The crossability percentages of 96 bread wheat landraces and cultivars from Japan with rye

Summary Crossability of bread wheat (Triticum aestivum L.) from Japan with rye (Secale cereale L.) was investigated by controlled pollination. No normal seeds were produced, but numbers of shrivelled and small seeds with embryos were used to estimate crossability amongst the 96 accessions, viz: 0–10% (29), 10–30% (23), 30–50% (11), 50–90% (33). The investigation for the pedigrees of varieties with more than 50% crossability percentages showed that the kr alleles of some accessions derived from common ancestors.     

Crossability percentages of some 1400 bread wheat varieties and lines with rye

Summary Two lists are provided: List 1 contains the percentages of crossability with rye of some 1400 varieties and lines of bread wheat; List 2 contains varieties having a high crossability with rye. It is believed that the publication of these data will be helpful to those wishing to cross bread varieties with rye and other species.     

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.     

Crossability percentages of bread wheat collections from Tibet,China with rye

Summary The crossability percentages of 282 accessions of wheat (Triticum aestivum L.) collected in Tibet, China with rye (Secale cereale L.) have been tested. Five collections have a similar to and 277 accessions have a lower crossability percentage than Chinese Spring or are non-crossable with rye. The accessions with high crossability percentage occur along the highway near Lhasa. No landraces with higher crossability than Chinese Spring and rare landraces with similar crossability to Chinese Spring indicated that the landraces in Tibet region are different from those in Sichuan, Shaanxi and Henan provinces in the distribution frequency of high crossability, and there is no distribution of recessive kr4 alleles.     

Crossability of some bread wheat landraces and improved cultivars from western Himalayas with rye

Summary Crossability of 62 bread wheat accessions (14 landraces from Himachal Pradesh and 48 others) was examined with rye. The 3 rye cultivars did not differ in their relative crossability with 4 of the wheat accessions studied. On the other hand, the wheat cultivars differed greatly among themselves in their crossability with rye. Most of the wheat cultivars showed poor (<10%) crossability. Two of the 14 landraces from Himachal Pradesh were found to be free from the crossability inhibitors as they showed very high (>50%) crossability, whereas none of the other 48 cultivars studied was so.     

Crossability percentages of bread wheat landraces from Shaanxi and Henan provinces,China with rye

Summary The crossability percentages of 118 landraces of wheat (Triticum aestivum L.) from Shaanxi and Henan provinces, China with rye (Secale cereale L.) have been tested. 14 landraces possess a higher crossability percentage than Chinese Spring, 30 landraces have a similar to and 74 landraces have a lower crossability percentage than Chinese Spring or are non-crossable with rye. Most landraces with high crossability percentage occur in south part of Shaanxi, and the west and southwest of Henan, their geographical distribution in these regions fits up with that in the Sichuan province.     

Crossability percentages of bread wheat landraces from Sichuan Province,China with rye

Summary The crossabilities of 177 landraces of wheat (Triticum aestivum L.) from Sichuan Basin and its adjacent mountain ranges with rye (Secale cereale L.) have been tested. 16 landraces possess a higher crossability than Chinese Spring, 34 landraces have a similar and 127 landraces have a lower crossability than Chinese Spring or are non-crossable with rye. Most landraces with high crossability occur in Qinling Mountain and Dabashan Mountain Ranges in north of Sichuan and the valleys of Minjiang River, Fujiang River and Jialinjiang River in Sichuan Basin.     

The derivation of compensating translocations involving homoeologous group 3 chromosomes of wheat and rye

Summary The Sr27 translocation in WRT238 was found to consist of chromosome arms 3RS of rye and 3AS of common wheat. An attempt was made to purposely produce compensating translocations having 3RS and a wheat homoeologous group 3L arm. To achieve this, plants, double monosomic for 3R and a wheat homoeologous group 3 chromosome, were irradiated (7.5 Gy gamma rays) or left untreated before being used to pollinate stem rust susceptible testers. Segregation for stem rust resistance was studied to identify F₂ families with Sr27-carrying translocated chromosomes, these were confirmed by means of C-banding. Compensating translocations 3RS3AL and 3RS3BL) were obtained readily and at similar frequencies from untreated and irradiated plants (respectively, 7.2% and 9.3%). Both translocation types have impaired transmission and segregate approximately 3: 2 (present: absent) in the F₂.     

