Cytogenetics of fertility improvement in artificial autotetraploids of Hyoscyamus niger L.

Genome ◽  
1991 ◽  
Vol 34 (2) ◽  
pp. 190-194 ◽  
Author(s):  
U. C. Lavania ◽  
Sangeeta Srivastava ◽  
J. Sybenga
Keyword(s):  
Seed Set ◽  
Colchicine Treatment ◽  
Tropane Alkaloid ◽  
High Fertility ◽  
Hyoscyamus Niger ◽  
Seed Fertility ◽  
Solanaceous Species ◽  
Selection For ◽  
Quadrivalent Frequency ◽  
Fertility Selection

Genetically stable artificial autotetraploids with over 90% seed set were obtained by colchicine treatment of the solanaceous species Hyoscyamus niger L. (4x = 68). The tetraploids were vigorous and had earlier been shown to yield considerably more tropane alkaloid per individual than the source diploids. The tetraploids had high bivalent frequencies at meiosis, and high fertility as a result of the formation of genetically balanced gametes. There was a systematic and significant decrease in quadrivalent frequency and an increase in bivalent frequency in three subsequent generations tested (C0, C1, C2). Possible causes of high bivalent frequency are discussed. Seed fertility can probably be increased in advanced generations by further selection for fertility and maximization of heterozygosity.Key words: Hyoscyamus niger, autotetraploid, meiosis, bivalents, fertility, selection.

CORRELATED RESPONSE IN BROWN SARSON

1970 ◽  
Vol 12 (4) ◽  
pp. 905-913 ◽  
Author(s):  
T. Swamy Rao
Keyword(s):  
Gamma Irradiation ◽  
Seed Set ◽  
Previous History ◽  
The Self ◽  
Correlated Response ◽  
History Of ◽  
Self Compatibility ◽  
Selection For ◽  
Direction Opposite ◽  
Brown Sarson

The correlated response with changes in self-compatibility in three varieties of brown sarson subjected to gamma irradiation was examined. Selection for improved seed set in the irradiated populations showed that substantial correlated response can result for a constellation of other characters in which the self-compatible and self-incompatible forms differ. The correlated response was in a direction opposite to that of the previous history of selection.

SELECTION FOR SEED SET IN NONINBRED AND PARTLY INBRED POPULATIONS OF ALFALFA

1977 ◽  
Vol 57 (3) ◽  
pp. 873-881 ◽  
Author(s):  
R. MICHAUD ◽  
T. H. BUSBICE
Keyword(s):  
Medicago Sativa ◽  
Seed Set ◽  
Exponential Model ◽  
Seed Setting ◽  
Medicago Sativa L ◽  
Selection For ◽  
Inbred Populations ◽  
The Relationship ◽  
Advanced Generation ◽  
Coefficient Of Inbreeding

Alfalfa (Medicago sativa L.) is a highly heterozygous cross-pollinating species, and most breeding efforts have been conducted on noninbred populations. The purpose of this study was to determine whether greater breeding progress could be made by selecting within partly inbred populations rather than within noninbred ones. One hundred and twenty F1 (noninbred) and 120 S1 (partly inbred) plants that were issued from crossing and selfing four alfalfa clones were evaluated for self-fertility. The most self-fertile 10% of the plants from each family were selected in each population. The selected plants within each level of inbreeding were intercrossed to produce an advanced generation in which the effectiveness of the selection was evaluated. Selection increased both self- and cross-fertility in the advanced generation. Selection was more effective at the F1 level than at the S1 level. Fertility was reduced drastically by inbreeding. The average self-fertility of the S1’s was only about 7% of the cross-fertility of their parental clones. An exponential model was proposed to describe the relationship between seed setting and the coefficient of inbreeding in the developing zygote. This model explained 95% of the variation among 11 unselected populations having differing levels of inbreeding.

INTERSPECIFIC HYBRIDS INVOLVING ALFALFA. VI. INEFFECTIVENESS OF ALLOPLOIDY IN INDUCTION FERTILITY IN MEDICAGO PIRONAE × M. DAGHESTANICA HYBRIDS

1971 ◽  
Vol 13 (3) ◽  
pp. 437-442 ◽  
Author(s):  
K. Lesins
Keyword(s):  
Interspecific Hybrids ◽  
Seed Set ◽  
Interspecific Cross ◽  
Pollen Grains ◽  
Colchicine Treatment ◽  
Plant Meiosis

Colchicine treatment of hybrids from the interspecific cross Medicago pironae Vis. × M. daghestanica Rupr. induced the formation of three tetraploid shoots, one with 2n = 29 and two with 2n = 32, in their somatic nuclei. Their flowers had 21, 44 and 62% plasma-filled pollen, respectively. No seed was obtained from these tetraploids after selfing and intercrossing more than 1,200 flowers, indicating the presence of a built-in fertility barrier between the two species.By applying pollen from the tetraploid hybrids to alfalfa (M. sativn L.) two trispecies hybrids with 2n = 34 and 30 chromosomcs were produced. The first had 32%, the second 22% plasma-filled pollen grains. On backcrossing to M. sativa, a higher seed set was obtained with pollen from the 2n = 34 plant than from the 2n = 30 plant. Meiosis in the 2n = 30 plant was abnormal. At MI multivalents were observed, indicating that chromosomal material may be interchanged between M. pironae-daghestanica and M. sativa. Approximately half the meiocytes at AI possessed lagging chromosomes and only 6% of secondary meiocytes at AII were without disturbances.

