New soybean cultivars

Written by Dr Antony Jarvie and Peet van der Walt for Pannar Seed

There are many factors that contribute to the trend of increased soybean yields over time. The simple truth is that rainfall is the most significant factor influencing the national crop because rainfall variability drives seasonal fluctuations, which commonly dwarfs all other factors. Only once we remove the effect of rainfall variability, is it possible to see the gain attributed to new technology. Very rarely do we see massive stepwise changes in yields attributed to technology, most often gains are realised by the accumulation of small incremental improvements to production systems.

Seed is often seen as the delivery system of technology to the farm, either on the seed (as in seed dressings) on in the seed (as in genetic improvements). South Africa is now on the brink of a new era in soybean GM traits, which has been made possible by the implementation of the End-Point-Royalty system that has been the incentive for seed companies to invest in soybean research. On the horizon in the Corteva group are traits like E3, which will enable soybean farmers to have unprecedented flexibility in weed control. Further, there are also plans for the deployment of a Bt- derived insect resistance in combination with these herbicide resistances to further improve production systems. These are great innovations, but amount to very little if not deployed within good cultivars and combined with the appropriate farming practices. In the background, cultivar improvement is the bedrock on which we build yield improvement.

There are different ways of determining genetic progress, but it is commonly measured as being between 1-2% per year. Assuming you have a new cultivar which is 5% better than the mean of all the cultivars in the market in the year of launching, by the second year the mean would have moved upwards by 1% leaving the new cultivar only 4% better than the mean. This continues until the cultivar is below average and then it drops out of the commercial market. From our experience, cultivars last about 6 years in the market. Obviously, those cultivars starting off only marginally better than the average lose traction quicker, and the blockbusters stay for many more years. The message here is that quick adoption of new cultivars is a sure way of keeping ahead of the average, but it also means that old trusted cultivars need to be relinquished in order to do this. There is an element of trust that goes with this, and the more trust that you have in your seed supplier’s yield data, the quicker you can transition to new varieties.

Assessment of the Pannar range for 2021

The Pannar range consists of six commercial varieties, all having been in the market for different lengths of time. As with all crops, there is a yield penalty for having a shorter growing season with which to amass grain yield. This sector of the maturity range turns over new cultivars much slower than the main maturity groups as expected. Pannar have a newish entrant to this maturity group (PAN 1479R) and a mature variety (PAN 1532R) to service this end of the market. Very often the short maturity is the primary attraction and the cultivar is chosen to fit a defined farming practice, such as late planting after double cropping with wheat. The cost of a lower yield due to the short maturity is made up for by the ability to double crop and generates a gain to the system as a whole.

The mid maturity range of MG5.5-6.4 is anchored PAN 1521R. This is probably the most versatile variety I have ever had the pleasure to work with. It is well established in the market and has an unquestionable track record. PAN 1555R combines superbly with PAN 1521R, to cover areas within mid-maturity range that are under serviced. The mid-maturity range covers a multitude of farming conditions: wide rows; narrow rows; dry land; very dry land; irrigation; no-till; sandy soils; high clay soils to name but a few. This is an important maturity sector, and it is serviced by two fine cultivars. Traditionally, high yield potential is associated with a longer grain-filling period. The Long growing season varieties within the Pannar range do not disappoint in this regard. PAN 1644R gained immediate traction in the market following its launch. It is an incredibly versatile variety, and perhaps the biggest danger with this variety is using it in areas that have unseasonal frost threats before the variety matures. PAN 1653R is a mature product within the Pannar range that has good all-round performance but a reasonably niche adoption. There are two new varieties in the wings that have not yet been released for production, so we wait with anticipation to see which of the new varieties will make it into this formidable range, and which will be forfeited in the name of technology gain.