“…The number of initiated spikelets per spike, spikelet initiation rate, and the length of the shoot apex from double ridge to terminal spikelet are important, and the final grain yield will be higher if those traits are higher. Thus, during the period from double ridge to terminal spikelet, two important traits, namely, number of spikelets per spike and number of florets per spikelet, are shaped, and they have an effect on the final grains number, consequently, the grain yield can be increased (Itoh et al, 1998), because there is a close positive relationship between the grains number per spike and the final grain yield (Duggan et al, 2000;Brancourt-Hulmel et al, 2003;Gonzá lez et al, 2003). Also, the relationship between the spikelet and the spike can determine the yield production capacity (Duggan & Fowler, 2006).…”