Hybrid seed set in wheat is a complex trait but can be improved indirectly by selection for male floral traits

Euphytica ◽  
2018 ◽  
Vol 214 (7) ◽  
Author(s):  
Philipp H. G. Boeven ◽  
Tobias Würschum ◽  
Julia Rudloff ◽  
Erhard Ebmeyer ◽  
C. Friedrich H. Longin
Keyword(s):  
Seed Set ◽  
Complex Trait ◽  
Hybrid Seed ◽  
Floral Traits ◽  
Selection For

scholarly journals Resident ryegrass in hill country pastures

1991 ◽  
pp. 91-95
Author(s):  
M.E. Wedderfsurn ◽  
W.J. Pengelly
Keyword(s):  
Genetic Diversity ◽  
Seed Set ◽  
Moisture Stress ◽  
High Fertility ◽  
Plant Origin ◽  
Relative Growth ◽  
Hill Country ◽  
The Mean ◽  
Low Nitrogen ◽  
New Cultivars

The attributes of 1800 ryegrass plants removed from North Island hill country aredescribed and the implications for oversowing discussed. Morphology was varied but the mean of the population was prostrate and densely tillered, resulting in dense pastures under intensive grazing. Although morphology was not related to the site of plant origin, agronomic response to low nitrogen and moisture stress was. Plants from north-facing steep areas responded least to application of nitrogen or water indicating a low relative growth rate. A probable survival mechanism for moisture-stressed plants is reduced vegetative growth and increased seed set. Response to moisture stress was found to be heritable. In moderate-high fertility steep sites total ryegrass production has not increased after oversowing new cultivars. It is assumed that this is a reflection of the number of niches available for ryegrass exploitation. Our studies show that the strength of existing ryegrass is its genetic diversity and its ability to exploit the various niches present in hill country. The growth and expansion of these ryegfass populations should be actively encouraged. In niches below the optimum for rycgrass growth new species should be introduced. Keywords hill country, perennial ryegrass, morphology, stress, genetics, oversowing, management

scholarly journals Evaluating Rosemary Cultivars for Use as Christmas Tree-shaped Topiaries

HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 860A-860
Author(s):  
Daniel Warnock* ◽  
Charles Voigt
Keyword(s):  
Christmas Tree ◽  
High Fertility ◽  
Greenhouse Production ◽  
Canopy Density ◽  
Commercial Use ◽  
Retail Outlets ◽  
Physical Attributes ◽  
Selection For ◽  
Foliage Quality ◽  
Mechanical Shearing

Greenhouse production of rosemary, Rosemarinus officinalis, as small potted Christmas tree topiaries for holiday sales have become necessary for many companies marketing to large retail outlets. Topiaries must be sheared multiple times to obtain an acceptable Christmas tree shape. Cultivars vary in physical attributes suggesting that they may respond differentially to mechanical shearing during production. This study assessed 16 rosemary cultivars for their potential as potted Christmas tree shaped topiaries. Beginning July 2001, rosemary plants derived from vegetative propagation of shoot tips were grown in a greenhouse with temperatures set at 73/65 °F day/night. Plants were pinched immediately after transplant and provided high fertility and maximum light. From August to October, plants were pruned monthly for a total of three shearing events. The crop was considered mature on the targeted market date of 5 Dec. Final plant quality was visually assessed using a 1 to 5 scale that accounted for plant-to-pot ratio, canopy density, foliage quality, taper, and overall appeal with one point being removed for each factor not meeting industry expectations. The cultivars varied in their performance as Christmas tree shaped topiaries with most being unacceptable. Many of these cultivars had minimal basal branching, perhaps due to selection for use as standard ball shaped topiary performance. Six of the cultivars, `Athens Blue Spire', `Taylor's Blue', `Herb Cottage', `Golden Rain', `Shady Acres', `Rex', and `302100', were suitable for commercial use having visual ratings ranging from 3.8 to 4.5. We suggest that these cultivars be examined for additional attributes that may enhance their performance as Christmas tree shaped topiaries.

scholarly journals Induction and evaluation of colchitetraploids of two species of Tinospora Miers, 1851

