Germinability and viability of susceptible vs glyphosate resistant biotypes of Lolium perenne L.

LONGÁS, MARÍA DE LAS MERCEDES; SABBATINI, MARIO RICARDO; SUPICICHE, MARÍA LAURA; CHANTRE, GUILLERMO RUBÉN; YANNICCARI, MARCOS; CASTRO, ANA MARÍA

Rosario

Congreso; II Congreso Nacional de Malezas; 2018

Asociación Argentina de la Ciencia de las Malezas

The widespread occurrence of herbicide-resistant Lolium sp. is an increasing concern for farmers and agronomists. Since agricultural practices impose selective forces on weeds, evolving traits adaption in response to continuous herbicide use, is expected. The success of a weed is dependent on the ability of its seed to germinate and emerge under a wide range of environmental conditions. Therefore, combination of seed dormancy and germination dynamics conjointly with ageing, are key factors contributing to scattered emergence patterns. Nonetheless, it is not clear how environment factors influence on germination and emergence of glyphosate-resistant (R) weed species compared with susceptible biotypes (S). It is required to examine the biological behavior of R and S biotypes to make reliable predictions and which could in turn, aid in its management. The objective of this study was to determine dormancy seed responses to temperature and potential differences in viability of glyphosate R and S ryegrass subpopulations under two dry postmaduration modes: seeds buried at field (F) and kept at laboratory conditions (L). Overall, germination increased as time storage progressed, as a result of dormancy alleviate. A widening of the temperature range for germination, given by an increase of the maximum temperature (Tc) observed in both subpopulations. However, R ceiling temperature was higher compare S subpopulation at L condition: 22,35 vs 19,89 ºC. Although S and R viability remained constant over storage time under L, a decrease was observed in S seeds after 96 days of dry storage in the field. Conversely, R seed viability remained unaltered over postmaduration time.