Progress 10/01/02 to 09/30/07
Outputs
Apple: A Golden Delicious rootstock trial was initiated at the UC Kearney Ag Center in 2003 with eight single tree reps of 20 rootstocks. Valuable information regarding fireblight has been obtained. More than half the trees on M26 and M9 have died including five more in 2007. In addition, six trees on experimental rootstocks died in 2007. Two of these were on B9, an extremely weak tree under California conditions. The trees probably didn't die from fireblight, but just progressive decline. Of the other four trees that died, two broke off below the graft union. One was on CG 5935 and broke under a heavy fruit load. The other was quite a large tree on CG 4210 and broke during heavy winds in October. Both trees were healthy looking before they broke. A third tree broke right at the graft union. It was on PiAu 51-11 and also appeared healthy before it snapped under a heavy crop load. The final tree that died in 2007 was on JM 2 and it collapsed suddenly mid season, typical
of what happens to the M9 and M26 trees when they die from fireblight. Thus, the experimental rootstocks have generally survived fireblight quite well, especially the CG series stocks. Peach: Peach: A NC-140 peach rootstock trial was planted in 2001. Unfortunately, there was potential of a serious virus infection and the trees had to be removed in January 2007.
Impacts
Increasing labor costs and decreasing labor availability have become major issues for California peach growers. Therefore they have rated dwarfing rootstocks as one of their highest priorities as there is the potential for greatly reducing labor costs. In addition, disease resistance rootstocks can also reduce labor and pest management costs as well as improve productivity. For the apple industry, this project has shown some very promising dwarfing rootstocks with good fireblight resistance. This will improve tree survival in the orchard and could eliminate such cultural practices as cutting out fireblight strikes. Thus, both these fresh fruit commodity groups consider this project to be crucial to the long-term health and survival of their industries.
Publications
- Autio, W.R., B.H. Barritt, J.A. Cline, R.M. Crassweller, C.G. Embree, D.C. Ferree, M.E. Garcia, G.M. Greene, E.E. Hoover, R.S. Johnson, K. Kosola, J. Masabni, M.L. Parker, R.l. Perry, G.L. Reighard, T.L. Robinson, S.D. Seeley, and M. Warmund. 2007. Early performance of 'Fuji' and 'McIntosh' apple trees on several dwarf rootstocks in the 1999 NC-140 rootstock trial. Acta Horticulturae 732:119-125.
- Autio, W.R., B.H. Barritt, J.A. Cline, R.M. Crassweller, C.G. Embree, D.C. Ferree, M.E. Garcia, G.M. Greene, E.E. Hoover, R.S. Johnson, K. Kosola, J. Masabni, M.L. Parker, R.l. Perry, G.L. Reighard, T.L. Robinson, S.D. Seeley, and M. Warmund. 2007. Early performance of 'Fuji' and 'McIntosh' apple trees on several semidwarf rootstocks in the 1999 NC-140 rootstock trial. Acta Horticulturae 732:127-133
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Progress 01/01/06 to 12/31/06
Outputs
Apple: A Golden Delicious rootstock trial was initiated at the UC Kearney Ag Center in 2003 with eight single tree reps of 20 rootstocks. Valuable information regarding fireblight has been obtained. A total of 39 trees have died in the last two years, presumably from fireblight. Most of those (32) were on the standard rootstocks M9 and M26. Of the experimental trees, three on PiAu 56-83, one on PiAu51-11 and one on Bud 62-396 have died. In addition, one each of B9 and J-TE-G has also died. However, these two are very weak rootstocks and the trees probably died from the extremely stressful summer conditions of central California. All of the Cornell-Geneva series (which were bred for fireblight resistance) have survived so far, as have the JM series from Japan. Peach: A NC-140 peach rootstock trial was planted in 2001. Fifteen rootstocks were planted in California and about 18 other states for evaluation. Of greatest interest is the dwarfing rootstock VVA-1 which makes
a healthy small tree with good fruit size. The two rootstocks patented by UC in 2004, Controller 9 and Controller 5, also look promising. Controller 5 and VVA-1 both make trees about half the size of standard peach trees. Numerous studies on Controller 5 have demonstrated that the dwarfing mechanism is related to water relations of the root system. An ongoing breeding program for stone fruit rootstocks will continue with the objective of combining tree size control with resistance to important diseases and pests including nematodes.
Impacts
Increasing labor costs and decreasing labor availability have become major issues for California peach growers. Therefore they have rated dwarfing rootstocks as one of their highest priorities as there is the potential for greatly reducing labor costs. In addition, disease resistance rootstocks can also reduce labor and pest management costs as well as improve productivity. For the apple industry, this project has shown some very promising dwarfing rootstocks with good fireblight resistance. This will improve tree survival in the orchard and could eliminate such cultural practices as cutting out fireblight strikes. Thus, both these fresh fruit commodity groups consider this project to be crucial to the long-term health and survival of their industries.
