Inheritance of resistance to fenoxaprop‐p‐ethyl in sprangletop (Leptochloa chinensis L. Nees) |
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| Authors: | Ekkasit Phongphitak Chanya Maneechote Benjavan Rerkasem Sansanee Jamjod |
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| Institution: | 1. CMUPNlab, Department of Plant Science and Natural Resources, Faculty of Agriculture, Chiang Mai University, , Chiang Mai, Thailand;2. Lanna Rice Research Center, Chiang Mai University, , Chiang Mai, Thailand;3. Plant Protection Research and Development Office, Department of Agriculture, Ministry of Agriculture and Co‐operatives, , Bangkok, Thailand |
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| Abstract: | Sprangletop (Leptochloa chinensis L. Nees) is a serious grass weed in direct‐seeded rice cropping systems in Thailand. One population of sprangletop, BLC1, was found to be resistant to fenoxaprop‐p‐ethyl at 62‐fold the concentration of a susceptible biotype, SLC1. This study elucidated the inheritance of resistance to fenoxaprop‐p‐ethyl in this sprangletop BLC1 genotype. The reaction to the herbicide at 0.12–2.4 mg ai L?1 was determined in the seedlings of self‐pollinated resistant BLC1, susceptible SLC1 and SLC1 that had been allowed to cross‐pollinate with BLC1. At 0.24 mg ai L?1, all the seedlings of SLC1 were killed, while 99% of BLC1 survived, along with 5% of the cross‐pollinated SLC1 seedlings, which were considered to be putative F1 hybrids. The root and shoot lengths of the F1 hybrids in 0.24 mg ai L?1 of fenoxaprop‐p‐ethyl, relative to those in the absence of the herbicide, were close to or the same as the resistant parent, indicating that the resistance is a nearly complete to complete dominant trait. One‐hundred‐and‐forty‐one of the F2‐derived F3 families were classified by their response to the herbicide at 0.24 and 0.48 mg ai L?1 into 39 homozygous susceptible : 72 segregating : 30 homozygous resistant, fitted with a 1:2:1 ratio at χ2 = 1.21 and P = 0.56, indicating that the resistance to fenoxaprop‐p‐ethyl in the sprangletop BLC1 genotype is controlled by a single gene. |
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| Keywords: | fenoxaprop‐p‐ethyl herbicide resistance inheritance Leptochloa chinensis L Nees sprangletop |
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