Plant Pathology Commons^™

Potential Suitability Of Spontaneously Reseeing Stylosanthes Spp. For Ley Farming In The Central Chaco Of Paraguay, A Glatzle

IGC Proceedings (1977-2023)

Continuously cropped regosols in the semi-arid Central Chaco are deficient in organic matter and prone to wind erosion. Ley-farming with self-regenerating legumes may be a sustainable alternative land use. In a 2-year field trial Stylosanthes hamata cv. Verano (V) and a 1: 2 mixture of S. humllis cv. Paterson and S. guianeuis var. intermedia cv. Oxley (P+O) were tested for their: preceding crop values to silage sorghum (S) as compared with continuously cropped S; and potential to recover spontaneously after a reduced tillage intermediate crop of S with weed control (we) or with the voluntary style underseed allowed to grow …

Potential Of Crotalaria Ochroleuca (Marejea) In Traditional Crop And Livestock Production Systems In Tanzania, S V. Sarwatt

IGC Proceedings (1977-2023)

In experiments to study the role of Crolalaria ochrroleuca (marejea) in traditional farming systems, the plant was used in the following way: (l) broadcast alone at a rate of 10 kg/ha of seed to determine dry matter (DM) yield, nutritive value and kg N/ha it can fix at different stages of growth, i.e., 2, 4, 6, 8, IO, 12, 14 and 16 weeks. (2) sown under after 3 weeks on alternate ridges with maize and maize alone as control. (3) the leaves at 10 weeks were harvested and supplemented to young sheep grazing 8 h/day. 12 male sheep …

Effect Of Gliricidia Provenances On The Yield Of Soybean And Cassava In An Alley-Cropping System, I M. Nitis, W Puger, M Suarna, W Sukanten, K Lana

IGC Proceedings (1977-2023)

An alley-cropping experiment was carried out for 3 years in a dry land farming area in Bali to study the effect of Gliricidia sepium (gliricidia) on soybean and cassava yields. Sixteen provenances of gliricidia were compared, in a completely randomised block design with 6 blocks and 12 plants/provenance. Six of the provenances originated from Mexico (M), 4 from Guatemala (G), I each from Costa Rica (R), Nicaragua (N), Panama (P), Colombia (C), Venezuela (V) and Indonesia (I). Plant spacings were 0.5 m within the alley, with 4 m between alleys. Soybean seeds and cassava sticks were planted between the alley …

Role Of Ley Farming In Crop Rotations In The Tropics, M A. Mohamed Saleem, M J. Fisher

IGC Proceedings (1977-2023)

Is there a role for ley farming in the agricultural changes desired across the tropics? Hopes were high after the identification of suitable traits for leys in tropical legumes, Despite agroclimatic-suitability similarities for a wide range of tropical crops and forages, socioeconomic conditions vary across the tropics. Increasing debt problems and low prices for agricultural commodities constrain many countries, particularly in tropical Africa, to achieve the needed agricultural growth rates at the current levels of inputs and subsistence land-use practices, Tropical agriculture's inability to meet the growing demand for food is further compounded by declining land productivity and rapid population …

Is Ley Farming In Mediterranean Zones Just A Passing Phase?, T G. Reeves, M A. Ewing

IGC Proceedings (1977-2023)

Ley farming in southern Australia has changed dramatically in the past decade or so. The present version is a more flexible, adaptive one that includes crop legumes, nitrogen fertiliser, direct drilling, and stubble retention. This has resulted in much longer phases of cropping between pasture periods, causing some to designate the new system as "phase farming". Su.ch changes are critical not only in Australia, but also elsewhere, when considering the development and adoption of ley farming in mediterranean-type regions. While the effects of traditional Icy-farming on soil fertility and crop, pasture and livestock production have been well established, there is …

Sesbania Sesban: A Promising Forage Legume In Semi-Arid Central Tanzania, D N. Msariri, M L. Kusekwa

