Evaluation of new hybrid brachiaria lines in Thailand. 2. Seed production

Abstract

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.

Managing forage and turf‐type bahiagrass for seed production

“…(Ramos Lopes et al., 2017), and Brachiaria spp. (Hare, Pizarro, Phengphet, Songsiri, & Sutin, 2015). Therefore, the significant reduction observed in this study seems to be more related to extreme weather conditions observed in Year 2, than factors related to the age of the pasture.…”

Effects of plant spacing on seed yield and seed quality in new Urochloa cultivars

“…Although OKI-1 and Br-203 can be established easily from seed, the principal constraint on its use and propagation is low seed availability and quality; this is also true for the other new hybrid Urochloa grasses, such as Mulato, Mulato II, Cayman and Cobra (Hare et al, 2015). Successful seed production depends on several factors, including selection of planting site, climatic conditions, irrigation, soil fertility and cultivation practices.…”

Impacto do método de pastejo sobre o acúmulo de forragem, estrutura do dossel e respostas morfofisiológicas da <em>Brachiaria</em> híbrida Convert HD 364

“…A Brachiaria híbrida Convert HD 364 vem sendo destaque em estudos com diferentes condições de manejo, que contemplam respostas sob lotação contínua com diferentes níveis de intensidade de pastejo e aporte de nitrogênio (SILVA et al, 2006a), frequência de desfolhação , lotação intermitente, comparações com capim Marandu (TEODORO, 2011; DEMSKI, 2013), além de comparações de produção e valor nutritivo com outros genótipos de Brachiarias híbridas (PIZARRO et al, 2013;HARE et al, 2015 . Em uma visão prática, a manutenção da produção de forragem e suas respostas próximas entre as características morfológicas em uma maior amplitude de alturas de manejo sob lotação contínua, reduz as limitações operacionais dos rigorosos controles das metas de alturas constantes (variação de ±10%) e implica em facilidade no manejo das pastagens pelo produtor.…”