Physical Sciences and Mathematics Commons^™

The Genetic Improvement Of Panicum Maximum Jacq. For The Seed Production, M Noirot

IGC Proceedings (1977-2023)

The genetic improvement of P.maximum for the seed production is based on two features : the number of spikelets and, especially, the number of every-day new panicles. With this purpose, we have set a topcross between an apomictic and four sexuals. The floral behavior is split into three independant factors and the heritabilities are estimated for this ones. This study has led to the choice of suitable methods of selection.

Isolation Of Sexual Plants In Guineagrass And The Potential Of Its Hybridization Breeding In Japan, K Nakajima

IGC Proceedings (1977-2023)

Guineagrass (Panicum maximum J acq.) is the most promising warm-season grass in the southwest areas of Japan, but its cultivation is limited because of its slow growth at initial growth stage and low seed-yield. As the mode of reproduction o( this grass is apomixis, its genetic improvement is restricted to selection or induced mutation. Sexual plants were screened in two trials to develop the hybridization breeding. In the second survey, 15 completely sexual accessions were isolated by embryo sac analysis from new African collections. They were added to 4 completely sexual plants, already obtained in the first survey, as …

Improvement Of Range Grasses Through Interspecific Hybridization With Quackgrass (Elytrigia Repens L. Neveski), K H. Asay, D R. Dewey

IGC Proceedings (1977-2023)

The USDA-ARS at Logan, Utah has developed breeding populations from hybrids between quackgrass [Elytrigia repens (L.) Nevski] and several range grasses of the tribe Triticeae. The most promising of these is the quackgrass X bluebunch wheatgrass [Pseudoroegneria spicata (Pursh) Love] hybrid (designated RS). The RS hybrid was only partially fertile, meiotically irregular, and of limited agronomic merit in the F1 generation. However, after eight generations of selection, it is as fertile as the parental species and has responded in a positive manner to selection pressure for degree of rhizome development, forage yield, vegetative vigor, and plant type. It …

Development Of Chromosome Substitution Triticale Lines And Their Utility Value As Feed, M Sasaki, Y Yasumuro, N Nakata

IGC Proceedings (1977-2023)

An effective method for producing chromosome substitutional triticale lines was proposed. Selection was made on hypoaneuploid plants from primary octoploid triticale population by use of the nature of spontaneous chromosome elimination owing to its meiotic instability. Five lines selected by this method were tested for their performance as grain feed and supplemental forage to other triticale, wheat, rye and barley cultivars. The selected lines S78 and S591 produced higher grain yield than other small grains, though not significant with other triticale cultivars. Lysine contents of the selected lines were intermediate between parental crops. S78 was the most promising line having …

Breeding Tropical Grasses For Ease Of Vegetative Propagation And For Improved Seed Production, J B. Hacker

IGC Proceedings (1977-2023)

Four case studies are briefly described in which seed production or ease of propagation of tropical grasses has been improved by genetic manipulation, viz:

I. Hybridization of a sterile tussock-forming Digitaria smutsii accession with a stoloniferous accession D. milanjiana produced an F1 hybrid which combined high yield with stolon development

ii., iii. Seed production has been successfully introduced into sterile D. smu"tsii and Setaria sphacelata var. splendida iv. Seed production of frost-tolerant Setaria sphacelata var. sericea has been doubled by doubling tiller fertility.

Interspecific Transfer Of Apomixis In Pennisetum, W W. Hanna, M Dujardin

IGC Proceedings (1977-2023)

Apomixis is a vegetative means of reproduction through the seed. It provides an opportunity to increase production, reduce production costs, simplify breeding methods and fix unique gene combinations in many of our major world food crops such as Pennisetum americanum L. Leeke, Zea mays L., and Triticum L. Genes controlling apomixis may not be present in the cultivated species but can be found in related wild species. The long-term objectives of this research are: 1) to transfer genes for obligate apomixis from the tertiary gene pool to pearl millet, a sexual species, and 2) to develop methods and principles that …

Interploidy Transfer Of Germplasm In Red Clover 2n Gametes, R R. Smith, W A. Parroti, M M. Smith

IGC Proceedings (1977-2023)

