Plant Pathology Commons^™

Arachus Spp.: Introduction And Evaluation Of New Accessions In Seasonally Flooded Land In The Brazilian Cerrado, E A. Pizarro, J.F. M. Valls, M A. Carvalho, M.J D'Avila Charchar

IGC Proceedings (1977-2023)

Results are summarised from the agronomic evaluation of 33 new accessions of Arachis spp., especially of the Ca1dorhizae and Rhizomatosae sections, on seasonally flooded land with 2 levels of fertiliser (low::pasture establishment and high=crop production). Level of fertiliser had no significant effect on the dry mailer yield (DMY) of any plant component. The edible green DMY of the best 9 accessions ranged from 2-6 tlha, with an average IVDMO of 63% for the stems and 61% for the leaves, respectively. The total DMY in the wet season ranged from 2.5 to 10 tlha, The ratio of above-ground to underground DMY …

Agronomic Evaluation Of Centrosema Germplasm On An Acid Utisol In The Humid Tropics Of Peru. Iii. Selected Centrosema Rubescens Benth. Accessions, Gerhard Keller-Grein, F Passoni

IGC Proceedings (1977-2023)

Agronomic performance of new accessions of Centroseum pubescens on an acid ultlsol (pH 4.5, 80% Al saturation) was assessed over a 26- month period in a small-plot cutting trial near Pucallpa, Peru. 23 accessions, selected from a collection of 575 introductions, were tested along with 2 lines of C. pubescens and 3 of C. acutifolium as controls. Several new accessions of C. pubescens had significantly higher dry matter yields and better stolon root development and produced more seeds than the C. pubescens control lines, which were considerably affected by cercospora leaf spot and rhizoctonia foliar blighi. The new accessions …

Agronomic Evaluation Of Centrosema Germplasm On Acid Utisol In The Humid Tropics Of Peru. Ii. Centrosema Tetragonolobum Schultze-Kraft & Williams, Gerhard Keller-Grein

IGC Proceedings (1977-2023)

The agronomic potential of 11 accessions of Centrosema tetragonolobum was assessed In a small-plot clipping trial conducted near Pucallpa, Peru. These accessions were compared with 8 selected accessions of C. acutifolium, C, brasilianum and C. macrocarpum, and 3 accessions of the agronomically little-known C. brachypodum and C. capitatum. All C. tetragonolobum accessions were well adapted to an acid ultisol (pH 4.S, 80% Al saturation). Several of them produced dry matter and seed yields similar to those of promising lines of C. acutifolium and C. macrocarpum, The capacity to root at trailing stems was poor for C. tetragonolobum …

Agronomic Evaluation Of Centrosema Germplasm On An Acid Utisol In The Humid Tropics Of Peru. I. Centrosema Macrocarpum Benth., Gerhard Keller-Grein

IGC Proceedings (1977-2023)

As part of the search for new forage germplasm options for cleared­forest ecosystems in the humid tropics of South America, a small­plot clipping trial was conducted with 128 accessions of Centrosema macrocarpum near Pucallpa, Peru. Most of the accessions showed good adaptation to an acid ultisol with a high Al level (pH 4.4, 81% Al saturation), Considerable variation was detected among accessions for the agronomic attributes studied. On the basis of seasonal dry matter production and seed yield, the germplasm tested was classified into 8 cluster groups. All accessions proved to have a high level of pest and disease tolerance …

Commercialization Of Arachis Pintoi Cv. Amarillo In Northern Australia, B G. Cook

IGC Proceedings (1977-2023)

Arachis pintoi is an herbaceous, stoloniferous perennial legume, native to river valleys of central Brazil. In 1987, the accession CPI 58113 was released in Australia as cv. Amarillo. It grows on a range of soils, produces good yields of high quality forage in Che humid tropics and subtropics, persists under heavy grazing even with competitive grasses, and is an effective shade-tolerant ground cover under ·orchard and plantation crops. New seed production and harvesting techniques were developed because conventional methods used for A. hypogaea are unsuitable, Commercial acceptance of Amarillo by extension workers and. farmers has been successfully promoted since release.

