Effects of Exogenous α-Ketoglutaric Acid on 2-Acetyl-1-Pyrroline, Yield Formation and Grain Quality Characters of Aromatic Rice

The improvement of grain quality in aromatic rice is very important for farmer to increase their income. Present study was conducted with a two-year field experiment and three aromatic rice cultivars in order to study the effects of exogenous α-ketoglutaric acid on yield formation, grain quality characters and the biosynthesis of 2-acetyl-1-pyrroline (2-AP, key component of aromatic rice’s fragrance) in aromatic rice. At heading stage, 0.50 mmol L–1 (T1) and 1.00 mmol L–1 (T2) α-ketoglutaric acid solutions were overhead sprinkle to aromatic rice plants, respectively while the treatment which was overhead sprinkled with distilled water was set as control (CK). The results showed that 17.34%–33.04% and 21.39%–34.74% higher grain 2-AP contents were recorded in T1 and T2 treatments, respectively. Compared with CK, T1 and T2 treatments significantly reduced the transcript level of gene BADH2 which is related to the 2-AP biosynthesis in aromatic rice. 3.86%–7.51% higher grain protein contents and 1.15%–3.37% higher head rice rates were also recorded in α-ketoglutaric acid treatments than CK. Moreover, T1 and T2 treatments remarkably decreased the chalky rice rate, chalkiness and grain amylose content. However, there was no remarkable difference in grain yield and related trails (effective panicle number, grain number per panicle, seed-setting rate and 1000-grain weight) among CK, T1 and T2 treatments. In conclusion, application of exogenous α-ketoglutaric acid enhanced 2-AP biosynthesis and improved grain quality of aromatic rice.