Publications
- Pernice, F., L. Solari, and T.M. DeJong. 2006. Comparison of growth potentials of epicormic shoots of nectarine trees grown on size-controlling and vigorous rootstocks. J. Hort. Sci. and Biotechnology 81:211-218.
- Solari, L.I. and T.M. DeJong. 2006. The effect of root pressurization on water relations, shoot growth, and leaf gas exchanges of peach (Prunus persica) trees on rootstocks with differing growth potential and hydraulic conductance. J. Experimental Botany 57:1981-1989.
- Solari, L.I., S. Johnson, and T.M. DeJong. 2006. Relationship of water status to vegetative growth and leaf gas exchange of peach (Prunus persica) trees on different rootstocks. Tree Physiology 26:1333-1341.
- Solari, L.I., S. Johnson, and T.M. DeJong. 2006. Hydraulic conductance characteristics of peach (Prunus persica) trees on different rootstocks are related to biomass production and distribution. Tree Physiology 26:1343-1350.
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Progress 01/01/05 to 12/31/05
Outputs
Apple: A Fuji rootstock trial was initiated at the UC Kearney Ag Center in 1999 with six single tree reps of 21 rootstocks. Valuable information regarding fireblight has been obtained. A total of 14 trees have died so far, presumably from fireblight. Thirteen of those were on the standard rootstocks M9 and M26. Of the experimental trees, only one on Supporter 1 has died. All of the Cornell-Geneva series (which were bred for fireblight resistance) have survived so far. A second NC-140 apple planting was initiated in 2003. The scion is Golden Delicious and there are 23 experimental rootstocks. Once again, fireblight has killed about 20 M9 and M26 trees but none of the experimental rootstocks. Peach: A NC-140 peach rootstock trial was planted in 2001. Fifteen rootstocks were planted in California and about 18 other states for evaluation. Of the semi dwarfing stocks, Bailey and Hiawatha looked the most promising. Both had good production and fruit size in 2005. Pumiselect
had small fruit size and was not very productive. Of the dwarfing rootstocks VVA-1 looked the most promising. An ongoing evaluation program for peach rootstocks is now entering its final stages of evaluation. Initially, over 80 items were evaluated for compatibility, productivity, dwarfism and root sucker production. Ten rootstocks showed promise and were put into a replicated trial at two different spacings with two different scion varieties. Two selections have continued to meet the criteria for commercial peach rootstocks and have been patented. Both are semi-dwarfing rootstocks with no root suckering, compatibility with a range of scion varieties and good productivity. An ongoing breeding program for stone fruit rootstocks will continue with the objective of combining tree size control with resistance to important diseases and pests including nematodes.
Impacts
The fruit growers in California have rated dwarfing rootstocks as one of their highest priorities. There is the potential for greatly reducing labor costs and disease resistance rootstocks can also reduce labor and pest management costs as well as improve productivity. Therefore, they are very interested in the potential this project offers for the future survival of their industry. For the apple industry, there are some very promising dwarfing rootstocks with good fireblight resistance. This will improve tree survival in the orchard and could eliminate such cultural practices as cutting out fireblight strikes. For the peach industry, currently there are no commercial dwarfing rootstocks. This project provides information on some very promising dwarf and semi-dwarf rootstocks that could greatly reduce labor costs in the orchard by eliminating much ladder work.
Publications
- DeJong, T., D. Ramming, S. Johnson and J. Doyle. 2004. Peach and nectarine rootstock named "K146-43." United States Plant Patent No. PP15, 228. Oct. 12, 2004.
- DeJong, T., D. Ramming, S. Johnson and J. Doyle. 2004. Peach and nectarine rootstock named "P30-135." United States Plant Patent No. PP15, 225. Oct. 12, 2004.
- DeJong, T.M., R.S. Johnson, J.F. Doyle and D. Ramming. 2005. Research yields size-controlling rootstocks for peach production. California Agriculture 59(2):80 through 83.
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Progress 01/01/04 to 12/31/04
Outputs
Apple: A Fuji rootstock trial was initiated at the UC Kearney Ag Center in 1999 with six single tree reps of 21 rootstocks. Due to various cultural and economic problems, no yield measurements were made in 2004. However, valuable information regarding fireblight was obtained. A total of 14 trees have died so far, presumably from fireblight. Thirteen of those were on the standard rootstocks M9 and M26. Of the experimental trees, only one on Supporter 1 has died. All of the Cornell-Geneva series (which were bred for fireblight resistance) have survived so far. Increased fireblight pressure will be imposed in the next few years to make sure there is strong resistance. A second NC-140 apple planting was initiated in 2003. The scion is Golden Delicious and there are 23 experimental rootstocks. In 2003, nearly 20% of the trees grew very poorly or died. In 2004 they did much better. By 2005 we will have good information on tree size and productivity. Peach: A NC-140 peach
rootstock trial was planted in 2001. Fifteen rootstocks were planted in California and about 18 other states for evaluation. The trees in this planting have separated into 3 statistically different tree size categories. The vigorous rootstocks include peach almond hybrids such as BH-4, Cadaman and SLAP, all of which have more vigor than Nemaguard. Of the semi dwarfing stocks, Bailey and Hiawatha looked the most promising. Both had good production and fruit size in 2003 and 2004. Pumiselect had small fruit size and was not very productive. Of the dwarfing rootstocks several had large fruit size including Jaspi, Julior and VVA-1. An ongoing evaluation program for peach rootstocks is now entering its final stages of evaluation. Initially, over 80 items were evaluated for compatibility, productivity, dwarfism and root sucker production. Ten rootstocks showed promise and were put into a replicated trial at two different spacings with two different scion varieties. Two selections have
continued to meet the criteria for commercial peach rootstocks and have been patented. Both are semi-dwarfing rootstocks with no root suckering, compatibility with a range of scion varieties and good productivity. An ongoing breeding program for stone fruit rootstocks will continue with the objective of combining tree size control with resistance to important diseases and pests including nematodes.
