The influence of seed rates on growth, biomass production and panicle development of a new aerobic rice variety-MARDI Aerob 1 / Nurulain Abdul Wahil

Seed rate affects plant architecture, alters growth and developmental patterns and influences biomass production and partitioning which affect rice yield considerably. Under this production system, rice is grown in well drained, non-puddled and non-saturated soils. Aerobic rice was developed to maximize yield per unit water input under water scarce environment as well as to minimize greenhouse gases (GHG) emission which is generally high under the wetland system. The field experiment using MARDI Aerob 1 rice variety was conducted at UiTM Melaka Jasin campus from February to December2015. The quantification of source and sink relationship of this new variety was carried out using seeds grown under three different. seed rates; 100 (Tl), 150 (T2) and 200kg/ha (T3) arranged in a randomized complete block design (RCBD with four replications. The source and sink relationship was examined based on overall growth, dry mass production and partitioning, panicle development and physiological performance during reproductive and ripening stages. AU-cultural practices were based on MARDI's recommended practice with standard seed rate of 100-130kg/ha and between rows distance of 25cm. The quantitative analysis on the aboveground biomass production and partitioning during reproductive and ripening stages were carried out using weekly sequential growth analysis technique. Ten uniform tillers per replicate from each treatment were harvested at 40, 47, 54, 61, 68, 75 and 82 days after sowing and harvested biomass were separated into leaves, culms and panicle for leaf area and biomass determinations. Five panicles per replicate from each treatment were used for detailed panicle analysis. The chlorophyll SP AD readings were monitored at three different stages; panicle initiation, flowering and ripening while stomatal conductance and chlorophyll a fluorescence were measured at active tillering and flowering stages.