Intersubspecific Hybrids Research Articles

Performance of tetraploid progeny derived from 2x–4x intersubspecific crosses in Dactylis glomerata L.

The Dactylis glomerata L. species complex is a genetically diverse group of naturally occurring diploid (2n = 2x = 14), tetraploid (2n = 4x = 28), and hexaploid (2n = 6x = 42) subspecies. The diploid subspecies tend to be geographically isolated and genetically distinct. Each subspecies probably possesses alleles for adaptation to specific environmental regimes. The objective of this research was to evaluate tetraploid progeny from 2x–4x intersubspecific crosses for forage yield and quality relative to their tetraploid parent. Progeny were developed by two stages of hybridization; intra- and inter-subspecific hybrids were generated from 2x–2x crosses, after which selected diploid progeny were mated, as females, to adapted tetraploid genotypes. From 14 2x–4x crosses, utilizing diploids known to produce 2n eggs, 59 tetraploid progeny were identified. These tetraploid progeny and their parents were vegetatively cloned and established in pots in two greenhouses. Forage was harvested from two replicates of each plant in each greenhouse for a total of six cuttings. Vigor, in vitro dry matter digestibility (IVDMD), and neutral detergent fiber (NDF) were determined. Parent–progeny regressions indicated evidence of heritable variation for vigor and IVDMD, but not for NDF. Favorable heterosis (relative to the tetraploid parent) on a family mean basis was significant only for IVDMD in one family. When selection among progeny within families was possible (in six families), favorable transgressive segregants were observed for all traits in at least one family and in a total of five families. The favorable performance of some tetraploid progeny, combined with the diverse nature of the species, indicate that improvements to cultivated orchard grass are possible. Selection at both the diploid and tetraploid levels will be necessary to achieve these goals.Key words: Dactylis glomerata L., gametic nonreduction, heterosis, heterozygosity, orchard grass, polysomic polyploids.

Genetic variation in three subspecies of Melanoplus sanguinipes (F.). I. Morphometric traits

Samples of three subspecies of Melanoplus sanguinipes (M. s. sanguinipes, M. s. vulturnus, and M. s. defectus), raised under the same laboratory conditions, differ significantly in a number of morphometric traits. The heritable nature of these differences was explored by performing intersubspecific crosses, hybrid crosses, and backcrosses. On the whole, the genetics underlying each trait was complex, with the presence or absence of heterosis, of genic interaction, and of maternal effects being dependent on the strains compared and the sex of the insects. Key words: Melanoplus sanguinipes, Acrididae, quantitative genetics, morphometric traits.

Electrophoretic and hybridization comparison of Glossina morsitans morsitans, G. m. centralis, and G. m. submorsitans (Diptera: Glossinidae)

Two colonies of Glossina morsitans morsitans Westwood, two colonies of Glossina morsitans submorsitans Newstead, and one colony of Glossina morsitans centralis Machado, each originating from a different geographic location, were compared genetically and by their ability to hybridize. There were marked asymmetries in results of intersubspecific hybridization. Most F1 males were sterile but most F1 females were fertile. Nei's mean genetic identity (based on 12 loci) and four hybridization indices (based upon proportion of females fertilized, puparia produced per fertilized female, F1 adults per fertilized female, and proportion of females fertilized in backcross experiments) yielded the same results: intrasubspecific similarities are greater than intersubspecific similarities, and G. m. centralis is more similar to G. m. morsitans than it is to G. m. submorsitans. Evidence is presented indicating that a phenogram based upon allele frequencies is as good as phenograms based upon hybridization as a means of representing relationships among tsetse flies.

Aspleniumhybrids in the New Zealand flora

Abstract Nineteen different inter-specific or inter-subspecific Asplenium hybrids occurring naturally in the New Zealand flora are described and illustrated. All produce shrivelled and aborted spores and are therefore thought to be largely sterile. Other hybrid combinations almost certainly occur, especially between different cytotypes of polymorphic species aggregates, but they require cytological detection and cannot be recognised by their morphological characteristics alone. The capacity for hybridisation varies considerably from species to species; some such as A. flaccidum, A. bulbiferum, and A. terrestre hybridise quite frequently, but others such as A. polyodon and A. trichomanes are not known to form hybrids in New Zealand. Possible reasons for this are discussed. Considerable taxonomic complexity results from the remarkable cross-compatibility of New Zealand Asplenium species, but introgressive hybridisation is thought to be of only minor importance due to the sterility of the inter-specific hybr...

