PERFORMANCE OF TWO APPLE CULTIVARS ON P SERIES DWARF ROOTSTOCKS

S.W. Zagaja
The P series dwarf apple rootstocks originate from crosses of M.9 rootstock with Antonovka, an old Russian winterhardy apple cultivar.

The crosses were made in the years 1954 to 1956. Following preliminary screening 9 clones were selected and tried in test orchards. The tested rootstocks were budded with 2 apple cultivars, McIntosh and Starking Delicious, and were compared with 6 standard rootstocks giving a range of vigour control. In a separate trial winter hardiness of the P rootstocks was assessed under field conditions. In addition their rooting ability and propagation index were compared with those of the known rootstocks.

Four of the P clones, P 1, P 2, P 16 and P 22 proved dwarfing. Of these P 1 and P 16 propagated and rooted better than M.9 while P 2 and P 22 were similar to M.9 in these respects. The level of winter hardiness of P 1 and P 16 was similar to that of M.9 while P 2 and P 22 were considerably more winter-hardy. In that respect they were equal to A 2 or Antonovka seedlings. The level of resistance of the P rootstocks to collar rot was apparently similar to that of M.9.

All the above listed P rootstocks induced very precocious bearing and high productivity in trees worked on them. As the rootstocks are still in short supply the clones P 2 and P 22 are extensively used in the Polish apple industry as dwarfing interstocks.

Zagaja, S.W. (1981). PERFORMANCE OF TWO APPLE CULTIVARS ON P SERIES DWARF ROOTSTOCKS. Acta Hortic. 114, 162-169
DOI: 10.17660/ActaHortic.1981.114.22
https://doi.org/10.17660/ActaHortic.1981.114.22

Acta Horticulturae