Preparation of Trial Plots

One of the best sources of information on the preparation of trial cereal plots is the webpage "Regeneration guidelines for small-grained cereals" found on the Crop Genebank Knowledge Base.

The following points were adapted from notes that were kindly sent to me by Angela Pattison of the Plant Breeding Institute, Faculty of Agriculture and Environment, The University of Sydney. I have included some additional points of my own.

• Sowing of wheat and barley is generally undertaken in Australia in Autumn and early winter, following ANZAC day up until the 2nd or 3rd week of June. Some varieties can be sown as late as July, but may need some protection and additional water to get them through to maturity, especially if hot weather threatens late in the season.

• Always prepare a field plan and stick to it. Use a number or letter for each plot (e.g. a genebank accession number) and write the same number on each packet of seed, then keep a very good record of packet numbers and their field location. An Excel spreadsheet that is saved, backed up, and printed out prior to planting is ideal for this purpose.

The following link shows my 2015 field plan as a basic spreadsheet.

CLICK HERE TO VIEW FULL SIZE IN A GOOGLE IMAGE WINDOW

• Each plot can be at least 1 metre square (depending of course on how many varieties you choose to grow). Measure your entire field and work out how many plots you will need. Hammer tomato stakes into each corner of the field and mark the borders out with taut string. Don't forget to include spacing for each column and row to allow for service access (e.g. for weeding, watering, spraying, taking photos, harvesting).

• Prepare ALL the channels in the soil first. If the soil is well prepared and soft, a 20 cm X 2.5 cm wide plank or similar is useful for keeping the rows straight. Lay the plank parallel to the intended row, then turn it on its edge. The edge can be pushed back and forth lengthwise to form a channel (this will be a row). Then lay it flat and repeat the procedure to form the next channel. I find this an easier method than pegging out and following string, or trying to furrow a crude ditch with a hoe or blade.

• SPACING: You will definitely need gaps to walk around your plots, for which I recommend about 50 cm on at least one side (e.g. you can make the rows wider than the columns). You can exclude the gap between varieties on the other sides if you wish to help reduce weeds.

• Lay ALL the packets out in the channels where the seed is to be sown BEFORE sowing anything. That way you will know what is going in where; you can check it lines up with your field plan, that it all fits, and you can work from one side of the field to the other and not double sow or skip any channels. Use small rocks or clods to hold down the packets if it is a windy day.

• Don’t sow all the seed from each packet. If there are gaps in emergence, you will need some extra seed in case you have to replant any missing spaces. It is also a good idea to retain at least a few seed as a record and for identification purposes.

• Outcrossing is not normally a problem as most wheat varieties are self-pollinating. However if you are really concerned about having pure seed to sow next season, simply place a white paper bag or glassine bag over a few heads when they are flowering and close the base with a twist tie. This will ensure all the heads in the bag have been selfed. You should remove the bag while the seed develops, but leave the twist tie so you know which heads contain the selfed grain.

• It is a good idea to place a name tag at the foot of each plot, with the variety name and accession number printed on it clearly. I use white aluminium plant tags and write on them with pencil, which remains legible outdoors for years. Conventional plastic tags are also suitable.

• Remember that harvesting and threshing by hand can be quite time consuming, and you will need to do something with all your wheat seed and straw at the end of the season.

• As many of the old genotypes will be tall and straggly, it is best to plant several very short rows for each genotype rather than one long line. That way they can prop up each other and you can trim lines that fall into neighbouring plots if you need to. Plots can also be propped up by hammering tomato stakes in each corner and tying string or rope around the whole plot, at a height of about half that of the crop. 

• The spacing of each channel within a plot should be about 18-25 cm apart (for example you could have a plot of 3 channels about 20 cm apart, with each channel being 50 cm to 1 m long).

• The individual plant spacing within each channel is largely up to you. For smaller plots I used a length of flat pine timber with holes drilled at 5 cm intervals. I used a blunt pencil with a length of about 4cm marked around it. Then it was simply a matter of lying the timber along the channel and pushing the pencil into each hole to the marked depth. Leave the timber in place until after you drop a seed in each hole. Then remove and backfill the channel. For larger plots or mass field planting, I usually take a pinch of seed and ‘sprinkle’ it along the channels; then thin the plants after they emerge rather than watch where I put the seed too closely. But about 5 cm between each seed is about right, if germination is good. An ideal depth is around 3-5 cm, but in well prepared garden soil a depth of just 1 cm will often prove sufficient, especially if artificial watering is available. Plants will also emerge from different depths okay to form an even crop in time. 

• You may need to check with the seed supplier how old the seed is and what the germination rate is likely to be. If you have old seed or seed of uncertain viability, you may need to double sow, or retain enough seed to re-sow any rows that do not fill. 

• STORAGE: Retain all original seed variety names and numbers on your grain storage bags and packets. Seed generally keeps up to 5 years if stored in cool, dry, dark conditions, in a breathable packet or bag (e.g. paper, hessian, calico). I use a combination of paper bags and calico "geologist sample" bags. I add a few whole cloves to each bag to help discourage insect pests. Bags need to be inspected regularly and may need to be fumigated if any insects are found. Fly spray is generally sufficient for this purpose. Open the bag, spray a small amount inside, close the bag and shake the contents, then leave the bag sealed at the top. If you intend to store seed for longer periods, you can refrigerate the seed in plastic bags or bottles that seal out moisture. The bottom of the door of most fridges provides an ideal temperature to keep seeds in stasis for long periods of time. DO NOT use plastic bags or sealed bottles for any grains to be stored on the shelf at room temperature.

Some final points to consider:

• Some older cultivars and varieties can be very susceptible to modern diseases e.g. rust and mildew (in wheat), and net blotch (in barley). Commercial fungicides in the Triazole group have shown good efficacy if used every 3-4 weeks as a preventative. I use Tebuconazole which works systemically from within the plant to control disease with Trifloxystrobin to prevent fungal infection. I use the formulation at half strength in the seedling stage, increasing to full strength once plants are mature. Be sure to follow directions on the label carefully.

• As soils in my area are generally low in Zinc, I decided to sprinkle some commercially available Zinc oxide powder into each channel prior to planting. Zinc is also thought to help lower disease susceptibility in wheat. Zinc oxide is harmless as it is a trace element. However it can dry out the skin if handled for long periods. A spoon, small flour sifter or fertilizer spreader may be used.

• Aphids and other insect pests can sometimes pose a problem. If they reach the level of an infestation the plots may need to be sprayed. I use a residual, systemic, low toxic insecticide containing 0.05g/L Acetamiprid at the recommended strength. Again, please follow all directions on the label carefully.