Perennial Arachis Germplasm For The Subtropics And Tropics, K H. Quesenberry, A E. Ruttinger-Lamperti, C A. Kelly

IGC Proceedings (1977-2023)

Evaluation of a limited number of perennial Aracliis plant introductions in the 1960s led to the release of the cultivars Florigraze and Arbrook of rhizoma peanut (Arachis glabrata Benth). Beginning in 1987, 110 more recently collected introductions of primarily rhizomatous perennial Arachis species were evaluated for response to 3 foliar leaf diseases, root-knot nematode (Meloidogyne arenarla) and agronomic traits related to establishment and production. Significant variability for plant spread, plant vigour, flowering, rhizome morphology and mass, leaf morphology, foliar disease response, and root-knot nematode resistance was identified. Some accessions showed small lesions in response to Cercospora arachidicola, …

Optimizing Biofungicide Use In Managing Winegrape Powdery Mildew On The Central Coast Of California, Edgar G. Godoy Monterroso

Master's Theses

Grapevine powdery mildew caused by the fungal pathogen Erysiphe necator is a persistent threat to wine grape production in California. While synthetic fungicides remain the primary management strategy, increasing concerns over pesticide resistance, environmental impact, and regulatory restrictions have driven interest in biofungicides as a sustainable alternative. However, their efficacy is inconsistent, requiring research into optimized application strategies, integration with synthetic fungicides, and their effects on disease suppression, grape yield, and fruit quality.

This two-year study (2023–2024) was conducted at two vineyard sites, Trestle Vineyard in the San Luis Obispo Coast AVA and a commercial vineyard in the Arroyo Grande …

Arkansas Soybean Performance Tests 2024, J. F. Carlin, R. D. Bond, T. C. Swanson, J. C. Mccoy

Arkansas Agricultural Experiment Station Research Series

Soybean variety and strain performance tests are conducted each year in Arkansas by the University of Arkansas System Division of Agriculture’s Arkansas Crop Variety Improvement Program. The tests provide information to companies developing varieties and/ or marketing seed within the state and aid the Arkansas Cooperative Extension Service in formulating variety recommendations for soybean producers.

Arkansas Soybean Research Studies 2023, Jeremy Ross

Arkansas Agricultural Experiment Station Research Series

The 2023 Arkansas Soybean Research Studies includes research reports on topics pertaining to soybean across several disciplines from breeding to post-harvest processing. Research reports contained in this publication may represent preliminary or only data from a single year or limited results; therefore, these results should not be used as a basis for long-term recommendations.

Several research reports in this publication will appear in other University of Arkansas System Division of Agriculture’s Arkansas Agricultural Experiment Station publications. This duplication is the result of the overlap in research coverage between disciplines and our effort to inform Arkansas soybean producers of the research …

Recurrent Selection For Partial Resistance To Anthracnose Disease In Shrubby Stylo (Stylosanthes Scabra), D F. Cameron, R A. Boland, S Chakraborty, B Jamieson, J.A G. Irwin

IGC Proceedings (1977-2023)

Three cycles of crossing have been completed in a recurrent selection programme for partial resistance to anthracnose disease of shrubby stylo (Stylosanthes scabra) In a field study of a subset of 40 F2 populations from the first cycle, highly significant differences (P<0.001) in anthracnose resistance were found for both male and female effects and for the female x male interaction, In a subsequent F3 progeny test of 99 families selected for disease resistance and yield, 92 of the families were resistant to highly resistant with leaf damage <1% (cf, >50% damage for the susceptible cultivar, Fitzroy). Strong discrimination for resistance was also obtained in a second subset of 23 F2 populations using combined glasshouse and field selection for resistance. Further improvement in anthracnose resistance was achieved in the second and third cycles of recurrent selection. The broadly based resistance of selections from the third cycle …

