CHROMOSOME HOMOLOGY AT PACHYTENE IN DIPLOID MEDICAGO SATIVA, M. FALCATA AND THEIR HYBRIDS

1972 ◽  
Vol 14 (4) ◽  
pp. 829-838 ◽  
Author(s):  
K. M. Ho ◽  
K. J. Kasha
Keyword(s):  
Medicago Sativa ◽  
Pollen Fertility ◽  
Meiotic Behaviour ◽  
Pachytene Stage ◽  
Parent Species ◽  
Linkage Studies ◽  
Chromosome Homology ◽  
High Pollen ◽  
Hybrid Plants

One line of diploid M. sativa, two lines of diploid M. falcata and 68 F1 hybrid plants were investigated. The meiotic processes were regular in the F1 hybrids and their pollen fertility was similar to the parent species. The idiograms of the pachytene chromosomes of M. sativa, M. falcata and their F1 hybrid were prepared from a total of 60 cells in which all the chromosomes were analysable. Although the idiograms differed in total lengths their patterns were very similar and indicate that the chromosomes of these lines are essentially identical. Based on meiotic behaviour and high pollen fertility of F1 hybrids and the idiograms at pachytene stage, it was concluded that the chromosomes of M. sativa and M. falcata appear to be homologous. It was suggested that genetical studies of the two species (especially linkage studies) can be combined and that trisomic plants produced from crosses between M. sativa and M. falcata could be used to identify the alfalfa chromosomes.

Interspecific Hybridisation Between Trifolium repens and T. uniflorum

1987 ◽  
Vol 35 (2) ◽  
pp. 171 ◽  
Author(s):  
KK Pandey ◽  
JE Grant ◽  
EG Williams
Keyword(s):  
Pollen Fertility ◽  
Morphological Characteristics ◽  
F1 Hybrids ◽  
Interspecific Hybridisation ◽  
Parent Species ◽  
F1 Hybrid ◽  
Hybrid Plants ◽  
F2 Hybrids ◽  
Fertile Hybrids

Several partially fertile hybrids (2n = 32) were produced by embryo culture from crosses of the type T. repens (2n = 32) female × T. uniflorum (2n = 32) male . The reciprocal crosses, although giving better seed development in vivo, were less successful in producing viable hybrid plants. Backcrosses to both parent species and F2 hybrids were also produced. Hybrid materials were variable with respect to morphological characteristics but broadly within the expected intermediate range. Their root systems were generally coarser and deeper than that of T. repens, offering the prospect of improved resistance to beetle larvae and drought. One F1 hybrid proved to be highly self-compatible, although derived from self-incompatible parent species. Pollen fertility ranged from 0 to 58% for F1 hybrids, 0 to 13% for F2 hybrids, 0 to 84% for backcrosses to T. repens and 0 to 26% for backcrosses to T. uniflorum. Marked seasonal variations in pollen fertility were also observed. Up to two quadrivalent chromosome associations per pollen mother cell were observed at meiosis in F1 hybrids, indicating some intragenomic pairing of T. repens chromosomes. Quadrivalent associations were also observed in an F2 hybrid and three backcrosses to T. repens.

Meiotic behaviour and pollen fertility in sexual and somatic hybrids ofPassifloraspecies

Caryologia ◽  
2003 ◽  
Vol 56 (1) ◽  
pp. 129-137 ◽  
Author(s):  
Marta D. Soares-Scott ◽  
Laura Molina Meletti ◽  
Shirlei M. Recco-Pimentel
Keyword(s):  
Pollen Fertility ◽  
Somatic Hybrids ◽  
Meiotic Behaviour

scholarly journals Pollen Fertility Status in Coastal Plant Species of Rotuma Island

2002 ◽  
Vol 20 (1) ◽  
pp. 30 ◽  
Author(s):  
Reijieli R. Rigamoto ◽  
Anand P. Tyagi
Keyword(s):  
Population Size ◽  
Plant Species ◽  
Pollen Fertility ◽  
Pollen Viability ◽  
Coastal Areas ◽  
High Pollen ◽  
Fertility Status ◽  
Coastal Species ◽  
Wide Range ◽  
Coastal Plant

and Abstract The Island of Rotuma is facing widespread destruction and degradation of its flora. This investigation was conducted to determine the pollen fertility status in thirty two species of economic and environmentally important coastal species, which are reproducing freely thus most suitable to rehabilitate coastal areas. Pollen fertility status in these species varied from as low as 38% in Canavalia cathertica to as high as 100% in Hernandia nymphaeifolia and Vigna marina. It was interesting to note that species within same genus showed wide range of pollen viability. However, most of the species investigated had high pollen viability especially in those species, which grow close to sea. It was recorded that pollen fertility was low in small fragmented populations. This showed the effect of population size on reproduction. Larger sized populations showed high percentage of pollen fertility.