Expression of 17 rye (Secale cereale L.) traits in a range of durum wheat (Triticum durum Desf.) and bread wheat (T. aestivum L.) genetic backgrounds

Summary Expression of 17 rye traits in 24 bread wheat x rye and 8 durum wheat x rye crosses was studied, using a self-compatible, homozygous, dwarf rye. Rye showed epistasis for hairiness on the peduncle in all the crosses of Triticum aestivum and T. durum wheats with rye. Dark greenness of leaves of rye was expressed in all the durum wheat x rye and in some of the bread wheat x rye crosses. Similarly, absence of auricle pubescence, a rye trait, was expressed in most of the durum wheat x rye crosses but not in the bread wheat x rye crosses, indicating the presence of inhibitors for these traits frequently on the D genome and rarely on the A and/or B genome of wheat. Most of the wide hybrids resembled rye fully or partially for intense waxy bloom on the leaf-sheath and for the absence of basal underdeveloped spikelets. Similarly, most of the amphihaploids resembled rye for the anthocyanin in the coleoptile, stem and node. The presence of some inhibitors on A and/or B genome of wheat was indicated in some of the wheat genotypes for the expression of rye traits viz. intense waxy bloom, anthocyanin in node and absence of basal underdeveloped spikelets. Enhancement in the level of expression of the intensity and length of bristles on the mid-rib of the glume of the hybrids might be due to wheat-rye interaction. Less number of florets/spikelet as in rye showed variable expression in different wheat backgrounds. Some other rye traits like absence of auricles, terminal spikelet and glume-awn were not expressed in the wheat background. The expression of some of the rye genes might have been influenced by their interaction with Triticum cytoplasm and/or the environment.     

Spontaneous wheat/rye translocations from female meiotic products of hybrids between octoploid triticale and wheat

Summary Heptaploid hybrids between octoploid triticale and wheat were backcrossed as female parents with wheat to examine the rye chromosome distribution in the resultant progenies using genomic in situ hybridization (GISH). One hundred and one backcross (BC) seeds were examined and whole rye chromosome additions and substitutions, wheat/rye centric and noncentric translocations and rye telocentric chromosomes were detected. Dicentric wheat/rye translocated chromosomes were also observed. Comparisons were made with previous results on the rye chromosome distribution from male gametes of the same cross and differences were found, where in the female derived population a deficit of plants with more than two rye chromosomes was apparent relative to the anther derived population.     

Transfer of the recessive crossability allele kr1 from Chinese Spring into the winter wheat variety Martonvásári 9

Summary The recessive of crossability allele kr1 was transferred from the spring wheat variety Chinese Spring (CS) into the winter wheat variety Martonvásári 9 (Mv9) by backcrossing the Mv9 × CS hybrids with Mv9. The Mv9 variety possesses dominant Kr1 alleles and is heterogeneous at the kr2 locus, so that some individual plants carry recessive kr2 alleles. The selection of plants possessing the recessive kr alleles from the (Mv9 × CS)Mv9 BC₁ generation was carried out according to the seed set achieved when pollinated with rye (Secale cereale L. cv. Mercator). The partial dominance of the Kr alleles made it possible to differentiate between plants heterozygous at the Kr1 locus and Kr1Kr1 homozygous dominant plants. Two selfed consecutive progenies were tested by pollination with rye to select the homozygous recessive kr1kr1kr2kr2 plants and to check the result of the selection after each backcross.As a result of three backcrosses with Mv9 and two selfings after each backcross the selected progenies had 61.6% seed set with rye tested on sixty individual plants. These data confirm that after the third backcross the selected Mv9 kr1 line carries necessive crossability alleles Kr1 and Kr2, but the genotype is 93.75% Mv9.     