IGC Proceedings (1977-2023)

Seventy-four accessions of Sesbania sesban were evaluated alongside 7 of S. goetzel for forage production at Mpwapwa, In Tanzania. The former was promising while the latter was generally unsuccessful. For S. sesban, germination of scarified inoculated seed in nursery was 34%. Survival of the seedlings was 96% at transplanting at 8 weeks. Growth in the field, measured in terms of mean incremental height, was 2.9 m at l year of establishment. On average, 50% of the plants flowered and formed pods at 158 and 190 days, respectively. Seed yield averaged 348 g per plant, while forage yield averaged 4.5 t …

Increasing The Germination Of Seed Of Fine-Stem Stylo (Stylosanthes Guianesis Var. Intermedia) Using A Heated, Rotating Cylinder, Colin J. Paton

IGC Proceedings (1977-2023)

Scarifying pasture legume seed to reduce hard seed content can improve pasture establishment. A heated, rotating cylinder suitable for treating large quantities of seed was used to test the effect of a range of heat doses (measured in cumulative degree-seconds of treatment above 90°C and expressed as degsecs>90°C) on seed of fine-stem stylo (Stylosanthes gulianensis var. lmermedla), Heat doses ranged from O to 1500 degsecs>90°C, A heat dose of 450 degsecs>90°C, achieved by heating seed at 120°C for 15 seconds in the cylinder, gave the highest germination without increasing the proportion of dead seed. This treatment …

Development Of New Stylosanthes Cultivar For Australia From Naturally Occurring Genotypes, L A. Edye, T J. Hall

IGC Proceedings (1977-2023)

The productivity and persistence of Stylosamhes hamata cvs, Verano and Amiga and S. scabra cv. Seca were compared in small swards in 20 dry tropical environments over periods of 2-4 years, For consistently high production Verano and Amiga appear to require tropical environments with >760 mm average annual rainfall even though they survive in regions with 500 mm. Seca is much more widely adapted than S. hamata, being highly productive and drought resistant in tropical and subtropical environments, but will not survive lieavy frosts. The opportunities for further plant improvement through selection within these species is described. However, the most …

Pasture Legumes In Cuba: Past, Present, And Future, F Funes, Marta Monzote

IGC Proceedings (1977-2023)

Before 1960 the utilisation of pasture legumes was scarce. During the decade 1960-1970 more than 10 thousand hectares of Medicago sativa. Neonolonia wightii, Cajanus cajan and Pueraria phaseoloides were sown, but interest decreased later. In the mid 1970s, research was reorganised and since 1980 results were attained showing outstanding performance of the species: N. wightii (10 t DM/ho/ year), ·Teramnus labialis (11.5 t), Lencaena leucocephala (12 I), Medicago sativa (12,5 t), Pueraria phaseoloides (14 t), Stylosanthes guianensis (IS I) and others. Results on ecological adaption, sowing, establishment, rhizobiology, seed production, pest and diseases and other agronomic aspects are …

Establishment And Animal Production Based On Tropical Grass-Legume Pastures, Marta Monzote, F Funes

IGC Proceedings (1977-2023)

Different experiments were carried out to study the establishment of grass-legume swards and animal performam;e from the pastures. Grasses were: Digitarla decumbens, Dichantum sp,, Botriocliloa sp,, Panicum maximum, Cllloris gayana, Cynodon dactylon, Cenchrus setigerus and Cenchrus ciliaris; legumes were: Neonotonia wightti, Macroptllium atropurpuretm, Desmodium intortum, Stylosanthes guianensis and Centrosema pubescens. Good establishment were obtained with minimum tillage of harrowing on the grass cover after heavy grazing or harvesting close to the ground, Broadcast sowing at 2-3 kg/ha was carried out. Growth was slow at I plant/m1 but rapid at S-10 plant/m1, In prepared …

