be whiter

Concise Bible Dictionary:

Wheat Growing in Israel
This cereal was extensively grown in Palestine; the harvest was in May and June. In the parable it is used by the Lord as representing the children of the kingdom, the fruit of the good seed that He was sowing on the earth, in contrast to the tares, or darnel, which Satan secretly sowed among the good seed.
The Lord Himself, being the second Man “out of heaven,” is compared to the grain of wheat that must have remained alone unless it had died, but which in dying would bring forth much fruit. This clearly shows that there was no union of Christ and natural man by His incarnation alone, and that through the death of Christ the fruit produced by His resurrection is of the same order as Christ Himself (Matt. 13:25-3025But while men slept, his enemy came and sowed tares among the wheat, and went his way. 26But when the blade was sprung up, and brought forth fruit, then appeared the tares also. 27So the servants of the householder came and said unto him, Sir, didst not thou sow good seed in thy field? from whence then hath it tares? 28He said unto them, An enemy hath done this. The servants said unto him, Wilt thou then that we go and gather them up? 29But he said, Nay; lest while ye gather up the tares, ye root up also the wheat with them. 30Let both grow together until the harvest: and in the time of harvest I will say to the reapers, Gather ye together first the tares, and bind them in bundles to burn them: but gather the wheat into my barn. (Matthew 13:25‑30); John 12:2424Verily, verily, I say unto you, Except a corn of wheat fall into the ground and die, it abideth alone: but if it die, it bringeth forth much fruit. (John 12:24); 1 Cor. 15:48-4948As is the earthy, such are they also that are earthy: and as is the heavenly, such are they also that are heavenly. 49And as we have borne the image of the earthy, we shall also bear the image of the heavenly. (1 Corinthians 15:48‑49)).
There are three or four varieties of Triticum grown in Palestine.

Strong’s Dictionary of Hebrew Words:

Number:
6705 (find all occurrences in KJV Bible)
Transliteration:
tsachach
Phonic:
tsaw-khakh’
Meaning:
a primitive root; to glare, i.e. be dazzling white
KJV Usage:
be whiter