Plant Pathology Commons^™

Basic Aspects, Objectives And Preliminary Results Of A Subterranean Clover Improvement Program In Sardinia (Italy), E Piano

IGC Proceedings (1977-2023)

The process of extended agronomical rehabilitation of the heavily deteriorated pastures, activated in Sardinia in the 1970's, has been largely supported by the introduction of subterranean clover (Trifolium subterranuem L. sensu lato) as a cultivated plant in the island. Although this annual self-reseeding species has readily become the most widely sown pasture legume in Sardinia, the broadscale use of imported varieties has not always been an unqualified success, particularly in terms of long-term persist­ence. Therefore, the need to define clearly the particular combi­nation of characters contributing to adaptation in Sardinia, and to develop local varieties specifically "adjusted" to Sardi­nian …

Yield, Flowering Pattern And Leaf Area Diversity In Macroptilium Atropurpureum (Dc.) Urb., A E. Kretschmer Jr, R M. Sonoda, T C. Wilson

IGC Proceedings (1977-2023)

Macroptilium atropurpureum (DC.) Orb. is a twining tropical forage legume. The only commercial cultivar, Siratro, has been tested worldwide in the tropics and subtropics (Krestschmer, 1972; Kretschmer et al., 1985). Since the genetic base for this hybrid was narrow, a good possibility exists to find better agronomic qualities such as persistence, higher yield, greater seed production, and pest resistance within a wider base of germ plasm. To determine the diversity of the species, introduction of germplasm from many of the world's tropical forage germ­plasm banks was begun in the late 1970s and as many of the available entries as possible …

Genotypic Differences In Seedling Vigor In Sericea Lespedeza, J A. Mosjidis

IGC Proceedings (1977-2023)

Slow seed germination and poor seedling establishment have been considered major problems in sericea lespedeza [Lespe­deza cuneata (Dumont de Courset) G. Don.], a summer peren­nial legume grown in the southeastern United States for forage and soil conservation (Logan et al., 1969). Wright et al. (1978) considered sericea lespedeza a nonaggressive species because of the low number of seedlings that emerge and the long time needed for emergence as compared to other species. Hoveland et al. (1971) indicated that sericea lespedeza seedlings are weak and compete poorly with weeds. Recommended planting time of sericea is early spring as soon as there …

Transfer Of Genes For Aphid Resistance From Medicago Truncatula (Barrel Medic) Via M. Littoralis (Strand Medic) To M. Tornata (Disc Medic), W H. Lake

IGC Proceedings (1977-2023)

Since_ the late 1970's, many medic based pasture leys in Australia have been consistently and severely damaged by both blue green aphid (BGA) (Acyrthosiphon kondoi) and to a lesser extent spotted alfafa aphid (SAA) (Theroaphis trifolii fm maculata). Where infested stands are not sprayed, seed set has been severely affected, and this seed set is vital if the system is to ?ea successfull self-regenerating one (Carter, 1981). Aphid resistant cultivars are likely to provide a long term answer to this problem, and since the early 1980's several new resistant barrel medic (M. truncatula) cultivars have been …

The Potential Of Lolium Multiflorum X Festuca Gigantea Hybrids, M O. Humphreys, H Thomas, B F. Tyler

IGC Proceedings (1977-2023)

The potential for combining traits from broadly adapted Festuca with more highly specialised Lolium has been investi­gated for many years especially with regard to cytological behaviour (Breese et al., 1981). In the USA, efforts to increase the nutritive value of tall fescue through hybrids with ryegrasses succeeded in producing the variety Kenhy (Buckner et al., 1977). So far, Lolium/Fescue hybrids have not been able to compete commercially with more productive ryegrasses in intensive UK farming systems (Breese and Lewis, 1984). How­ever, with recent economic changes in European agriculture there is a need for more efficient, lower input grassland …

Evaluation And Hybridization Of Germplasm In The Desmodium Hetercarpon- D. Ovalifolium Species Complex, K H. Quesenberry, M A. Mckellar, D E. Moon

IGC Proceedings (1977-2023)

Although Ohashi (1973) classified Desmodium ovalifolium Wall. as synonimous with D. heterocarpon (L.) DC. and placed both in the same subspecies and variety, most forage resear­chers have chosen to maintain species rank for both taxa. Ohashi's criteria for lumping these two taxa was inflorescences densely flowered with distinctly hooked-hairy pods ; however, germplasm characterization by CIAT (1981) has identified growth habit and flowering pattern as other more complex traits by which these species differ. Desmodium ovalifolium has been shown to have potential for pasture use in the Llanos of Columbia and other acid soil sites (CIAT, 1981). A cultivar of …

Intergeneric Hybridization Between Festuca And Lolium Genus By In Vitro Pollination And By Ovule Transder, Ho-Jin Lee, Ji-Yeon Han

IGC Proceedings (1977-2023)

