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Selective Breeding.

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Selective Breeding

In terms of growth and development, crops are all over the place this year. The dry September gave an emergence period in many crops of over a month, if not more. Some early sown wheat that got away in moisture look very well, but in general winter wheat does tend to look a little backward and in need of some sunshine. The warm open autumn and winter has allowed the uneven emergence to even out somewhat and even the later emerged plants are tillering well.

Manage crops to produce 600-750 ears at harvest to produce the highest yields and quality. It’s a little too early to see how things develop but in general first wheat shouldn’t require any nitrogen before mid April at stem extension, although some min tilled crops may need a boost before that as non inverted soil will not necessarily release any nitrogen until it is thoroughly warmed. With these and with second or consecutive wheat, apply nitrogen in mid march to ensure tiller numbers are sufficient to produce the correct ear numbers. About 50 kg/ha should be enough.
Don’t forget to put on sulphur with the nitrogen at GS 31/32. About 25 - 30kg/ha (63 – 75 kg SO3/Ha) when you do go on.

Good nitrogen management is the best PGR, but not the only.

...read more.


Winter barley
There are some very lush barley crops around the country, many with far too many tillers to support, also there are some fairly backward crops too. Over thick crops will increase management time, disease and lodging risk and potentially reduce yield and grain quality. The best thing to do with crops that are too tillered is leave them alone. Don’t be tempted to apply nitrogen too early, as this will encourage tiller survival. You will need, for a 2 row barley, somewhere in the region of 900-1200 ears/m2, for a 6 row 700-900 ears/m2. More than this and specific weight will begin to drop, screenings, disease risk and lodging risk will increase.

Less well developed crops will need some nitrogen in mid March to ensure tiller numbers are maintained or increased to give the ear numbers needed. About 30 - 40kg ha –1 should be enough, then wait for GS 31/32 (around early to mid April) before applying anymore.

An application of PGR at GS 27/29 to even up the tillers (and maybe encourage better rooting) is recommended.

Don’t forget the sulphur. As with wheat, barley requires sulphur and the soils are not now supplying enough in most areas. About 15kg S (37kg SO3) should be enough in average yield situations. Yield and grain quality (particularly screenings)

...read more.


Selective breeding.

Selective breeding means choosing the animals with the characteristics you want to breed with because they probably have the genes you want to pass on.

So, if you want sheep with larger bodies, but less fatty meat, you select parents which are most like the offspring you want. If you keep repeating the same selection year after year, then you increase the proportion of the genes you want.

Here is an example


This breed of sheep is called the Mouflon. It was known to stone age farmers. It is one of the two main ancestors of modern sheep. It is small, and has strong fatty meat. Instead of having a fleece which can be removed in one go, it is hairy and looses its wool in clumps.


This is the Gallway sheep, it has a tightly curled fleece, no horns (easier to handle), and a good sized body with lean tasty meat.

If you were an early sheep farmer with a flock of Mouflon, what would you look for in the parents of next year’s lambs?

In different parts of the world, sheep farmers have selected different characteristics. For example, Sheep in the Yemen have been selected over many generations for wool which is suitable for making carpets.

In hilly and mountainous areas, sheep have tended to be breed which are lighter and more agile.

As a result of many different farmers needs there are numerous breeds of sheep.

...read more.

This student written piece of work is one of many that can be found in our GCSE Height and Weight of Pupils and other Mayfield High School investigations section.

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