Grain Yield, Quality and 2-Acetyl-1-Pyrroline of Fragrant Rice in Response to Different Planting Seasons in South China

Abstract

Climate conditions is an important factor affected the fragrant rice growth and development. In order to study the effects of different planting seasons on fragrant rice performance in South China, present study was conducted with three planting seasons (early season (April to July), middle season (June to September) and late season (August to November)) and three fragrant rice cultivars, ‘Basmati-385’, ‘Meixiangzhan-2’ and ‘Xiangyaxiangzhan’. The results showed that the highest grain yield and grain 2-acetyl-1-pyrroline (2-AP, key component of fragrant rice aroma) content were both recorded in late season treatment while the fragrant rice in middle season treatment produced the lowest grain yield, grain filling percentage, 1000-grain weight and gain 2-AP content. The highest contents of precursors (proline, pyrroline-5-carboxylic acid and 1-pyrroline) which related to 2-AP biosynthesis were recorded in late season treatment compared with early season treatment and middle season treatment. The highest activities of enzymes (proline dehydrogenase, pyrroline-5-carboxylic acid synthetase and ornithine transaminase) which involved in 2-AP biosynthesis were also observed in late season treatment. Moreover, the fragrant rice cultivars in late season possessed the lowest chalk rice rate, chalkiness as well as the highest brown rice rate, head rice and protein content. Thus, the optimal season for fragrant rice production in South China is the late season.