Emergence timing and morphological characteristics of Galium species in western Canada
De Roo, A.C.
Catchweed bedstraw (Galium aparine L.) and false cleavers (Galium spurium L.), collectively known as cleavers, have become an increasing problem in grain fields across the Canadian prairies. The increasing presence of cleavers on the prairies has resulted in canola infested with cleavers seeds, and its tangling behaviour can cause difficulties during harvest. Although there are many herbicide options available, the development of resistance in cleavers to Group 2 and Group 4 (quinclorac) herbicides has complicated their management. Understanding germination and emergence characteristics can provide a better understanding of how populations of Galium species are behaving in western Canada, and whether emergence timing of these populations are preventing adequate weed control. The objectives of this research are to 1) To determine the emergence timing of several cleavers populations 2) To characterize the morphological characteristics and differences between the populations 3) To determine the speciation and relatedness of the populations. Germination, emergence, and morphological characteristics were examined in 6 representative samples of cleavers obtained from various locations across the prairies. To determine if populations are acting as winter or summer annuals, two sowing dates (early May and early September) were utilized. Throughout the experiment, measurements on morphological characteristics such as leaf area, leaf weight, branch number, shoot biomass, plant height, flowering, seed production and thousand seed weight were taken. After the first year of data collection, differences between populations with regard to some morphological characteristics was observed. Emergence patterns suggest that the populations start to emerge at the same time, but the time to reach 50% and 100% emergence is different between populations. Among populations, fall emergence appeared to be very low in comparison to spring emergence.
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