A program was designed to sexually produce tetraploid red clover, Trifolium pratense L. adapted to the northern zone of the United States using 2n gametes to effectively transfer diploid (2x) germ plasm to the tetraploid ( 4x) level. Both unilateral (2x-4x and 4x-2x) and bilateral (2x-2x) crosses were conducted using diploid parents which produced 2n gametes. Red clover genotypes were isolated which produced an average of 0.21 2n eggs per 1000 and 12 and 16% tetraploids in unilateral and bilateral crosses, respectively. Genotypes were also identified which either produced 2n pollen exclusively or at a high frequency. Tetraploid and fertile …

Methodology And Breeding Of Tetraploid Red Clover, N L. Taylor, E O. Wiseman

IGC Proceedings (1977-2023)

Research is underway to develop tetraploid cultivars of red clover (Trifolium pratense L.) for use in the United States that will be more resistant and higher yielding than presently used diploid cultivars. Cultivars have been produced by use of colchicine, nitrous oxide, and unreduced gametes (2X-4X and 4X-2X crosses). Nitrous oxide treatments have produced up to 71 percent tetraploids which is much higher than that from colchicine (about 4 percent). This nitrous-oxide developed tetraploids population from the cultivar 'Kenstar' has been used as one parent in 2X-4X and 4X-2X crosses. The former yielded a high percentage of tetraploids whereas …

Application Of Ovule Culture To Interspecific Hybridization Between Trifolium Repens And T. Ambiguum, T Yamada, H Fukoka

IGC Proceedings (1977-2023)

The objective of the present study was to apply the ovule culture for the production of interspecific hybrids between Trifolium repens and T. ambiguum. Significant ovary development occurred only when T. ambiguum was used as the female parent. After interspecific fertilization, almost all hybrid ovules fail to develop from about 7th day after pollination. Observation of the growth pattern of hybrid ovules suggests that these should be excised and transplanted to the culture medium by the 5th day after pollination, A medium containing minerals of the minor modified Nitsch (1951), Vitamines (Murashige and Skoog 1962), 7% sucrose, 0.2% Casein …

Chromosome Differentiation In Several Species Of The Genus Melilotus (Sweetclover), F Kita, M Maekawa, K Ise, Y Uehara

IGC Proceedings (1977-2023)

Examining 10 species of the subgenus Micromelilotus, the interspecific cross compatibility is recognized among 5 species, M.infesta, M.macrocarpa, M. messane.nsis, M.segetalis, and M. sulcata. Chromosome behaviors at meiosis of the F1 hybrids reared to maturity are investigated. It is revealed that structural differentiation of chromosomes due to a reciprocal translocation and a complex of paracentric inversions play a significant role in speciation. These basic informations are also useful for sweetclover breeding program using interspecific hybridizations.

The Alfalfa Anthracnose Resistance Success Story, J H. Elgin Jr

IGC Proceedings (1977-2023)

In the past 18 years since anthracnose was first recognized as a serious disease of alfalfa, breeders and pathologists have been highly successful in developing cultivars with high resistance. The availability of these resistant cultivars has resulted in a 10% annual increase in yield in areas of the USA where anthracnose is a problem and has an estimated value in excess of $240 million. This paper reviews the research which contributed to that successful effort.

Breeding Alfalfa For Southern Blight Resistance, S Inami, M Kanbe, F Fujimoto, K Nakashima, Shinji Suzuki

IGC Proceedings (1977-2023)

Difference in disease occurrence was observed in the reaction of seven varieties of alfalfa, Medicago sativa L., to southern blight, Corticium rolfsii, which is an important disease in warm region of Japan. The varieties were tested in space planted condition under inoculation in 1972 and 1973 in Aichi-ken Agricultural Research Center. The correlation coefficient in percentage of the dead plants between the first and the second test was 0.930**, and the varietal difference in analysis of variance for dead plant percentage was highly significant. Based on these results, breeding of resistant alfalfa to southern blight, was started from 1973, …

Key Factors In The Rapid Development And Seed Increase Of Alfalfa With Insect Resistance, W F. Lehman, V L. Marble, M W. Nielson

IGC Proceedings (1977-2023)