Calliandra Calothyrsus - A Potential New Shrub Legume For Tropical Animal Production?, B Palmer, R A. Bray, T M. Ibrahim

IGC Proceedings (1977-2023)

Calliandra calothyrsus outyielded leucaena in cutting experiments at 2 sites in northern Australia and I in Indonesia. Drying significantly depressed the voluntary intake and digestibility of leaf, possibly due to the presence of tannin. Calliandra has the potential as a supplement for the low quality grass common to the tropics both ln grazing and cut-and-carry systems.

Glycine Latifolia- A Potentially Useful Native Legume For Clay Soils In Tropical And Subtropical Australia, M C. Rees, R M. Jones, A.H D. Brown, J N. Coote

IGC Proceedings (1977-2023)

In tropical and subtropical Australia, more than 5 million ha of heavy-textured soils receive adequate rainfall for cropping or pasture improvement. Glycine latifolla, a perennial legume native to these areas, shows promise for permanent pastures or long term leys. It occurs from latitudes 22"8 to 31 •s on heavy textured soils in the 500-1200 mm rainfall zone. It is a prostrate plant that roots from stolons and sets seed under grazing, It is drought tolerant, frost resistant, and produces dry matter yields comparable to those from the introduced legumes Desmanthus virgatus and Indigofera schimperi, There is a need to …

Development Of Rhizoma Peanut For Forage In Lower South, Usa, Gordon M. Prine, Edwin C. French

IGC Proceedings (1977-2023)

Rhizoma (perennial) peanut (Arachiis glabrata Benth.) (RP) is n perennial, warm-season legume, adapted to well-drained soils of humid tropics and subtropics. It is grown in Florida and warmer portions of the south-eastern USA up to about 32°N. Cultivar Florigraze was released in 1978 and cv. Arbrook in 1986. Commercial hectarage of RP has increased about 40% annually to approximately 2000 ha in 1992. Propagated vegetatively from rhizomes, RP Is slow to establish. Rhizoma peanut is drought-tolerant, persistent, grows well on droughty, low-fertility soils, requires moderate to excessive soil drainage and requires no N and usually no P fertiliser. It …

Effects Of Cutting Heights And Cutting Frequencies On The Annual Yield Of Leucaena And Calliandra Hedges, O Ncamihigo, P Brandelard

IGC Proceedings (1977-2023)

A 3-year study was conducted in Burundi to examine the effects of 3 cutting heights (0, 50 and 100 cm) and 3 cutting frequencies (3, 4 and 6 months) on the total annual biomass yield and leaf production of 3 shrub legumes, Leucaena diverslfolia cv, Buitenzorg, L. leucocephala cv, Peruvian and Calliandra calothyrsus. Highest annual biomass and leaf production were obtained at the 100 cm cutting hejght, There was no significant effect of cutting interval on L. leucocephala but for Calliandra calothyrsus, leaf production was highest at the 4- month cutting frequency. Both biomass production and leaf production …

Performance Of Desmanthus Virgatus Accessions In The Caribbean, M B. Adjei, K Albrecht

IGC Proceedings (1977-2023)

Twenty-three Desmanthus virgatus accessions, established on a mildly alkaline clay soil (Typic Rendoll Mollisol), were repeatedly harvested to 10 cm stubble over a 2-year period whenever regrowths reached the early-pod stage of maturity to determine forage yield, leaf/stem proportions, forage quality and stand persistence. Differences were observed in seasonal growth distribution and annual forage yield of accessions. Collections from Venezeula and Mexico were among the most productive (8-11 t dry matter/ha/year) and from the Dominican Republic, the least productive (<6 t/ha/year) accessions. Most accessions perissted well under the lenient garvesting regime imposed. The proportion of leaf in dry forage ranged from 34 to 43% with average leaf crude protein (CP) content in vitro organic matter digestibility (IVOMD) of 19.2% and 83.4%, respectively. The average stem CP and IVOMD were 7.4% and 48.9%, respectively, and were not affected by accessions. Leaf samples of all Desmanthus accessions contained high levels of tannins (26-31 g tannic acid equivalent s/kg DM). However, unlike fibre fractions, leaf IVOMD was only weakly correlated with leaf tannin content (r-0.38).

