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Alexander grass seed physiology and production: a step towards the conversion of a weed into a forage plant

Alexander grass is a Brachiaria species with great potential to produce plentiful and high quality forage. It is broadly found in Southern Brazil, and taken most of the time as a weed given the habit to develop spontaneously in fields of grain crops. Several studies assessed grazing and confirmed it...

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Autor principal:	Oliveira, Juliano Rossi
Formato:	Tese
Idioma:	Inglês
Publicado em:	Universidade Tecnológica Federal do Paraná 2017
Assuntos:	Plantas forrageiras Forragem Lavoura Pecuária Pastejo Forage plants Forage Tillage Animal culture Grazing CNPQ::CIENCIAS AGRARIAS::AGRONOMIA Fitotecnia
Acesso em linha:	http://repositorio.utfpr.edu.br/jspui/handle/1/2327
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spelling	riut-1-23272017-08-23T14:32:03Z Alexander grass seed physiology and production: a step towards the conversion of a weed into a forage plant Oliveira, Juliano Rossi Soares, André Brugnara http://lattes.cnpq.br/8437766432982210 Possenti, Jean Carlo http://lattes.cnpq.br/1962026290421057 Valle, Cacilda Borges do Montardo, Daniel Portella Adami, Paulo Fernando Pereira, Giovana Faneco Plantas forrageiras Forragem Lavoura Pecuária Pastejo Forage plants Forage Tillage Animal culture Grazing CNPQ::CIENCIAS AGRARIAS::AGRONOMIA Fitotecnia Alexander grass is a Brachiaria species with great potential to produce plentiful and high quality forage. It is broadly found in Southern Brazil, and taken most of the time as a weed given the habit to develop spontaneously in fields of grain crops. Several studies assessed grazing and confirmed its characteristics as a good forage plant, especially in integrated production systems. Regardless, its use stills limited by the lack of knowledge on reproductive traits that could (1) endorse the establishment of an organized seed production to spread it as a pasture and (2) help to design control strategies when the plant is not desired. The major aim of this work was to compile experiment results and literature review to provide a big picture on the Alexander grass seed physiology, from the seed development until the dispersal. Forage characteristics are also discussed to provide a systematic and complete understanding of the plant behavior. The reproductive morphology was assessed through quantitative traits such as the number of inflorescences produced, the seasonal timing of inflorescence production, branching of the inflorescence, number of seeds according to the inflorescence organs, inflorescence and racemes length, shattering timing, shattering speed, shattering intensity, and other characteristics according to the panicle age and the plant phenology. Maturation and germination of the seeds are discussed according to reproductive components such as thousand seed weight and seed dry mass percentage; relativized yet to the elapsing of the cycle. Seed gathering methods are compared according to the physiological quality of the seed and practicability. Plant response to environmental stimulus to flowering and germination are presented and theorized. Further, treatments to release dormancy and improve the seed performance were tested, looking to establish a production management and to understand the seed biochemical responses. Behavior of soil seed bank under environmental influences were reviewed and discussed, and seed borne pathogens i.e. potential microbiological threatens are presented. On the base of this information, some guidelines were established for the overall management to sow, produce and harvest Alexander grass. Scarce literature and data are found on the species. Fortunately, lessons and previous experience with Brachiaria widely used as pasture in Brazil helped the comparisons and supported the conclusions. It was found that ground-sweeping method is the most proper way to harvest Alexander grass seed. Defoliation management did not influence the synchrony and the amount of panicle emerged. Alexander grass presents high panicle production per area, reaching near 1,750 panicles m-2. Seed shattering starts rapidly, after 11 days from the panicle emergence near 30% of seed already shed, after 20 days near 60% of the seed already shed. Shattering also influences the distribution of the thousand seed weight along the panicle. Alexander grass presents smaller racemes, smaller seeds, longer panicles and more racemes per panicle than most of the Brachiariagrasses widespread in Brazil. Seed maturation and filling follows the same direction of the shattering, happening from the distal to the proximal fraction of the panicles (basipetally). Seeds threshed from the panicle present low germination and low shelf life. Generally, seeds present large variability even when collected from the ground. Seeds collected after the natural shatter present better germination than seeds collected directly from the panicle. The higher the thousand seed weight, the higher the seed germination. After six-month storage, one minute of physic scarification in a rotational machine with sandpaper was enough