Durum wheat quality in Mediterranean environments III. Stability and comparative methods in analysing G E interaction

Stability of grain quality characteristics is an interesting feature of today’s durum wheat breeding programmes, due to the high annual variation in both grain yield and quality, particularly in the Mediterranean area. Ten field trials were carried out during two seasons (1998 and 1999) in both the north (Lleida) and south (Granada and Jerez) of Spain. Ten durum wheat genotypes were used, including four Spanish commercial varieties and six advanced lines from the durum wheat breeding programme of CIMMYT-ICARDA. Many quality parameters were evaluated in this study including thousand kernel weight, test weight, vitreousness, ash content, protein content, pigment content and the SDS sedimentation test. Several statistical methods and techniques were used to describe the genotype environment (G E) interaction and to define stable genotypes in relation to the seven quality parameters considered in this study. The partition and interpretation of the G E interaction revealed that the joint regression analysis was not efficient and demonstrated the usefulness of AMMI for describing the interaction patterns. The study of genotypic stability demonstrated that the Spanish commercial varieties, Altar-aos and Jabato and the CIMMYTICARDA advanced line, Waha, had high stability for quality characteristics and proved to be the best within the pool of the studied genotypes. # 2002 Elsevier Science B.V. All rights reserved.