Morpho-physiological differences and responses to source-sink manipulation in Aus rice varieties

Rice is the staple food crop of Bangladesh, playing a critical role in national food security. This study investigated the morpho-physiological traits and the impact of source-sink manipulations on grain yield in four rice varieties Binadhan-14, Binadhan-19, China IRRI and Kalihatta under field conditions. Various treatments, including partial spikelet and flag leaf removal at different growth stages, were applied to assess their effects on yield components. Among the tested varieties, Binadhan-19 exhibited the highest grain yield under normal conditions, attributed to a greater number of grains per panicle and fewer sterile spikelets. Source-sink manipulations revealed that spikelet removal significantly increased individual grain size and weight, indicating that yield was sink-limited. Conversely, flag leaf removal reduced grain size and weight, emphasizing the importance of source strength for grain filling. These findings highlight that grain yield in rice is co-regulated by both source activity, sink capacity and strategic manipulation of these factors could be a promising approach in breeding programs aimed at enhancing rice productivity.