to promote the germination; Substrate imbibition with KNO3 at the dose of 0.4% promotes the germination and H2SO4 acid scarification is deleterious to the seed. CAPES; Fundação Araucária O papuã é uma espécie do gênero Brachiaria que apresenta elevado potencial de produção de forragem de alta qualidade. A planta é comumente encontrada no Sul do Brasil e tomada na maioria das vezes como uma invasora de cultivos de grãos, dado seu hábito de emergir espontaneamente do banco de sementes do solo. Vários estudos avaliaram o pastejo de papuã e confirmaram sua alta capacidade em produzir forragem, todavia, o uso apropriado da planta ainda está limitado pela falta de informações a respeito do seu comportamento reprodutivo, informações estas que poderiam (1) embasar o estabelecimento de um sistema de produção de sementes para disseminar a espécie como pastagem e, em contraponto, (2) apoiar o desenvolvimento de estratégias de controle quando a planta não é desejada. O objetivo deste trabalho foi compilar resultados de experimentos e revisões de literatura visando apresentar uma análise geral da fisiologia das sementes do papuã, desde o início do seu desenvolvimento até a dispersão. Características forrageiras foram ocasionalmente discutidas, com vistas a relacionar as conclusões ao comportamento sistemático da planta. A morfologia reprodutiva foi avaliada por meio de características como o número de inflorescências, a emergência das inflorescências ao longo do tempo, a ramificação da inflorescência, o número de sementes, o comprimento das inflorescências e dos racemos, o tempo e a intensidade da degrana, o sentido da degrana na panícula, entre outros; todas relacionadas com a idade das panículas. Ainda, a maturação e a germinação das sementes foram discutidas de acordo com componentes reprodutivos como o peso de mil sementes e a porcentagem de massa seca. Métodos de coleta foram comparados de acordo com a qualidade fisiológica da semente. As respostas da planta aos estímulos ambientais para germinação e indução floral foram apresentadas e teorizadas. Tratamentos para melhorar o desempenho e a qualidade das sementes e quebrar mecanismos de dormência foram testados, buscando estabelecer tanto manejos para a produção bem como entender as respostas bioquímicas das sementes. O comportamento do banco de sementes do solo é apresentado e por fim são feitas algumas considerações a respeito dos patógenos que atacam as sementes do papuã. Com base nas informações coletadas alguns rumos foram estabelecidos para o manejo de produção, colheita e plantio do papuã. A literatura encontrada tratando da espécie é vaga, todavia, experiências e dados apresentados para outras espécies de Brachiaria amplamente cultivadas para pastejo e produção de sementes no Brasil, serviram de suporte para as conclusões. De forma geral, o método de varredura é o mais apropriado para a colheita das sementes de papuã. O manejo de cortes de uniformização não influenciou a sincronia e a quantidades de panículas produzidas. A espécie produz grande quantidade de panículas por área, atingindo em torno de 1.750 panículas m-2. A degrana natural das sementes acontece de maneira rápida, 11 dias após a emergência das panículas em torno de 30% das sementes já se desprendeu, após 20 dias este valor sobe para em torno de 60% das sementes. A degrana também influencia na distribuição do peso de mil sementes ao longo da panícula. O papuã apresenta racemos menores, sementes menores, panículas mais longas e mais rácemos por panícula do que a maioria das Brachiarias comumente utilizadas no Brasil. A maturação e enchimento das sementes ocorre na mesma direção da degrana, acontecendo da parte distal para a parte proximal da panícula. Quanto maior o peso da semente, maior a germinação. Depois de seis meses de armazenamento um minuto de escarificação física usando um escarificador rotacional com lixa é suficiente para promover a germinação do papuã. A embebição do substrato de germinação com KNO3 na dose de 0.4% v.v. promove a germinação, e o uso de escarificação ácida com H2SO4 é deletério para a semente. 2017-08-23T14:32:03Z 2017-08-23T14:32:03Z 2017-04-25 doctoralThesis OLIVEIRA, Juliano Rossi. Alexander grass seed physiology and production: a step towards the conversion of a weed into a forage plant. 2017. 356 f. Tese (Doutorado em Agronomia) - Universidade Tecnológica Federal do Paraná, Pato Branco, 2017. http://repositorio.utfpr.edu.br/jspui/handle/1/2327 eng openAccess application/pdf Universidade Tecnológica Federal do Paraná Pato Branco Brasil Programa de Pós-Graduação em Agronomia UTFPR
institution	Universidade Tecnológica Federal do Paraná
collection	RIUT
language	Inglês
topic	Plantas forrageiras Forragem Lavoura Pecuária Pastejo Forage plants Forage Tillage Animal culture Grazing CNPQ::CIENCIAS AGRARIAS::AGRONOMIA Fitotecnia
spellingShingle	Plantas forrageiras Forragem Lavoura Pecuária Pastejo Forage plants Forage Tillage Animal culture Grazing CNPQ::CIENCIAS AGRARIAS::AGRONOMIA Fitotecnia Oliveira, Juliano Rossi Alexander grass seed physiology and production: a step towards the conversion of a weed into a forage plant
