Seed germination of waterplantain (Alisma Plantago-Aquatica) populations resistant and susceptible to bensulfuron-methyl

Abstract

Seed germination of bensulfuron-methyl resistant (R) and susceptible (S) Alisma plantagoaquatica biotypes collected in rice fields from Baixo Mondego (6 samples); Sorraia river valey (2 samples) and Sado river valey (2 samples) were compared at 15 ºC and 15/30 ºC. All seed samples were two years old and an extra sample three years old was also included to assess the effect of seed age on germination. Three year seeds reached higher germination rates than two year seeds at both temperature conditions. Cumulative germination characterized for each biotype using non linear regression (SSlogis) was different according to geographic origin, resistance trait and seed age. The model could not fit data from Sado S biotype and two Baixo Mondego R biotypes due to immature seed. Samples with the highest cumulative germination also have the highest germination rate. Seed germination of S populations was similar at both temperature conditions, whilst for R populations seed germination was favoured by different temperature depending on geographic origin: temperature of 15/30 ºC gave the best results for Mondego river valley (Centre region) and temperature of 15 ºC for Sorraia and Sado river valleys (Centre-South region of Portugal). The resistant trait affects germination of A. plantago-aquatica seeds and may affect resistant-weed management strategies implemented early in the growing season when temperatures are lower.