ความแตกต่างระหว่างพันธุ์ข้าวหอมไทยในการตอบสนองต่อแมงกานีสในการสังเคราะห์ 2-Acetyl-1-Pyrroline และผลผลิต

Abstract

At present, fragrant rice is popular because of its special properties, the production of fragrant substances. In addition, fragrant rice has good cooking qualities such as softness of grain. Making fragrant rice popular and growing demand for consumption. However, fragrant rice has low grain yield and unstable aroma quality, which is controlled by many factors such as genetics and environment. Therefore, the objective of this research was to analyze the difference between Thai fragrant rice varieties in response to manganese (Mn) in 2-Acetyl-1-Pyrroline (2AP) biosynthesis and yield. The study of differences between Thai fragrant rice varieties in response to Mn in 2AP and yield was conducted as pots experiments in greenhouses at the research field of Agronomy Division at Mae Hia Agricultural Research, Demonstrative and Training Center of the Faculty of Agriculture, Chiang Mai University. This study employed a completely randomized design with a factorial treatment design. The first factor was four Mn (MnSO4) rates comprising the control pot without Mn application (Mn0) and those with Mn application at rates of 150 mg/kg soil (Mn150), 200 mg/kg soil (Mn200) and 250 mg/kg soil (Mn250) and the second factor was the three rice varieties Buer Ner Moo 4 (BNM4: indica subspecies), Khao Dok Mali 105 (KDML105: indica subspecies) and Kum Hom Morchor (KH CMU: Tropical japonica subspecies). At five days after flowering, OsPRODH gene expression was analyzed in rice leaves by semi-quantitative RT-PCR technique. At maturity, aromatic compounds (2AP: 2-Acetyl-1-Pyrroline) in rice were analyzed using HS-GC/NPD technique. The concentration of Mn in straws and grains were analyzed. Yield and yield components were recorded. The results showed that Mn concentration affects grain aroma, the expression of OsPRODH gene, yield and yield components. For grain aroma, it was found that rice varieties responded differently to Mn concentrations in term of 2AP. The indica subspecies showed the highest response to Mn with the highest 2AP content at Mn250 with the content of 0.02 mg/plant in BNM4 and the content of 0.06 mg/plant in KDML105 and 2AP tended to increase with increasing Mn concentrations. However, the KH CMU which is a Tropical japonica subspecies did not respond to Mn application in the term of 2AP content, with the average of 2AP content less than 0.01 mg/plant. While the expression level of OsPRODH gene in Tropical japonica subspecies with no Mn in soil showed higher expression level of OsPRODH gene than those with Mn application. Whereas the indica subspecies, higher expression levels of the OsPRODH gene were found when Mn were applied. In addition, higher Mn concentrations increased several yield components, such as the number of tiller/plants, number of panicle/plants, number of secondary brunch, plant height, straw dry weight, including the percentage of filled grain, resulting in higher grain yields. In addition, higher Mn concentration affected Mn concentrations in grain and straw and the amount of total Mn uptake/plant. A correlation was also found between the concentrations of Mn in grain and straw and the productivity of Thai fragrant rice as well. The results obtained in this study demonstrated that proper management of Mn concentration in rice varieties was necessary to improve both grain yield and aroma of Thai fragrant rice. The results of this study may be used as guidelines for improving Mn management. For the highest efficiency in using Mn to increase grain yield and aroma and used in physiological studies to improve the quality of Thai fragrant rice and also, the basis for the development of other fragrant rice varieties. This information will also be useful for the development of other types of fragrant rice that can meet consumer demand.