Apomixis And The Reproductive Dynamics Of Eastern Gamagrass Tripsacum Dactyloides L.,
2024
USDA, Agricultural Research Service
Apomixis And The Reproductive Dynamics Of Eastern Gamagrass Tripsacum Dactyloides L., B Kindiger, C L. Dewald
IGC Proceedings (1997-2023)
Studies were conducted to determine the reproductive characteristics of Tripsacum, a perennial, native pasture species and to identify methods for breeding agronomically superior cultivars. Reproductive methods and types of individuals generated were evaluated with triploid and hexaploids possessing a novel method for transferring sexual germplasm into apomictic tetraploids and tetraploid germplasm into sexual diploids. Triploids and hexaploids are demonstrated to be useful materials for introgressing and transferring desirable alleles across ploidy levels and reproductive barriers.
Cytogenetical Studies In Range Grasses Of Iran,
2024
University of Shahid Beheshti
Cytogenetical Studies In Range Grasses Of Iran, M Sheidai, A Tavasoli, P Derakhshandeh
IGC Proceedings (1997-2023)
Cytogenetical and breeding studies of range grasses are in hand. Present article describes preliminary cytogenetical analysis of wheatgrass (Agropyron) and bromegrass (Bromus) taxa (Agropyron trichophorum n = 21, A. pectinoforome n = 21), two different populations of A. repens (n = 28) and Bromus stenostachyus (n = 14). The species varied with regard to chiasma number and distribution. The highest value occurred in A. repens (Mako population). Heterogenity test for the paired samples showed lack of heterogenity for chiasmata indicating homogenity of Agropyron taxa. However a test for ring and rod bivalents showed significant differences …
Direct Selection Response For Stem Rust Resistance In Tall Fescue,
2024
Oregon State University
Direct Selection Response For Stem Rust Resistance In Tall Fescue, R E. Barker, R E. Welty
IGC Proceedings (1997-2023)
Resistance to stem rust (caused by Puccinia graminis Pers.: Pers. subsp. graminicola Z. Urban.) would be beneficial in tall fescue (Festuca arundinacea Schreb.). Two cycles of polycross (PX) selection on progenies from thirty-four parent plants (14 forage-types and 20 turf-types) were compared to one cycle of open pollination (OP) followed by one cycle of PX selection using a 2-stage greenhouse screening process. Response from selection was determined from composite half-sib progenies from each cycle. Number of plants with resistant reaction based on pustule type increased from 5 to 54% in the PX forage-type population and from 6 to 50% …
Assessment Of Grazing Procedures In The Evaluation Of Plant Breeding Material,
2024
Pasture Research Programme, INIA, Uruguay
Assessment Of Grazing Procedures In The Evaluation Of Plant Breeding Material, D Real, I L. Gordon, J Hodgson
IGC Proceedings (1997-2023)
Four stocking densities (2, 3, 5 and 9 sheep/18 m2 for one hour) and two times of grazing (morning or evening) were imposed on a spaced plant nursery of nine red clover (Trifolium pratense L.) populations of varying growth habit, in order to optimize measurement of sheep grazing preference. Plant height, spread and leafiness were measured before and after each of three grazings. Sheep preference was viewed multivariately, using combined measurements of these plant characteristics. MANOVA revealed that the effect of stocking density was significant (P-0.05), but that of time of grazing was not. The plant, population and overall …
Developing Well Adapted Early To Midseason Cultivars Of Trifoiloum Subterraneum Ssp. Brachycalycinum,
2024
South Australian Research Development Institute (SARDI)
Developing Well Adapted Early To Midseason Cultivars Of Trifoiloum Subterraneum Ssp. Brachycalycinum, C T. De Koning, P G.H. Nichols, R L. Tuckwell, N Schubert
IGC Proceedings (1997-2023)
Development and selection of early to midseason cultivars of subterranean clover (Trifolium subterraneum L.) ssp. brachycalycinum has mostly involved the use of early generation selection nursery swards (F2-progeny method). Four sites were sown in the mid-North region of South Australia. At the end of 1995, the top 20 lines from each site had burrs (seed pods) sampled at random. The burr will proceed into the final early generation selection phase (1 - 2 years). Dependent on the site, many lines have out-performed the standard checkplot cultivar, Clare. High hardseed levels have also been incorporated into 1989 crossbreds.