GENETIC DIVERSITY OF CITRUS PLANTS BY SELECTION SIGNIFICANT CHARACTERISTICS

1970 ◽  
pp. 47-51
Author(s):  
R. V. Kulyan
Keyword(s):  
Genetic Diversity ◽  
Pollen Fertility ◽  
Extreme Conditions ◽  
High Quality ◽  
Early Maturity ◽  
High Pollen ◽  
Group A ◽  
Early Ripening ◽  
Citrus Reticulate

This article analyzes the main collection samples of citrus crops, identified forms according to selection characteristics for using existing biodiversity in selective work. In FGBNY VNIIiSK saved collection of citrus (Rutaceae, Aurantioideae, Citrus reticulate, C. limon, C. sinensis, C. paradise, C. maxima, C. medica, C. aurantium, C. junos, C. ichangensis, Genus Fortunella, Genus Poncirus) in the amount of 138 hybrids.Success in creating new forms depends on the presence of a variety of sources of economically valuable characteristics. Recommended in hybridization to include the best sources that have a combination of positive features. For the tangerine group, these are Izeki Wase, Kowano-Wase, Miyagawa Wase, Ochi Wase, September, Jubilee, Glory to Vavilova, Millennium 1, with short stature, early ripeness, early maturity, productivity and high quality of fruits. Sources of winter hardiness and productivity: Sochi 23, Iveria, Unshiu Shirokolistny, hybrid 3252. For the lemon group, a complex of positive characteristics has Lunario, Lisbon, Italian, Dioscuria. In order to create new frost-resistant semi-deciduous hybrids, which can be grown in extreme conditions, was used one of the components of the hybridization: P. trifoliata, C. ×insitorum, C. ichangensis, С. × сitrangeqwat. Сomplex sources of large-fruited, high quality fruits, productivity, pollen fertility are. C. maxima: Natsu mikan and C. sinensis Valensia, which is recommended as paternal forms for the creation of inter-specific hybrids. From all the hybrid type of citrus, which can be used as pollinators to create new combined forms, can be used C. aurantiifolia, C. × meyeri, C. × microcarpa, C. × limonelloides, which have such characteristics as early ripening, stunting, early maturity, and high pollen fertility. Remontancy and high vitality of pollen have C. bergamia, C. medica, C. insitorum, C. restaurantium, C. myrtifolia, and C. × junos.

Meiotic behaviour and pollen fertility in the seventeen Brazilian species of Adesmia DC. (Leguminosae)

Caryologia ◽  
2002 ◽  
Vol 55 (4) ◽  
pp. 341-347 ◽  
Author(s):  
Solange Bosio Tedesco ◽  
Maria Teresa Schifino-Wittmann ◽  
Miguel Dall'Agnol
Keyword(s):  
Pollen Fertility ◽  
Meiotic Behaviour ◽  
Brazilian Species

Low glucosinolate Brassica juncea breeding line revealed to be nullisomic

Genome ◽  
2001 ◽  
Vol 44 (4) ◽  
pp. 738-741 ◽  
Author(s):  
B F Cheng ◽  
G Séguin-Swartz ◽  
D J Somers ◽  
G Rakow
Keyword(s):  
Brassica Juncea ◽  
Interspecific Cross ◽  
Meiotic Behaviour ◽  
Breeding Line ◽  
Pollen Mother Cells ◽  
Chromosomal Segregation ◽  
B Genome ◽  
Hybrid Plants ◽  
Mother Cells ◽  
Metaphase I

The low glucosinolate Brassica juncea breeding line 1058 was derived from a BC1F3 plant of an interspecific cross between high glucosinolate Indian B. juncea (genome AABB, 2n = 36) line 60143 and B. rapa (genome AA, 2n = 20) canola strain CZY. Line 60143 had 2n = 36 chromosomes (18 bivalents at metaphase I) and strain CZY had 2n = 20 chromosomes (10 bivalents). Line 1058 was nullisomic, with 2n - 2 = 34 chromosomes, with 17 bivalents formed at metaphase I and an even chromosomal segregation of 17:17 at anaphase I. In F1 hybrid plants of the cross 1058 × CZY, 98.3% of the pollen mother cells had 10 bivalents and seven univalents. This is evidence that plants of line 1058 are nullisomic, missing one pair of B-genome chromosomes.Key words: low glucosinolate mustard, meiotic behaviour, cytogenetics.

Interspecific hybridization of Medicago sativa L. and M. rupestris M. B. using ovule–embryo culture

1985 ◽  
Vol 27 (2) ◽  
pp. 238-245 ◽  
Author(s):  
T. J. McCoy
Keyword(s):  
Medicago Sativa ◽  
Embryo Culture ◽  
Interspecific Hybrid ◽  
Interspecific Hybrids ◽  
Embryo Rescue ◽  
Culture Method ◽  
Hybrid Plants ◽  
Successful Recovery ◽  
Hybrid Embryo ◽  
Medicago Sativa L

An ovule–embryo culture method was used to produce the first interspecific hybrids between alfalfa (Medicago sativa L.) and Medicago rupestris M. B. Culture of fertilized ovules from the cross diploid (2n = 2x = 16) M. sativa (jpjp) × diploid (2n = 2x = 16) M. rupestris began 14 days after pollination. After 5 days in culture, the interspecific hybrid embryo was removed and transferred to fresh medium, where development into a plant occurred. Forty-six M. sativa – M. rupestris F1 hybrids have been recovered using this technique. All but one of the 46 F1 hybrids were diploid (2n = 2x = 16); the only exception was tetraploid (2n = 4x = 32). The most frequent meiotic configurations observed in the F1 hybrid plants were eight bivalents or seven bivalents and two univalents, indicating significant homology between M. sativa and M. rupestris genomes. However, pollen stainability (0–12%) and pollen germination (0–6%) were extremely low. Similar to the production of the F1, no first backcross (BC1) plants were obtained from seed; however, the ovule–embryo culture method was found to be a very effective method for recovering BC1 plants and hundreds of BC1 plants have been produced. The BC1 plants from crossing the F1 with diploid M. sativa were predominantly diploid. Medicago rupestris can now be considered a potential germplasm source for alfalfa improvement. The ovule–embryo culture method represents the first successful recovery of Medicago interspecific hybrids via some form of embryo rescue. Importantly, it appears this technique can be applied to other interspecific hybrid combinations in the Medicago genus.Key words: Medicago, alfalfa, embryo culture, interspecific hybrid.

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