From Petri dish to field: testing Greek lentil accessions for imazamox tolerance

Document Type: Research Paper

Authors

1 Aristotle University of Thessaloniki, Faculty of Agriculture, Lab. of Agronomy, 541 24 Thessaloniki, Hellas.

2 Aristotle University of Thessaloniki, Faculty of Agriculture, Lab. of Agronomy, 541 24 Thessaloniki, Hellas

3 Biological Sciences, Syngenta, Jealott’s Hill International Research Centre, Bracknell, Berkshire RG42 6EY, UK.

Abstract

This work aimed to study the intrinsic tolerance of Greek lentil accessions to imazamox
herbicide by combining bioassays, pot and field experiments. Initially, 31 genotypes were
evaluated in Petri dish bioassays for their tolerance to six concentrations of imazamox. The
average root length of 10 lentil seedlings/dish at seven days after herbicide application was used
for non-linear regression analysis and the GR50 values (the amount of the herbicide required for
50% root length reduction of the seedlings) were estimated to calculate the resistance ratio (R/S)
of each cultivar. The results of the in vitro test clued the selection of nine accessions for further
study in pot experiment, to assess their tolerance to four rates [0 (control), 20, 30, 40 g ai ha-1]
of imazamox post-emergently applied at the seven true-leaf stage (V7 stage). Five weeks after
treatment, the number of survived plants was recorded and the above-ground dry weight was
determined in each pot. There was no direct correlation in the results of in vitro test and the pot
experiment, suggesting no matching between the two methods. The evaluation of five
accessions (cultivars with high commercial interest and accessions sporting tolerance in pot
experiment) in field experiment demonstrated different but increased susceptibility to
imazamox. Specifically, compared to the untreated control, the imazamox treatments reduced
plant growth, delayed flowering and maturity and reduced yield, dry weight, 1000-seed weight
and harvest index. Yet the protein concentration was increased in herbicide treatments. The
findings of the study showed clearly that the evaluated lentil accessions lack genes with
resistance to imazamox and different methods have to be used for assessing any potential
tolerance.


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