In 1998, two multi-site replicated rootstock trials were established by the US national rootstock testing group, "NC-140". The trials compared 2 elite dwarf Geneva apple rootstocks that are tolerant to fireblight and Phytophthora root rot. The first trial used 'Jonagold' as,the scion and compared 'M.9' with Geneva (R) 'G.16' and 'G.41'. It was planted at 10 locations across North America. The second trial, which was planted at 9 locations, used Gala as the scion and compared only 'M.9' and 'G.16'. At the end of 6 years, 'G.16' produced a tree slightly larger than 'M.9' EMLA with Gala, while with Jonagold, tree size was similar to 'M.9' EMLA. Productivity of 1G.16' was similar to 'M.9' in all trials. Trees of Jonagold on 'G.41' were slightly, but significantly smaller in size than 'M.9' EMLA, yet productivity was similar to 'M.9'. Yield efficiency of 'G.41' was higher, but not significantly different than 'M.9' EMLA. At the Geneva NY site, there was no effect of tissue culturing of the stoolbed mother plants used to create the nursery liners of 'G.16'. Tree size, yield, yield efficiency or root suckers were similar to non tissue culture stoolbeds indicating that with at least this stock, plants can be multiplied by tissue culture to establish stoolbeds without negative effects. Tree survival of 'G.16' and IGAV was better than 'M.9' where fireblight caused tree losses. Tree survival of 'G.16' was better than 'M.9', 'M.26' or 'B.9' following a mid winter cold event in January 2004 at a Northern NY site. 'G.16' is currently being commercialized in the US and Canada. 'G.41' will be patented and commercialized in Feb. 2005.

A multi-site experiment to evaluate the performance of apple cultivars was established in 1995 with twenty different cultivars. The purpose of the experiment was to evaluate new and promising apple cultivars in a range of geographical and climatic areas within North America. All trees were propagated on M.9 and minimally pruned to encourage early bearing. At the end of the fifth growing season 'Shizuka' were the largest trees, and had the highest yields. 'Honeycrisp' and 'Braeburn' were among the smallest trees and had low cumulative yields. 'Gala Supreme', 'Golden Supreme' and 'Pristine' were among the least yield efficient. Across all sites, 'Fortune', 'Golden Supreme', 'Pristine', 'Suncrisp' and 'Yataka' had biennial bearing indices (BI) that suggested that they were more prone to biennial bearing. 'GoldRush' had the highest cumulative yield efficiency and cumulative crop load of all the cultivars tested. 'Arlet' had the highest mean number of fruit per year, while the largest fruit were produced by 'Shizuka'. 'Pristine' and 'Golden Supreme' had high levels of preharvest fruit drop. Days from full bloom to harvest varied depending upon cultivar with 'Pristine' maturing first and 'GoldRush' last. A stability analysis was performed for all variable measured. No cultivar proved perfectly stable. However, 'Fuji' had the fewest significant stability variances while 'Honeycrisp' had the most significant variances.

A multidisciplinary regional project for the evaluation of new apple cultivars was established in 1994 and given the designation of NE-183. Apples are and will continue to be an important fruit crop grown in much of the world. New cultivars are continually being discovered as chance seedlings or generated as the result of controlled crosses. There is no uniform system in place to systematically and uniformly evaluate and identify the most promising cultivars that are suitable to plant in specific climatic regions and that have a high probability for success. Apples are one of the most costly fruit crops to establish and bring into production; thus a mistake in cultivar selection may be economically catastrophic. This project was initiated to aid growers in making intelligent and information-based decisions about which new apple cultivars to grow. The NE-183 project "Multidisciplinary Evaluation of New Apple Cultivars" is unique in that it unites horticulturists, plant pathologists and entomologists and their individual expertise in selecting cultivars that not only have outstanding horticultural qualities but may also have resistance to important diseases and insects that afflict apples.

