scholarly journals Selection based on meiotic behavior in Urochloa decumbens hybrids from non-shattered seed

2020 ◽  
Vol 8 (2) ◽  
pp. 133-140
Author(s):  
Joana Neres da Cruz Baldissera ◽  
Andréa Beatriz Diverio Mendes ◽  
Marlon Mathias Dacal Coan ◽  
Claudete Aparecida Mangolin ◽  
Cacilda Borges do Valle ◽  
...  
Keyword(s):  
Meiotic Behavior ◽  
Viable Seed ◽  
Breeding Programs ◽  
Seed Shattering ◽  
Viable Pollen ◽  
Cultivar Development ◽  
Good Production ◽  
End Products ◽  
Urochloa Decumbens ◽  
Intraspecific Hybrids

This study aimed to evaluate the end-products of meiosis in sexual and apomictic hybrids of Urochloa decumbens, so as to identify genotypes with good production of viable pollen for use in breeding programs to increase yields of pure viable seed and reduce degree of seed shattering. From 457 intraspecific hybrids of U. decumbens arising from crosses between 3 artificially tetraploidized sexual plants and the apomictic cultivar Basilisk, 27 hybrids from non-shattered seed were selected. Slides were prepared by smearing anthers and staining to determine the presence of abnormalities. The abnormalities found were micronuclei, microcytes and polyads. The data were compared by the Scott-Knott test at P<0.05. Data obtained enabled separation of hybrids into 4 groups depending on the presence of micronuclei and formation of polyads and into 6 groups based on the presence of microcytes in the tetrads. Among the analyzed apomictic hybrids, R179 has the attributes for viable seed production to proceed to cultivar development. Among the sexual hybrids, R161, R181, R193 and S47 are recommended as female parents for use in crossing programs.

scholarly journals Influence of Corn (Zea maysL.) Cultivar Development on Grain Nutrient Concentration

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Carla Fernanda Ferreira ◽  
Antônio Carlos Vargas Motta ◽  
Stephen A. Prior ◽  
Carlos Bruno Reissman ◽  
Nicolas Z. dos Santos ◽  
...  
Keyword(s):  
Nutrient Concentration ◽  
High Yield ◽  
High Fertility ◽  
Breeding Programs ◽  
Nutrient Quality ◽  
Cultivar Development ◽  
Zn And Cu In ◽  
Corn Productivity ◽  
Climate Events

While corn productivity has been increased by the adoption of high-yield hybrids, there are concerns that increased grain potential may be associated with diminished grain nutrient concentration. Ten corn (Zea maysL.) cultivars representing five technological levels (landrace variety, commercial variety, and double, triple, and single cross-hybrids) were cropped on a Rhodic Ferralsol Eutric soil with high fertility in 2006 (dry year) and 2007 (normal year) in Rolândia County, Brazil. At maturity, grain was evaluated for concentrations of P, K, Ca, Mg, Fe, Mn, Zn, and Cu. In general, differences among cultivars were noted for all nutrients in both years. Concentrations of P, K, Fe, and Mn were lower in the dry year, while Ca, Mg, Cu, and Zn were higher. Soil water availability appeared to exert more influence on grain nutrient concentration than did cultivar development; nutrient removal due to grain harvest was also greatly influenced by rainfall patterns and their impact on corn productivity. Even though genetic differences were noted, which may be useful to breeding programs, long-term testing in subtropical environments will be required to clarify the interaction between genetics and climate events on grain nutrient quality and exportation.

scholarly journals Trends in Stone Fruit Cultivar Development

2005 ◽  
Vol 15 (3) ◽  
pp. 494-500 ◽  
Author(s):  
David H. Byrne
Keyword(s):  
Public Sector ◽  
Stone Fruit ◽  
Agricultural Chemicals ◽  
Fresh Market ◽  
Breeding Programs ◽  
Global Marketing ◽  
The Public ◽  
Cultivar Development ◽  
World Markets ◽  
The World

Despite the hundreds of existing stone fruit (Prunus spp.) cultivars used for fresh market, there is a continuing need to develop new stone fruit cultivars as the requirements of the industry change. Over the last 20 years there has been a shift toward private breeding as the public sector decreases its support of these long-range programs. As a result there are fewer public breeding programs and many of those still operating protect their releases and partially fund their programs with royalty payments. Other trends that are shaping the development of new stone fruit cultivars are a need for smaller or more easily managed tree architecture, a trend toward the use of fewer agricultural chemicals, the expansion of production zones into the milder winter zones to allow year-round availability of stone fruit, a general diversification of fruit types being marketed, the increased awareness of the health benefits of fruit consumption, the need for better and more consistent quality, and given the global marketing of these fruit the increased need for enhanced postharvest qualities. The breeding programs of the world are responding to these trends and working toward developing the cultivars for the world markets of the future.

