Page 15 - 05 Cotton SA March 2015

Nuus • News
Navorsing • Research
Finding the right cultivar to plant

at a particular planting time

By Coleen Fourie, ARC Institute for Industrial widen the window period for sowing and The trial was conducted under irrigated
Crops. ultimately optimize the total yield and conditions, following practices that are
quality of fi bre. commonly used in commercial cotton
production systems. The eff ect on
In 2013/14, a fi eld trial was conducted planting time on plant growth, yield, fi bre
btaining a vigorous and optimal at the ARC – Loskop Research Farm, qualities and the degree of whiteness
stand is the fi rst step for Groblersdal, by planting diff erent cotton (colour values) of the diff erent cotton
profi table cotton production. cultivars were determined. The air and
OThe use of appropriate cultivars cultivars over a period of eight weeks to soil temperatures were measured daily.
determine which cultivar is most suitable
and agronomic practices in suitable A soil temperature meter was installed
environmental factors is a prerequisite for for a particular planting date. Seven cotton on the 30th of September to record soil
such success. Environmental factors such cultivars: three standards (Candia B2RF, temperature during the sowing season of
as soil temperature determines the time of Delta12BRF and DP210BRF), three new the eight planting dates. Records on the air
planting cotton. cultivars (13P3001B2R2, 13P3005B2R2 temperature were obtained from the local
and Delta1240B2RF), and one Okra leaf weather station.
In South Africa, the window for sowing (DP1441RF) were selected for this trial. Each
cotton in is very narrow and has a major cultivar was planted weekly in the window Cultivar adaptation and successful
infl uence on the yield and fi bre qualities. period of 7 October 2013 to 25 November production are infl uenced by climatic
Finding the most suitable cultivar for 2013, making a total of 8 planting dates for conditions, especially temperatures during
a particular planting date can help to each. specifi c phases of the growing season. The
minimum and maximum temperature data
Air temperature – October for October and November 2013 is given
below in Fig 1.
The minimum temperature data collected
at the weather station was lower during the
fi rst part of October 2013 than the long-
term values. In contrast, the minimum
and maximum temperature data collected
at the weather station or November 2013
indicated warmer temperatures than the
long-term values.

Cotton should not be planted before the
top 30mm of soil has not maintained a
temperature of 16 to 18°C or higher. A few
cold fronts during the fi rst half of October
2013 kept soil temperatures below 16°C.
However, during November 2013, the soil
temperatures were normal.
Air temperature - November
From the compared analysis, the fi rst
planting date (7-Oct-13) resulted in very low
average germination percentages of 10.1 at
7 days after planting but this increased to
49.9% by 14 days for all the cultivars. The
germination percentage of the third (21-
Oct-13) and fourth (23-Oct-13) planting
dates were infl uence by heavy rains and hail.
The eff ect on yield, fi bre qualities and the
degree of whiteness (colour values) of the
diff erent cotton cultivars were determined
at various planting dates.

From the combined analysis, the cultivars
13P3005B2R2, 13P3001B2R2 and DP210BRF
had the highest yields. Over all, the cultivar
13P3005B2R2 had the highest seed cotton
Figure 1. Daily air temperature at ARC – Loskop Research Farm, Groblersdal, during October yield compared to the rest of the eight

and November 2013. >>> 16
Katoen SA Cotton 15 January-March 2015