Brother I didn't have specialty in this field but I like your question and hope to see some useful answers. ALLAH bless you.

Interesting question

Average number of grains per ear in optimal conditions  can be  about 70, but some modern wheat cultivars have 80 or more. Average number of spikes per plant in field in optimal conditions  can be from 6 to 9 depending on cultivar (bread wheat).  A single grown cereal plant can produce up to 90 ears.  

Thanks Husain; Kulasekaran and Alex

A 100 fertilized flower and matured to be complete grain in each one of seven ears; why no one can reach it yet?

 JK Agri Genetics Ltd.(JKAL) http://www.jkseeds.net/jk/index.php?option=com_content&view=article&id=71&Itemid=435 has reported about wheat cultivars that produce 3-5 grains per spikelet and 19-23 spikelets per spike. It gives up to 115 grains per spike.

I think that potential yield per sq.m. is more important trait.

Cereal Crops in the Light of the Qur'an Abstract Belonging to Graminea (Poaceae) family, Cereal crops contain especially wheat and other cool season cereals such as barley, rye and oats and also warm season cereal such as rice, corn and sorghum. As a grain with the highest sowing area (221 million hectares) in the world and meeting 20% of the energy people need, how wheat appears within the context of the universe recitation, Qur'an? Announcing the unity of the creator of universe, 477 promoting other sciences and attainments besides pointing to their final boundaries, Quran of course does not neglect the cereals as the main food of humankind. The example of those who spend their wealth in the way of Allah is like a seed [of grain] which grows seven spikes; in each spike is a hundred grains. And Allah multiplies [His reward] for whom He wills. And Allah is all-Encompassing and Knowing. (Al Baqarah, 261). This verse points that from the wheat as a cereal, the ultimate rate can be seven hundred from one wheat kernel. If this is the case, the verse points to a second green revolution in cereal research by promoting studying and finding. Verse encourages researchers in terms of yield components such as number of fertile spikes, grain number and weight per spike in cereal species in this group basic chromosome number of which is seven. In order to achieve this goal, it is understood from the sign of verse that it is possible to reach the yield potency which is finally drawn by the use of compatible technologies in breeding studies, mainly genetic. In order to achieve this goal, it is understood from the sign that it is possible to reach the yield potency which is finally drawn by the Qur’an using of technologies suitable for creation in breeding studies, especially genetic. Keywords: Al-Baqarah, cereal, grain yield, spike, Qur'an, verse 261 and wheat

Thanks Mr. Hasan

we find about 45-60 grain per spike in wheat in iraq ,if one plant gave more than ten spikes ,at this time we get 700 grains from grain.We need optimal condition to get that.