Genetic control of cone clusters and precocious flowering in Pinus sylvestris

1969 ◽  
Vol 47 (7) ◽  
pp. 1081-1084 ◽  
Author(s):  
A. H. Teich ◽  
M. J. Holst
Keyword(s):  
Genetic Variation ◽  
Pinus Sylvestris ◽  
Seed Yield ◽  
Normal Cone ◽  
Major Gene ◽  
Viable Seed ◽  
Breeding Programs ◽  
Genetic Studies ◽  
Precocious Flowering ◽  
The Cost

A Scots pine clone bearing cone clusters transmitted precocity to a portion of its progeny resulting from crosses to clones having normal cone distribution. Inheritance appeared to be governed by a single major gene whose expression was dominant or recessive depending upon which clone it was mated to. Differences of reciprocal crosses indicated maternal or cytoplasmic influence. This genetic variation in precocity can be used to reduce the generation interval, thereby facilitating genetic studies and breeding programs. Seed yield per pollination bag was several times greater for cone clusters than for normally distributed cones although viable seed per cone was 20% less. This can reduce the cost of producing hybrid seed if artificial pollination is required.

scholarly journals Dissecting genetic diversity and genomic background of Petunia cultivars with contrasting growth habits

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Yufang Guo ◽  
Ryan M. Warner
Keyword(s):  
Genetic Diversity ◽  
Wild Species ◽  
Growth Habit ◽  
Morphological Variability ◽  
Flower Color ◽  
Genetic Origin ◽  
Breeding Programs ◽  
Cultivar Development ◽  
Growth Habits ◽  
Insight Into

Abstract The cultivated petunia (Petunia ×hybrida) is derived from the progenitor species P. axillaris and P. integrifolia. The hybridization dates back only to the 1830s, though intensive breeding efforts have yielded cultivars exhibiting incredible diversity for many traits, including growth habit, flower color, and flower size. Until now, little is known about the genetic diversity and genomic background of modern cultivars. Here we selected a panel of 13 cultivars with contrasting growth habits and three wild species (the progenitors and P. exserta) to estimate the genomic contribution from the ancestral species and to study whether the variation of the genetic origin could be associated with different breeding programs or morphological variability. Transcriptome sequencing identified 1,164,566 SNPs representing 98.4% (32,451) of the transcripts that cover 99.2% (of 52,697,361 bp) of the P. axillaris transcriptome. Cultivars with an upright growth habit had more homozygous alleles and more P. axillaris-derived alleles than trailing cultivars, while mounded cultivars had intermediate heterozygosity. Unlike previous studies, we found the proportions of alleles derived from each progenitor species varied across cultivars but overall were not biased toward one progenitor species, suggesting diverse selection during cultivar development. For trailing cultivars, alleles potentially introgressed from other wild species (“out” alleles) were enriched. The “out” alleles were clustered in particular regions of chromosomes, suggesting that these regions may be hotspots of introgression. Transcripts in these regions were enriched with gene ontology terms associated with growth habit. This study provides novel insight into the contributions of progenitor species to the genomic background of modern petunia cultivars and identifies genome regions that may harbor genes conferring the trailing growth habit for further exploration.

scholarly journals Analysis of self-fertilization and meiotic behavior of eleven Brazilian triticale cultivars at two sowing dates

2011 ◽  
Vol 11 (2) ◽  
pp. 114-124 ◽  
Author(s):  
Divanilde Guerra ◽  
Marcelo Teixeira Pacheco ◽  
Luiz Carlos Federizzi
Keyword(s):  
Pollen Viability ◽  
Sowing Date ◽  
Meiotic Behavior ◽  
Hexaploid Triticale ◽  
Breeding Programs ◽  
Normal Cells ◽  
Meiotic Analysis ◽  
Mean Values ◽  
Sowing Dates ◽  
Self Fertilization