Nineteen Prunus rootstock cultivars and selections budded with 'Redhaven' peach were planted at 20 locations in North America in 1994 as an uniform planting of the NC-140 Cooperative Regional Rootstock Project. The rootstocks included peach seedlings from 'Lovell', 'Nemaguard', 'Bailey', 'Tennessee Natural 281-1', 'Stark's Redleaf', 'GF 305', 'Higama', 'Montclar', 'Rubira', 'Chui Lum Tao', 'Tzim Pee Tao', 'H7338013', 'H7338019', 'BY520-8', and 'Guardian(TM) BY520-9'. Clonal rootstocks included 'Ishtara', 'Myran', 'S.2729', and 'Ta Tao 5' interstem on 'Lovell'. Data were summarized across the 20 sites in 18 states and provinces over eight years. Tree survival was lowest in the Michigan, Indiana and southeastern Missouri plantings and best in Arkansas, Kansas, Maryland, New York, South Carolina, and Utah. Trunk circumference was largest in southern Illinois, central Tennessee, southeastern Missouri, and central New Jersey. 'Myran' was the most vigorous rootstock followed by 'S.2729' and 'Guardian(TM) BY520-9'. 'Ishtara', 'Tzim Pee Tao', and 'Chui Lum Tao' produced the smallest trees. Full bloom date was significantly advanced (< 1 day) on 'Myran' rootstock and delayed (1-5 days) on the 'Ta Tao 5' interstem. Fruit maturity was advanced <1 day on 'Myran' and 'Tennessee Natural 281-1' and delayed 1-4 days on 'Ta Tao 5' interstems when compared to 'Lovell'. The effect of 'Ta Tao 5' on bloom and ripening delay in days was more prolonged in the South (i.e., Georgia, South Carolina). Fruit weight was significantly influenced by rootstock as 'Redhaven' fruit from 'BY520-8' and 'Ta Tao 5' interstem trees were smaller (similar to10 g) and fruit from 'Ishtara' and 'H7338013' were larger (6-7 g) than fruit from trees on 'Lovell'. Cumulative fruit yield (1996-2001) significantly varied among rootstocks, and yield differences were evident between locations as the highest cumulative fruit yields were from Ohio, north central New Jersey, Maryland, and South Carolina. No rootstock yielded significantly more than 'Lovell'. However, 'GF 305', 'Montclar', 'Guardian(TM) BY520-9' and 'H7338019' yielded equivalent to 'Lovell'. In contrast, 'Ishtara', 'Chui Lum Tao', 'Tzim Pee Tao', 'Bailey', 'Higama', and 'Rubira' and the 'Ta Tao 5' interstem trees often had significantly lower yields than 'Lovell'. Relative ranking of cumulative yields according to rootstocks and geographic locations tended to remain unchanged after the fifth year.

From 1992 to 1999, five multi-site replicated rootstock trials were established by the US national rootstock testing group, "NC-140". The trials compared elite Geneva apple rootstocks which were bred for tolerance to fire blight and Phytophthora root rot, high yield efficiency and good tree survival to commercial standards. The named Geneva rootstocks are designated as Geneva(TM) or "G" stocks while unnamed numbered selections from Geneva are designated as 'CG' stocks. In the 1992 plots which used 'Liberty' as the scion, Geneva(TM) 11 and CG.3029 had the highest cumulative yield efficiency, good tree survival and also had good average fruit size. They had similar tree size as M.9, but exceeded the yield performance of M.9. In contrast, Geneva(TM) 65 was more dwarfing than M.9 and had significantly lower cumulative yield efficiency and smaller fruit size than M.9. Among semi-dwarf stocks, Geneva(TM) 30, CG.6210, CG.4222 and CG.5179 all exceeded the performance of M.7 and MM.106. In the 1993 plots which also used 'Liberty' as the scion, CG.4247, CG.3041, CG.3902 and CG.3007 had the highest yield efficiencies and had good tree survival. All were similar in size to M.9, but performed significantly better than M.9 or M.26. Among the semi-dwarf stocks top performers were G.30, CG.6210, CG.222 and Geneva(TM) 202. All performed significantly better than M.7. In the 1994 plots which used Gala as the scion, Geneva(TM) 30 produced a tree similar in size to M.26 and more efficient than M.26 at 12 sites and less efficient at 6 sites. Fruit size was similar to M.26. G.30 generally had good survival; however, in 5 of 23 sites 50-60% of the trees broke off at the graft union during wind storms. In the 1998 and 1999 trials, Geneva(TM) 16 has been slightly larger than M.9 with Gala, Fuji and McIntosh, but similar to M.9 with Jonagold. Productivity of Geneva(TM) 16 has been similar to M.9 in all trials. CG.3041 has been similar in size and productivity to M.9 with Jonagold, Fuji and McIntosh.

