Tolerance of DAS-444ø6-6 and DAS-444ø6-6 x DAS-81419-2 Soybeans to 2,4-D and Glyphosate in the Cerrado Region of Brazil

ABSTRACT: The DAS-444Ø6-6 soybean expresses AAD-12, 2mEPSPS and PAT enzymes to provide, respectively, tolerance to 2,4-D, glyphosate and ammonium glufosinate. This event is also associated with DAS-81419-2 expressing Cry1Ac and Cry1F proteins to provide protection against a broad spectrum of soybean lepidopteran insect species. Successful adoption by growers of these technologies relies on the traits performing in the diverse environments of Brazil, especially under adverse weather conditions. The objective of this study was to characterize the tolerance of DAS 444Ø6-6 and DAS-444Ø6-6 x DAS-81419-2 soybeans to 2,4-D and glyphosate in the Cerrado region of Brazil. Eight trials across four sites were conducted in the 2015/2016 summer rainy season using a randomized complete block design, with a factorial arrangement of treatments. Factor A was 2,4-D choline salt (456 g a.e. L-1) + glyphosate DMA salt (480 g a.e. L-1) at 975 + 1,025 and 1,950 + 2,050 g a.e. ha-1, respectively and ready-mix of (2,4-D choline salt 195 g a.e. L-1 + glyphosate DMA salt 205 g a.e. L-1) at 2,000 (975 + 1,025) and 4,000 (1,950 + 2,050) g a.e. ha-1. Factor B was application timing at V3, V6 and R2 soybean growth stages. No visible symptoms of leaf chlorosis, epinasty, or growth inhibition were observed. Slight leaf droop was observed at 1 day after treatment (DAT), but it was null at 7 DAT. Less than 6% and 13% of leaf necrosis or injury were observed at 7 DAT, respectively, at 975 + 1,025 and 1,950 + 2,050 g a.e. ha-1 of 2,4-D choline salt + glyphosate DMA salt, regardless of applied as a ready-mix or not, but it was always 2% or less at 28 DAT. Crop grain yield was not influenced by herbicide treatments, application timing and their interaction, regardless of the soybean event and experimental site. DAS-444Ø6-6 and DAS-444Ø6-6 x DAS-81419-2 soybeans showed high tolerance to 2,4-D choline salt and glyphosate DMA in the Cerrado region of Brazil.

摘要：DAS-444Ø6-6大豆表达AAD-12、2mEPSPS及PAT酶，分别赋予其对2,4-D、草甘膦以及草铵膦铵盐的耐受性。该转化事件同时结合了表达Cry1Ac与Cry1F蛋白的DAS-81419-2转化事件，从而可广谱防控大豆鳞翅目害虫。该技术能否被种植者顺利应用，取决于其性状在巴西多样的种植环境（尤其逆境天气条件下）中的表现。本研究旨在表征DAS-444Ø6-6以及DAS-444Ø6-6 × DAS-81419-2大豆在巴西塞拉多（Cerrado）地区对2,4-D与草甘膦的耐受性。试验于2015/2016夏季雨季在4个试验点共开展8个试验，采用随机完全区组设计，处理因子采用析因排列。因子A为2,4-滴胆碱盐（酸当量浓度456 g·L⁻¹）+草甘膦DMA盐（酸当量浓度480 g·L⁻¹），分别以975+1025 g酸当量·公顷⁻¹、1950+2050 g酸当量·公顷⁻¹的剂量施用，以及二者的预混制剂（2,4-滴胆碱盐195 g酸当量·L⁻¹+草甘膦DMA盐205 g酸当量·L⁻¹），分别以2000（对应975+1025）g酸当量·公顷⁻¹与4000（对应1950+2050）g酸当量·公顷⁻¹的剂量施用。因子B为施药时期，设置大豆V3、V6及R2生育期三个处理。试验未观测到叶片褪绿、偏上性生长或生长抑制的可见症状。施药后1天（DAT）观测到轻微叶片萎蔫，但施药后7天（DAT）该症状完全消失。当施用2,4-滴胆碱盐+草甘膦DMA盐的剂量为975+1025与1950+2050 g酸当量·公顷⁻¹时，无论是否采用预混制剂，施药后7天观测到的叶片坏死或药害率分别低于6%与13%，但施药后28天该药害率始终不超过2%。无论大豆转化事件类型与试验地点如何，除草剂处理、施药时期及其交互作用均未对作物籽粒产量产生显著影响。DAS-444Ø6-6与DAS-444Ø6-6 × DAS-81419-2大豆在巴西塞拉多地区对2,4-滴胆碱盐与草甘膦DMA盐均表现出高耐受性。