Red Rice (Oryza sativa) Biology. II. Ecotype Sensitivity to Herbicides

Abstract

Greenhouse studies were conducted to evaluate sensitivity of red rice ecotypes from Arkansas, Louisiana, Mississippi, and Texas to soil- and foliar-applied herbicides. Ecotype response to herbicides was variable. Molinate at 4.48 kg ai/ha controlled red rice ecotypes 92 to 100% and cultivars ‘Lemont,’ ‘Mars,’ and ‘Maybelle’ 39 to 63%. Red rice control with thiobencarb at 4.48 kg ai/ha was at least 89%. The tank mixture of fenoxaprop at 0.08 kg ai/ha plus fluazifop-P at 0.10 kg ai/ha controlled red rice and rice cultivars more than for either herbicide applied alone. Red rice and rice cultivar control with paraquat at 0.70 kg ai/ha was 83 to 100%. Blackhulled red rice TX 4 was less sensitive to paraquat and glufosinate than other ecotypes and cultivars. Glufosinate at 1.12 kg ai/ha was required to provide at least 94% control of ecotype TX 4.

Measuring variability in phytotoxicity testing using crop and wild plant species

“…These findings agree with previous research, in which inequality in herbicide susceptibility among ecotypes has been demonstrated for several weed species [25][26][27]. However, many of the studies included species with previous exposure to herbicides and were often focused on understanding the development of herbicide resistance [28].…”

Sensitivity of imidazolinone-resistant red rice (Oryza sativa L.) to glyphosate and glufosinate

“…A research showed that blackhulled red rice TX 4 was less sensitive to paraquat and glufosinate than other ecotypes and rice cultivars when these herbicides were applied at 0.35 and 0.56kg a.i. ha -1 , respectively (NOLDIN et al, 1999). As a result, glufosinate at 1.12kg a.i ha -1 was required to provide 94% control of TX 4 (NOLDIN et al, 1999).…”

“…ha -1 , respectively (NOLDIN et al, 1999). As a result, glufosinate at 1.12kg a.i ha -1 was required to provide 94% control of TX 4 (NOLDIN et al, 1999).…”

“…In this rotation, glyphosate and glufosinate are commonly used as desiccation treatment prior rice planting and, in particular, glyphosate is also applied several times during the soybean season to control imidazolinone-resistant red rice. However, studies carried out in the United States have been reported differential sensitivity of some red rice ecotypes and accessions to glufosinate and glyphosate suggesting that selection pressure imposed by the continued use of these herbicides could increase resistance development in red rice populations (BURGOS et al, 2011;NOLDIN et al, 1999).…”

Avaliação de germinação e dormência de ecótipos de arroz-vermelho

“…Semelhantemente a outras plantas daninhas, a dormência distribui a germinação ao longo do tempo e reduz a eficiência das práticas de controle (Noldin et al, 1999a). Estabelecer a distribuição dos diferentes ecótipos, bem como suas características de dormência e germinação, constituise em prática primordial para aprimorar as técnicas de controle (Noldin et al, 1999b).…”