description	Alexander grass is a Brachiaria species with great potential to produce plentiful and high quality forage. It is broadly found in Southern Brazil, and taken most of the time as a weed given the habit to develop spontaneously in fields of grain crops. Several studies assessed grazing and confirmed its characteristics as a good forage plant, especially in integrated production systems. Regardless, its use stills limited by the lack of knowledge on reproductive traits that could (1) endorse the establishment of an organized seed production to spread it as a pasture and (2) help to design control strategies when the plant is not desired. The major aim of this work was to compile experiment results and literature review to provide a big picture on the Alexander grass seed physiology, from the seed development until the dispersal. Forage characteristics are also discussed to provide a systematic and complete understanding of the plant behavior. The reproductive morphology was assessed through quantitative traits such as the number of inflorescences produced, the seasonal timing of inflorescence production, branching of the inflorescence, number of seeds according to the inflorescence organs, inflorescence and racemes length, shattering timing, shattering speed, shattering intensity, and other characteristics according to the panicle age and the plant phenology. Maturation and germination of the seeds are discussed according to reproductive components such as thousand seed weight and seed dry mass percentage; relativized yet to the elapsing of the cycle. Seed gathering methods are compared according to the physiological quality of the seed and practicability. Plant response to environmental stimulus to flowering and germination are presented and theorized. Further, treatments to release dormancy and improve the seed performance were tested, looking to establish a production management and to understand the seed biochemical responses. Behavior of soil seed bank under environmental influences were reviewed and discussed, and seed borne pathogens i.e. potential microbiological threatens are presented. On the base of this information, some guidelines were established for the overall management to sow, produce and harvest Alexander grass. Scarce literature and data are found on the species. Fortunately, lessons and previous experience with Brachiaria widely used as pasture in Brazil helped the comparisons and supported the conclusions. It was found that ground-sweeping method is the most proper way to harvest Alexander grass seed. Defoliation management did not influence the synchrony and the amount of panicle emerged. Alexander grass presents high panicle production per area, reaching near 1,750 panicles m-2. Seed shattering starts rapidly, after 11 days from the panicle emergence near 30% of seed already shed, after 20 days near 60% of the seed already shed. Shattering also influences the distribution of the thousand seed weight along the panicle. Alexander grass presents smaller racemes, smaller seeds, longer panicles and more racemes per panicle than most of the Brachiariagrasses widespread in Brazil. Seed maturation and filling follows the same direction of the shattering, happening from the distal to the proximal fraction of the panicles (basipetally). Seeds threshed from the panicle present low germination and low shelf life. Generally, seeds present large variability even when collected from the ground. Seeds collected after the natural shatter present better germination than seeds collected directly from the panicle. The higher the thousand seed weight, the higher the seed germination. After six-month storage, one minute of physic scarification in a rotational machine with sandpaper was enough to promote the germination; Substrate imbibition with KNO3 at the dose of 0.4% promotes the germination and H2SO4 acid scarification is deleterious to the seed.
format	Tese
author	Oliveira, Juliano Rossi
author_sort	Oliveira, Juliano Rossi
title	Alexander grass seed physiology and production: a step towards the conversion of a weed into a forage plant
title_short	Alexander grass seed physiology and production: a step towards the conversion of a weed into a forage plant
title_full	Alexander grass seed physiology and production: a step towards the conversion of a weed into a forage plant
title_fullStr	Alexander grass seed physiology and production: a step towards the conversion of a weed into a forage plant
title_full_unstemmed	Alexander grass seed physiology and production: a step towards the conversion of a weed into a forage plant
title_sort	alexander grass seed physiology and production: a step towards the conversion of a weed into a forage plant
publisher	Universidade Tecnológica Federal do Paraná
publishDate	2017
citation	OLIVEIRA, Juliano Rossi. Alexander grass seed physiology and production: a step towards the conversion of a weed into a forage plant. 2017. 356 f. Tese (Doutorado em Agronomia) - Universidade Tecnológica Federal do Paraná, Pato Branco, 2017.
url	http://repositorio.utfpr.edu.br/jspui/handle/1/2327
_version_	1805300922583089152
score	10,814766

Alexander grass seed physiology and production: a step towards the conversion of a weed into a forage plant

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