Original Articles

The effect of plant population on the quality of sunflower seed for processing

Published in: South African Journal of Plant and Soil
Volume 17, issue 1, 2000 , pages: 6–9
DOI: 10.1080/02571862.2000.10634858
Author(s): A.A. Nel, Republic of South Africa, H.L. Loubser, Republic of South Africa, P.S. HammesDepartment of Plant Production and Soil Science, Republic of South Africa


Among other disadvantages, low hullability of sunflower seed results in oil cake with a high fibre and low protein content. Hullability is known to increase with increased seed size. Seed size generally decreases with an increase in plant density. The objective of this experiment was to determine the effect of plant density on hullability other physical trails and chemical seed composition of three sunflower cultivars. In a field trial at Potchefstroom the cultivars HV 3037, PAM 7392 and SNK 37 were planted in rows 0.9 m apart at densities of 20 000, 35 000 and 50 000 plants per ha in a randomised complete block, design with two replicates. Yield and seed trails differed among cultivars. Seed oil and protein content was not affected by plant population. Grain yield and hull content were significantly higher for the 20 000 than for the 35 000 and 50 000 populations. The thousand seed weight, a measure of seed size, decreased for all cultivars with increased plant population, The hullability of HV 3037 and SNK 37 declined with increased plant population, while it changed relatively little for PAH 7392. Higher hullability for the 20 000 population resulted in a higher protein content of the kernel rich fraction. Indications are that plant populations lower than the recommended 35 000 plants ha−1 will maximise hullability and minimise losses due to fine material.

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