2020 ◽  
Vol 14 (2) ◽  
pp. 211-229
Author(s):  
Rakesh Kr. Thakur ◽  
Vijay Rani Rajpal ◽  
Satyawada Rama Rao ◽  
Apekshita Singh ◽  
Lata Joshi ◽  
...  
Keyword(s):  
Genetic Improvement ◽  
Diploid Species ◽  
Colchicine Treatment ◽  
Tinospora Cordifolia ◽  
Cotton Swab ◽  
Crop Species ◽  
Unequal Distribution ◽  
Quadrivalent Frequency

Autotetraploidy, both natural and/or induced, has potential for genetic improvement of various crop species including that of medicinal importance. Tinospora cordifolia (Willdenow, 1806) Miers, 1851 ex Hooker et Thomson, 1855 and T. sinensis (Loureiro, 1790) Merrill, 1934 are two diploid species, which are dioecious, deciduous and climbing shrubs with high medicinal importance. Among the three methods used for induction of polyploidy by colchicine treatment, it was cotton swab method which successfully induced the polyploidy in both species. The morphological and cytogenetical features of the synthetic tetraploids were compared with their diploid counterparts. The tetraploids were morphologically distinct from diploid plants. They exhibited larger organs, such as stem, leaves, inflorescence, fruits, flowers and seeds. The tetraploids were characterized by the presence of low quadrivalent frequency and high bivalent average. Unequal distribution of chromosomes at anaphase I was found in 60% cells. The present study provides important information on the superiority of autotetraploids as compared to diploid counterparts in both species.

FERTILITY OF BARLEY AUTOTETRAPLOIDS: II. THE RELATIONSHIP OF ANEUPLOIDY, DWARFING AND FERTILITY IN FOUR AUTOTETRAPLOID BARLEY VARIETIES

1961 ◽  
Vol 41 (1) ◽  
pp. 124-133 ◽  
Author(s):  
E. Reinbergs ◽  
L. H. Shebeski
Keyword(s):  
Continuous Selection ◽  
The Other ◽  
High Fertility ◽  
Chromosome Distribution ◽  
Apparent Relationship ◽  
Identical Number ◽  
The Mean ◽  
Selection For ◽  
Relationship Of ◽  
The Relationship

A considerable number of dwarf plants (16.4 to 85.7 per cent) was found in C2 to C5 generations of four artificially-induced barley autotetraploids from the varieties OA.C. 21, Brant, York and Montcalm.The Montcalm tetraploid, which was the lowest in mean fertility, had the highest percentage of dwarfs. In the other three tetraploids there was no apparent relationship between the frequency of dwarfs and the mean per cent fertility. In the O.A.C. 21 tetraploid continuous selection for plants with high fertility did not reduce the occurrence of dwarfs.Most of the dwarf plants were aneuploids with 26, 27, 29, 30 or 31 chromosomes, but plants with identical number of chromosomes often showed differences in phenotype. Among the aneuploids 29-chromosome plants were most frequently found. The 26- and 31-chromosome plants were completely sterile. Only a low percentage of the other aneuploid plants produced seed. By considering the observed percentages of dwarf plants and the ratio of hypoploids to hyperploids produced, the largest part of sterility in the four barley autotetraploids could be attributed to irregular chromosome distribution.

Effect of coflowering Mimulus ringens on phenotypic selection on floral traits of gynodioecious Lobelia siphilitica

Botany ◽  
2013 ◽  
Vol 91 (11) ◽  
pp. 745-751 ◽  
Author(s):  
Erica Wassink ◽  
Christina M. Caruso
Keyword(s):  
Seed Set ◽  
Flower Colour ◽  
Phenotypic Selection ◽  
Character Displacement ◽  
Floral Traits ◽  
Competition For Pollination ◽  
Mimulus Ringens ◽  
Potential Competitor ◽  
Selection For ◽  
Presence And Absence

Although interspecific competition for pollination is hypothesized to result in divergence in floral traits (i.e., character displacement), few studies have tested whether selection on these traits differs in the presence and absence of a competitor for pollination. We measured phenotypic selection on floral traits of Lobelia siphilitica L. growing in the presence and absence of Mimulus ringens L., a potential competitor for pollination. Because L. siphilitica is gynodioecious, we estimated selection separately for female and hermaphrodite plants. The presence of M. ringens did not decrease seed set of L. siphilitica. However, the presence of M. ringens did affect selection on daily display size of female L. siphilitica; there was significant selection for smaller daily displays in the absence of M. ringens, but nonsignificant selection for larger displays in the presence of M. ringens. In addition, selection on flower colour did not differ in the presence and absence of M. ringens, but did differ between female and hermaphrodite L. siphilitica. Consequently, our results suggest that the evolution of floral traits in L. siphilitica, but not the evolution of sexual dimorphism in these traits, can be affected by interactions for pollination with M. ringens.

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