Genetic progress of spring wheat grain yield in various production regions of South Africa

Abstract

Successful wheat production depends on several informed production decisions, including availing stable and high yielding cultivars. Periodic evaluation of the genetic gains in grain yield is a means of determining the effectiveness of current breeding efforts in increasing wheat productivity. Data collected from the Agricultural Research Council's Small Grain National Wheat Cultivar Evaluation program (NWCEP) over the period from 1998 to 2013 were used to estimate genetic gains in grain yield of irrigated spring wheat in South Africa. Compared with three control cultivars (ʻSST 822', ʻSST 876' and ʻKariega'), the estimated genetic gain in grain yield potential in the Eastern Highveld was approximately 0.82% y−1 for all entries and 1.17% y−1 for the highest yielding entries. In the Cooler Central areas, the genetic gain was 0.40% y−1 for all entries. In the Warmer Northern areas and KwaZulu-Natal province, there was yield stagnation over the years. Strong positive correlations of yield and hectolitre mass were observed, suggesting that much of the genetic yield gains over the period were achieved through increase in seed density. However, prospects of improving genetic yield gains in the country are high through the recently implemented end-point royalty system.