The effect of storage on viability of the Lolium endophyte fungus (Acremonium loliae Latch, Christensen and Samuels) in seed of perennial ryegrass was studied. Treatments included four initial seed moistures (13.8, 12.1, 10.0, and 8.6%); different storage bags (calico, polyethylene film (9, 35, or 70 /lm thickness), and laminated aluminium foil-polyethylene); and four storage conditions (ambient 5-2YC, 5°Cj70% RH; 0°C/30% RH; -1 YC/90% RH). After 12 months of ambient temperature storage, seeds with final moisture contents > 11.3% had a rapid linear decline in endophyte viability from an initial 84% to < 15% at 13.0% seed moisture. Samples in 70 /lm thick polyethylene and aluminium foil laminated packets had the highest endophyte viability (70-78%) at ambient temperatures. Seed stored at 5, 0, or -15°C had high endophyte viability with no effect of seed moisture. Seed germination was not affected by any treatments. Cool or low humidity environments ( < 60% RH) are required to maintain viability of Lolium endophyte fungus in stored seed.
A brachiaria breeding program initiated in 1988 at CIAT (Centro Internacional de Agricultura Tropical, Cali, Colombia) combined desirable attributes found in accessions of Brachiaria brizantha and B. decumbens. Three apomictic hybrids have been released (cvv. Mulato, Mulato II and Cayman). Mulato showed agronomic potential but seed yields were low. Trials in Central America demonstrated the superiority of Mulato II, a vigorous grass with deep and branched roots, giving it excellent drought tolerance in the Brazilian Cerrado and Mexico, plus outstanding nutritional value. Following trials in Mexico and Thailand, evaluating 155 new hybrids for 7 years, cv. Cayman was released due to strong waterlogging tolerance. Research on production, quality and seed yields of brachiaria hybrids in Asia, the Americas and Africa from 2003 to 2013 is summarized in this paper. ResumenUn programa de mejoramiento de brachiaria iniciado en 1988 en el CIAT (Centro Internacional de Agricultura Tropical, Cali, Colombia) combinó los atributos deseables encontrados en accesiones de Brachiaria brizantha y B. decumbens y condujo a la liberación de 3 híbridos apomícticos (cvs. Mulato, Mulato II y Cayman). Mulato mostró potencial agronómico pero la producción de semilla fue baja. Ensayos conducidos en Centroamérica demostraron la superioridad de Mulato II, un pasto de crecimiento vigoroso y con raíces profundas y ramificadas que proporcionan excelente resistencia a la sequía en el Cerrado brasileño y México. Mulato II también tiene un valor nutritivo sobresaliente. Después de ensayos en México y Tailandia, evaluando 155 nuevos híbridos durante 7 años, cv. Cayman fue liberado debido a su alta tolerancia de inundación. En este trabajo se resume la investigación conducida en Asia, las Américas y África durante 2003−20013, sobre la producción, calidad y rendimiento de semilla de híbridos de brachiaria.
