Many models were developed to estimate harvest index (HI), but all still lack experience in estimating crop efficiency and selecting genotypes with higher productive capacity, for the calculation or equation which lying must be encompass numerous traits, beginning from cultivated seed and rate of emergence, because of the variation in emergency and seedling growth and plants will affect plant architecture and its crowding by shading that leads to variation in source strength which is very important to form the sink. The post anthesis dry matter accumulation contributes with greater ratio in sink formation, but the increasing in post anthesis dry matter accumulation is resulting from increased source size. Thus, management must be act to establish strong source capable to establish and support big better sink. The good understanding of assimilated partitioning don’t ensure an effective progress in plant breeding, and the lack in HI requires more care on factors that control the partitioning. The changes in root system architecture, high plant density tolerance improved stress tolerance effect of additive and non additive effects, and select high post anthesis accumulation biomass genotypes with less leaves senescence during post anthesis and possess high ability to translocation assimilate to seed. But the lack in favorable genetic variation within the germplasm pool, gives no chance to improve conventional breeding approaches, thus we should study HI as an assimilated partitioning ratio, and that means that the increasing HI resulting from assimilated partitioning contributed in yield increase, and in this status it is easier control than the control of yield by improving plant ability to assimilate translocation to sink more than to source. In this case it takes part in the increasing of HI. If we consider the HI as the ratio of yield to dry matter it means that yield control the HI, but in this situation, the heritability of yield is low and more affected by environment. If we use HI as selection criteria for high yield, it should be high variation, heritability and high translocation efficiency.