A note on the larva and pupa of Mycalesis gotama amamiana Fujioka (Lepidoptera:Satyridae), from Amami Island, and the inter-subspecific hybrid between subsp. fulginia Fruhstorfer and subsp. amamiana Fujioka

A note on the larva and pupa of Mycalesis gotama amamiana Fujioka (Lepidoptera:Satyridae), from Amami Island, and the inter-subspecific hybrid between subsp. fulginia Fruhstorfer and subsp. amamiana Fujioka

Studies of the squirrel monkey, Saimiri sciureus, genome. I. Cytological characterization of chromosomal heterozygosity.

Chromosomal banding analyses have revealed two nonhomologous pericentric inversions in the telocentric group of chromosomes of a squirrel monkey, Saimiri sciureus. This individual is probably an intersubspecific hybrid whose parents originated from different geographical locations. The C-banding pattern shows polymorphism in location and amount of constitutive heterochromatin in at least four pairs of chromosomes. Ammoniacal silver (Ag-AS) staining specific for locating the nucleolar organizers indicates that these are located on only one pair of chromosomes and that there is a difference in the size of the nucleolus organizer regions between the homologs of this pair.

A Systematic Study of the Genus hulsea (Asteraceae)

A systematic treatment based on genetic, biochemical, and morphological studies is presented for the 11 recognized taxa ofHulsea. A uniform diploid complement of 38 chromosomes was found in the 37 populations examined, including all species and representing first reports forH. brevifolia, H. californica, andH. mexicana. Thirteen flavonoid compounds, based on the aglycones quercetin, apigenin, cyanidin, and the 4′-O-methyl ether of luteolin, were detected inHulsea. Patterns of the flavonoid compounds are discussed with respect to the systematic treatment. The results of 595 synthetic crosses indicate thatHulsea species are self-incompatible, relatively cross-compatible, and that their F1 hybrids are relatively fertile. Heterozygosity for one or two translocations is reported for 11 interspecific and intersubspecific hybrid combinations.

New Certation Gene on the First Linkage Group Found by Inter-subspecific Hybridization of Cultivated Rice

In the hybrid progenies between Japanese testers and exotic varieties of rice plants, the segregation-distortions of four marker genes belonging to the first linkage group, wx, dpl, alk and ws, were found. From the genetic behaviors of the four characters in Fr, F,, FI, F, and B,F,, it was concluded that the segregation-distortion was not caused by any of the abnormality of germination of F, seeds, duplication of genes themselves, complementary fertility genes and cytoplasmic factors, but caused by the linkage between the marker genes and a certation gene, gametophyte gene (gad). The recombination value between ga, and wx was calculated on each of the all cross combinations. Based on the linkage intensities, the pollinating ability of ga, against ga: pollen grains at the time of pollination of F1 plants was also calculated. The presence of gametophyte genes shows at least distinct information regarding reproductive isolation, and the fact that the phylogenetic differentiation widely took place in Oryra sativa species.

Gametophyte Genes and Their Loci on the Eleventh Linkage Group of Cultivated Rice

The differential fertilization genes, the gametophyte genes (ga), recognized in the progenies of the inter-subspecific hybridization of rice plants link with the some Japanese marker genes belonging to the eleventh linkage group. The linkage relationships between gametophyte genes(ga2, ga3) and some marker genes such as bc(brittle culm), dl(drooping leaf) and ch(chlorina) were clarified.

A virus complex of subterranean clover

A study was made of subterranean clover plants from areas of New South Wales where clovers were not re-establishing. Eight field isolates of diseased plants were collected in central and southern New South Wales and in the Australian Capital Territory. Mixed infections of strains of subterranean clover stunt virus (SCSV) and a bean yellow mosaic virus (BYMV) were transmitted from the isolates. Four species of aphids, Aphis cvaccivora (Koch), A. gossypii (Glov.), Macrosighum euphorbiae (Thomas), and Myzus persicae (Sulz.), transmitted strains of SCSV and the BYMV and a mixture of these to a number of legumes. Four stable strains of SCSV were separated after a large number of transfers and selections. BYMV was isolated by mechanical inoculation. One Australian cultivar, four Mediterranean introductions, and one intersubspecific hybrid of subterranean clovers were highly resistant to two strains of SCSV and to BYMV. Mixed infection with SCSV and BYMV and infection with one severe strain of SCSV seriously reduced pod formation and seeding in peas and canning beans as well as in subterranean clover.

