Genotype x environment analysis in sunflower (Helianthus annuus) in South Africa

English: Sunflower (Helianthus annuus) is the most important oilseed crop in South Africa with a current demand of around 600 000 ton of seed per year. The average national yield is from 1 to 1.3 t/ha. Because sunflower is planted in the marginal maize areas, the climate and interaction varies considerably. It is this variation that present selection problems for breeders and scientists. The aim of this study was to evaluate and recommend methods of stability analyses better than the normal yield ranking and ANOVA that is mostly the tools used in selection. • For this study the trials performed by the Agricultural Research Council and its cooperators were used. Entries in the trials are commercial hybrids or registered hybrids and the results would be used to ensure quality hybrids entering the market and recommending hybrids based on yield stability and oil content. • The literature review highlighted all the studies performed recently on different traits of sunflowers. Although G x E interaction has been used in India to prove the suitability of some hybrids, no comparative studies of the stability analysis could be found that would assist a breeder or scientist. • Since the rate of success of these trials was not consistent from season to season, some locations could not be used. The hybrids were not all evaluated in successive years. Since only four entries are allowed per company in one year, the hybrids are usually rotated. Thus only six locations were used in the analysis and for the across year analysis eight hybrids were common. • Using the stability analysis of Eberhardt and RusselI, Wricke's ecovalence, Shukla and Lin and Binns superiority measure, the most stable hybrids were PAN 7351 for the 1998 /99 seasons, HV3037 for the 1999 / 00 seasons, PAN 7351 for 1998/00 and PAN7355 for 1998/99/00. According to the AMMI analysis the hybrids PAN 7355 and HV3037 were most stable for the 1998/99 seasons, PAN 7351, HV3037, PAN 7371 and AGSUN8751 were most stable for the 1999/00 seasons, SUNSTRIPE350, HYSUN 345 and PAN 7392 for 1998/00 seasons and PAN 7351, PAN 7371 and AGSUN 8751 for the combined 1998/99/00 seasons. The implementation of ASV does have an influence on the use of the AMMI analysis. The ASV showed AGSUN 8751 to be more stable than PAN 7355. • Combining all the analysis measures to make a selection, PAN 7355 and PAN 7371 were the most stable. Using the advantage of the information provided by the AMMI analysis of hybrids and their adaptation to certain locations, a high yielding stable hybrid could be selected.