Selectivity of Saflufenacil for Sweet Sorghum and Potential use of Na-Bentazon as a Safener

The objective of this study was to assess the selectivity herbicide saflufenacil for two sweet sorghum hybrids, when sprayed in preemergence and postemergence, besides the use of Na-bentazon as a 'safener' for saflufenacil. Three experiments were conducted, in pots, maintained in an ambient condition (second and third experiments) and in a greenhouse (first experiment). In each experiment a completely randomized distribution was used, with four replicates. In the first (2 x 6 factorial) two hybrids of sweet sorghum (CVSW 80007 and CVSW 80147) and six dosages (0; 35; 52.5; 70; 87.5 and 105 g ha-1) of saflufenacil were studied, applied in preemergence of the plants. In the second (2 x 5 factorial) the same hybrids of sweet sorghum sprayed in postemergence with saflufenacil (0; 35; 52.5; 70 and 87.5 g h-1) were assessed. In the third (4 x 5 factorial) the association of Na-bentazon (0; 240; 480 and 720 g ha-1) to saflufenacil (0.35; 52.5; 70 and 87.5 g ha-1) was studied, when sprayed in postemergence on the sweet sorghum plants (CVSW 80007). Hybrid CVSW 80147 was more tolerant to saflufenacil than hybrid CVSW 800007, in preemergence or postemergence applications. The variables that best assessed the sensibility of the sweet sorghum to saflufenacil were number of emerged plants, for preemergence applications, and dry matter of stem for postemergence. Na-bentazon showed promise for use as 'safener' in postemergence applications of saflufenacil in sweet sorghum for dosages up to 70 g ha-1.

本研究旨在评估除草剂氟氯草胺（saflufenacil）对两个甜高粱杂交品种的选择性，分别采用播前与苗后两种施药方式，并探究苯达松钠盐（Na-bentazon）作为氟氯草胺安全剂的应用效果。本研究共开展3组盆栽试验：其中第二、第三试验置于室外环境，第一试验设于温室中。所有试验均采用完全随机设计，设置4次重复。第一组试验为2×6因子设计，供试材料为两个甜高粱杂交品种（CVSW 80007与CVSW 80147），设置6个氟氯草胺施药剂量（0、35、52.5、70、87.5及105克/公顷），均采用播前施药方式。第二组试验为2×5因子设计，采用相同的两个甜高粱杂交品种，开展苗后施药处理，设置5个氟氯草胺施药剂量（0、35、52.5、70及87.5克/公顷）。第三组试验为4×5因子设计，以甜高粱杂交品种CVSW 80007为供试材料，研究苯达松钠盐（0、240、480及720克/公顷）与氟氯草胺（0.35、52.5、70及87.5克/公顷）复配使用的效果，施药方式为苗后施药。结果表明，无论播前还是苗后施药，杂交品种CVSW 80147对氟氯草胺的耐受性均优于CVSW 80007。用于评估甜高粱对氟氯草胺敏感性的最优指标分别为：播前施药下的出苗株数，以及苗后施药下的茎干干物质重量。苯达松钠盐作为氟氯草胺的安全剂，在甜高粱苗后施药、氟氯草胺剂量不超过70克/公顷的场景下具备应用潜力。