Promising new cultivars for Western Cape

Willem Kilian and Ernest Dube of the Agricultural Research Council (ARC) Small Grain Institute in Bethlehem, and Henzel Saul of the institute’s branch in Stellenbosch, report on trials conducted on two new wheat cultivars for the winter rainfall region.

In the latest field trials on wheat cultivars in the winter rainfall region, the average yield across all cultivars was lower than that of the previous season, due to lower rainfall later in the season.
Photo: Courtesy of Sensako

As part of the National Cultivar Evaluation Programme, trials were conducted on two new wheat cultivars in different environments in the Western Cape during the 2014 season. Sensako’s SST 0127 and Pannar’s PAN 3515 were tested along with 12 better-known cultivars in seven sub-regions of the winter rainfall region.

The average yields for wheat in the winter rainfall region in the 2014 season were lower than those of the previous season, mainly due to drier periods in August and September. In the Swartland, the average yield was 4,03t/ ha, compared with 4,77t/ ha in the 2013 season.

In the Rûens region, the average yield was 3,1t/ ha. This was 0,56t/ ha lower than the average of 3,66t/ha in 2013.
The yields achieved in 2014 should rather be compared with the average yields for the 10-year period from 2005 to 2014 (see graph 1). The 10-year average for the Swartland was 3,91t/ ha and for Rûens 3,44t/ha.

Compared with these averages, the 2014 yield in the Swartland was slightly above average, while the average yield in Rûens was marginally lower. Production was relatively stable over the 10-year period, with the lowest yields achieved in both production areas in 2010 (3,11t/ha in the Swartland and 2,63t/ ha in Rûens).

All the results in graph 1, as well as the cultivar performance results for 2014, were from trials jointly conducted by the ARC Small Grain Institute and the Western Cape Department of Agriculture. The National Cultivar Evaluation Working Group approves the results every year and makes recommendations for the regions.

Gradual phase-in

Producers are advised to gradually phase in new cultivars, while also taking into account the long-term yield stability of cultivars. For this purpose, the three-year average yield figures are also given. These reflect a direct measure of yield stability across a number of sub-regions.

Swartland trial results

The contributions of each of the 14 cultivars to the average yield of 4,03t/ ha for the 2014 season are shown in graph 2.
The cultivar SST 0127 delivered the best yield (4,24t/ha), followed by SST 087, SST 027 and PAN 3408. The yields of the latter three cultivars showed no significant statistical differences when compared with SST 0127.

The three-year data from 2012 to 2014 indicated a good average yield of 4,28t/ ha (see graph 3). From a producer’s perspective, it is good news that the top five cultivars, four of which are commercially available, do not differ statistically. This means that any of the four, SST 087, PAN 3408, SST 015 and SST 056, can be recommended with confidence.

Rûens trial results
The yield performance of all cultivars in Rûens for the 2014 season is shown in graph 4. The average yield across all cultivars and locations was 3,1t/ ha, compared with 3,66t/ ha in the 2013 season. In this area, as with the Swartland trials, the new cultivar, SST 0127, had a significantly higher yield at 3,61t/ ha than any of the other cultivars. There was no significant statistical differences between the performance of the six cultivars; they ranged from SST 087 to SST 047.

The average yield achieved in Rûens by the 12 cultivars in all locations for the three-year period from 2012 to 2014 was 3,57t/ha (see graph 5). The one cultivar that really stood out in this area was SST 087, with an average yield of 3,98t/ha.
Over the three-year period, SST 087 achieved a significantly higher yield statistically than the other cultivars. There were no significant statistical differences between the performance of SST 056, Ratel and PAN 3471.

Other important properties
According to the cultivar evaluation team’s report, it is clear that there are a number of wheat cultivars available that can achieve good yields in the Western Cape, if factors such as climate and pest and disease risk are excluded. Various expert groups, including seed companies, the Small Grain Institute, and the University of the Free State, made important contributions to the cultivar assessment process. These are summarised in tables 1 and 2 and offer important information for environmentally-specific cultivar selection.

Recommendations
The National Cultivar Evaluation Working Group made a final selection of the cultivars recommended in each specific production region, and no changes were made to the list of recommendations for the 2015 production season.

This research was made possible by the financial support of the Winter Cereal Trust and the Agricultural Research Council.
Email Willem Kilian at
[email protected].