Breeding For Rust Resistance In Marcoptilium Atropurpureum, R A. Bray

IGC Proceedings (1977-2023)

Rust in Macroptilium atropurpurewn cv. Siratro is an important disease, reducing both yield and quality, Resistance to the disease is conditioned by several genetic mechanisms, including single dominant. genes, multiple dominant genes, single major genes together with genes of lesser effect, and single recessive genes. Near-isogenic lines have been developed by backcrossing dominant genes into Slratro background, and these lines used to demonstrate pathogenic specialisation in Mexican collections of the rust organism. No variation In virulence is apparent in S Australian isolates of the fungus, Pour of the backcross populations, with resistance genes from geographically diverse origins, have been mixed …

Phenological Development Of Line 8400 Stylo And Alyeclover Planted At Two Dates In Subtropical Florida, M J. Williams, C G. Chambliss, J B. Brolmann

IGC Proceedings (1977-2023)

Line 8400 slylo (Stylosathes guianensis) remains vegetative later in the autumn than many tropical annual legumes. The objective of our study was lo determine the effect of planting dale (April or June) on the phenological development of Line 8400 stylo compared with alyceclover (Alysicarpus vaginalis). Root/shoot ratio of Line 8400 stylo (0.16) was not affected by planting date and was similar to April-planted alyceclover (0.15), but was lower (P<0.05) than June­planted alyceclover (0,21). Legume leaf/stem ratio was not affected by planting date, declined (P=0.0001) from an average of 2.79 at 4 weeks to 0.55 by 16 weeks post-planting, and was higher (P=0.03) for Line 8400 stylo (1.76) than alyceclover (1.29). Maximum dry mailer yield was 10.1 and 5.0 Mg/ha for April- and 7.2 and 5.6 Mg/ ha for June-planted Line 8400 stylo and alyceclover, respectively.

Selection Of Sylosanthes Spp. For The Cerrados Of Brazil, B Grof, A.T F. Fernandes, C D. Fernandez

IGC Proceedings (1977-2023)

Improved seed yield and leaf retention during the dry season coupled with anthracnose resistance were recorded among mid-season flowering progenies of intervarietal hybrids of Stylosantheses guianensis var. vulgaris x var. panciflora. Mineirao, a late-flowering accession of S. g11ia11e11sis var. vulgaris, displayed similar agronomic traits, but produced lower seed yields. Venezuelan accessions of S. capitata, and a binary mixture of S. capitata-S. ,nacrocepllala showed field resistance to anthracnose. Inter- and intraspecific variation for resistance to anthracnose disease was demonstrated by inoculation with virulent local and introduced pathotypes of Colletotrichum gloeosporioides. The development from these heterogeneous populations of cultivars …

Meeting The Challenge Of Adapting Leucaena Leucocephala To The Acid Oxisols And Utisolds Of South America And South-East Asia, E M. Hutton, Chin Peng Chen

IGC Proceedings (1977-2023)

Shtteen lines from 2 families of Leucaena leucocephala-L. diversifolia hybrids selected for acid-soil tolerance in Brazil were reselected in the Kuala Linggi acid-sulphate soil and Serdang oxisol in Malaysia. In the K. Linggi soil with 81 % Al saturation, highly acid-tolerant hybrids were selected with 35-79% more growth than the intolerant cv. Cunningham. At Serdang the oxisol had ·a mean 68% Al saturation and hybrids were selected with 19-49% more growth than Cunningham which lacked intolerance symptoms due to annual dolomite application. In a severe psyllid infestation at K. Linggi, 5 of the 14 hybrids from one family had …

