transfers, embryo rescue techniques were used to obtain F₁ hybrids. The F₁ hybrids were treated with colchicine to obtain tetraploid hybrids, that were selfed to obtain F₂, F₃ and F₄ progenies. All of the hybrids and subsequent progenies had an intermediate morphology between the two parents. Backcrossing of the tetraploid hybrids with cultivated pigeonpea was not possible given embryo abortion, with smaller aborted embryos than those obtained in the F₀ parental cross.As a route of introgression, diploid F₁ hybrids were backcrossed with cultivated pigeonpea and BC₁ progeny obtained by in vitro culture of aborting embryos. BC₂ plants were obtained by normal, mature seed germination. Although embryo rescue techniques had to be used to obtain F₁ and BC₁ plants, it was possible to produce BC₂ and subsequent generations through direct mature seed. Every backcross to cultivated pigeonpea increased pollen fertility and the formation of mature seeds.Special project assistant till December, 2003.     

Interspecific cross of Brassica oleracea var. alboglabra and B. napus : effects of growth condition and silique age on the efficiency of hybrid production, and inheritance of erucic acid in the self-pollinated backcross generation

Interspecific hybrids were produced from reciprocal crosses between Brassica napus (2n = 38, AACC) and B. oleracea var. alboglabra (2n = 18, CC) to introgress the zero-erucic acid alleles from B. napus into B. oleracea. The ovule culture embryo rescue technique was applied for production of F₁ plants. The effects of silique age, as measured by days after pollination (DAP), and growth condition (temperature) on the efficiency of this technique was investigated. The greatest numbers of hybrids per pollination were produced under 20°/15°C (day/night) at 16 DAP for B. oleracea (♀) × B. napus crosses, while under 15°/10°C at 14 DAP for B. napus (♀) × B. oleracea crosses. Application of the ovule culture technique also increased the efficiency of BC₁ (F₁ × B. oleracea) hybrid production by 10-fold over in vivo seed set. The segregation of erucic acid alleles in the self-pollinated backcross generation, i.e. in BC₁S₁ seeds, revealed that the gametes of the F₁ and BC₁ plants carrying a greater number of A-genome chromosomes were more viable. This resulted in a significantly greater number of intermediate and a smaller number of high-erucic acid BC₁S₁ seeds.     

The crossing of common wheat (Triticum aestivum L.) with cultivated rye (Secale cereale L.). I. crossability,pollen grain germination and pollen tube growth

Summary The crossing of common wheat (Triticum aestivum L.) with rye (Secale cereale L.), and especially the action of the crossability genes of wheat, was studied using the readily crossable wheat cv Chinese Spring (genotype kr ₁ kr ₁ kr ₂ kr ₂ >), the poorly crossable wheat cv Hope (genotype Kr ₁ Kr ₁ Kr ₂ Kr ₂ ), as well as the disomic substitution line of chromosome 5B of Hope into Chinese Spring (CS/Hope 5B, genotype Kr ₁ Kr ₁ kr ₂ kr ₂ ). By comparing crossability and actual fertilization, the poor crossability with rye of both cv Hope and the CS/Hope 5B substitution line was shown to result from absence of fertilization. Studies of pollen grain germination and pollen tube growth showed that the dominant alleles of the crossability genes manifested themselves through retardation and eventually inhibition of pollen tube growth at the style base and in the ovary wall. In Hope the growth of all pollen tubes was inhibited, whereas in CS/Hope 5B rarely fertilization was achieved. The recessive alleles of the crossability genes do not seem to have an influence on the growth of rye pollen tubes in wheat pistils.     

Comparison of near-isogenic lines for anthracnoseAre are genes in common bean,Phaseolus vulgaris L.

Summary This study was undertaken to determine whether the Are gene controlling anthracnose resistance had an adverse effect on maturity and yield because backcross-derived cultivars/lines had numerically lower yield and later maturity than the respective recurrent parent. Three pairs of common bean lines near-isogenic for theAre gene were developed fromAre are F₂ plants of the sixth backcross of Seafarer, Fleetwood, and Ex Rico 23. The near-isogenic lines were tested along with the recurrent cultivars and backcross-derived cultivars/lines. The results showed no evidence of any adverse effect of theAre gene on the agronomic characteristics in 11 trails at 5 locations in 3 years.     