Eleven Brazilian hexaploid triticale cultivars (2n = 6x = 42), from three breeding programs, were evaluated for their ability of self-fertilization in 2006 and for meiotic behavior, meiotic index and pollen viability at two sowing dates in 2007. High potential of self-fertilization was observed, with values up to 89.52 %. Many irregularities were found in the meiotic analysis, such as the presence of univalents, laggard chromosomes and micronuclei in tetrads, which compromised both meiotic behavior and meiotic index. At the first sowing date, more suitable for normal plant development, overall mean values of 52.68 % for normal cells and 64.95 % for meiotic index were observed. At the second sowing date, less appropriate for the crop, overall means of 52.23 % for normal cells and 58.24 % for meiotic index were obtained. Despite all the irregularities, considerable pollen viability was observed, reaching overall means of 92.08 % and 91.07 % for the first and second sowing dates, respectively.

scholarly journals Performance of 19 Pecan Cultivars and Selections in Southern Georgia

2014 ◽  
Vol 24 (3) ◽  
pp. 407-412
Author(s):  
Patrick J. Conner
Keyword(s):  
Scab Resistance ◽  
Development Programs ◽  
Alternate Bearing ◽  
Department Of Agriculture ◽  
Breeding Programs ◽  
Cultivar Development ◽  
Kernel Quality ◽  
Pecan Scab ◽  
Nut Production ◽  
Southern Georgia

Nineteen pecan (Carya illinoinensis) clones were evaluated over a period of 18 years in a test orchard located in southern Georgia. Clones tested were primarily U.S. Department of Agriculture selections, but two grower-discovered cultivars, Jubilee and Surprize, were also trialed. Annual yields were measured for each tree in the test throughout the test period and the alternate bearing intensity of each cultivar was calculated. Average annual in-shell nut production in years 1–10 ranged from 12 lb in the precocious USDA 76-4-41 to 0 lb in the non-precocious USDA 72-8-4. Wide variation was seen in nut production of trees in years 11–18, averaging from 10 to 60 lb nut yield per year. A subsample of nuts was taken from each tree annually and percent kernel, nuts per pound, specific gravity, and nut volume were determined. Significant differences were found between clones for each of these traits. Differences were also found for the presence of damage from pecan scab [Fusicladium effusum (synonym Cladosporium caryigenum)] and black pecan aphid (Melanocallis caryaefoliae). Most clones were not acceptable for use in Georgia due to small nut size or poor kernel quality, but two clones merit further testing in this region. USDA 70-3-34 produced a large nut with good quality and scab resistance, but needs to be evaluated with mechanical crop thinning to improve kernel quality in high crop-set years. USDA 74-1-12 produced good yields of excellent quality, medium-sized pecans and should be trialed with greater tree numbers. Several other clones were found to have traits of interest to pecan breeding programs including: pecan scab resistance, large nut size, and high kernel percentage. Results of this trial suggest that cultivar development programs in Georgia should place greater selection emphasis on large nut size.

scholarly journals Karyologic and Heterosis Studies of the Artificial Inter- and Intraspecific Hybrids of Viola ×wittrockiana and Viola cornuta

HortScience ◽  
2018 ◽  
Vol 53 (9) ◽  
pp. 1300-1305
Author(s):  
Xiaohua Du ◽  
Mengye Wang ◽  
Aneta Słomka ◽  
Huichao Liu
Keyword(s):  
Seed Germination ◽  
Interspecific Hybrids ◽  
Size Range ◽  
Breeding Programs ◽  
Height Range ◽  
Hand Pollination ◽  
Selection Mechanisms ◽  
Positive Heterosis ◽  
The Given ◽  
Intraspecific Hybrids

An artificial crossing was made between four Viola ×wittrockiana (2n = 48) lines and one Viola cornuta inbred (2n = 26) line as well as among V. ×wittrockiana lines to investigate the cytologic characteristics, fertility, and heteroses of hybrids. The sizes of flowers and stomata and the leaf areas of the V. ×wittrockiana plants were larger than those of the V. cornuta plants. The karyologic stability of V. cornuta was greater than that of V. ×wittrockiana, and ≈20% of individuals in the latter deviated from the given 2n = 48. Capsule setting after interspecies hand pollination ranged from 28% to 94%, and F1 seed germination ranged from 16% to 88%, revealing no obvious pre- or postzygotic selection mechanisms. The chromosome numbers in V. ×wittrockiana × V. cornuta F1 seedlings varied (2n = 34–38), with about half the cells exhibiting the intermediate (2n = 36) value. These interspecific hybrids exhibited positive heterosis in flower size (range, 11% to 66%) and negative heterosis in plant height (range, –12% to –57%). Both of these traits are desirable in pansy breeding programs.

scholarly journals Meiotic behavior of wild Caricaceae species potentially suitable for papaya improvement