Autosomal polymorphism due to pericentric inversions in the deer mouse (Peromyscus maniculatus), and some evidence of somatic segregation.

The existence of extensive autosomal polymorphism due to pericentric inversions in a colony of deer mice, Peromyscus maniculatus, has been reported (Arakaki and Sparkes, personal communication). A background of intersubspecific hybridization was suspected to have contributed to the observed polymorphism. The present study describes findings on two separate subspecies, P. m. hollisteri and P. m. bairdii. Autosomal polymorphism existed within each subspecies. In P. m. bairdii, the two polymorphic autosomal pairs were identified. In one pair, a large subterminal element was homologous to an acrocentric of comparable size, while in the other pair, a small mediocentric and an acrocentric were homologous. Among splenic cells of animals made heteromorphic for the larger of the two autosomal pairs, the tendency toward reconstitution of homomorphic cell types was observed. This was taken as evidence of somatic segregation among immunologically competent cells.

Relationship between free amino acids and sterility in rice plant

In order to study the relationship between pollen sterility and free amino acids in the anthers of rice plants, the experiment was carried out. About 60 plants which showed various degrees of sterility caused by haploidy, triploidy, tetraploidy, translocation, asynapsis and F1 hybrid between Indica and Japonica types, were analysed fcr free amino acids, especially for proline, hy paper chromatography. The results were compared with those from about 50 normal plants comprising various species, sub-species and varieties including wild types, Indica types and Japonica types(Tables 1, 2 and 3) . The chromatograms of the anthers from all normal plants had a very distinct yellow spot of proline, which was either lacking or very faint in the chromatograms of the sterile anthers of haploid and asynaptic rice plants. All other serni- and complete-sterile anthers in rice plants, that is, translocation, triploidy, and intersubspecific hybrid, however, gave a highly sterrile remarkable yellow spot of proline in spite of their high sterility of ahthers. From these results, the semi- or complete-sterile anthers except for haploid and asynaptic plants are not necessarily characterized by a lack of proline

Sexual affinity between the lines derived from the intersubspecific hybrid and the ecotypes of rice plant

In a previous paper, the authors reported on the affinity between the lines derived from the intersubspecific hybrid of rice, Oryza sativa L., and their original parents. In short, most of these lines were thought to have returned to Japonica type parent, but some lines differed from their original parents and seemed to become a new type. To elucidate it more thoroughly, the authors produced the F1 hybrids between the 17 lines chosen at random from the progeny of the intersubspecific hybrid and the ecotypes of rice plant, Japanese rice, aus, aman, bulu, tjereh and boro, and investigated their seed fertilities. The results of the investigation lines were divided into two froups, “a” and “b”, according to sexual affinity between thses lines and the ecotypes. The lines of “a” group showed the highest affinity to Japanese rice, and moreover, the affinity to other ecotypes were similar to that between Japanese rice and other ecotypes. The authors considered form these results that the lines belonging to “a” group had returned to Japonica type parent. Three lines of “b” group were, on the other hand, thought to belong to intermediate tyoe grouped by morinaga, as they showed considerably high affinity to all ecotypes. They, however, differed from one another, and also differed from aus and bulu which were typical intermediate type. It gives us much interest in understanding the phylogenetic differentiation of cultivated rice varieties that the intermediate type was produced experimentally from Japonica-Indica hybrid.

Correlations between varietal hybrid sterility and tetraploid sterility in rice plants.

It is a well known fact that the hybrid sterility is not found frequently in rice when Japonica type varieties are crossed with Indica type ones.. On the other hand, it is also known that the sterility occurs in tetraploid plants when diploids are artificially doubled in chromosomes. In the previous paper. MASIMA reported with UCHlYAMADA about some relationships between the two types of sterility and concluded that the fertility of subspecific hybrids, showing high sterility in diploid level is recovered in some degree when they are doubled to the tetraploid level (MASIMA and UCHIYAMADA 1955). This reason was considered due to the selective pairing among the four homologous chromosomes which have small structural differences between the two original varieties. Here another brief report is given as we recognize.d the same conclusions by a successive experiment using new materials. Tetraploids were newly induced in 38 Iines using 11. other varieties. They are grouped in to four different kinds of tetraploids, originated from simple varieties, fertile varietal hybrids (intra-subspecific hybrids), semisterile ' varietal hybrids (inter-subspecific hybrids) and sterile varietal hybrids (inter-subspecfic hybrids) .

