Introgressions from Oryza rufipogon Increase Photosynthetic Efficiency of KMR3 Rice Lines

Abstract

To understand the wild Oryza genome effect on photosynthesis and its relation to total dry matter accumulation in an elite rice variety, a set of 40 stable introgression lines (ILs) BC3F8 derived from a cross of Oryza sativa (KMR3) × Oryza rufipogon (WR120) were grown under well watered conditions. Leaf gas exchange measurements and leaf chlorophyll estimates were conducted at the flowering stage. The results revealed significant variations in net photosynthetic rate (Pn), transpiration rate (E), transpiration efficiency (Pn/E) and carboxylation efficiency (Pn/Ci). Pn showed significant positive correlation with E, stomatal conductance (gs), Pn/Ci and total canopy dry matter. Specific leaf area and leaf thickness were not significantly correlated with Pn. Thirty-seven out of 40 ILs showed higher Pn than KMR3 [11.28 μmol/(m2·s)], and 20 ILs showed higher Pn than WR120 [15.08 μmol/(m2·s)]. The line IL194 showed the highest Pn [21.62 μmol/(m2·s)] with increased total canopy dry matter followed by lines IL381, IL106, IL363-12, IL198, IL86-18 and IL50, which exhibited Pn above 18.0 μmol/(m2·s). The ILs with enhanced Pn are a potential source for developing rice varieties and hybrids with higher biomass and yield.

Keywords

• photosynthesis
• wild species
• rice
• yield
• biomass
• introgression line