Which of these crops was the earliest staple of the Rig Vedic Aryans?

Yava (Barley) was the earliest staple mentioned, while Vrihi (Rice) gained prominence during the later Vedic migration eastward.

Ancient Names of Crops: Rice, Mung, Barley, Sugarcane

In ancient India, Vrihi refers to Rice, Mudga to Mung bean, Yava to Barley, and Ikshu to Sugarcane.

ID: HIS_ANC_2021_181 Ref: Standard Educational Reference