Container grown, own-rooted Seyval blanc grapevines (Vitis spp.) trained to a single shoot with one cluster were grown with seven different ground covers and a control of no ground cover. The ground covers were also grown without grapevines. The ground covers had no effect on total dry weight of the grapevine and no effect on the dry weight of the shoots, petioles and roots. Grapevine total leaf area was only diminished significantly by English pennyroyal. There was no effect by the ground covers on the cluster characteristics or the pH, titratable acidity, and soluble solids levels of the juice. At the end of the growing season, mazus and English pennyroyal had produced twice the dry weight of creeping thyme and veronica, with companion grass, strawberry clover, and Kentucky-31 being intermediate. At destructive harvest, strawberry clover and Kentucky-31 had over 40% of their total root biomass located in the bottom half of their pots; companion grass and veronica between 21% and 23%, while English pennyroyal, mazus, and creeping thyme grew less than 15% of their roots in the bottom half of their respective pots. Mazus and English pennyroyal gave the earliest complete coverage of the soil surface, while companion grass, creeping thyme, and Kentucky-31 never reached complete coverage in the 14 weeks of the experiment. Strawberry clover had the highest amount of above-ground growth removed during the growing season, followed by English pennyroyal, Kentucky-31, and companion grass. Much less above ground growth was removed from mazus and veronica, and none was removed from creeping thyme. The competition from the grapevine resulted in a 20% reduction in the growth of the ground cover, and this effect was seen across all ground covers.

In 1984, trees of 'Redhaven' peach [Prunus persica (L.) Batsch] on 9 rootstocks were planted at 16 sites in North America according to guidelines established for cooperative testing by the North Central Regional Cooperative Project (NC-140). After 7 years, tree loss was greatest on 'Citation' (52%) and 'Damas 1869' (32%). Survival was greatest for trees on 'Bailey,' 'Halford' and own-rooted 'Redhaven.' Tree loss was greatest at the Ohio and Kentucky sites, due primarily to winter damage and heavy soil conditions, respectively. Trees on 'GF 677' were the most vigorous and those on 'Citation,' 'GF 655-2' and 'Damas 1869' were the least vigorous. Greatest cumulative yield was experienced on 'GF 677: 'Halford,' 'Bailey,' 'Siberian C' and own-rooted 'Redhaven.'

The International Apple Growth Study (IAGS) is a multi-national cooperative research initiative established to study apple growth responses to climate and environment. The goal of the study is to identify how environmental factors mediate tree growth and determine yield and fruit quality by using experimental protocols which standardize cultivar, rootstock and cultural orchard management. The study commenced in 1991/92 with the establishment of identical plantings of Jonagold/M.9 in 9 diverse apple production regions across maritime and continental climates ranging in latitude from 33 degrees to 51 degrees N and 39 degrees S. Sites are located on agriculture experiment stations at Kent, England (Horticulture Research International); Cadriano, Italy (University of Bologna); Havelock North, New Zealand (HortResearch); and in 6 regions of the United StatesCWooster, Ohio (Ohio State University); Clarksville, Michigan (Michigan State University); Wenatchee, Washington (Washington State University); Geneva, New York (Cornell University); Blairsville, Georgia (University of Georgia); Fayetteville, Arkansas (University of Arkansas). This paper introduces the purpose of the IAGS, the co-operators participating in the project and some apple growth characteristics from among the nine climatic regions. The main properties of growth and fruiting have been measured in the formative years, while growing trees to a suitable size for experimental manipulation. Results are presented describing shoot and trunk growth, floral precocity, yield and fruit size, which characterize young tree development among the nine distinct climates.

