DEVELOPMENT OF NEW RICE STRAIN WITH IMPROVED SINK SIZE AND SOURCE CAPACITY USING A MULTI-PARENT ADVANCED GENERATION INTERCROSS (MAGIC) APPROACH

Abstract

A new rice strain that grows six feet tall with four times higher potential yield than the conventionally bred variety, JP5, was developed using the MAGIC approach. This new rice type underwent analysis on sink size and source capacity traits, including superior and inferior spikelets, vascular bundles of panicle neck and stem internode, tillering pattern, grain filling pattern, yield, and other morphological attributes. Results indicated that the new strain had more vascular bundles of the stem (42) and panicle neck (35), primary rachis branches of panicle (16.1), superior spikelets, and greater grain weight than the conventionally bred variety, JP5. The panicle measured 45 cm long, with fertile grains of 500 per panicle and a stem diameter of 1.2 cm. During the grain filling duration, the spikelets of this strain and superior spikelets of JP5 gained maximum weight earlier than the inferior spikelets of JP5. Six feet tall plants of this new strain with long and heavy panicles had greater stem wall thickness. There occurred a positive and significant correlation (0.97) between yield and small vascular bundles of the panicle neck, lumen diameter (0.98), leaf length (0.99), leaf width (0.99), flag leaf length (0.99*), flag leaf width (0.97<), panicle length (0.97), fertile grains per panicle (0.98), and plant height (0.97*). The study noted that improving sink size, source capacity, and transportation of assimilation contributed positively toward yield. This novel strategy for grain yield enhancement in rice proved beneficial for other cereals to get significant breakthroughs in their production for ensuring food security.