2012 ◽  
Vol 12 (1) ◽  
pp. 52-59 ◽  
Author(s):  
Emanuelli Narducci da Silva ◽  
Monique Freitas Neto ◽  
Telma N. S. Pereira ◽  
Messias G. Pereira
Keyword(s):  
Wild Species ◽  
Significant Variation ◽  
Pollen Viability ◽  
Meiotic Behavior ◽  
Breeding Programs ◽  
Meiotic Analysis ◽  
Spindle Fibers

The purpose of this study was to evaluate the meiotic behavior and determine the meiotic index and pollen viability of representative plants of the wild species V. goudotiana, V. quercifolia and J. spinosa. Meiotic analysis confirmed that the species are diploid and have 18 chromosomes. Meiosis was partially normal, since some abnormalities, e.g, sticky and lagging chromosomes, precocious segregation, lack of synchrony, and disturbances in the spindle fibers were observed. These abnormalities resulted in post-meiotic products (monads, dyads, triads, and polyads) that probably contributed to the meiotic index of 85.7 % (V. goudotiana) to 95.9 % (J. spinosa); significant variation was observed in the species V. goudotiana. The pollen viability of 68.0 % (V. goudotiana) to 96.0 % (J. spinosa) was reasonably good in these wild species. Crossings in breeding programs involving V. goudotiana should therefore be carefully planned, since part of the gametes of this species is unviable.

scholarly journals Genealogy of Contemporary North American Lettuce

HortScience ◽  
2007 ◽  
Vol 42 (3) ◽  
pp. 489-493 ◽  
Author(s):  
Mark A. Mikel
Keyword(s):  
Interspecific Cross ◽  
The United States ◽  
Breeding Programs ◽  
Journal Publication ◽  
Cultivar Development ◽  
Plant Variety ◽  
Breeding Populations ◽  
Cultivar Selection ◽  
Variety Protection ◽  
New Cultivars

To determine the genealogy of cultivated lettuce in the United States, a survey was conducted on the pedigree of proprietary and publicly developed lettuce cultivars registered from 1970 through 2004. This was facilitated through information furnished by the U.S. Plant Variety Protection Act, U.S. patent, and journal publication of registered cultivars. In total, there were 328 registered cultivars of which 90.5% (297 cultivars) were from proprietary and 9.5% (31) from public breeding programs. The lettuce cultivars of this era are 61.6% crisphead, 19.5% loose leaf, 13.7% cos/romaine, 4.9% butterhead, and 0.3% latin lettuce types. To facilitate an understanding of current U.S. lettuce germplasm, the most recombined and putatively elite cultivars in the development of new cultivars were identified. The 10 most recombined cultivars were ‘Salinas’ (parent of 28 new cultivars), ‘Calmar’ (27), ‘Vanguard’ (22), ‘Vanguard 75’ (13), ‘Vanmax’ (13), ‘Prize Head’ (12), ‘Parris Island Cos’ (12), ‘Empire’ (11), ‘Great Lakes 659’ (11), and ‘Red Coach 74’ (10). The types of breeding populations used for new cultivar development during this era were two-parent (52% of new cultivars), within cultivar selection (31%), three-parent (7%), backcross two or greater (5%), backcross one (2%), four or more parents (2%), and interspecific cross (1%).

Maize population hybrids: Successful genetic resources for breeding programs and potential alternatives to single-cross hybrids

2007 ◽  
Vol 55 (1) ◽  
pp. 27-36 ◽  
Author(s):  
M. Carena
Keyword(s):  
Genetic Resources ◽  
Germplasm Conservation ◽  
Breeding Programs ◽  
Public And Private ◽  
The Public ◽  
Maize Population ◽  
Cultivar Development ◽  
Single Cross ◽  
Successful Approach ◽  
Single Cross Hybrids

Conservation of maize ( Zea mays L.) genetic resources has been the emphasis of national and international institutions for the benefit of mankind. However, limited resources have been devoted to their adequate exploitation, making genetic resources less useful to the public and private scientific community. As a consequence, public maize breeders have exploited a limited number of heterotic combinations for cultivar development and basic molecular studies while genetic effects are different for different hybrids. Extensive testing of maize population hybrids is a successful approach to choose and improve germplasm sources with high mean performance, useful genetic variability, and excellent combining ability. There is a need to keep applied breeding programs strong in order to link efforts in germplasm conservation with its improvement and utilization.

Sign in / Sign up

Export Citation Format

Share Document