(Mishnah): One may tithe from a Jew's produce for a gentile's produce and vice-versa. A Jew may also tithe for a Kusi's produce and one may tithe from a Kusi's produce for a Kusi's produce.

R. Eliezer prohibits tithing for a Kusi's produce for a Kusi's produce.

A planter with a hole (at its base) is considered to be part of the ground. If a person separated Terumah from produce of the ground for produce in such a planter, or vice-versa, it is valid.

If he separated from produce from a planter without a hole (whose obligation is only Rabbinic) for one with a hole, it is Terumah, but he must separate again.

If he separated from a planter with a hole for one without a hole, it is Terumah, but he may not eat from that Terumah until he separates Terumos and Maaseros for it.

If he separated Terumah from Demai for Demai, it is Demai.

If it was separated for definite Tevel, it is Terumah, but he must separate again.

If from definite Tevel for Demai, it is Terumah, but he may not eat it until he separates Terumos and Maaseros for it.

(Gemara): The Mishnah follows the opinion of R. Meir, who said that a gentile's acquisition in Eretz Yisrael does not exempt it from (the obligation of) Maaser.

R. Yehuda and R. Shimon say that his acquisition does exempt it from Maaser.

(R. Imi citing R. Shimon ben Lakish): R. Meir's source is the pasuk (Vayikra 25:46), "And you shall bequeath (your slaves) as a heritage to your children after you to inherit as a possession". The Torah compares 'a possession' to slaves - just as for slaves, you acquire from (amongst) them and they don't acquire from (amongst) you, so too you acquire possessions (of land) from them but they do not acquire from you.

(R. Elazar bei R. Yosi to R. Yasa): This pasuk supports R. Meir (Vayikra 25:23), "The land shall not be sold Litzmisus, because the land belongs to Me" - Litzmisus means completely - as it is returned in Yovel - similarly, it is not sold completely to a gentile - as it is still obligated in tithes.

Rebuttal (R. Yasa): The entire pasuk says that it's a support for R. Shimon - 'Do not sell', but if it was sold (to a gentile), it is permanent (and exempt from tithes)!

(Rav Huna the Great of Tziporin): R. Chanina established the custom in Tziporin like R. Shimon. And R. Zeira also said this.

(R. Zeira to R. Abahu citing R. Elazar): Even though R. Meir said that a gentile's acquisition of the land of Eretz Yisrael does not exempt it from Maaser, he agrees that he can acquire the fruits.

(R. Ba): The gentile eats from the fruits of the field that he bought.

Question (Mishnah in Gitin): One who sells a field to a gentile, he must buy fruits from the gentile in order to bring them as Bikurim - as a deterent to stop a Jew selling his land to a gentile. But according to this (that a gentile's acquisition does not exempt from Maaser), there should be a Torah obligation of Bikurim? (The Gemara leaves this question unanswered.)