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Desember 2015
30
An overview of the
local wheat crop quality
of the 2014/2015 production season
T
he commercial wheat crop of the 2014/2015 season was set
at 1,750 million tons, which is 120 000 tons lower than the
previous season’s crop and 7% lower than the ten year pro-
duction average of 1 885 800 tons (2004/2005 to 2013/2014
seasons).
The Western Cape contributed just more than half of the total crop.
The Northern Cape’s irrigation areas, although still the second larg-
est producer of wheat, with 285 000 tons, produced 35 000 tons
less than the previous season.
The area utilised for wheat production continued its declining trend,
decreasing by almost 43% from the 2004/2005 season and by 6%
compared to the 2013/2014 season. Decreased plantings by dryland
wheat producers in the summer rainfall area (Free State) are the larg-
est contributing factor to this observed decline. Dryland wheat is
planted on approximately 73% of the total 476 570 ha, although its
contribution is only 53% to the total crop figure.
The average national yield was 3,67 t/ha and varied with only
0,04 t/ha over the last three seasons. The yield in the main pro-
duction areas ranged from 2,85 t/ha in the winter rainfall area
(Western Cape) to 7,50 t/ha for irrigation wheat produced in the
Northern Cape.
Wheat grades
The 337 representative crop samples were graded as follows: 31%
was graded B1, 18% B2, 13% B3, 5% B4, 26% utility grade (UT) and
7% class other wheat (COW). The majority of the samples (69%)
downgraded to utility grade was as a result of the percentage of ei-
ther other grain and unthreshed ears or insect damaged kernels or
a combination of both exceeding the maximum allowable level for
grades B1 to B4.
The percentage total damaged kernels and/or combined devia-
tions (19%) were also contributing factors. Of the samples down-
graded to class other wheat, 68% was due to the presence of live
insects and 24% as a result of the percentage field fungi infected
kernels exceeding the maximum allowable level of 2%.
Grade B1 wheat in the Free State amounted to 48% (38% in the previ-
ous season). In the irrigation areas 46% (39% in the previous season)
of the wheat graded as B1 and in the Western Cape 8% graded as
B1 (12% in the previous season).
Cultivars
The most popular cultivars in the Western Cape were SST 015
(31,4%), SST 88 (28,7%), SST 056 (12,4%) and SST 027 (12,0%).
Producers in the Vaal and Orange River areas preferred SST 835
(26,7%) and PAN 3471 (23,9%), followed by SST 843 (16,4%) and
SST 875 (13,7%). The most preferred cultivar in the North West
Province was SST 843 (29,9%) followed by SST 835 (27,3%), Duzi
(18,8%) and SST 884 (11,3%).
In regions 21 to 24 of the Free State, SST 387 (20,3%) was the prev-
alent cultivar, followed by PAN 3120 (14,1%), SST 835 (11,1%) and
SST 843 (11%). Elands (17,3%) was the most planted cultivar in
regions 25 to 28, SST 835, PAN 3161 and SST 356 were also popu-
lar cultivars with 16,3%, 15,5% and 10,7% respectively. In Mpuma-
langa, Gauteng, Limpopo and KwaZulu-Natal, SST 843 (29,3%)
and SST 835 (26,8%) were the dominant cultivars, followed by
SST 884 (15,8%).
The abovementioned percentages are weighted averages based
on the top five cultivars per region as calculated from the cultivar
identification done on each of the 337 crop samples.
Quality
All national, seasonal and regional averages provided in this article
are weighted averages.
The national whole wheat protein average has varied with less
than half a percent over the last three seasons, from 11,4% in the
2012/2013 season to 11,8% in the 2014/2015 season. The percentage
of samples that has a minimum protein content of 12% (reported on
a 12% moisture basis), increased from 39,5% in the previous season
to 45,5%.
Although the winter rainfall areas again reported the lowest aver-
age whole wheat protein, namely 11,1%, this value is slightly higher
than the previous two seasons. The production regions in the
Free State reported the highest average protein content (12,4%)
followed by the 12,1% of the irrigation areas.
The flour protein content of 10,7% was equal to the previous two
seasons. The flour protein content is on average 0,5% to 1,2% lower
than that of whole wheat. This protein loss can be attributed to the
removal of the bran and aleuron layer as well as the germ during
the milling process.
The Dumas combustion analysis technique is used for the deter-
mination of crude protein. Combustion of the sample at a high
temperature (1 100°C) in pure oxygen sets nitrogen free, which is
measured by thermal conductivity detection. The total nitrogen
content of the sample is determined and converted to equivalent
protein by multiplication with a factor of 5,7 to obtain the protein
content. This factor is based on the amino acid composition of
the proteins in wheat as well as the varying levels of non-protein
nitrogen present in wheat.
Compared to the previous season, the average hectolitre mass in-
creased by 0,7 kg/hl to 80,2 kg/hl and was just below the six year
weighted average of 80,3 kg/hl. Of the 26 samples that reported
values below the minimum level for grade B1 wheat, ten originated in
the Western Cape (winter rainfall area), 15 in the Free State and only
one in Mpumalanga. The regional averages ranged from 79,2 kg/hl
in the Free State regions to 81,2 kg/hl in the irrigation areas.
The thousand kernel mass, reported on a 13% moisture basis, de-
creased from 39,3 g in the 2013/2014 season to 38,8 g this season.
The winter rainfall areas had the highest average value, namely
39,7 g and the Free State the lowest at 36,8 g. Screenings
(1,8 mm sieve) averaging 1,55% compared well with the previous
two seasons.
RELEVANT
JOLANDA NORTJÉ,
manager: Laboratory, Southern African Grain Laboratory NPC