Hello Don and Evan, I have been interested in MAC 9 since I saw it growing in an Irish Bramley's Seedling (cooking apple) orchard. The grower in question was always very enthusiastic about its productivity, and indeed, he still has the trees today, and has not experienced breakages, though soil-line swelling is a characteristic. I think the important question is what happened to MAC9 when it was made virus free (accompanied by a name-change to Mark), to make it more prone to breakages?
For people like Evan, who are still enthusiastic about the original stock, it would be possible to take some original MAC 9 tissue, and make another attempt at eliminating viruses. However, if the result is going to be the same (more brittle unions), there would not be any point in doing this. Con Traas The Apple Farm Cahir Ireland PS I wonder if these changes could be epigenetic. It has recently been established that it is not only the DNA code that we inherit from our parents that determines our makeup, but that events in their lives that affect their cells (but not DNA) can also be passed on in reproduction via some type of "cell memory". The more we find out, the more we realise what we don't know. ________________________________ From: apple-crop@virtualorchard.net [mailto:[EMAIL PROTECTED] On Behalf Of Elfving, Donald C Sent: 19 November 2008 22:54 To: Apple-Crop Subject: RE: Apple-Crop: MARK vs Mac-9 root stock Back in 1980 I was involved in planting apple trees from the 1980 NC-140 Apple Rootstock trial at the Hort. Research Institute of Ontario research station at Simcoe, Ontario, Canada. Among the 9 rootstocks in that trial was what we were told was the original MAC-9. The top was 'Starkspur Supreme Delicious' For the first few years, the MAC-9 trees grew well and displayed remarkable precocity. By about 5 years of age, however, their vigor began to diminish and they became quite spur-bound. Examination of the trees showed clearly that all 5 were suffering from what has become known as "soil-line swelling", a proliferation of tissue at the crown of the tree that significantly disrupts the vascular connection between root and scion. I also was initially impressed with the early performance of these trees. As a result, starting in 1986 I planted a lot of trees on what by then was being called 'Mark'. Again, the initial performance of the 'Mark' trees was good, but within 3 years we were starting to see some evidence of breakage at the union and, within a few more years, clear evidence of "soil-line swelling". The MAC-9 trees in the 1980 NC-140 trial were propagated at least 7-8 years before the official release of 'Mark', and we were told that they in fact were the original MAC-9. If that is the case, then our experience indicates that both MAC-9 and 'Mark' displayed the same problem of uncontrolled tissue proliferation on the rootstock shank. Regards to all, Don C. Elfving, Horticulturist and Professor Washington State University Tree Fruit Research and Extension Center 1100 N. Western Ave. Wenatchee, WA 98801-1230 (509) 663-8181, ext. 252 (509) 662-8714 (fax) [EMAIL PROTECTED] ________________________________ From: apple-crop@virtualorchard.net [mailto:[EMAIL PROTECTED] On Behalf Of Evan B. Milburn Sent: Wednesday, November 19, 2008 1:16 PM To: Apple-Crop Subject: Apple-Crop: MARK vs Mac-9 root stock Hello all, Back in the late 70's and early 80's I was lucky to have known and closely followed the research of Dr. Robert Carlson, MI on his development of the MAC-9 apple rootstock. Those of you that belonged and was active in the then, IDFTA as I was (and still am) kept watching its testing and development. By the late 80's I was con vined this rootstock was a real winner . Smaller than the M-26, More productive than M-9. For 1987 I had ordered some 15,000 trees to plant that year but only could get about 500. These were planted and still very productive to this day. These will be removed next year only because the variety Red Del is no longer viable.Than it was discovered the MAC-9 had a "virus" and had to be go thru radiation to clean it up. This was done and reintroduced as MARK. I planted the rest of my order in 1989.on this MARK. They were a disaster! By year five and six they were all removed because of the bud union problem I called cancer. Those of you who have planted them know what I mean. On the IDFTA trip to Australia 2000 we visited one grower who had a large block of Reds planted side by side. One block on MARK ,the other on MAC-9. Same results. MAC-9 were absolutely beautiful, the MARKS were a disaster. Question-- Has any one had the same experience? I realize not many out there have the true MAC-9. To the 'experts out there; What in the process of "cleaning up the virus" would make this kind of change ? Please do not tell me ,as many have ,there was no change. I've seen my self and dearly paid for it! If any one wants to see the true MAC-9 come see them before the Fall of 2009. Evan B. Milburn,Grower Elkton Maryland www.milburnorchards.com