Genetic control of esterase-6 isozymes in hexaploid wheat and rye

Summary The EST-6 leaf esterase phenotypes from euploid, nullisomic-tetrasomic and rye chromosome addition and substitution lines of common wheat were determined using polyacrylamide gel electrophoresis. Evidence is presented to demonstrate that Est-6 is a new set of genes, that are expressed in the leaf. The Est-6 gene set were clearly distinguished from the Est-5 genes which are expressed in the grain. The three homoeoallelic loci, Est-A6, Est-B6 and Est-D6, were located on chromosomes 3A, 3B and 3D. An Est-R6 gene was located on chromosome 6R is involved in rye. Some considerations concerning homoeology between homoeologous group 3 of wheat and the rye chromosome 6R are made.     

A gene for hybrid necrosis in an inbred line of rye (Secale cereale L.)

Summary An inbred line of rye (Secale cereale L.) has been found to carry a gene for hybrid necrosis. This gene was detected in crosses with a highly crossable wheat (Triticum aestivum L.) genotype which carries the gene Ne₂. This appears to be the first report of a gene for hybrid necrosis being present in the rye genome.     

The crossing of common wheat (Triticum aestivum L.) with cultivated rye (Secale cereale L.). II. Fertilization and early post-fertilization developments

Summary Fertilization and early seed development was studied in the variety Chinese Spring of common wheat (Triticum aestivum L.) after pollination with rye (Secale cereale L.) and selfing, and in the common wheat variety Hope after selfing. In all three combinations the first pollen tube reached the micropyle in about 40 min after pollination. When pollinated with rye the migration of the sperm nuclei to the egg cell and the polar nuclei was delayed by about an hour. In the subsequent development until 72 hours after pollination the average cellular and nuclear doubling times of embryo and endosperm were about 16 and 8 hours for the interspecific combination. 18 and 9 hours for Chinese Spring selfed and 20 and 12 hours for Hope selfed.     

The site of action of crossability genes (Kr 1, Kr 2) between Triticum and Secale. II. Proportion of pistils containing pollen tubes and effects of alternate pollination on seed set

Summary Different wheat genotypes (T. aestivum) were crossed with rye to ascertain the site or sites of manifestation of the crossability genes, Kr ₁ and Kr ₂. By using fluorescence microscopy, it was found that the order of increasing proportion of wheat micropyles containing pollen tubes is strongly correlated with the levels of crossability with rye. High crossable genotypes have more micropyles containing pollen tubes than those of the low crossable ones. Most of the inhibition or retardation of pollen tubes occurred between the style base and top of the embryo sac, expecially with the low crossable genotypes where both Kr-genes are present. The results also indicate that Kr ₁ is a greater inhibitor than Kr ₂. Seed set is also highly correlated with the number or proportion of micropyles having pollen tubes. Alternate pollinations seem to support the view that rye pollen tubes do not reach the micropyles of the low crossable genotypes, and hence when repollinated with wheat selfed seeds are produced.     

Hybridization barriers between wheat and rye: In vitro pollen assays and electrophoretic survey

Summary Five- to seven-day-old ovaries from Triticum aestivum vars Hope (non-crossable), Chinese Spring (CS, crossable) and the chromosomal substitution line Chinese Spring/Hope 5B (CS/H5B) were used to test the hypothesis that an ovarian substance inhibits rye (Secale cereale var Wrens) pollen tube growth. In vitro assays on a semi-solid medium demonstrated that a soluble, dialyzed lysate from Hope or CS/H5B ovaries inhibited rye pollen tube elongation significantly more than a similar lysate from CS ovaries (26%, 13% and 5% respectively compared to controls). When only the 20 longest tubes from each sample were included in the analysis the relationship was maintained (33%, 22% and 15% for Hope, CS/H5B and CS respectively). Heating the Hope lysate at 100° C for 10 min reduced the inhibition from 26% to 14% for all pollen tubes measured (n = 51 per sample) and from 33% to 20% when only the 20 longest pollen tubes per sample were analyzed. Isoelectric focusing followed by sodium dodecyl sulfate polyacrylamide electrophoresis (IEF/SDS-PAGE) and non-equilibrium pH gradient electrophoresis (NEPHGE) revealed several differences in the polypeptide profiles of soluble lysates from vars Hope, CS and CS/H5B. While two striking differences were observed, a 50 kilodalton (kD) polypeptide with an isoelectric point (pI) of approximately 8.5 and 100 kD polypeptide (pI4) from CS lysates which were considerably reduced in lysates of Hope and CS/H5B, none were obviously associated with the Hope 5B chromosome and therefore cross-incompatibility.Mention of a trademark or proprietary product is for identification only and does not imply a guarantee or warranty of the product by the U.S. Department of Agriculture.     