The major rootstocks used in North America for the production of cherry cultivars are seedlings of Prunus avium L. (Mazzard) and Prunus mahaleb L. (Mahaleb). While these rootstocks have been used for more than 250 years, horticultural limitations exist, and new rootstock cultivars are sought which can increase scion productivity, control vigor and widen the range of soil adaptability. A NC-140 trial was established in 1987 to test many new rootstocks in twenty sites in North America with scion cultivars of 'Montmorency' sour cherry or one of two sweet cherries, 'Hedelfingen' or 'Bing' (eastern and western North America, respectively). The rootstocks under test included those from Belgium (the GM series); those from Giessen, Germany (the GI series); a series of Mazzard x Mahaleb (MxM) hybrids originally selected in Oregon; Prunus mahaleb clones (the St. Lucie or SL series) selected at Bordeaux, France; Colt, a P. avium x P. pseudocerasus hybrid from East Malling, England and the current standard rootstocks, Mazzard or Mahaleb seedlings. Because of the complexity of multiple scion evaluation at various sites and that of non-uniform rootstock treatments, this report is presented to highlight the performance of scion cultivars on various rootstocks within each location and followed by a summary on general performance in the overall trial. Geographical location and sweet cherry scion cultivar appeared to play a major role in rootstock performance. In western locations,'Bing' on GI 148/1 was as vigorous as Mazzard, and in the east, 'Hedelfingen' was 38, 51 and 114% the size of trees on Mazzard at Michigan, New York and Ontario, respectively. Scions on Gisela stocks were generally very precocious. Early in the trials, sweet cherry was impressively productive on GI 148/1 and GI 195/1. However, as the trees in most plots reached the sixth growing season, shoot length reduced to only a few inches per year and branches appeared to become spur bound. The precocious Gisela rootstocks also had a tendency to change the canopy morphology of cherry cultivars. In general, trees on these rootstocks had a tendency to be more spreading and wide open in growth habit. Generally, 'Montmorency' was consistently most productive on Mahaleb seedling and Mahaleb clonal SL 275 and MxM 39. Canopies of 'Montmorency' on Gisela stocks had a tendency to produce a large amount of blind wood, caused by the precocious influence on buds of one-year-old wood. 'Hedelfingen' was most yield efficient on GI 154/7 rootstock. The largest fruit was produced on GI 154/7 and MxM 2; the smallest on GM 9. 'Hedelfingen' was most vigorous on Colt, MxM 2 and Mazzard. 'Bing' was most yield efficient on GI 148/1 and GI 148/2; Colt was the least yield efficient. 'Bing' fruit size was largely influenced by crop load relative to canopy area, MxM 2 consistently had large fruit and GM 9 consistently had small fruit. 'Bing' was most vigorous on Colt, the MxM series, Mazzard, Mahaleb, and GI 148/1. Sweet and sour cherry orchardists are encouraged by the NC-140 authors to experiment, on a limited scale, with those new rootstocks reported in this first test that exhibit horticultural merits for particular site, market, and/or scion requirements.

Interstems of M.9 on MM.111, Antonovka and Ottawa 11 rootstocks with 2 scion cultivars were planted in 10 locations in 1976 and handled according to the guidelines established by NC-140. Tree loss on MM.111 was 9% or less over 9 years, but losses exceeded 16% on the other rootstocks. Trees of ‘Empire’ were 25% larger and 36% more productive than trees of ‘Sturdeespur,’ as well as more efficient on each rootstock. ‘Empire’ was more efficient than ‘Sturdeespur’ and trees on Antonovka were most efficient followed by Ottawa 11 and MM.111. Scions and interstems on Ottawa 11 suffered the greatest winter injury, MM.111 the least with Antonovka intermediate.