Introduction: All the plants of a maize population or hybrid PP (plant population) do not dehisce anthers and do not emerge silk simultaneously. Generally, male flowering or anther dehiscence (anthesis) is leading and female flowering (silk emergence or silking) is lagging under both optimum and stressful environment. Enough and timely pollen availability is indispensable when silks come out of maize ears for largest number of kernel set. So; study of flowering and reproductive behavior of newly bred maize hybrids are indispensable to confirm high grain yielding hybrid with traits of synchrony in anthesis and silking, coming out of all silks and enough pollen availability in short duration. Materials and methods: Flowering and reproductive behaviors of fifteen newly bred single cross hybrids of yellow maize have been examined growing them in an RCBD trial planting their seeds on October 3, 2012 to expose flowering to the natural winter in subtropical foot plain of Himalaya. For flowering behavior; emergence of tassel, anthesis, silking, silk senescence, tassel-anthesis interval, anthesis-silking interval, silking-silk senescence interval of the hybrids have been examined dissecting the PP into four equal parts (percent) as the first earliest, second earliest, third earliest and terminal 25% of the hybrid PP denominated as 25, 50, 75 and 100% respectively of the each of the fifteen hybrids. So, whether third earliest 25% and terminal 25% silk emerging PP of each of the hybrids (SILK75 and SILK100%) respectively received enough pollen from the PP of the same hybrid can be determined through ASI 75 and ASI 100 of the hybrid PP. Results and discussion: Among some polynomial regression equations (PREs) discovered based on floral traits, a grain yield estimating PRE (t ha-1) Y = - 11922 + 507.3*(TSS25)1 - 7.183*(TSS25)2 + 0.03387*(TSS25)3 with r2 value 66% has been discovered from days taken for TSS25. Similarly, high r2 bearing PREs were from days for anthesis and silking. PREs with the lowest r2 were for the days required for the silk senescence (S SEN). Reasons of the low r2 are: the observation of silk browning or withering could not be precise for naked eye since the silks looked fresh longer in high humidity, well-irrigated state, low temperature, low sun-shine and foggy or cloudy day although the silks lost receptivity earlier in the winter. In addition, interval duration from SILK INI to S SEN cannot be the duration of silk receptivity in the winter of subtropical Nepalese Himalayan foot plain. For reproductive behavior; number of functional egg cells that became successful zygotes to pull assimilates for complete kernel development can reflect aroma about reproductive strength (RS) of the hybrid. Accordingly, hybrids 8 and 5 have been found of the highest RS.