Heading Uniformity: A New Comprehensive Indicator of Rice Population Quality

Productive tiller percentage (PTP) is the only available comprehensive indicator of rice population quality. However, productive panicle number (PN) has a great effect on its characterization accuracy. Panicle exsertion an important but difficult to describe morphological index; therefore, it cannot be easily determined. The aims this study were develop heading uniformity (HU), which describes difference in degree exsertion, as new by designing representative sampling and calculation method exploring relationship between HU yield components. first decreased then increased after initial heading, exhibiting single-valley curve. Adequate was obtained day two or three (panicle N fertilizer proportion ≤40 >40%) heading. explanatory power PTP for grain variance markedly insufficient low- high-PN populations. Compared with percent contribution (12.32–41.26%), that (49.02–61.93%) greater more stable across populations different PNs. Moreover, showed fewer interannual variations, despite large differences weather soil conditions. Hence, may have applications