(R. Avahu citing R. Yochanan): If an Esrog had Chanatah in years of Orlah, and he was Mesapek it to another [Esrog tree], even if it grew much, it is forbidden, for growth of Heter is not Mevatel the Isur.

Inference: If one grafted a Yaldah [onto a Zekenah], the Yaldah is exempt.

If you would say that it is not exempt, why does it say 'even if it grew much, it is forbidden [for growth of Heter is not Mevatel the Isur'? Also the additional growth is Isur!]

(R. Ze'ira citing Rabanan): If an Esrog had Chanatah in years of Orlah, and it developed at a time of Heter (after years of Orlah), even if it grew much, it is forbidden. One is lashed for a k'Zayis of it.

Question (R. Maisha, to Ze'ira): You say two laws - do they not contradict each other?!

Note: CHAZON ISH (Orlah 2:7) says that R. Ze'ira taught also what R. Avahu said above in the name of R. Yochanan.

Here you say that growth of Heter is not Mevatel the Isur, and here you say that one is lashed for a k'Zayis of it! He should be lashed according to the calculation [of how much Isur he ate]!

Answer (R. Yonah): Here (Chanatah was in years of Orlah, and it developed after years of Orlah) it lives (and grows) due to itself (all the growth is Isur). Here (above) it lives (and grows) due to the graft (the additional growth is Heter.)

Consequence: Based on this, if Chanatah of an Esrog was in years of Orlah, and it developed at a time of Heter, and he grafted it onto its colleague (a tree like itself), and [grafted] its colleague onto a colleague, and similarly its colleague grafted to each other (the first tree), they permitted each other. (The Esrogim are forbidden, for the new growth is not Mevatel the Isur. However, they permit each other, i.e. the additional growth is like Heter, i.e. one is lashed only for a k'Zayis of the original Isur. We explained this primarily like SEFER NIR.)

(R. Avahu citing R. Yochanan, and Rav Chisda): (Our Mishnah said that Sipuk is permitted (exempt from Orlah). R. Meir said, where it is strong, it is permitted; where it is weak, it is forbidden.) They argue Stam.

Question: What is the case?

If it is clear that it lives (nurtures) due to the Zekenah, all permit! If it is clear that it lives due to the Yaldah, all forbid!

Answer: The case [in which they argue] is Stam.

Question: How does one know [if it lives due to the Zekenah or the Yaldah]?

Answer (Rav Bivi citing R. Chaninah): If the leaves are turned towards the Yaldah, surely it lives due to the Zekenah. If the leaves are turned towards the Zekenah, surely it lives due to the Yaldah.

(R. Yudan bar Chanin): A Siman is that one who eats from his friend is embarrassed to look at him.

Note: There is an implied question - why do the Tana'im argue? It is easy to tell from which it lives!

Answer (R. Yudan, the father of R. Masniyah): The case is, its leaves fell off.