Analysis Of Growth Characteristics And Evaluation As Fodder Resources Of Tropical Leguminous Browses In Subtropical Area In Japan, Y Kawamoto, M Honma

IGC Proceedings (1977-2023)

To evaluate the potential of several tropical leguminous browse species as fodder plants in the subtropical area of Japan, the dry matter yield and quality and resistance to clipping and drought in the first year were examined and compared in browse species. Species such as Deamodiwn tortuoaum, Desmodium discolor, Aeschynomene villosa and herbaceous Stylosanthes guianensis, had relatively high water stress tolerance, All the species were resistant to clipping. The species such as Desmodium tortuosum. Desmodium discolor among Desmodium genus have high potential for dry matter production and nutritive value in this region.

The Aeschynomene Genus As A Source Of Pasture Legumes For Tropical And Subtropical Australia, H G. Bishop, T B. Hilder

IGC Proceedings (1977-2023)

Three Aeschynomene cultivars are currently used as pasture legumes for tropical and subtropical Australia; A. falcata·cv, Bargoo released in 1973, A. americana cv, Glenn released in 1983 and A. americana cv. Lee released in 1991. Five other Aeschynomene accessions from 2 species are on "pre-release" registration with the Queensland Herbage Plant Liaison Committee pending additional data on adaptation and animal production: A. brasiliana CPI 92519 and CPI 93592 and A. villosa CPI 37235, 91209 and 93621. A collection of over 300 Aesc/1y1wme11e accessions was grown at Mackay, Queensland, in 1982-83 to describe the diversity within this genus. This diversity supports …

Characterization And Prelimiary Evaluation Of A Large Germplasm Collection Of The Tropical Forage Legume Stylosanthes Scabra Vog., Brigitte L. Maass, R Schultze-Kraft

IGC Proceedings (1977-2023)

Within the genus, Stylosamhes scabra Vog. has the second largest number of collected accessions worldwide. This tropical forage legume has potential to improve extensive, tropical pastures in subhumid to semi-arid regions with acid and infertile soils, Characterisation and preliminary evaluation of 557 accessions were carried out at Quilichao, Colombia. The main objectives were to characterise. variability within the species and to guide further agronomic evaluation. Wide ranges of morphological, phenological, and agronomic variation exist within the germplasm collection, Accessions originated from north-east and south-east Brazil gave the highest forage yields in 2 cuts. Several accessions were more productive than the …

A Flower Color Marker In The Tropical Forage Legume Centrosema Brasilianum (L.) Benth., Brigitte L. Maass, A M. Torres

IGC Proceedings (1977-2023)

Cemrosema brasillianum is a legume with high potential for pasture improvement in the semi-arid tropics with acid and infertile soils. Although genetic improvement for disease and pest resistance is taken into consideration, little is known about the species' breeding ·system. Moreover, no plant character inherited in simple Mendelian fashion has been reported for any Centrosema species. In experiments at Palmira, Colombia, 2 white-flowered accessions were hybridised with 6 violet­flowered accessions, each of a different hue. Segregation for flower colourin F2 populations fitted a single gene model,colour being dominant over white, Hence, flower colour is a useful genetic marker, Because segregation …

Evaluation And Development Of Desmanthus Virgatus On Medium- To Heavy Textured Soils In Queensland, Australia, B G. Cook, T.W.G Graham, R L. Clem, T J. Hall, M F. Quirk

IGC Proceedings (1977-2023)

Desmanthmus virgatus is a summer-growing, perennial legume comprising a wide diversity of growth forms. It is native to North and South America where it is often found on neutral to alkaline soils and in areas of low rainfall. Its potential for persistence and spread under grazing on clay soils in semi-arid environments in Queensland has been demonstrated in various experiments since 1978. Three varieties have been selected for commercial release through a state-wide co­ordinated programme of evaluation which began in 1987. These were selected on the basis of yield and persistence, and to exploit the range of growth habits and …

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).