Avena fatua, Bromus catharticus, Chenopodium album and Phalaris minor) with implications for their dispersal and control]]>

摘要

Climatic conditions for seed germination of four weed species,Avena fatua,Bromus catharticus,Chenopodium albumandPhalaris minor, which occur commonly in cereal fields in the north of Saudi Arabia, were compared. Proportionately, most seeds of the two collected seed lots germinated during the first three weeks of the experiment, confirming an early response pattern. Overall, germination was higher inBromus catharticus, Avena fatuaandPhalaris minorthanChenopodium album.Compared to the other species, proportionately morePhalaris minorseeds germinated in the second period, indicating a higher propensity for slow germination. Germination in all species favoured alternating temperatures (10/20?°C or 5/25?°C) over a constant (15?°C), in a light/dark (16/8 h) regime. However,Avena fatuaandBromus catharticusseeds also showed significant germination in a dark only (24?h) regime, indicating light has less influence on their germination. Variation in germination between geographically separate seed collections of all four species was significant in some conditions, however, the general pattern was of similar responses between the two seed lots. Results determined that, in respect of interactions between temperature and light, the most important climatic condition for maximum seed germination, in all four weed species, is alternating temperatures. The outcomes of this study can lead to the expected timings of weed species' germination and dispersal in field conditions, and are used to make recommendations for practical weed control measures.