b'WHEAT SPPROUTINGInterpreting Resistance to Sprouting in WheatWHAT DOES RESISTANCEto sprouting of wheat in the Albertaa root or coleoptile. The number of heads with visible evidence of Seed Guide (ASG) mean? When a wheat or durum wheat varietysprouting is recorded. reaches physiological maturity (30 to 35 per cent moisture), theFollowing the artificial rain simulation treatment and scoring seeds generally wont germinate until dormancy has been overcome.for number of heads with visible sprouting, the samples are dried The length of time of this dormancy is referred to as degree ofdown, threshed and percentage of kernels sprouted measured. The resistance to sprouting. The dormancy period is under geneticsame procedure is repeated for the heads collected at the second control and is a trait of each variety. sampling date.How is the length of dormancy period or resistance to sproutingThus, four variables are measured, namely, time-one heads measured? Specialized field trials are grown at the Agriculturesprouted, time-two heads sprouted, time-one kernels sprouted and and Agri-Food Canada Swift Current Research and Developmenttime-two kernels sprouted. The data are analyzed using a statistical Centre. All newly registered varieties and checks are grown inprocedure called Least Squares Means. Five categories of resistance replicated trials for a minimum of three years. All varieties areto sprouting have been established based on a set of checks that given the same time-period between the seed reaching 18 per centhave been tested for many years and have expressed sprouting moisture and an initial sampling time. A sample of 10 heads fromresponse consistently regardless of growing season. The more primary tillers are then collected and stored at -20 C stopping theresistant a variety is to these artificial sprouting conditions, the after-ripening process. Ten days later another set of 10 heads ismore robust the dormancy is under wet field conditions.collected and stored at -20 C.The reported resistance to sprouting for some varieties has The heads of all varieties from the first sampling time are placedchanged between the 2023 and 2024 seed guides resulting from upright in a specialized rain-simulator. An initial wetting treatmentsome issues arising from COVID-19 and staff changes. The January of about 135 mm over five hours is followed by 30 minutes of2024 ratings have been thoroughly reviewed.misting every 12 hours. Temperature is maintained at 18 C andHow does the ratings for sprouting resistance reported in ASG relative humidity greater than 95 per cent.relate to Hagberg Falling Number (HFN)? HFN measures the After five to six days, the sprouting susceptible checks will havechanges in the pasting properties of the starch component of the roots and coleoptiles visible on multiple kernels while the sproutinggrain caused by alpha-amylase activity. To conduct a HFN test, resistant checks will have none or very limited visible evidencegrain is ground into meal, water is added, mixed with a stirrer and of sprouting. This difference in sprouting of the checks is used toheated for 60 seconds. The falling number is the number of seconds establish a range in expected sprouting response of the varietiesit takes for the stirrer to fall to the bottom of the test tube. Alpha being characterized. Each head is assayed for visible sprouting ofamylase is an enzyme thats produced during the germination of grain. Therefore, sprouted kernels and severely sprouted kernels are grain grading factors. HFN can be used as an indicator of the soundness of the grain. Typically, varieties with a high level of resistance to sprouting maintain a relatively high falling number under wet harvest conditions better than varieties with poor sprouting tolerance.Sprouting resistance measures the level of dormancy of ripened grain under conditions favorable for germination. Hagberg Falling Number measures the breakdown of starch to sugar by the alpha amylase enzyme and the resulting changes to the structural integrity of the starch protein matrix of grain.Because the amount of alpha amylase in the kernel can negatively affect grain quality, grain millers and manufactures might specify minimum HFN values. In summary, a good sprouting resistance rating can be used as a predictor that a variety will remain dormant and maintain a high falling number (and usually better grade) under wet harvest conditions. Ron DePauw24seed.ab.ca'