The development of alfalfa cultivars with insect and disease resistance and the subsequent seed increase is usually a relatively slow process, but it can be rapid if certain key factors are followed as was done in the development of CUF 101, the first cultivar with resistance to the blue alfalfa aphid (Acyrthosiphon kondoi) (BAA). The BAA was identified as a new, damaging aphid species in about March, 1975. A severely damaged field of a well adapted cultivar was soon located and in April the parent plants of the new cultivar had been selected after a careful, systematic selection …

Some Results Of Selection For Disease Resistance In Herbage Legumes At Svalof, Sweden, Bengt Andersson

IGC Proceedings (1977-2023)

Herbage legumes are very important for forage production in Sweden. One of the main problems when growing red clover and lucerne is their susceptibility to diseases of which the most important are stem nematodes, verticillium wilt, clover rot and root rot. Breeding for improved disease resistance has for a long time been one of the principal objectives in breeding programmes. The first successful result was obtained when a red clover cultivar resistant to stem nematodes was released. By the development of efficient laboratory, screening methods it is nowadays possible to introduce nematode resistance in all new cultivars of red clover …

An Interdisciplinary Approach To Breeding Bloat-Safe Forage Legumes, B P. Goplen, R E. Howarth, G L. Lees, K J. Cheng, W Majak

IGC Proceedings (1977-2023)

This paper reviews the progress of bloat research carried out in Canada over the past 20 years to clarify the etiology of bloat, identify bloat-safe characteristics in forage legumes, and develop techniques to breed a bloat-safe cultivar of alfalfa. To this end a number of research institutions have been involved and a number of diverse and complementary disciplines have contributed.

Mean Aspects Of Lucerne Breeding Work Practiced At The Forage Crop Institute In Lodi, P Rotili

IGC Proceedings (1977-2023)

The choice of mother plants and the progeny test had to be made in dense sward. This proposition is most important chiefly when the construction of the new cultivars concerns an intensive forage system like that of the Northern and Central Italy plains. In these conditions, being possible to control the major part of natural environment factors, the effects of artificial factors introduced by the farmer, become predominant. Among these, the high number of cuttings (six per year) is the most important. The major point for a breeder is to improve the lucerne meadow structure. The choice of the plant …

Heterosis Effect In Advanced Generations Of Synthetic Varieties Of Alfalfa, M Seki, F Fujimoto, S Inami, M Kanbe

IGC Proceedings (1977-2023)

Heterosis effect in advanced generations of synthetic varieties of alfalfa, Medicago sativa L., using component lines bred for one breeding objective and those using unrelated component lines for different objectives was investigated. Heterosis effect in yield in advanced generations of synthetic variety composed of unrelated lines selected from different varieties were higher than that of synthetics composed of lines from the same variety. In synthetics composed of selfed lines, component lines more than 6 seem to be necessary to avoid inbreeding depression. Futhermore, even with parents from maternally selected lines inbreeding would be unavoidable when lines are closely related. Considering …

The Release Process And Initial Adoption Of Andropogon Gayanus In Tropical Latin America, J E. Ferguson, C Sere, R R. Vera

IGC Proceedings (1977-2023)

Following introduction into Colombia in 1973, Andropogon gayanus CIAT 621 has been evaluated within various countries by many institutions and researchers. Between 1981-1985 it has achieved the status of a cultivar by a formal release process within Colombia, Brazil, Panama, Peru and Venezuela as Carimagua 1, Planaltina, Veranero, San Martin and Sabanero, respectively. The release process evolved independently in each country. The decision to release was taken by a single institution, except in the case of Panama. Each country elected to give a different name to an equivalent cultivar. Ample supplies of basic seed generally were made available, especially in …

Domestication Of Phalaris Aquatica As A Pasture Grass, R N. Oram, H E. Schroeder, R A. Culvenor

IGC Proceedings (1977-2023)

The Australian cultivar of phalaris (Phalaris aquatica L.) is a wild Mediterranean population that has been useful for increasing and stabilizing pasture productivity in south-eastern Australia, but it has many deficiencies. This review describes the discovery and exploitation of the genetic variation needed to domesticate and improve the species. Domestication began with the reduction of dimethyltryptamine alkaloids in the herbage. However, the low alkaloid cultivar, Sirolan, is still toxic, possibly due to hypomagnesaemia. The second domestication step is the suppression of seed dispersal. At least four recessive genes and dominance modifiers appear to control the non-shedding trait. These are …

