Effects of homoeologous group 1 and 6 chromosomes of the Cappelle-Desprez (Bezostaya 1) substitution lines on aspects of bread-making quality of wheat

Summary The group 1 and 6 inter-varietal chromosome substitution lines of Cappelle-Desprez (Bezostaya 1) were intercrossed along with the donor and recipient varieties, Cappelle-Desprez and Bezostaya 1, to give 36 genetically different families. The analysis of the means of these families showed that variation in SDS-sedimentation volume fitted a predominantly additive model. There were no significant within or between chromosome interactions among the group 1 and 6 chromosomes. Nor was there any evidence for interactions between these chromosomes and those of the background. Significant dominance/within chromosome interactions amongst the background chromosomes were however detected. Some of the positive effects on SDS-sedimentation were associated with increased grain hardness. Chromosome effects on % grain protein were not correlated with SDS-sedimentation.     

Isolation of a Spontaneous Chromosome Translocation in Common Wheat

The genes Ms2 for male sterility and Rht10 for dominant dwarfing located on the short arm of chromosome 4D in common wheat arc closely linked. Male sterile, dwarf F₁ plants from the cross of male sterile‘Chinese Spring’× dwarf‘Ai-bian’were backcrossed with the variety‘Chinese Spring, From this offspring a spontaneous chromosome translocation was isolated resulting in a recombinant male sterile and dwarf genotype.     

Production and characterization of Raphanus sativus-Brassica rapa monosomic chromosome addition lines

Breeding of Raphanus sativus‐Brassica rapa monosomic chromosome addition lines (MALs, 2n = 19) was carried out by backcrossing the synthesized amphidiploid line, Raphanobrassica (R. sativus×B. rapa, 2n = 38, RRAA, line RA89) with R. sativus cv. ‘Shogoin’ (2n = 18, RR). In the first cross of Raphanobrassica× radish, four sesquidiploidal BC₁ plants (2n = 28, RRA, RA89‐36‐1, RA89‐31‐1, RA89‐31‐2, RA89‐31‐3) were successfully developed. In these plants, the chromosome configurations of 9II + 10I and 10II + 8I were observed frequently at first metaphase (MI) of meiosis in pollen mother cells (PMCs). The RA 89‐36‐1 plant produced many seeds in the reciprocal backcrosses with radish. About 50% of the BC₂ plants obtained from the cross of RA89‐36‐1 plant × radish were 2n = 19 plants, followed by 2n = 18 plants (24%) and 2n = 20 plants (19%). In the reciprocal cross, 2n = 19 plants were also developed at the rate of 40%. From analysis of specific morphological traits, 2n = 19 plants were classified into eight types (a‐h). When 25 selected primers were used in polyacrylamide gel electrophoresis, random amplified polymorphic DNA (RAPD) markers derived from B. rapa for each type of MAL were detected in numbers between three for e‐type and 16 for b‐type. RAPD markers specific for each type alone were from one (OPE 05‐344) for h‐type to nine for b‐type. In the g‐type, no marker specific to this type alone was observed. However, 19 bands were common between at least two types. These MAL plants exhibited predominantly the chromosome configuration of 9II + 1I at MI of PMCs, pollen and seed fertility being the same level as the radish cv. ‘Shogoin’. From the morphological traits and DNA markers, eight different MAL types among 10 expected were identified.     

Chromosome locations of leaf rust resistance genes in selected tetraploid wheats through substitution lines

Langdon durum D-genome disomic substitution lines were used to study the chromosome locations of adult-plant leaf rust resistance genes identified from tetraploid wheat accessions. The accessions are 104 (Triticum turgidum subsp. dicoccum var. arras) and 127 (T. turgidum subsp. durum var. aestivum). The complete sets of the substitution lines were crossed as female parents with the accessions and F₁ double monosomic individuals selected at metaphase I. Segregating F₂ individuals were inoculated during the flag leaf stage with pathotype UVPrt2 of Puccinia triticina. The substitution analysis involving accession 104 showed that the gene for leaf rust resistance is located on chromosome 6B. The analysis with accession 127 indicated that chromosome 4A carries a gene for leaf rust resistance. The two novel genes are temporarily designated as Lrac104 and Lrac127, respectively from accessions 104 and 127.     

