Nitrogen effects on SPAD meter and grain yield relationships in F2 durum wheat populations

Abstract

This study was conducted to evaluate the effectiveness of SPAD-502 chlorophyll meter reading as indirect selection criteria for grain yield under different nitrogen (N) conditions in F₂ durum wheat populations. In this study six durum wheat parents and their 6x6 half-sib F₂ diallel cross populations were grown under N0 (zero N), N1 (120 kg/ha) and N2 (240 kg/ha) nitrogen conditions. Chlorophyll content at heading stage was obtained by using SPAD meter (SPAD-502; Minolta, Osaka, Japan). SPAD readings and grain yield of durum wheat increased with increasing nitrogen level. Genotypic variation for grain yield and SPAD was found to be highest in N₁ and N₂ levels, respectively. General combining ability (GCA) effects were significant for plant grain yield in N1 conditions, while significant for SPAD in N1 and N2. Significant specific combining ability (SCA) effect was observed only SPAD readings in N2 condition. High GCA/SCA ratio showed that additive genes have significant role at SPAD values of N1 and N2. Grain yield correlated with SPAD of N0 (R² = 0.328). The results indicate that  genotypic differences for SPAD reading among F₂ durum wheat progenies can be effectively detected in high nitrogen condition.