Regeneration Of Somatic Hybrids Between Festuca Arundinacea Var. Glacescens And Lolium Multiflorum Lam.,
2024
Forage Crop Breeding and Seed Research Institute, Japan
Regeneration Of Somatic Hybrids Between Festuca Arundinacea Var. Glacescens And Lolium Multiflorum Lam., T Sasaki, T Hasegawa, S Ueda
IGC Proceedings (1997-2023)
Protoplasts derived from ten suspension cultures of tetraploid Festuca arundinacea var. glaucescens (2n = 4x = 28) and diploid Lolium multiflorum Lam. (2n = 2x =14) were fused to produce somatic hybrids. Regenerated green plants in three fusion combinations were identified as somatic hybrids because they showed characters that were peculiar to both Festuca arundinacea var. glaucescens (hairs on auricle) and Lolium multiflorum Lam. (root-fluorescence). Moreover, the hybrids also had a chromosome number of about forty two.
Breeding Morphogenetic Traits To Match Genotypes To Their Utilization,
2024
INRA Amélioration des plantes fourragères
Breeding Morphogenetic Traits To Match Genotypes To Their Utilization, L Hazard, M Betin, M Ghesquiere
IGC Proceedings (1997-2023)
A divergent selection for lamina length was done from natural populations of perennial ryegrass. Tested in a multi-site experiment in France, the short-leaved perennial ryegrass was more productive under simulated grazing and less productive under infrequent cutting than the long-leaved perennial ryegrass. Matching cultivars to their management is possible by selecting for morphogenetic traits. However, our results suggest the range of adaptation to different managements of perennial ryegrass cultivars could be extended by increasing their phenotypic plasticity.
Improving Forage Productivity By Using Cytoplasmic Male Sterility Of Pearl Millet,
2024
Field Crops Research Institute, Egypt
Improving Forage Productivity By Using Cytoplasmic Male Sterility Of Pearl Millet, A A. Younis, A H. Belal
IGC Proceedings (1997-2023)
Fourteen forage millet hybrids were produced by crossing 7 male fertile lines to 2 different lines of dwarf cytoplasmic male sterile (cms) lines of forage millet (Pennisetum americanum). Hybrids were evaluated with their male parents at the Giza experimental station in summer 1994. The evaluations included fodder yield traits and chemical composition. The objectives of the study were: 1 - to assess hybrid vigor, and 2 - to select the superior hybrids to be used in commercial production in Egypt. Present results showed that the 14 F1 hybrids and their male parents varied significantly in green and dry …
Protogynous Interval In Elephantgrass (Pennisetum Purpureum Schum.),
2024
EMBRAPA, Brazil
Protogynous Interval In Elephantgrass (Pennisetum Purpureum Schum.), A V. Pereira, R B. Barra, J C. Abreu, V De P. Freitas
IGC Proceedings (1997-2023)
A study was carried out to examine the protogyny duration in elephantgrass inflorescences. Nine accessions were selected, divided into three groups, according to early, intermediate or late flowering. From each cultivar, 10 panicles were sampled for evaluation. The criterion for estimating the duration of protogyny was the time interval (number of days) from the first visual detection of exserted stigmas up to the first visual appearance of open anthers (±5%). Duration of protogyny averaged 7.43±1.37 d, confirming that the species is protoginous. Late flowering accessions exhibited an average of 8.97 d for the duration of protogyny, which was significantly higher …
Evolution In Segregating Genotype Mixtures Of Subterranean Clover,
2024
University of Western Australia
Evolution In Segregating Genotype Mixtures Of Subterranean Clover, P.G. H. Nichols, P S. Cocks
IGC Proceedings (1997-2023)
A complex segregating mixture of subterranean clover (Trifolium subterraneum L.), was sown in 1978 at Nabawa and Mt Barker, two contrasting sites in Western Australia. Seed harvested from both sites from 1980-1994 was grown out at Shenton Park in 1995, along with seed of the original mixture. Populations diverged markedly for mean days to first flowering (DFF) within three seasons. No further trends in mean DFF occurred in plants derived from the next 14 years, although standard deviation declined significantly in plants from Mt Barker. Between season differences in mean DFF were correlated with estimated growing season length at …
Prediction Of Seed Yield Of Festuca X Lolium Hybrids From The Nursery Mother Plants,
2024
INRA Amélioration des Plantes Fourragères, France
Prediction Of Seed Yield Of Festuca X Lolium Hybrids From The Nursery Mother Plants, C Mousset, L Hazard, M Ghesquiere
IGC Proceedings (1997-2023)
In order to develop commercial Festuca x Lolium hybrids, their seed production has to be improved. Seed yields of Festuca x Lolium progenies were assessed in dense plots. Prediction of those seed yields was based on the morphological observations done on spaced plants in the nursery of both mother plants and their progenies. The best prediction of the progeny seed yields is a linear regression on the stem density and the seed weight per inflorescence assessed on the mother plants.