Collecting And Breeding Legumes For Brazilian Tropical Pastures, E M. Hutton, F B. De Sousa

IGC Proceedings (1977-2023)

Brazil has a wealth of native legumes in Stylosanthes, Centrosema and Zomia in soils with pH 4.2-6.5. Collection of those with pasture potential is needed before elimination by agricultural development. Main ecological zones for legume collection include the Cerrados, Amazonia and the Caatinga. Acid-soil factors determining legume adaptation are discussed. Efficient root absorption in the presence of high Al saturation is critical. Increased Ca migration into subsoils through the use of appropriate compounds in needed. Native legumes like Stylosanthes species from areas with pH 4.2-5.4 have potential for oxisols-ultisols. Anthracnose resitance is essential in all Stylosanthes species, and …

Variation In Photoperiodical Response Of Heading In Italian Ryegrass (Lolium Multiflorum Lam.), H Yamaguchi, Shigeru Suzuki

IGC Proceedings (1977-2023)

The response of heading to short day and low temperature has been studied in 48 lines of Lolium species grown under four photoperiod conditions. After fully vernalized in field, materials were grown under four conditions: 24 hours at high and natural temperatures, 13 hours and natural daylength. The number of days from beginning of treatment to flag leaf expansion was recorded. We considered response to short day (RSD), response to low temperature(RLT), and earliness in a narrow sense as three important components controlling heading behavior after vernalization. RSD was measured by difference of the number of days to flag leaf …

A Method Of Accelerating Generation-Cycles In Orchardgrass, F Ikegaya, S Kawabata, S Sato

IGC Proceedings (1977-2023)

advance two generations a year was designed and demonstrated by using two cultivars with different maturity. The method consisted of the following five procedures; 1) growing of seedlings under 24 hr day-length at day/night temperature of 25°C/15°C, 2) floral induction treatment under 10 hr day-length at 10°C, 3) promotion of the period from inflorescence differentiation to seed ripening under 24 hr day-length at the temperature which increased gradually from 15°C to 24°C, 4) air-drying of freshly harvested seeds at room temperature, and 5) breaking of seed dormancy by prechilling at 50°C.

Germinable seeds were obtained from more than 90 percent …

A Dimorphic Pollination System In A Potentially Valueable Semi-Arid Pasture Legume, The Psoralea Patens Complex, E J. Britten, Ian S. Dundas

IGC Proceedings (1977-2023)

A closely related group of leguminous plants in the genus Psoralea has been reported to be potentially useful for pasture in the semi-arid tropics and sub-tropics of Australia. Attempts to produce seed for research purposes were frustrated by seed failure in certain lines while other lines produced seed freely. Examination of meiosis, pollen production and embryo development indicated no abnormality leading to seed failure. Pollination experiments by hand manipulation showed self incompatibility not to be the cause of poor seed set. Close examination of the structure of the flowers disclosed two types of stigmas. The stigmas of the free seeding …

Grass-Legume Associations And Breeding For Yield, L Zannone, R Paoletti, C Scotti, P Jacquard

IGC Proceedings (1977-2023)

The results obtained at the Forage Crops Institute of Lodi concerning binary grass-legume associations are discussed. The experiments were realized either in greenhouse or in field with different techniques. Varieties were grown in association and in pure stand. The nature of inter-specific interference proved to be the same as the intra-specific interference; its interpretation is based on the biological density hypothesis (Rotili, 1979). Within the grass-legume associations situations of competition with overcompensation are created alternatively in favour of one species or the other, depending upon their earliness and biological cycle. The overcompensation effects are cumulated, bringing to an agronomical advantage …

Using Acid Soil Selection To Develop Alfalfa Cultivars, J H. Bouton, M E. Sumner

IGC Proceedings (1977-2023)