Evaluation Of Wild Nut-Producing Arachis Species For Forage, A E. Kretschmer Jr, C E. Simpson, T C. Wilson, W D. Pitman

IGC Proceedings (1977-2023)

Fourteen nut-producing wild peanut (Arachis spp,) accessions were evaluated in single-plant plots and in ranchers' fields under grazing. Transplants were used for initial and some secondary planting, Agronomic characteristics and persistence were measured. The cv. Amarillo (4222) and a selection previously evaluated (2273) were used as controls. Plant yield, leaf and stem weights, nut production and other attributes varied among the accessions. Accession 2273 was one of the earliest and most prolific flowering and nut producers, while 4222 was the most persistent under initial grazing evaluation,

Production And Growth Characteristics Of Sixteen Gliricidia Provenances Grown In A Dryland Farming Are In Bali, W Puger, I M. Nitis, K Lana, M Suarna, W Sukanten

IGC Proceedings (1977-2023)

At evaluation of Gliricidia sepium provenances was conducted in Bali for 3 years on a calcareous-based red-brown Mediternn soil at a lowland site with 1000 mm annual rainfall. Fifteen provenances representing diverse geographical regions in Latin America were compared with an Indonesian provenance using a randomised block design. Plants were grown in alleys 4 m apart with plants spaced at 0.5 m apart within the alley. All the plants were cut at 150 cm height periodically, twice during the 4-month wet season and twice during the 8-month dry season. Significant differences were found between provenances for leaf and branch …

Advances In Forage Legumes: A Subsahara African Perspective, B H. Dzowela

IGC Proceedings (1977-2023)

In the context of diverse agricultural production systems in subSaharan Africa, advances made with forage legume research are outlined. The direction of research has been geared to evaluating and incorporating the forage legume technology in crop farming and pastoral livestock feeding systems, In systems with minimal fertiliser inputs; legumes have contributed to the crop phase by reducing the rate. of soil fertility decline, In pastoral systems legumes have contributed to rehabilitating the range and in improving the quality of grazing. In agropastoral systems legumes have conferred better quality and improved utilisation of crop residues, natural pastures and fallow lands. Major …

Advances In Research And Development With Sylosanthes And Other Tropical Pasture Legumes, D F. Cameron, C P. Miller, L A. Edye, J W. Miles

IGC Proceedings (1977-2023)

The last 20 years have seen major advances in research and development wilh tropical legumes. Research advances have been closely associated with substantial increases in the number and diversity of genetic resource collections, Release of a wide range of new cultivars has been based on selection for plant adaptation, persistence and productivity, screening for resistance to pest's and diseases, and the development of efficient seed production. Determination of fertiliser requirements and grazing management practices has resulted in sustainable animal production from legume-based pasture systems. Extensive pasture development has now occurred in both high and low input systems. Options vary from …

Integration Of Wildlife And Cattle On Communal Lands In Kangwane, South Africa, M Stalmans, A Van Wyk, M T. Mentis

IGC Proceedings (1977-2023)

The feasibility of integrating wildlife with the current livestock husbandry on communal lands in KaNgwane was investigated. Present stocking rates were 3 times the recommended figure for production farming. This fitted predictions based on the Jones-Sandland model for populations where the major consideration is maximum number of animals rather than high productivity. The integration of game was seen as a means to increase economic output, while spreading benefits from the use of natural resources to the community at large and establishing a form of ecologically sustainable land use. The active involvement of the community in the planning process and their …

Integrated Gamebird Farming As An Incentive To Promote Biodiversity And Conservation Of Rangelands, P J. Wiljoen, C R. Hurt

IGC Proceedings (1977-2023)

