Vegetative and reproductive development of Costa Rican weedy rice compared with commercial rice (Oryza sativa)

• Published in: Planta daninha 2007-01, Vol.25 (1), p.13-23
• Main Authors: Sanchez-Olguin, E, Arrieta-Espinoza, G, Espinoza Esquivel, A.M
• Format: Article
• Language: English
• Subjects: anthesis overlapping; ARROZ; ARROZ VERMELHO; arroz-daninho; BIOLOGICAL COMPETITION; COMPETENCIA BIOLOGICA; COMPETITION BIOLOGIQUE; COMPETIÇÃO DE VARIEDADE; ERVA DANINHA; fases de desenvolvimento; FLORACION; FLORAISON; FLORAÇÃO; FLOWERING; growth stages; http://www.fao.org/aos/agrovoc#c_2992; http://www.fao.org/aos/agrovoc#c_5438; http://www.fao.org/aos/agrovoc#c_8157; http://www.fao.org/aos/agrovoc#c_8347; http://www.fao.org/aos/agrovoc#c_917; MALEZAS; MAUVAISE HERBE; ORYZA SATIVA; PLANT SCIENCES; red rice; rice varieties; sobreposição de floração; VARIEDADE; VARIEDADES; variedades de arroz; VARIETE; VARIETIES; WEEDS
• ISSN: 0100-8358; 1806-9681; 1806-9681; 0100-8358
• DOI: 10.1590/s0100-83582007000100002

The variability in the chronology of the vegetative and reproductive development of weedy rice complex has been little studied. However, a field trial was established to study the timing of growth stages of sixteen weedy rice morphotypes and five rice varieties of Costa Rica. Weedy rice presented a wide range of variation for all descriptors among and within morphotypes. Weedy rice was taller than the rice varieties during vegetative phase and showed a growth increase of 14-23 cm every two weeks. Six morphotypes emerged earlier than commercial rice varieties, but no differences where found between samples for the time required for starting tillering. Early emergence of weedy rice morphotypes was not associated with early flowering, thus no correlation was detected between the vegetative and reproductive phases. All weedy rice morphotypes reached anthesis and maturity earlier than the rice varieties. Nevertheless, varieties Setesa-9 and CR-5272 overlapped anthesis with eleven morphotypes and variety CR-4338 overlapped flowering with eight weedy rice morphotypes. In contrast, none of the morphotypes overlapped anthesis with varieties CR-1821 and CR-1113. The results obtained showed the competitive capacity of weedy rice and provided valuable information about flowering overlap between weedy rice morphotypes and rice varieties which will be useful in the design of gene flow studies among them. O desenvolvimento vegetativo e reprodutivo das diferentes variantes morfológicas do arroz-vermelho tem sido pouco estudado. Um ensaio de campo com dezesseis morfotipos de arroz-vermelho e cinco variedades comerciais de arroz da Costa Rica foi estabelecido com o fim de estudar o crescimento dessa planta daninha. Nos resultados, observou-se que o arroz-vermelho mostrou amplo intervalo de variação durante seu ciclo de vida. Em geral, essas plantas foram mais altas que as variedades durante a fase vegetativa e apresentaram incrementos de altura entre 14 e 23 cm quinzenal. Seis dos morfotipos avaliados emergiram antes que as variedades comerciais de arroz, porém nao foram detectadas diferenças entre as amostras quanto ao momento em que iniciaram o perfilhamento. Os morfotipos que emergiram primeiro não foram os mesmos que alcançaram a floração primeiro; por esse motivo, não se pode estabelecer correlação entre a fase vegetativa e a reprodutiva. Todos os tipos de arroz-vermelho floresceram e amadureceram sua semente antes das cinco variedades comerciais de arroz. Entretanto,