Seed of 6 forage species, Mulato II hybrid brachiaria (Brachiaria ruziziensis x B. decumbens x B. brizantha), Cayman hybrid brachiaria (B. ruziziensis x B. decumbens x B. brizantha), Mombasa guinea (Panicum maximum), Tanzania guinea (P. maximum), Ubon stylo (Stylosanthes guianensis var. vulgaris x var. pauciflora) and Ubon paspalum (Paspalum atratum), is currently being produced by more than 1,000 smallholder farmers in villages in northeast Thailand and northern Laos, under contract to Ubon Forage Seeds, Faculty of Agriculture, Ubon Ratchathani University, Thailand. The seed is mainly exported (95%), with the remainder sold within Thailand. Tropical Seeds LLC, a subsidiary of a Mexican seed company, Grupo Papalotla, employs Ubon Forage Seeds to manage seed production, seed sales and export, and to conduct research on new forage species. This paper details how the development of a smallholderfarmer seed-production program in Thailand and Laos produced positive social and economic outcomes for the village seed-growers. In addition, the strong emphasis on seed quality, high purity, high vigor and high germination enabled pasture growers in more than 20 tropical countries in Asia, Africa, the Pacific and Central and South America, to establish more than 20,000 ha of pastures over the past 3 years. ResumenEn aldeas de Tailandia y norte de Laos existen más de 1,000 pequeños agricultores dedicados a la producción de semillas de los híbridos de braquiaria (Brachiaria ruziziensis x B. decumbens x B. brizantha) cvs. Mulato II y Cayman; guinea (Panicum maximum) cvs. Mombasa y Tanzania; Stylosanthes guianensis cv. Ubon stylo y Paspalum atratum cv. Ubon paspalum, en contrato con Ubon Forage Seeds, Faculty of Agriculture, Ubon Ratchathani University, Tailandia. El 95% de las semillas producidas es exportado y el restante 5% vendido localmente. La Tropical Seeds LLC, una subsidiaria de la compañía mexicana de semillas del Grupo Papalotla, contrata a Ubon Forage Seeds para manejar la producción, venta y exportación de semilla y para conducir investigaciones en búsqueda de nuevos cultivares forrajeros. En este documento se presenta la forma cómo un programa de producción de semilla por productores aldeanos en Tailandia y Laos ha resultado en impactos positivos para los pequeños productores, desde el punto de vista social y económico. Adicionalmente, productores de forrajes en más de 20 países tropicales de Asia, Africa, la región del Pacífico y de Centro y Suramérica se han beneficiado de semilla de alta calidad, en términos de pureza, vigor y germinación, para el establecimiento de más de 20,000 ha en los últimos 3 años.
A field trial in Northeast Thailand during 2011-2012 compared the effects of nitrogen fertilizer, applied as urea in the wet season, on the growth and quality of Panicum maximum cvv. Mombasa and Tanzania. In the establishment year, increasing rates of nitrogen (0, 20, 40 and 60 kg N/ha every 4045 days) (0-180 kg N/ha for growing period) progressively increased stem, leaf and total DM production (P<0.05). At higher rates (80 and 100 kg N/ha or 240-300 kg N/ha for growing period), only total DM increased at the highest rate. In the second year, a rate of 20 kg N/ha every 4045 days (80 kg N/ha for growing season) doubled the amount of DM compared with no nitrogen, and 80 kg N/ha every 4045 days (320 kg N/ha for growing period) produced significantly higher stem, leaf and total DM yields than most other rates. The yield response (kg DM/kg N) decreased linearly (24.7 to 20.3 in 2011; 56.7 to 15.1 in 2012) from the lowest to the highest rate of nitrogen. In both years, increasing rates of nitrogen significantly increased CP and NDF concentrations in stems and leaves and ADF concentrations in stems. Mombasa produced 17 and 19% more leaf and 18 and 22% more total DM than Tanzania, in the first and the second year, respectively. Mombasa also produced 30% more stem DM than Tanzania in the second year. While Tanzania produced higher CP levels than Mombasa in the establishment year, in the second year, Tanzania had higher levels than Mombasa only when N rates of 80-100 kg N/ha were applied every 4045 days (320-400 kg N/ha for growing period). Applying 60 kg N/ha every 4045 days appears to be a reasonable compromise to achieve satisfactory DM yields in the wet season (8,000 kg/ha first year and 12,000 kg/ha second year), leaf percentage of 68-70% and leaf CP concentrations above 7%. ResumenEn el noreste de Tailandia durante 2011−2012 se compararon bajo condiciones de campo los efectos de la fertilización con nitrógeno, aplicado en forma de urea en época de lluvias, en el crecimiento y la calidad de los cultivares Mombasa y Tanzania de Panicum maximum. En el año de establecimiento, el incremento de los niveles de nitrógeno (0, 20, 40 y 60 kg/ha, aplicados cada 40−45 días, o sea 0−180 kg N/ha para el período de crecimiento) aumentó proporcionalmente la producción de materia seca (MS) de tallos y hojas, así como la MS total (P<0.05). En los 2 niveles más altos (80 y 100 kg/ha o 240−300 kg N/ha para el período de crecimiento), sólo la producción de MS total mostró respuesta significativa y sólo al nivel más alto de N. En el segundo año, la fertilización con 20 kg N/ha cada 40−45 días (80 kg N/ha para el período de crecimiento) duplicó la producción de MS en comparación con el testigo (0 kg N/ha), y la aplicación de 80 kg N/ha cada 40−45 días (320 kg N/ha para el período de crecimiento) permitió obtener producciones de MS de tallos, hojas y MS total significativamente mayores que los de demás niveles de N aplicados. La respuesta de la producción a la fertilización (kg MS/kg N) disminuyó linealmente (de 24.7 a 20.3...
