Recommended maize varieties - attempt to weather-proof your choices

The new forage maize recommended lists were published recently by the Department of Agriculture. These lists see significant change in the varieties recommended for sowing in the open and there are two additional new varieties recommended for planting under plastic.

The list for planting under plastic contains Award, Justina and Tekni with full recommendation, plus Grosso and P7905 with provisional recommendation for the first time.

Of these, the new latter P7905 from Pioneer has the highest dry matter yield with a good combination of starch and dry matter content. The list for planting in the open has seven varieties (one less than last year) and two new provisionally recommended varieties, Activate and Severus.

Why use a recommended variety?

This is a valid question for a grower to ask. Start with the obvious – maize is a notoriously variable crop from year to year, with yield performance and variety relativity highly variable.

Indeed, it is the most variable of all crops, so picking last year’s winner provides no guarantee of next year’s success.

Most growers know this, but the variability of crop performance is also heavily influenced by variety choice. And this situation is exaggerated by the fact that more than two-thirds of commercial maize crops are currently grown from non-proven and non-recommended varieties.

Recommended lists are used in all crops to help evaluate, in advance, the varieties that are best suited to growing conditions in this country. Growers depend on them for their variety choice in most crops and this process is even more critical in a highly variable crop like maize.

What the recommended list tries to do in all crops is to have a list of recommended varieties that are relatively weather- and year-proof.

Recommended varieties should be a safe bet for growers every year. Recommended lists may not contain the headline variety in a really good year if it subsequently performed very badly in a poor year.

To help do this, varieties are assessed over a three-year period and at a number of different sites in the country to help iron out this variability.

It’s not just about yield. For other crops like cereals, yield is an important consideration, but so are disease resistance, standing ability, grain quality, etc. However, these latter characteristics tend to be relatively stable from year to year.

Maize is more complex. Yield is the initial measure of performance for the crop, but its usefulness to the end user depends on how this is composed.

Yield equates to bulk, but its usefulness to an animal depends on the dry matter present in this bulk and the proportion of the total yield that is made up of starch, the most useful component of the crop for animal performance.

These values can differ considerably in varieties from year to year and they can also vary from site to site.

A suitable variety with a strong average yield and good starch content can provide the user with more feeding value than a bigger bulk with low starch.

Variability

Varieties that show big site-to-site variation and big year-to-year variability are potentially dangerous choices. It shows that that variety is quite sensitive to some element of the environment, which could be site or weather, or some combination of both.

In the uncovered recommended list trials, the average yield of the control varieties was 9.35t/ha, 17.6t/ha and 19.8t/ha in 2012, 2013 and 2014 respectively. In the same years, the starch contents were 15.4%, 26.1% and 28.4% respectively.

Variability is not just confined to planting in the open. In the covered trial at the Cork site, the variety Tekni produced a relative yield of 115% in 2012, but it was only 94% of the control varieties in the better growing year of 2014.

The new variety, P7905, yielded 117% in Cork in 2012, but still yielded almost 104% in 2014. Similar variation occurred with other varieties at other sites, with Justina going from 109% in Kilkenny in 2012 to 100% in 2014.

Not all varieties show the same year-to-year variability – these seem to cope better with the relative vagaries of the Irish weather.

The recommended variety Award did 105%, 105% and 103% over the past three years in Cork. And while Cork would be a more favourable county for maize production, the average yields at that site ranged from 15.21t/ha in 2012 to 20.16t/ha in 2014.

But at the Kildare site, the average yields ranged from 13.9t/ha to 22.4t/ha. And this is happening with varieties that are proven to be better suited to Irish conditions.

Plastic performance

The use of plastic, and varieties that are suited to growing under plastic, is seen by many as an insurance policy against the vagaries of climate. It certainly helps, but it is not enough to boost a poorly suited variety.

Remember, there can be no full compensation for poor conditions and less suitable varieties will still struggle under plastic when such years occur.

Up to 2015, there were very few varieties on the recommended list for planting under plastic. This was primarily due to the fact that other varieties tested just did not measure up over time. This tells growers that it is difficult to get new varieties that will outperform the consistency of proven performers.

An individual variety might have one good year but then suffer badly in a bad year. Such a variety is unlikely to produce good average performance results and so is unlikely to be recommended.

So the recommended list provides performance confidence to a grower over time. It also identifies varieties suitable for less favourable sites and also with specific traits for end users, such as high starch.

Grower confidence

The recommended list attempts to combine the relative benefits of yield, maturity and starch content into the evaluation of the potential of that variety for Irish growers in Irish conditions.

On the recommended list, a relative yield of 100% represents high yield potential because it is selected from among the best.

Figures of 100 also provide a good guide against which to assess variety dry matter and starch content.

