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Genetic variation in herbicide resistance in scentless mayweed ( Tripleurospermum inodorum (L.) Schultz Bip.) III. Selection for increased resistance to ioxynil, MCPA and simazine
Author(s) -
Ellis M.,
KAY Q. O. N.
Publication year - 1975
Publication title -
weed research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.693
H-Index - 74
eISSN - 1365-3180
pISSN - 0043-1737
DOI - 10.1111/j.1365-3180.1975.tb01325.x
Subject(s) - mcpa , biology , herbicide resistance , population , simazine , weed , cross resistance , horticulture , pesticide resistance , botany , agronomy , weed control , pesticide , genetics , demography , atrazine , sociology
Summary A sample of 100 seedlings from a weed population of T. inodorum which had been found to be relatively sensitive to MCPA was exposed to an MCPA concentration sufficient to give a 38% kill, and the five most vigorous survivors were combined in a polycross. When sprayed with MCPA, the progeny of the polycross had an LD 50 15·4% greater and a mean fresh weight per plant 30·2% greater than that of unselected controls. In a similar selection among plants from the same population for ioxynil resistance, the initial kill was 81% and (he progeny of selected plants had an LD 50 77·3% greater and a mean fresh weight per plant 43·3% greater than that of unselected controls; and in a similar selection for simazine resistance, the initial kill was 99% and the progeny of a selected plant had an LD 50 17·0% greater and a fresh weight per plant 88·4% greater than that of unselected controls. The increase in resistance to MCPA and ioxynil was less than the differences between populations observed in previous screenings, and the selected plants were considerably less resistant than the most resistant wild populations.