Use Of Flow Cytometer In Breeding Festuca X Lolium Hybrids,
2024
INRA Station d’ Amélioration des Plantes Fourragères, France
Use Of Flow Cytometer In Breeding Festuca X Lolium Hybrids, M C. Kerlan, M Ghesquiere
IGC Proceedings (1997-2023)
Ploidy in various generic Lolium - Festuca progenies were assessed by flow cytometry and compared to conventional chromosome counting. In non-segregating triploid and tetraploid progenies, the cytometer estimated so accurately the level of plant ploidy that chromosomes counting would be no use. In segregant progenies, all the tetraploid plants according to the cytometer had effectively 28 chromosomes. Among the triploid and pentaploid plants detected by the cytometer, 40% of the plants were tetraploid. They represented only 29% of the progeny which must be counted. The flow cytometry can be used in routine interspecific breeding programmes. Conventional chromosome counting should be …
Persistency In Lolium X Festuca Hybrid Derivatives And Its Relationships With Flowering Traits,
2024
Station d’Amélioration des Plantes Fourragères, France
Persistency In Lolium X Festuca Hybrid Derivatives And Its Relationships With Flowering Traits, M Ghesquiere, C Mousset
IGC Proceedings (1997-2023)
Using amphiploid and backcrossed derivatives of Italian ryegrass x tall fescue hybrids, the paper emphasizes the interest of introgression vs amphiploidization in breeding for specific traits such as persistency or seed production from tall fescue or ryegrass resp. Persistency in amphiploid and Lolium-introgressed progenies were assessed in nursery together with variation of flowering traits. Persistency was found lower, on average, in introgressed progenies than in hybrid progenies but with enlarged variability within progeny suggesting possible advantageous rearrangements of fescue chromosomes. Although significantly associated, persistency in both populations was only very little affected by the variations in flowering traits such …
Field Evaluation Of Crown Rust In Annual Ryegrass Populations,
2024
University of Florida
Field Evaluation Of Crown Rust In Annual Ryegrass Populations, G M. Prine
IGC Proceedings (1997-2023)
Crown rust (Puccinia coronata [Pers.] Cda.) is the most prevalent disease found on annual ryegrass (Lolium multiflorum L.) of the southeastern USA. Determination of crown rust resistance is difficult because of the erratic nature of infections at most locations. As crown rust is present at Gainesville, FL each year, a rust nursery was designed to evaluate rust resistance and susceptibility of annual ryegrass. Evaluation consists of periodic rust ratings of the seed crop and regrowth of part of each plot after cutting. Nursery results indicate the buildup of rust, including at the date of 90% heading (start of …
Selection Of Interspecific Hybrids Of Brachiaria-A Tropical Forage Grass,
2024
EMBRAPA/CNPGC
Selection Of Interspecific Hybrids Of Brachiaria-A Tropical Forage Grass, C B. Do Valle
IGC Proceedings (1997-2023)
The aim of the breeding program at the National Beef Cattle Research Center (CNPGC) of the Brazilian Corporation for Agricultural Research (EMBRAPA), is to produce vigorous apomictic hybrids with wide edaphic adaptation, good production and nutritive value combined with spittlebug (Homoptera:Cercopidea) resistance. Fiftysix superior hybrids were selected based on visual estimates of vigor, leafiness, tolerance to drought and natural spittlebug infestation in the field. These were characterized for mode of reproduction, spittlebug reaction under controlled conditions and for morphological diversity using nine selected traits. Multivariate analysis classified the population into seven groups where the hybrids were clearly intermediate in plant …
Mitochondrial Genome Polymorphism In Lolium Perenne,
2024
Hokkaido University
Mitochondrial Genome Polymorphism In Lolium Perenne, Y Shimamoto, Y Tominaga, M Sato, T Mikami
IGC Proceedings (1997-2023)
