). Rootstock regrowth removal is an expensive, labor-intensive process and has been prohibitive to the adoption of grafted transplants in U.S. watermelon production. Rootstock treatment with fatty alcohol can control meristematic regrowth by burning the
Shawna L. Daley, William Patrick Wechter, and Richard L. Hassell
Fan Cao, Yunchu Wei, Xinwang Wang, Yongrong Li, and Fangren Peng
treatments in a greenhouse. Twenty grafted trees of each rootstock, a total of 240 grafted trees, were planted in four blocks in 2012. That is to say, there were 60 trees, five of 12 rootstock treatments, in each block, which included four rows, 15 grafted
David H Suchoff, Christopher C. Gunter, Jonathan R. Schultheis, Matthew D. Kleinhenz, and Frank J. Louws
latter two ( Fig. 6 ). At normal irrigation, φ PSII was similar among the three rootstock treatments; however, at reduced irrigation B had higher φ PSII (0.3374) than C (0.2756) and S (0.2670; Fig. 6C ). Table 1. Results of analysis of variance for the
Michael W. Smith and William D. Goff
for budding. Rootstock treatments. Seedling ‘Elliott’ rootstocks were interplanted into the established orchard or a new orchard site during Feb. 2012. Treatments included 1) removal of ≈4 inches of the rootstock top on 2–3 Aug. 2013 ≈2 weeks before
Malcolm W. Smith, Jeremy D. Bright, Mark D. Hoult, Richard A. Renfree, Tony Maddern, and Neil Coombes
. Measures of tree size and growth rate revealed large differences between the rootstock treatments ( Table 1 ). ‘Kurukan’ produced the largest tree canopy (CSA = 7.52 m −2 ), whereas ‘Vellaikulamban’ was the smallest (CSA = 4.16 m −2 ). The small tree size
Kristine M. Lang, Ajay Nair, and Kenneth J. Moore
). Fruit pH, TTA, and SSC:TTA were also not different among treatments in 2018 ( Table 5 ). In 2017, both pH and TTA varied slightly among rootstock treatments but none were higher or lower than the nongrafted treatment, except for a lower pH in ‘946 TRS
R. Thomas Fernandez, Ronald L. Perry, and James A. Flore
`Imperial Gala' apple trees (Malus ×domestica Borkh.) on M.9 EMLA, MM.111, and Mark rootstocks were subjected to two drought-stress and recovery periods in a rainshelter. Water relations, gas-exchange parameters per unit leaf area and per tree, chlorophyll fluorescence, and leaf abscisic acid content were determined during each stress and recovery period. Whole-plant calculated gas exchange best indicated plant response to drought stress, with consistent reductions in CO2 assimilation, transpiration, and leaf conductance. Variable and maximal chlorophyll fluorescence and fluorescence quenching were not as sensitive to stress. Other fluorescence parameters showed little difference. The most consistent decreases due to stress for gas exchange per square meter were in transpiration and leaf conductance, with few differences in CO2 assimilation and fewer for mesophyll conductance, internal CO2 concentration, and water-use efficiency. Leaf water potential was consistently lower during drought stress and returned to control values upon irrigation. Leaf abscisic acid content was higher for drought-stressed trees on M.9 EMLA than control trees during the stress periods but inconsistently different for the other rootstock treatments. Trees on M.9 EMLA were least affected by drought stress, MM.111 was intermediate, and Mark was the most sensitive; these results are consistent with the growth data.
Michael A. Maurer and Frederick S. Davies
Two field studies conducted from 1990 to 1991 evaluated the effects of reclaimed water on growth and development of 1- and 2-year-old `Redblush' grapefruit (Citrus paradisi Macf.) trees on Swingle citrumelo [Citrus paradisi (L.) Osb. ×Poncirus trifoliata (L.) Raf.] rootstock. Treatments were arranged as a3 (water sources) x 3 (irrigation levels) factorial at two locations on an Arredondo (well drained) and Kanapaha (poorly drained) fine sand near Gainesville, Fla. Irrigation treatments included 1) reclaimed water, 2) reclaimed water plus fertigation, and 3) well water plus fertigation. The reclaimed water was formulated to simulate that of a sewage treatment plant at Vero Beach, Fla. Irrigation was applied at 20% soil moisture depletion, or at 19 or 25 mm·week regardless of rainfall. In both experiments, visual ratings of tree vigor, and measured tree height and trunk diameter, were significantly lower for trees watered with reclaimed water without fertilizer than for the others in both years. Moreover, there was no fourth leaf flush in 1991 with reclaimed water. There was a significant increase in leaf Na, Cl, and B concentrations for the reclaimed water and reclaimed water plus fertigation treatments in 1990; however, in 1991 only leaf B concentrations showed a similar trend. In 1991, there were no significant differences in leaf Cl concentrations. Visual symptoms of N deficiency were observed by the end of the first season in trees grown with reclaimed water. Irrigation levels generallv did not affect tree growth.
R.L Perry and J. N. Cummins
In 1987, the NC 140 Regional Rootstock Testing Committee established sweet and sour cherry rootstock trials in 16 locations in North America. This paper will present preliminary results on the performance of Hedelfingen (sweet) and Montmoreney (sour) cherry cultivars at the New York and Michigan sites. The rootstock under test include 3 clones from Gembloux, Belgium, Colt, 4 MxM hybrids, and 9 to 13 interspecific hybrid clones from Giessen, West Germany. Clonal rootstock also under test for Montmorency include St. Lucie 64, 275 and, in New York, Holly Jolivette. Rootstock treatments differ slightly among sites and are replicated 7-8 times in a randomized complete block design. The Giessen rootstock 148/1 and 195/1 have, to date, demonstrated excellent influence on sweet cherry precocity. Sweet and sour cherry on Colt and the MxM hybrids have been most vigorous at both sites. Montmorency is most precocious on Mahaleb seedling followed by Giessen 148/1 at both locations. Data for 1990 on rootstock performance will be included in the oral presentation.
Ronald L Perry*, Dario Stefanelli, and Gail Byler
Trees of Gala were planted in 1994 on 18 rootstocks at the Clarksville Horticulture Experiment Station as one cooperating site of 26 North American sites organized by the NC-140 Regional Pome and Stone fruit rootstock committee. One tree each of seven rootstock treatments and two on B.9 and B.491 have died since establishment. Death has been caused by wind (brittle union) on most of the trees in replication one, on the western exterior of the plot which is exposed to strong wind. The most vigorous trees in this planting are those on V.1 and M.26 and least vigorous on M.27 and P.22. Cropping in 2003 was highest on Pajam 2, Ottawa 3 and M.9 NAKB 337, yielding an average of between 60 to 70 kg per tree. Cropping over the years has been highest on PJ.2, M.9 EMLA, and O.3. Cumulative yield efficiency in this plot is highest on P.16, followed by P.22 and B.491. Trees on M.26 are the least efficient over the years. Average fruit weight was highest in 2003 on V.1 and PJ.2. M.9 NAKB 337, the dominant international an national standard M.9 clonal rootstock is not as productive and as precocious as many other M.9 clonal stocks in this trial. After 10 years of evaluation, there appears to be no significant difference in cropping, cumulative yield, for `Gala' among the top eight rootstocks led by M.9 Pajam 2. M.9 NAKB 337 is not among the top eight rootstocks at this site. Pajam 2 is impressive from the view that while it is the top cropping stock, it is the rootstock in 2003 which also averaged the largest fruit. Among the M.9 clonal rootstocks, PJ 2 is also the most vigorous which for North American commercial apple orchards, has excellent commercial potential to withstand field and production stresses.