Wheat (Triticum Spp.) is one of the major food crops globally, in terms of cultivated area and food source. With the production of 713 million tons per annum worldwide, it is the third most-produced cereal grain after maize and rice. The grain yield of wheat is highly associated with grain number (GN/m2). It was suggested that optimal biomass partitioning expressed in high spike dry matter (DM) at anthesis (SDWa) could contribute to GN. Understanding of pre-anthesis spike growth dynamics [separated into terminal spikelet (TS) and stem-elongation (SE)] is essential if such optimization is desired. In this study, we examined spring wheat under Mediterranean conditions focusing on: (1) Studying the genotypic component of pre-anthesis phases, (2) Testing if and how pre-anthesis phase duration may influence spike traits. For this purpose, a panel of Israeli bread wheat commercial cultivars (representing the phenological span) were grown in the field during 2016/17 (three environments) and 2017/18 (two environments). The panel was characterized for differences in preanthesis phases’ duration (TS and SE), spike growth dynamics via histological measurements and estimation of yield components. Significant variability in the timing of pre-anthesis phases was detected within the tested panel in 2016/17. We also identified three pairs of genotypes in which each pair flowered simultaneously but showed significant differences in TS and SE phases and were further evaluated in 2017/18 (cv. Yuval-Zahir, Gedera-Negev and BarNir-Galil, in each couple the first cultivar has shorter TS phase). Pairwise correlation among the yield components and pre-anthesis phases suggest that duration of TS, and even more SE, positively associated with improved DM of fertile florets per spike at both anthesis (r=0.25 and 0.29 respectively) and maturity (r=0.25 and 0.37 respectively). However only days to TS have shown significant association with SDWa (0.3), fruiting efficiency (0.22) and GN (0.20). Mean contrast analysis was performed between each couple of cultivars. In the majority of cases, the cultivar with the longer TS duration had significant higher DM and GN per spike. We could conclude that both phase’s duration (TS and SE) affect spike fertility. However, under short season with terminal drought and heat, TS duration was a stronger driver of GN enhancement. This is a contrast to previous findings, which highlighted SE duration effect on SDWa and GN. Applications of bread wheat in Mediterranean semi-arid environment for future breeding are also discussed.