The popularity of gamebird hunting as a sport in Southern Africa serves as an incentive to rangeland owners to increase biodiversity on their properties. Gamebird utilisation is compatible with virtually all forms of land use, be it crop, domestic stock or wildlife production or a combination thereof, The range in habitat requirements, behaviour patterns and feeding niches of indigenous gameblrds ensures that at least one species is compatible with a specific agricultural practice, climate or vegetation type. Marginal and wasteland areas such as marsl}es, gullies, road verges and rocky outcrops, are prime gamebird production areas. The prospects of sport and …

Game Production On Private Land In South Africa, J C. Pauw, M J.S Peel

IGC Proceedings (1977-2023)

The game industry on private land in South Africa has grown considerably in the last 30 years, resulting in a greatly increased biodiversity on private rangeland. However, animals are not domesticated and management is difficult. Management becomes even more complex because commercial game production normally involves a number of species, including domestic stock, in the same production system. Mixed livestock-game ranching holds certain advantages for management and is generally perceived to be more profitable than either alone. Because of human preferences, a lack of clearly defined management objectives and lack of practical management recommendations, veld is generally heavily utilised and …

Determinants Of Herbaceous Species Composition On Wildlife Utilization Areas In The Eastern Transvaal Lowveld Of South Africa- A Preliminary Investigation, M.J S. Peel, G C. Stuart-Hill

IGC Proceedings (1977-2023)

This study investigated the. effect of recent past annual rainfall and stocking rate on herbaceous plant species composition in the Lowveld of the eastern Transvaal, South Africa. Annual rainfall and grazing (stocking rate) act synergistically in determining herbaceous species composition, annual rainfall exerting the greatest influence and grazing having a modifying effect particularly under extreme conditions. In mesic areas (mean annual rainfall of around 600 mm) a relatively favourable herbaceous composition was found under relatively higher grazer stocking rates of around 10 grazer units/JOO ha (10 GU/100 ha) In semi-arid areas (mean annual rainfall of around 400 mm) a lighter …

Cattle And Wildlife Ranching In The Zimbabwe Midlands: Are They Economically Compatible?, Urs P. Kreuter, John P. Workman

IGC Proceedings (1977-2023)

Thirty-five Midlands ranches earning revenue from beef caltle, wildlife, or both during 1989-90 were surveyed to determine their financial and economic· profitability. Market prices were used to calculate financial profit, and opportunity costs were used to estimate economic profit of each operation. Under current market conditions, only mixed ranches produced positive financial profits, Economic profits were significantly higher than financial profits for all three types of operation. This implies that they all faced production disincentives due to government policy interventions. However, there were no significant differences between the economic profits of the three types of operations and none of them …

Overcoming Limitations On The Productivity Of Browsing Ungulates In Africa, Norman Owen-Smith

IGC Proceedings (1977-2023)

In African savannas primary production by woody plants may match that by the grass layer. However, maximum population levels attained by browsing ruminants are only one tenth of those reached by similar sized grazers, The productivity of browsers is limited because (I) much foliage is out of reach, and dispersed by wind when shed; (2) most palatable trees are deciduous, leading to a food bottleneck during the late dry season; (3) leaves of many woody species are rendered unpalatable, indigestible or toxic by plant secondary metabolites. Management actions to overcome these limitations include (I) lopping trees to restrict their height; …

Southern United States Forest Range Management: History And Development, Henry A. Pearson

IGC Proceedings (1977-2023)

The history and development of forest range management in the southern USA are discussed, including influences of domestic livestock, wildlife, forestry, research, education and societies, Domestic cattle entered the USA in 1521; since then grazing the "piney woods" has been common. By the early 1930s, old growth timber was harvested from Texas to Florida and South Carolina. Fire control legislation helped reforestation to peak in 1959. This forced many cattlemen out of business owing to the fast-growing pines. Wildlife declined with colonisation but many populations were re­established after World War II. Public agencies, universities, and the Society for Range Management …