Molecular markers linked to the <Emphasis Type="Italic">fin</Emphasis> gene controlling determinate growth habit in common bean

The S-genotypes of 16 apricot (Prunus armeniaca L.) cultivars native to China were determined by the S-allele PCR approach and the results were confirmed by cross-pollination tests among these cultivars. Primer combination EM-PC2consFD + EM-PC3consR, based on the conserved regions C2 and C3 of Rosaceous S-RNase genes, was the most useful primer combination for identifying Chinese apricot S-alleles. Twelve S-RNase alleles were identified using this primer combination, and they were defined as follows: S ₉ was 657 bp, S ₁₀ was 266 bp, S ₁₁ was 464 bp, S ₁₂ was 360 bp, S ₁₃ was 401 bp, S ₁₄ was 492 bp, S ₁₅ was 469 bp, S ₁₆ was 481 bp, S ₁₇ was 487 bp, S ₁₈ was 1337 bp, S ₁₉ was 546 bp and S ₂₀ was 1934 bp. S ₁₁–S ₂₀ were new S-RNase genes deposited in GenBank under accession numbers DQ868316, DQ870628-DQ870634, EF133689 and EF160078, respectively. Our findings contribute to a more efficient breeding program of Chinese apricot and further studies on the S-RNase genes.     

Cytogenetic and morphological characteristics of new types of diploids (2n=22, 24, 40) derived from consecutive selfing of aneuploids in brassica crops

Summary New types of diploids in Brassica crops were synthesized after three consecutive selfing of aneuploids derived from backcrossing of sesquidiploids (2n=29, AAC) with B. campestris (2n=20, AA). The cytogenetic and morphological characteristics of plants with 2n=22, 24 and 40 in the S₃ generation were analyzed in order to establish the extent in which these addition and polyploid lines were stabilized. A high frequency of 11_II (79.7%), 12_II (84.6%) and 20_II (100%), were observed at metaphase _I of pollen mother cells in 2n=22, 24 and 40 plants, respectively. The chromosome configuration at methaphase _II also indicates that a certain level of stability has been attained cytogenetically. Although pollen stainability was relatively high, the seed set percentage was still low. Variation in morphological characteristics indicate the incorporation of one or more chromosome pairs from the C genome of B. oleracea. Other diagnostic characters such as the formation of determinate inflorescence, branching from the base of the stem, and the shift from self-incompatibility to self-compatibility must have resulted from the interaction between A and C genomes. Thus plants with 2n=22, 24 and 40 have been stabilized to some extent and can be developed into new breeding lines of Brassica. It is suggested that limited pollination could be effective in increasing the seed fertility of these plants.     

DNA fingerprinting in soybean (Glycine max (L.) Merrill) with oligonucleotide probes for simple repetitive sequences

Summary Soybean DNA fingerprints were analyzed by digoxigenin-labeled oligonucleotide probes complementary to simple repetitive sequences. The clearest and most polymorphic patterns were obtained with (AAT)₆ as a probe, with which all 47 soybean cultivars tested could be distinguished. However, DNA fingerprints of individuals within cultivars showed the same pattern. Using (CT)₈, (GAA)₅ or (AAGG)₄ as probes, clear polymorphic patterns among cultivars and accessions in the subgenus Soja (Glycine max and Glycine soja) were not observed, while quite different patterns were found in accessions in the subgenus Glycine. The results suggest that G. max and G. soja are closer in their genome structure. DNA fingerprints of reciprocal crosses between cultivars and accessions in the subgenus Soja were similar, and contained bands of both parents. In an F₂ population from these crosses, such bands segregated in a Mendelian fashion.     

Inheritance in Solanum aethiopicum,the scarlet eggplant

Summary Analyses of F₁ and F₂ hybrid progenies from crosses between the ancestral species Solanum anguivi and cultivars of its domesticated derivative S. aethiopicum, have proved the mode of inheritance of prickles, stellate hairs and some other morphological characters and suggested the mode for several more. Most wild-type traits were dominant: many recessive domesticated traits involved imperfect morphogenesis suggesting loss of genetic control. F₁ hybrids between cultivars show marked heterosis and are recommended for crop production.     

The importance of wild potato species resistant to the potato cyst nematode,Globodera pallida,pathotypes P4A and P5A,in potato breeding. II. The crossability of resistant species

Summary Over 2400 pollinations were made to investigate the crossability relationships between cultivated potatoes, and wild diploid species from Series Tuberosa and Circaeifolia, as well as wild polyploid species in Series Tuberosa and Longipedicellata resistant to potato cyst nematode, Globodera pallida pathotypes P₄A and P₅A. Wild diploids in Series Tuberosa crossed easily with cultivated diploid species, except with Solanum lignicaule where most pollinations failed, and seed set was extremely low (0.2 seeds per pollination or less). It is suggested that this species is 1EBN. S. capsicibaccatum is clearly isolated from Series Tuberosa, but can form hybrids with S. lignicaule, which can act as a bridging species to S. tuberosum haploids. S. gourlayi and S. oplocense can be crossed with both subspecies of S. tuberosum, but S. papita, Series Longipedicellata is reproductively isolated from the tetraploid cultigens. The crossability data are discussed in the light of germplasm utilisation for breeding potato varieties resistant to potato cyst nematode.