Since alfalfa (Medicago sativa L.) is very sensitive to acid soils, it is logical to question whether alfalfa cultivars selected for acid soil tolerance will be as productive as cultivars selected in limed fertile soils when tested under production schemes which exhibit a range of soil pH and fertility conditions, especially in the subsoils. In this paper, the value of acid soil selection for developing alfalfa cultivars productive in both limed and acidic soil profiles are reported. Selection in acid soils was found to be better than selection in limed, fertile soil for developing alfalfa germplasms more productive in …

Competitional Effects Of Neighbor Plants And Genetic Variations In Experimental Populations Of Timothy, Phleum Pratense L., Y Shimamoto, Ch Tsuda

IGC Proceedings (1977-2023)

Genet and Ram et populations of timothy, Phleum pratense L., were raised to investigate the effects of neighbour plants on their growth. The adjoining plants were positively or none correlated in Ramet and negatively or none done in Genet populations in a number of traits. In number of tillers at both the first and second cuts negative and none correlation coefficients between the adjoining plants were observed in Genet and Ramet populations, respectively. Also competitional effects were obviously distinguished in dry weight of Genet population at both first and second cuts. Thus competitional variances for these characters were significantly observed …

Acid-Soil Tolerant Hybrids In The Tree Legume, Leucaena, E M. Hutton

IGC Proceedings (1977-2023)

Leucaena Jeucocephala (Lam.) de Wit is adapted to less acid and alkaline soils. It is potentially valuable for the American tropics, but much of this vast area has low pH soils (oxisols and ultisols) with high Al and low Ca saturations. Adaptation to these conditions needed sources of acid-soil tolerance in Leucaena and a definition of the characters basic to this tolerance. A field trial at Carimagua (Colombian llanos) indicated that subsoil Ca rather than Al was the main factor in Leucaena adaptation. Consequently interspecific crosses mainly between L. leucocephala and acid-soil tolerant L. diversifolia (Schlecht) Benth. Hook. …

Evaluation Of Orchardgrass And Alfalfa For Its Nutritive Value And Voluntary Intake By Neutral Detergent Analysis, T Ishiguri

IGC Proceedings (1977-2023)

A series of trials has been carried out over a ten-year period to determine the ad lib. intake and digestibility of clipped orchardgrass and alfalfa fed at several growth stages to wethers. Forage and feces were fractionated into cell wall (CW) and cell content (CC) with neutral detergent solution, moreover the digestibility and the digestible amount of CW, CC were determined. The changing amount of digestible dry matter (D DM) in grass and legume related to the amount of digestible CC and indigestible CW, whereas digestible CW was observed to have little relation.

orchardgrass varied little between the first cut …

Seasonal Beef Performance On Au Triumph And Kentucky 31 Tall Fescue At Three Fungal Endophyte Infection Levels, J P. Pedersen, S P. Schmidt, C C. King Jr, C S. Hoveland, J A. Mcguire

IGC Proceedings (1977-2023)

Greatly improved performance has been reported from cattle grazing tall fescue (Festuca arundinacea Schreb.) free of Acremonium coenophialum Morgan-Jones and Garns compared to those grazing heavily infected tall fescue. However, cultivar effects and the effects of intermediate infection levels have not been adequately explored. Therefore, a 3-year grazing study was conducted in west-central Alabama to compare beef steer performance on non infected 'AU Triumph' and 'Kentucky 31' tall fescue at three levels of A coenophialum infection. A. coenophialum infection levels of 0% on AU Triumph and 1, 34, and 90% on Kentucky 31 resulted in average daily gains (ADG) …

Effects Of Fluidized Bed Combustion Residue Application To Reclaimed Mine Land On Yield And Composition Of Forage And Performance Of Grazing Steers, K O. Smedley, J P. Fontenot, V G. Allen, H D. Perry, O L. Bennett

IGC Proceedings (1977-2023)

Fluidized bed combustion residue (FBCR), a waste product resulting from the addition of limestone to coal prior to combustion, is high in sulfur (S) and has approximately 50% of the neutralizing capacity of limestone. Research was conducted to study effects of repeated applications of FBCR to pastures on forage yield and composition, and on performance and health of grazing cattle. Three treatments were applied in three replicated .81 ha pastures located on acidic reclaimed land which had been previously mined by mountain top removal. Treatments were control, dolomitic limestone (3380 kg/ha) and FBCR (6760 kg/ha), applied in split applications. Pastures …