Reduced chromosome association between the short arms of 5H homologues in Hordeum vulgare L. at metaphase I

Rod or ring bivalents at metaphase I (MI) reflect whether crossing-over has occurred on one or both pairs of chromosome arms, respectively, during meiotic prophase (pachytene). In cultivated barley ( Hordeum vulgare ) the highest frequencies of rod bivalents were found for satellite chromosomes (either 5H or 6H). To distinguish between chromosome 5H and 6H associations, a recombinant line derived from an H. vulgare × H. bulbosum hybrid with a hemizygous introgression from H. bulbosum on the short arm of chromosome 6H was probed with 45S rDNA and pSc119.2 using fluorescent in situ hybridization and compared with non-recombinant H. vulgare. The frequencies of rod bivalents, caused by failure of the short arms of 5H chromosomes (5HS) to associate during meiosis in the recombinant line, were similar to the frequencies of rod bivalents involving the satellite chromosomes in H. vulgare. Hence, rod bivalent formation in H. vulgare satellite chromosomes is probably based on reduced association of 5HS, corresponding to a low frequency of genetic recombination. 5HS is, therefore, more likely to show linkage disequilibrium than the other chromosome arms.     

Inheritance and chromosomal location of the homoeologous genes affecting phenol colour reaction of kernels in durum wheat

End-use quality of wheat for noodles is influenced by polyphenol oxidase activity and its corresponding substrates. This study investigated the chromosomal location of genes that determine phenol colour reaction of kernels in tetraploid wheat using aneuploid stocks. Polyphenol oxidase activity was estimated by the colour reaction of kernels to phenol solution. It was found that the genes located on homoeologous group 2 chromosomes have an important effect on the level of phenol colour reaction of kernels. The genes (Tc1 and Tc2) responsible for high phenol colour reaction of kernels were mapped to the long arms of chromosome 2A and chromosome 2B, respectively. The map distances were estimated to be 46.8 cM for Tc1 and 40.7 cM for Tc2 from the centromere using double-diltelosomics of durum wheat.     

Identification and breeding behaviour of a major deletion of chromosome 5D ofTriticum aestivum

Summary A study was undertaken to evaluate the breeding behaviour and to identify a spontaneously produced putative chromosomal deletion in the winter wheat (Triticum aestivum L. em. Thell.) cv Norstar. Male and female transmission studies of plants heterozygous for the deletion chromosome indicated 9.5% and 48.8% transmission through the pollen and the egg, respectively. Meiotic analyses of progeny from deletion heterozygotes indicated that the deletion chromosome was eliminated from half of the plants, which agreed with the male and female transmission frequencies. Testcrosses of the deletion chromosome with telocentrics and nullisomic-tetrasomic combinations suggested that the deletion involved the long arm of chromosome 5D. This was confirmed by restriction fragment length polymorphism (RFLP) analysis. Also, monosomic plants obtained in progeny of deletion heterozygotes were shown to be monosomic for 5D. Studies of plants homozygous for the deletion showed relatively normal pairing between the deletion chromosomes, and with the short arm (5DS), but not the long arm (5DL). Deletion homozygotes were self-sterile, and morphologically similar to plants nullisomic for 5D, but plants that also contained 5DL, or a homoeologous chromosome were self-fertile and had normal morphology. Studies of chromosome morphology indicated that the deletion chromosome was metacentric, and the length of the long arm was reduced by approximately 60%. RFLP studies showed that, in terms of genetic distance, 90% of the arm was missing.     

Production of an interspecific hybrid in Gypsophila by ovule-embryo culture

Summary We have succeeded in producing useful interspecific hybrid using ovule-embryo culture between Gypsophila paniculata L. Red Sea and G. manginii, an incompatible combination by ordinary cross breeding methods. The hybrid plant had double flowers with a color of pale purplish pink. Hybrid characteristics of the plant were firmed by observation of plant form, flower type, chromosome number and peroxidase isozyme patterns.     

Utilization of Intervarietal Chromosome Substitutions in Breeding Winter Wheat

Using monosomic lines of wheat cultivars ‘Palur’ and ‘Compal’ as recipient parents as well as disomic substitution lines of chromosomes 5A and 5D of the wheat cv. ‘Atlas 66’, F₃-populations and BC₁′- to BC₃′-populations with limited and free recombination of the 20 and 21 parental chromosomes, respectively, were realized and tested in field trials in comparison to the corresponding recipient cvs. ‘Palur’ and ‘Compal’. F₃- and BC'-populations with the homozygous chromosomes 5A and 5D of the wheat cv. ‘Atlas 66’ expressed higher and more stable grain protein values than the comparable populations with free recombination of the same chromosomes. The grain protein content of populations with limited recombination was significantly increased compared with the recipient cultivars. Some advantages of using intervarietal substitutions in wheat breeding are discussed.     

Chromosome association and pollen fertility in some interspecific hybrids of Lilium

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 1.4_II, 0.8_II and 1.5_II 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.