The restriction fragment length polymorphisms (RFLPs) of mitochondrial DNA (mtDNA) of perennial ryegrass (Lolium perenne L.) were investigated to elucidate the genetic relatedness among the 128 cultivars including diploid and tetraploid. Many patterns of RFLPs were observed and allowed assigning of the cultivars into the main eight haplotypes of mitochondrial genome relatedness. The American cultivars were classified into haplotype I and VIII which were remote at the mitochondrial genome from each other, the European ones were distributed to all haplotypes and the tetraploid ones were mostly assigned into the haplotype V. The assessment of mtDNA RFLPs may be a …
Inbreeding Of Some Populations In The Genus Agrostis L.,
2024
Center for Forage Crops, Yugoslavia
Inbreeding Of Some Populations In The Genus Agrostis L., Zorica Tomic, Gordana Surlan Momirovic, Dusica Delic, S Ostojic
IGC Proceedings (1997-2023)
This work presents some properties on produced inbred lines of the 5 best populations of 4 species of Agrostis for breeding purposes. The cultivars of forage grasses should meet a given aim for selection, which is the increasing dry matter and quality. The populations used in this research were the best ones for morphological and productive properties from a previous study. By the process of selfing there have been produced S1 offsprings which appeared to be quite superior in relation to open pollinated offspring from the mother plants. The obtained results were processed by multiple range regression analyses. According to …
The Effect Of Abscisic Acid On The Freezing Tolerance In Lolium Temulentum L.,
2024
Hokuriku National Agricultural Experiment Station
The Effect Of Abscisic Acid On The Freezing Tolerance In Lolium Temulentum L., K Tase, H Fujii
IGC Proceedings (1997-2023)
This study was conducted to clarify the effect of abscisic acid (ABA) on the development of freezing tolerance in Lolium temulentum L. We compared the changes of freezing tolerance and endogenous ABA content by the ABA treatment with those by the hardening treatment. Exogenous ABA applications (7.5 x 10-5 M) increased freezing tolerance, but did not completely substitute for the hardening process. This treatment resulted in great increase in endogenous ABA content, as compared with the control or the hardening treatment. Since the relationship between endogenous ABA content and freezing tolerance was not parallel, it is considered that freezing tolerance …
Introduction Of Vegetative And Reproductive Characters Into Trifolium Repens By Interspecific Hybridisation,
2024
Institute of Grassland and Environmental Research, UK
Introduction Of Vegetative And Reproductive Characters Into Trifolium Repens By Interspecific Hybridisation, A H. Marshall, T P.T Michaelson-Yeates, M Meredith, D H. Hides
IGC Proceedings (1997-2023)
Interspecific hybridization between white clover (Trifolium repens L.) and ball clover (T.nigrescens) and Caucasian clover (T.ambiguum) is a means of improving the reproductive growth and persistency of T.repens. F1 hybrids between T.repens and T.nigrescens were produced without ovule culture and confirmed as true hybrids by chromosome counts, isoenzyme analysis and leaf markers. Their growth habit was generally intermediate between the two parents. After backcrossing to T.repens the BC1 and BC2 hybrids had more of the characteristics associated with T.repens though they retained some of the greater reproductive growth of …
Colchicine-Doubling Of Germinating Seedlings Of Interspecific Wildrye Hybrids,
2024
Utah State University
Colchicine-Doubling Of Germinating Seedlings Of Interspecific Wildrye Hybrids, T A. Jones, D C. Nielson, H Jaussi
IGC Proceedings (1997-2023)
Colchicine has usually been applied to sterile clones of interspecific grass hybrids to restore fertility. However, when hybrids are partially fertile, colchicine can be applied to germinating seedlings. Four populations of Basin wildrye (Leymus cinereus) X beardless wildrye (L. triticoides) were treated with a 0.2% colchicine solution to double chromosome number from 4x=28 to 8x=56. Doubling percentage was 28, 33, 42, and 44% of all root-tips examined for the four populations. When plants without doubled sectors were discarded, doubling percentage increased to 56, 68, 78, and 78%. Plants with doubled sectors have been placed in crossing blocks …
