Varied Responses of System of Rice Intensification to Medium and Short-aged Rice and Types of Planting Material in Central Plains of Thailand

ABSTRACT
Background and Objectives: The System of Rice Intensification (SRI) as one of the methods of producing rice under controlled water management is known to contribute to the increasing demand for food and ensuring water security and ecological balance of the environment. The performance of short- aged rice under SRI has not tested adequately. Hence a pot experiment was conducted to investigate the performance of short and medium-aged rice varieties and different types of planting materials in SRI. Materials and Methods: Six treatments composed of 2 x 3-factor factorial combinations of two age groups of rice and three types of planting materials were tested in a Completely Randomized Design with three replicates each. Time for reaching different phenological stages, above and below ground growth parameters, and per plant yield parameters were assessed. Results: The medium-aged rice (MAR) variety (115-day-old) showed its adherence to its exact life duration and phenological stages, while the short-aged (SAR) variety (90-day-old) extended its all phenological stages beyond its stipulated durations under SRI practices. The shoot and root growth parameters were significantly different among the two age groups. A significantly higher per hill grain weight was observed in the medium-aged rice variety compared to the short-aged variety. Short-aged rice varieties irrespective of the type of planting material extended the duration of their phenological stages. Conclusions: Short-aged rice extends its phenological stages and performs poor growth and offers less yield under the System of Rice Intensification in the Central Plain of Thailand.