Śatapatha Brāhmaṇa ("of a hundred paths") 5.3.3.6

5.3.3.6

athendrāya jyeṣṭhāya | hāyanānāṃ caruṃ nirvapati tadenamindra eva jyeṣṭho jyaiṣṭhyamabhi pariṇayatyatha yaddhāyanānām bhavatyatiṣṭhā vā etā oṣadhayo yaddhāyanā atiṣṭho vā indrastasmāddhāyanānām bhavati

For Indra Gyeshtha (the most excellent) he then prepares a pap of red rice-grains (hâyana): thereby Indra, the most excellent, leads him to excellence (or, lordship). And as to its being prepared of red rice: outstanding doubtless are those plants, the red rice, and outstanding is Indra: therefore it is prepared of red rice.