Irrigation and Nitrogen Management Practices Affect Grain Yield and 2-Acetyl-1-Pyrroline Content in Aromatic Rice

Aromatic rice has a high market value due to its special fragrance and the most important compound in the grains of aromatic rice is 2-acetyl-1-pyrroline (2-AP). In an effort to improve the 2-AP content and the yield of aromatic rice, two known rice cultivars, Yungao and Yundi, were cultivated across two seasons, and two irrigation and nitrogen management practices were investigated. The results showed that the treatment management practice (TNW) treatment improved panicle number per hill, seed setting rate, and 1000 grain weight and grain yield for both cultivars in early and late season. Significant improvement in grain yield was only observed in Yundi in both seasons. Moreover, the 2-AP content in grains was increased for both cultivars in both seasons during grain filling period. Significant increase in 2-AP in grains was observed for Yungao at maturity in both seasons, at 7 d AH in early season and at 14 d AH in late season whilst for Yundi at 7 d AH, 14 d AH and 21 d AH in early season, and at 14 d AH in late season. Furthermore, 2-AP content in leaves and grains was decrease during grain filling period while proline content in grains was enhanced during grain filling period. Significant relationships were also observed between 2-AP and proline contents in the leaves/grains of both rice cultivars.