Abstract
Rice which belongs to the grass family is vulnerable to water stress. As water resources get limited, the productivity of rice is affected especially in granaries located at drought prone areas. It would be even worse in granaries located in drought prone areas such as KADA that receives the lowest rainfall in Malaysia. Spermine (SPM), a polyamine compound that is found ubiquitiosly in plants is involved in adaptation of biotic and abiotic stresses. The effect of SPM on growth,grain filling and yield of rice at three main granaries namely, IADA BLS, MADA and KADA representing unlimited water, limited water and water stress conditions respectively, were tested during the main season. Additinally, the growth enhancer was also tested during off season at KADA. Spermine increased plant height, number of tillers per hill and chlorophyll content in all three granaries. Application of SPM improved yield by 38, 29 and 20% in MADA, KADA and IADA BLS, respectively. Harvest index showed 2.6, 6 and 16% increases at IADA BLS, KADA and MADA, respectively in SPM treated plants as compared to untreated. Except for KADA which showed a reduction in yield at 2.54 tha−1, SPM improved yield at MADA, 7.21 tha−1 and IADA BLS, 9.13 tha−1 as compared to the average yield at these respective granaries. In the second trial, SPM increased the yield to 7.0 and 6.4 tha−1 during main and off seasons, respectively, indicating that it was significantly higher than control and the average yield reported by KADA. The yield of SPM treatments improved by 25 and 33% with an increment of farmer’s income at main and off seasons, respectively. Stomatal width was significantly higher than control at 11.89 µm. In conclusion, irrespective of the tested granaries and rice variety, spermine mediated plots displayed increment in grain yield.
Highlights
Rice which belongs to the grass family is vulnerable to water stress
Tuong and B ouman[5] predicted that by 2025, 15–20 million hectares of irrigated terrain will endure water shortage resulting in water stress that can affect the development and yield of r ice[6,7] especially if it occurs during grain filling
Foliar application of growth enhancer such as polyamines that can be economical, feasible, easy to apply and readily available to the farmers could be a possible solution for rice growing in water stress e nvironment[10,11]
Summary
As water resources get limited, the productivity of rice is affected especially in granaries located at drought prone areas. The effect of SPM on growth,grain filling and yield of rice at three main granaries namely, IADA BLS, MADA and KADA representing unlimited water, limited water and water stress conditions respectively, were tested during the main season. Application of SPM improved yield by 38, 29 and 20% in MADA, KADA and IADA BLS, respectively. Plants adapt to drought stress or water shortage by altering physiological, biochemical and molecular p rocesses[3,4]. Foliar application of growth enhancer such as polyamines that can be economical, feasible, easy to apply and readily available to the farmers could be a possible solution for rice growing in water stress e nvironment[10,11]. Prior research agree that the exogenous application of the many forms of PA at variable concentrations has conferred the plants with enhanced tolerance to various stresses 18 besides regulating stomatal responses by reducing their aperture and prompting its closure under water deficit conditions as a vital drought tolerant m echanism[19,20,21]
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