Three post-harvest management systems, burning, grazing, and straw removal, imposed on the stubble of tall fescue (Festuca arundinacea Schreb.) immediately following seed harvest produced similar seed yields in the following season. Autumn defoliation by grazing or cutting produced similar tall fescue seed yields compared to tall fescue plants which were undefoliated from the previous harvest. Applying atrazine (3 kg a.i./ha) initially reduced vegetative tiller numbers but seed yields were not affected.
Forty-three new hybrid bracharia lines bred at CIAT, Colombia, were evaluated for seed production in Northeast Thailand between 2006 and 2010 in 2 experiments at 2 sites, Ubon Ratchathani and Amnart Charoen. These lines were compared with Mulato II hybrid brachiaria. From the BR02 collection, 4 lines, BR02/1718, BR02/1752, BR02/1794 and BR02/0465, were granted Plant Variety Rights in 2011. BR02/1794 produced more seed than Mulato II on most occasions, including both harvests at Ubon Ratchathani and 2 of 3 harvests at Amnart Charoen. The next best yielding lines were BR02/1718 and BR02/0465, which produced more seed than Mulato II in 1 of 2 harvests at Ubon Ratchathani and 2 of 3 harvests at Amnart Charoen. Seed-set (percentage of cleaned seed to spikelets) was generally very low in all hybrid lines (1-12%). The reasons for low seed-set in hybrid brachiaria grasses are discussed, including: being a common defect in newly formed apomictic forage hybrids; previous selection for seed yield not being rigorous enough; and insufficient selection at latitudes and sites where commercial brachiaria seed production is practiced. ResumenEn el período 2006-11 en 2 sitios del noreste de Tailandia (Ubon Ratchathani y Amnart Charoen) fueron evaluadas por su producción de semilla 43 líneas nuevas de híbridos de Brachiaria, incluyendo el cultivar (cv.) Mulato II como testigo, procedentes del CIAT. La línea BR02/1794 produjo más semilla que cv. Mulato II en 2 cosechas realizadas en Ubon Ratchathani y en 2 de las 3 cosechas en Amnart Charoen. Otras líneas con buenos rendimientos de semilla fueron BR02/1718 y BR02/0465 que produjeron más semilla que cv. Mulato II en una de las 2 cosechas en Ubon Ratchathani y 2 de 3 cosechas en Amnart Charoen. La formación de semilla (porcentaje del número de semillas limpias en relación con el número de espiguillas formadas) fue, en general, muy baja en todas las líneas, con un valor entre 1 y 12%. Se analizan las posibles razones de este bajo porcentaje en los híbridos de Brachiaria evaluados, entre ellas, un defecto común en híbridos apomícticos recién formados, falta de rigor en las etapas previas de selección para producción de semilla, y fallas en la selección de las latitudes y los sitios de producción comercial de semilla de Brachiaria. Las líneas BR02/1718, BR02/1752, BR02/1794 y BR02/0465 alcanzaron la protección de obtención vegetal (Plant Variety Rights) en 2011.
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