KWS Maize visit

Earlier in September I had the pleasure of going to the KWS demonstration site in Lydney, Gloucestershire to look at current and possible new varieties that are currently in the market and the development of seed that may enter the market in upcoming years. Whilst I was there, I had the opportunity to learn about the development of maize and how the seed is produced.

Desires of maize

An average maize crop will produce 15-18 tonnes to the acre, with 50% of yield being from the stalk of the plant and 50% of the dry matter yield being from the cob. The cob allows the production of grain and starch, so as breeders this is where most focus goes in creating new varieties for higher yields and early harvesting. When harvesting, a farmer should aim to cut at a peak time in order to allow the highest level of digestibility and starch.

To know when the best time to harvest is, you can check this by breaking a cob in half and squeezing the grain. There should be little to no ‘milk’ in the grain with the seed being white inside. With the grain, you can also indent this with your nail and it should just about take an imprint.

Another useful way is to cut the stalk above the second node, twist the stalk and ring it where you should see the odd drip, you don’t want it to be too wet!

The first commercial hybrid growth

A hybrid maize crop is a cross of two different varieties – Flint and Dent. Flint is the female of the varieties, bringing earliness and tolerance within the crop. Flint is not very high yielding, therefore it is bred with Dent, the male variety, to bring the component of yield.

In this image, you can see that the male parent (Dent) is stunted in growth. This is because the seed is interbred with itself over 7 generations in a concealed area to be able to produce a pure genetic of itself before it can be bred with flint, which undergoes the same process.

Dent and Flint maize are not commercially viable to be grown alone as they don’t have high yielding contributes. Therefore, they are crossed. To do this, four rows of the female, Flint, are grown with two rows of the male, Dent, either side. Once the female reaches a certain height, the tops of the female are cut off. This is because the reproductive element of the female is the silk on the cob, so you don’t want the crop to reproduce with itself. Instead, the male component from Dent is produced in the tassel of the crop as pollen, therefore the desire is that the pollen produced from the Dent lands on the silk of the Flint, producing a hybrid grain. This is known as a two way cross.

The Dent line 1 is a bigger plant than the F1, showing its yield ability. These plants bred together gives you a hybrid plant – in this case, D1 X F1.

A more modern way of breeding is a three way cross. This is where a breeder will take two dent lines, for example Dent A and Dent B and cross these to produce Dent C, which can then be bred with Flint. By doing this, it allows a new set of genetics that allows more productivity on the production site of seed per acre with a more vigorous and bigger plant.

This gives the breeder the parent line, which allows the beginning of a commercial seed process to begin. Commercial seed processes happen outside of the UK in European countries due to better weather conditions, this is so pollen doesn’t shut down in the cold or get washed away which can caused stunted growth. The hybrid seed will be sent to the UK for trialling and sale once produced.

Seed rate discussion

There was clearly plenty to learn at the KWS site and there were lots of interesting viewpoints to talk about! However, one of the most interesting part of the site for me was the wheel trial.

This photo shows the difference between a seed rate of 42,000 seeds per acre (right cob) as opposed to the 45,000 +seeds per acre (left cob).

Farmers may increase seed to try and gain higher yields at harvest, however due to competition for light this means that stalks are tall and cobs shrink, delaying maturity and offering more chance of lodging and fallen crop.

This image shows where over 45.000+ seeds have been planted, with over 180,000 in the middle of the wheel, showing increased prevalence in lodging.

This is why it is important for farmers to work with nutritionists and forage experts, selecting varieties that work for their soil type, altitude and climate in order to reach maximum yield, but also provides the maximum nutritional value for the animal.