Plant regeneration from immature inflorescence callus cultures of wheat,rye and triticale

Summary Callus cultures were initiated from inflorescence explants of wheat, rye and triticale on MS medium supplemented with 2 mgl^-1 2,4-D+5% CW or 2 mgl^-1 2,4-D+0.5 mgl^-1 BA. On transfer of the cultures to medium supplemented with 15% CW+0.2 mgl^-1 NAA or 1 mgl^-1 BA+0.1 mgl^-1 IAA, shoot buds and embryoids were produced. Full fledged plantlets obtained on MS medium supplemented with NAA were transferred to the field. Cytological analysis showed the plants to be diploid. However, the regenerated plantlets were shorter, produced fewer tillers and had lower fertility compared to the control.Abbreviations BA Benzyladenine - CW coconut water - IAA indoleacetic acid - NAA -naphthaleneacetic acid - 2,4-D 2,4-dichlorophenoxyacetic acid     

Structure of the isozymes of the AAT-2 and AAT-3 systems of asparate aminotransferase in wheat,rye and triticale

Summary The electrophoretic isozyme phenotypes for the AAT-2 and AAT-3 regions of leaves of Triticum turgidum, T. aestivum, Secale cereale, x Triticosecale (hexaploid) and T. aestivum/ S. cereale 6R addition line are described. The phenotypes varied in distribution and relative intensity of the isozyme bands, which were densitometrically measured. The results are consistent with a hypothesis of the dimeric structure for the AAT-2 and AAT-3 systems.     

In vitro culture variation of wheat and rye caused by genes affecting plant growth habit in vivo

Summary The influence of genes affecting the plant growth habit in wheat (Rht8 and Ppd1) and rye (ct1 and ct2) on tissue culture response was studied using immature embryos. Whereas the semi-dwarfing gene Rht8 seems to promote only a minor effect, the day-length sensitive allele ppd1 determined a major increase in callus growth and regeneration ability. With regards to their tissue culture efficiency, the four alleles studied could be ranked as follows: ppd1>Rht8>rht8>Ppd1.In contrast to wheat, the GA insensitive semi-dwarfing genes of rye (ct1 and ct2) appear not to influence in vitro response.     

Influence of selected wheat and rye genotypes on the direct synthesis of hexaploid triticale

Summary In the synthesis of primary hexaploid triticale, a cross-incompatibility barrier exists when tetraploid wheat (4X) is crossed with diploid (2X) rye. Fertilization may occur, however, abnormal endosperm development usually leads to premature embryo death. Four selected tetraploid wheat lines were crossed as females with seven open-pollinated rye lines and the resulting embryos were rescued in vitro 13–16 days after pollination. The wheat genotypes showed a major influence on crossability (seed set), embryo development and plant recovery. The highest efficiency of amphihaploid plant recovery (18.3 plants per 100 pollinated florets) was obtained from one 4X wheat line originally selected from the cross T. carthlicum × T. dicoccoides. Some of the 3X amphihaploid plants (ABR) derived from two wheat lines showed relatively high level of partial fertility presumably as a result of meiotic restitution. Correlation analysis showed that crossability (seed set), normal hybrid embryo development in vivo and embryo culturability were independent of each other.