The barriers to intergeneric crosses in the grass family were commonly known as inviability of the developing embryo, embryo abortion, or endosperm abnormalities, which might have occured after fertilization. To avoid incompatibility in wide cross, in vitro pollination or fertilization techniques have been attempted and made success in Nicotiana (Marubashi and Nakajima, 1985) and in Maize (Gengenbach, 1977). Our program has intended to improve forage quality of tall fescue through crossing to Italian ryegrass. The artificial cross between these genus had relatively low chance for obtaining hybrid offspring. The purpose of this research was to overcome the incompatibility barrier in …

2n Gamete Producer In Diploid Species Of Genus Medicago, F Veronesi, A Mariani, S Tavoletti

IGC Proceedings (1977-2023)

In Medicago genus, the importance of gametes with unreduced chromosome number (2n gametes) has been stressed both in the evolution (Stanford et al., 1972) and breeding (Bingham, 1968) of cultivated alfalfa, wich is a cross-fertilizing natural polysomic polyploid (Medicago sativa L., 2n = 4x = 32). In this species heterozygosity can be maximized but not fixed by the usual methods of cultivar development (Dubier and Bingham, 1975). As an alternative to normal sexual repro­duction, hybridization of 2n gametes from diploid hybrids can transmit, through bilateral sexual polyploidization, a large part of the heterozygosity of the diploid parents to the …

Ploidy Level And Competitive Response In Dactylis Glomerata L., N Maceira, P Jacquard, R Lumaret

IGC Proceedings (1977-2023)

Dactylis glomerata L is a widely distributed autopolyploid complex, which includes mainly diploid and tetraploid cytotypes. In Galicia (Spain), morphologically indistinguish­able and genetically very closely related diploid and tetraploid plants are sympatric, but they differ in habitat preference and life-history traits (Lumaret et al., 1987). Diploids are usually confined to low density forest understories of Quercus robur, while tetraploids are predominant in open areas with more dense herbaceous vegetation. Rothera and Davy (1986) found a similar habitat distribution in other polyploid complex (Deschampsia cespitosa) and suggested that diploids might be more sensitive to competition than tetraploids. Tetraploid …

Potential Uses Of Embryo Culture Derived Interspecific Hybrids Of Alfalfa (Medicago Sativa L.), T J. Mccoy, L J. Mancino

IGC Proceedings (1977-2023)

Interspecific hybridization has frequently been used in crop improvement programs to introgress economic traits from wild species into the cultivated germplasm pool. In alfalfa (Medicago sativa) unadapted accessions have been important sources of disease resistance and winterhardiness. However, unadapted germplasm sources used in alfalfa improvement to date have been limited to the M. sativa complex (McCoy and Bingham, 1988) A number of valuable traits have been ident­ified in other Medicago species (summarized in McCoy, 1985) but the obstacle to using other species had been the inability to recover interspecific hybrids.

Recently, the limits of crossability in the genus …

Seasonal Changes In Palatability Of Hybrids Between Phalaris Aquatica And Hexaploid P. Arundinacea, R N. Oram, H E. Schroeder

IGC Proceedings (1977-2023)

F 1 hybrids between P. aquatica L. and the hexaploid (6x) race of P. arundinacea L. produce more herbage than their parents in summer and autumn in south-eastern Australia if rainfall exceeds 50 mm per month (Mc William, 1962). Both the tetraploid and hexaploid races of P. arundinacea are more tol­erant of excess aluminium in acid soils than P. aquatica ; acid­ity is an increasing problem in the region (Culvenor et al., 1986). However neither race of P. arundinacea can survive the summer droughts characteristic of the modified Mediterranean climate. Also, the F 1 of P. aquatica with 6x P. …

Evaluation Of Annual Medics And Subclovers In Oklahoma, S Christiansen, T Svejcar

IGC Proceedings (1977-2023)

Oklahoma has a continental climate with cold winters and a late spring or early-summer rainfall peak. Kneebone (1959) found little justification for attempts to use native legumes for revegetation purposes in western Oklahoma rangelands. Den­man et al. (1961) evaluated 54 genera, 216 species and 1,366 entries of legumes in Stillwater, Oklahoma between 1951 and 1959. They concluded that only alfalfa and some vetches (Vicia spp.) had any forage potential. Most clovers and medics failed to survive the winter cold.