Having all of the data compared in the same way enables the grower to select varieties that better suit his/her specific site and situation each year.

If you depend on maize for your forage, then it is important that your crop performs.

One can choose on the basis of earliness, or not, or safeness, or not, as suits the site. But you do need to know where you are on this scale and understand the choices you are making.

Ultimately, maturity is the key to the risk you are taking with a variety and its subsequent performance.

The target remains 28% to 32% dry matter and 25%+ starch content. Your variety needs to use every day of its growing life to optimise its yield potential on that site.

If you are forced to sow late, then you should plant an early maturing variety. The converse is also true – later maturing varieties offer better potential when sown earlier.

Site variability

Site is an important part of the production jigsaw and the quality of the field, its orientation and fertility, can limit or enhance the performance of a specific variety.

Uncertain farm yields

Growers have relatively little knowledge of actual farm yields. Yields are extrapolated from bulk and trailer loads, so there is very little real measurement of actual farm and field yields.

Some varieties with high yield potential are relatively late maturing, so if the year is not favourable, one can lose crop dry matter and starch content, as well as bulk.

It could be that potential gains in a good year could be more than offset by disappointing performance when weather conditions are less suitable.

The 2015 recommended lists

The 2015 recommended list for sowing in the open has one less variety at seven, while the number of varieties recommended for planting under plastic is increased from three to five.

The list also provides, for the first time, information on the other varieties in trials in 2014. Varieties with poor performance are discontinued after one to three years and some varieties currently grown commercially in Ireland have never been submitted for official trialling. Others have long been discarded. The absence of sufficient lodging during the three relevant years (2012 to 2014) means that no lodging data can be provided.

In the tables, a variety name followed by (R) is recommended for general use, while (PR) signifies provisional recommendation and the number after the PR indicates the number of years the variety has been provisionally recommended.

It must be emphasised that the yield and quality data shown in Table 1 and Table 2 should not be compared directly because the different sets of trials were grown in different locations and under different conditions.

Varieties for sowing in the open

Details of the recommended varieties and their characteristics are shown in Table 1. The data is based on results of trials carried out over three years in the period 2012 to 2014. Acclaim, Destiny and Kougar have been dropped.

Activate (PR-1)

Yield is below average, but this is a very early-maturing, high-starch variety (similar to Acclaim). Its high dry matter content indicates its suitability for unfavourable sites. Bred by Limagrain Verneuil Holding and handled here by Goldcrop.

Ambition (R)

Now fully recommended. It has very high relative yield, good DM levels and good starch content. So it is a tall but versatile variety with early maturity. It has a very high ME value. Bred by Limagrain and handled by Goldcrop.

Atrium (R)

Now fully recommended. High yield potential with good starch but low dry matter content. Late maturing. Also from Limagrain but it is handled by SeedTech.

Beacon (R)

Average dry matter yield and content with good starch. It is tall and is medium to early maturing. Another Limagrain variety handled by Goldcrop.

Beethoven (R)

High yield potential but with only moderate dry matter and low starch content. Medium late maturing and tall. Its ME value is well below average. Needs good growing sites. A Limagrain variety through SeedTech.

Kroft (R)

Below-average yield potential but it has very high DM and starch content. Early maturing. This one was bred by KWS and comes through SeedTech.

Severus (PR-1)

New on the list with good yield and dry matter ratings and high starch content. Early maturing but with lowish ME value. Also bred by KWS and handled by SeedTech.

Varieties for planting under plastic

The yield data in Table 2 shows that the plastic system is leaving higher yield than the uncovered controls in Table 1. But the last two good years have reduced the quality benefits from plastic cover in the trial results.

In recent years, over 80% of the maize area was grown under plastic to help reduce the climate risk to the crop. But the planting of later-maturing, higher-yield potential varieties under plastic to help derive benefit from the additional cost involved still contributes to production risk.

Award (R)

High yield potential with high dry matter and very high starch content. It is medium to early maturing with very high ME value. It is relatively slow getting through the plastic. A Limagrain variety which comes through Goldcrop.

Grosso (PR-1)

Good yield with low dry matter but very high starch content. Medium to late maturing. More suited for early sowing in favourable sites (more towards the south of the country). Bred by KWS and handled by SeedTech.

Justina (R)

A long-serving variety with very high yield potential, but its dry matter and starch content are only moderate. It has good ME value but is medium to late maturing and benefits from early sowing. It is fast through plastic. Bred by DuPont Pioneer.

P7905 (PR-1)

The highest yielding variety with low dry matter and good average starch content. Medium to late maturing. More suited for early sowing in favourable sites. Bred by DuPont Pioneer.

Tekni (R)

High-yielding variety with good dry matter and starch content. It is medium to early maturing and is quite fast through plastic. Bred by Caussade and handled by Goldcrop.