Sexual affinity of F<SUB>1</SUB> hybrid between new lines from japonica-indica intersubspecific hybrids and their original parents.

1) To ascertain the sexual affinity of the new lines obtained from the japonica-indica intersubspecific hybrid of rice, 27 strains corresponding to Fll and F12 were crossed to their original parents. 2) 133 F1 plants from 17 strains crossed to japonica parent and 172 F1 plants from 23 strains to indica parent were grown, and the seed fertility of each F1 plant was determined for three strong panicles. The results were tabulated in table 1, as the values of max. min. and mean seed fertility with their variances and grain shape index. 3) Sexual affinitie, s of those newly tested lines were r6ughly grouped into two ; one group, having 26 lines, showed strong affinity to japonica type parent and weaker afiinity to indica type parent, in the former case the mean seed fertility of F1 was higher than 85%, but in the later case it remained below 45% The other group, represented by only one line, showed on the contrary weak affinity to japonica parent, that is 52% seed fertility, and strong affinity to indica parent namely 87% seed setting. Such relationship is clearly represented in fig. 1 and 2.

Observations on some characters in F2 and F3 of induced inter-subspecific tetraploid rice, with special reference to the sterility and nurnber of spikelet per ear compared with autotetraploid.

Four highly fertile tetraploid rice plant were sent to the autlllor in the spring of 1951 from Dr. Luong Dirih Cua. Which were produced by colchicine treatment of the highly sterile inter-subspecific hybrid Sekitori (Japonica) xKonanto (Indica). In the same year 341 F2 plants were reared from these F1 plants in our experimental farm by the ustial transplanting method. Such important practical characters as date of heading, culm height. panicle length, number of ears per plant, number of spikelet per ear, and percentage of sterillity were recorded about all F2 plants. Wide variations were observed among these characters as shown in tables 2-7. 100 F2 piants selected for their larg.e panicle and high fertility were treated in next generation and 360 F3 plants were selected am-ong 82 Iines. Number of spikelet per ear and percentage of sterility were measured about 3-5 ears perplant of the selected F3 plants. These results were compared as in table.s 8, 9, 10 and fig. 1, 2 with those of F2 and autotetraploid plants which were consisted of 30 Iines decended from 5 original stocks discovered by Dr. T. MORlNAGA and E. FUKUSHIMA about 20 years ago. The author discussed briefly from the data obtained that we may be able to hope to use such intersubspecific tetraploid ricefor future breeding materials.

Fertile new lines of rice, Oryza sativa L.selected from the progenies of highly sterile intersubspecific hybrid(japonica x indica) by bulk method.

1. It has been assumed by Japanese rice breeders that it is very hard or almost impossible to obtain superior varieties from, highly sterile intersubspeciflc hybrid(japonica X indica) for their high sterility a, nd complicate segregating behaviors. 2. In this report the writers present one example of obtaining some fertile constant new lines of rice from such highly sterile intersubspecific hybrid by bulk method. 3. The F1 between Murasakimuyozetsuto-japonica type, liguleless, short-grained, non-glutinous, long-awned variety and Koiketsu mochi. indica type, long grained, glutinous, awnless, variety-showed highly vigorous growth habit, but set only 23% fertile grain. 4. The progenies of these F1 plants were reared in bulk ori the relatively small area less than 1/20 acre from F2 to F6 geheration. 5. 45 plants were selected in F6 population and tested their segregating behavior in F7 and F8 generations by pedigree culture. 6. Two families and two single lines were determined to be new constant lines and some characters of these lines such as culm length, ear length, panicle number per plant, fertility, length and breadth of unhulled grain, grain, shape, and endosperm character wre tabulated i.n table 1, 2 and 3, with those of their parents and' F1 plants. 7. The writers briefiy discussed on the problem of utilization of such sterile intersubspecific hybrid for future rice breeding.