Subclover is largely but not wholly Mediterranean in its dis­tribution (Morley, 1961) and has been grown on limited hecta­rages in the …

Introduction And Evaluation Of Tropical Forages In Various Ecosystems Of Costa Rica, E A. Pizarro, S Diulgheroff, P Argel

IGC Proceedings (1977-2023)

In 1987, three germplasm screening sites were established in Costa Rica for Central America and the Caribbean islands. They represent typical agroecological conditions where cattle are raised : namely subhumid, seasonal and humid tropics. Field work in 1987-88 concentrated on establishing grasses and legumes for trial evaluation of 31 genera and 88 species for a total of 790 accessions. Seed multiplication plots (9 ha) of promising materials were also established, as well as grazing tri­als and on-farm research activities. Preliminary results showed that some accessions of Andropogon gayanus, Brachiaria spp, Panicum maximum, Cen­trosema brasilianum, Arachis pintoi and Desmodium ovalifolium have …

The Study On The High Yield Property Of Billion Dollar Grass, Wan Lishong, Liu Shenglin, Geng Renren, Shao Shengrong, Jiang Wenkui

IGC Proceedings (1977-2023)

In 1964, one plant of billion dollar grass (Echinochloa crus­galli Link) was found by Wan Lisheng in artificial grassland in mid-part of the desert steppe in Ningxia, China. 50 g of seeds were collected in the same year. After 24 years' systematic selec­tion breeding, a new variety named Hai zi-1 billion dollar grass (BDG) was developed. The characteristics of the grass were high-yield and fine quality with extraordinary plant height. The average height of the community was 180-230 cm, the highest plant could be 250 cm high. Its field yield was 16,866 t/ha DM in Ningxia plain irrigated area …

Cynodon Dactylon Pers. A Common Fodder Grass Of Grasslands Of The Upper Gangetic Plain Of India, H R. Sant

IGC Proceedings (1977-2023)

The grasslands of the Upper Gangetic Plain of India are composed ofUttar Pradesh, Bihar and Bengal, and this area is fertile. The chief climatic factors, the temperature and rainfall together are responsible for a distinct type of vegetation. The rainfall is less than 70 cm. in west Uttar Pradesh being more than 150 cm. in Bengal.

In India, natural grasslands are hardly present, and most of them are maintained in their present serial stages due to biotic influence. Hence the grasslands occupy vast chunks of land in the outskirts of villages. Given proper care and managements either for available cultivation …

Observations Sur La Repartition Et L’Ecologie De Luzernes Annuelles Et De Trefle Souterrain En Corse, J M. Prosperi, V Gensollen, I Olivieri, P Mansat

IGC Proceedings (1977-2023)

Des missions de prospection du genre Medicago, realisees entre 1985 et 87, ont permis de mieux connaitre !es relations especes-milieux, pour mieux cerner la variabilite de ces especes, leur distribution et la gamme de milieux favorables a chacune d'entre-elles.

Grass Adaptation In Cuba. Ii. Regional Results With New Cultivars, J J. Paretas

IGC Proceedings (1977-2023)

In Cuba, bovine feeding is based on the maximum pasture and forage utilization. Pastures occupy approximately 3.0 mil­lion hectares, the highest agricultural area of the country. From there, one million hectares are sown with improved varieties and the rest with low yielding and poor quality natural species or shrub areas with a very poor utilization area (Paretas and Carballar, 1988). On considering the high genetic potential of the animals mainly pures or with a high Holstein blood percentage, empha­sis is made to transform the areas dedicated to pasture by improving the varieties yielding more and with a more stable production …

Comparative Study Of Some Varieties Of Cowpea I- Productivity And Nutritive Analysis, K M. Ghobrial, M A. Gabra

IGC Proceedings (1977-2023)

In Egypt, the serious problem of feed shortage, especially of green summer fodder suppresses the improvement of animal production. Therefore, dependence on improving local food and food resources for both animals and humans becomes a «must» for a right policy. The animal feeding system is depen­ding on the cultivation of berseem (Trifolium alexandrium L.). It produces annually around 4.81 million tons starch value/year and could cover the requirements of animals with surplus of 0.92 million tons starch value. However, in summer period, there will be at least a deficiency of 1.50 million tons starch value and most animals are …

Synthese De La Recherche Sur Les Especes Annuelles De Medicago En Elgerie, L Adem

IGC Proceedings (1977-2023)

En Algerie, ii existe pratiquement une dichotomie entre la cerealiculture dans la zone Nord (300 a 500 mm de pluie) et l'elevage ovin relegue en zone steppique (250 mm de pluie). Le cheptel ovin ne peut survivre uniquement sur !es maigres res­sources de la steppe; !es apports de fourrages secs et !es migra­tions estivales vers le Nord restent necessaires. Pour !'integration cerealiculture-elevage, la creation des piiturages annuels de Medicago au depens des jacheres impro­ductives (mains de 250 UF/ha) etait imperative et a debute des octobre 1972. Ces piiturages ameliores contribueraient a reduire un deficit de 3 milliards d'UF sur un …

Early-Maturing And High-Yielding New Pea Varieties Zhongwan N1, N2, N3, And N4, Yunyue Sun, Jiakai Su

IGC Proceedings (1977-2023)

Pea is one of the main edible beans for the Chinese people. The total output of pea in China is third only to that of soybean and broad bean. In the main producing area, pea is a protein supplement feed for the animals and poultry next to bean meal. However, the planting area was restricted because most of the old varieties have long growing periods. The yield is low, the seed quality is poor, the plant is high, so it is easy to lodge. Therefore we selected and bred new pea varieties with early­maturing,' high-yielding, low-plant and erect as well …