Comparison in Dry Matter Production and Assimilate Partitioning between 'Jonagold' Apple Trees on an Invigorating Rootstock Versus a Dwarfing Rootstock

Abstract

Growth characteristics and dry matter production in 'Jonagold' apple trees on M. 26 dwarfing rootstock were compared with those on Maruba-Kaido (Motifs prunifolia Borkh. var. ringo Asami), an invigorating rootstock during 1991. Fresh weights of scion and root- stock of trees on Maruba-Kaido were 14.2 and 12.6 times heavier, respectively, than those on M. 26. Top (scion) /rootstock fresh weight ratio (T/R), however, did not differ significantly between these trees on different rootstocks, indicating that the scion and rootstock sections of the trees grew proportionately.
The ratio of tree weights (T + R) to leaf weights (B) of the trees on Maruba-kaido was 1.5 times greater than that of the trees on M. 26. This indicates that leaves on trees on Maruba-Kaido contributed to the production of more woody tissue than did those on trees on M. 26. However, we found that the fruit/leaf dry weight ratio (F/L) of 'Jonagold'/M. 26 was about twice that of 'Jonagold'/Maruba-Kaido. In spite of a relatively heavier fruit load the average weight per fruit and the annual incremental change in wood volume did not differ significantly between these trees on different rootstocks.
Our findings on the relationship between (T+R) /B and F/L elucidate how invigorating and dwarfing apple rootstocks can affect assimilate partitioning.