Impacts
The fruit growers in California have rated dwarfing rootstocks as one of their highest priorities. There is the potential for greatly reducing labor costs and disease resistance rootstocks can also reduce labor and pest management costs as well as improve productivity. Therefore, they are very interested in the potential this project offers for the future survival of their industry.
Publications
- Autio, W.R., J.L. Anderson, B.H. Barritt, R.M. Crassweller, D.C. Ferree, G.M. Greene, S. Johnson, J. Masabni, M.L. Parker, G.L. Reighard, and M. Warmund. 2004. Early performance of 'Fuji' apple on several dwarf rootstocks in the 1999 NC-140 Rootstock Trial. HortScience 39:800.
- Autio, W.R., J.L. Anderson, B.H. Barritt, R.M. Crassweller, D.C. Ferree, G.M. Greene, S. Johnson, J. Masabni, M.L. Parker, G.L. Reighard, and M. Warmund. 2004. Early performance of 'Fuji' apple on several semidwarf rootstocks in the 1999 NC-140 Rootstock Trial. HortScience 39:799-800.
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Progress 01/01/03 to 12/31/03
Outputs
Apple: A Fuji rootstock trial was initiated at the UC Kearney Ag Center in 1999 with six single tree reps of 21 rootstocks. Due to a wet spring, fireblight was a problem in 2003. Major pruning cuts were needed on some trees to remove all infections. This reduced yield somewhat but it was still comparable to 2002. In addition to fireblight, problems with sunburn, codling moth and other disorders lead to a low percentage of marketable fruit in this block. In the dwarf planting, G16T looks like a promising rootstock with high yield and good fruit size. CG179 also had high yield but fruit size was a little smaller. CG13 is too vigorous for this spacing. In the semi dwarf trial, CG814 has performed well the last two years with high production and good fruit size. It was clearly superior to the two standard rootstocks, M26 and M7. CG30T also had very good production in 2003. Peach: A NC-140 peach rootstock trial was planted in 2001. Fifteen rootstocks were planted in
California and about 18 other states for evaluation. The trees in this planting have separated into 3 statistically different tree size categories. Of the vigorous rootstocks, BH-4 is the strongest and is significantly larger than Lovell or Nemaguard. Two of 8 SLAP trees collapsed during the season and SC-17 had more suckers than any other rootstock in the trial. Of the semi dwarfing stocks, Bailey and Hiawatha looked the most promising. Both had good production and fruit size in 2003. Pumiselect had small fruit size and was not very productive. The dwarfing rootstocks generally had smaller fruit size. The exception to this was VVA-1 which had excellent fruit size, although very low yield. Also, two of the 8 trees on this rootstock have died so far and three others have still not produced a substantial crop. Therefore, it is premature to make judgement on this rootstock. An ongoing evaluation program for peach rootstocks is now entering its final stages of evaluation. Initially, over
80 items were evaluated for compatibility, productivity, dwarfism and root sucker production. Ten rootstocks showed promise and were put into a replicated trial at two different spacings with two different scion varieties. Two selections have continued to meet the criteria for commercial peach rootstocks and are now being patented. Both are semi-dwarfing rootstocks with no root suckering, compatibility with a range of scion varieties and good productivity. An ongoing breeding program for stone fruit rootstocks will continue with the objective of combining tree size control with resistance to important diseases and pests including nematodes.
Impacts
California fruit growers are struggling economically because of poor prices and high labor costs. New dwarfing and disease resistance rootstocks can greatly reduce labor and pest management costs as well as improve productivity. Therefore, they are very interested in the potential this project offers for the future survival of their industry.
Publications
- Weibel, A., Johnson, R.S., and DeJong, T. M. 2003. Comparative vegetative growth responses of two peach cultivars grown on size-controlling versus standard rootstocks. J. Amer. Soc. Hort. Sci. 128:463-471.
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Progress 01/01/02 to 12/31/02
Outputs
Apple: In March, 1999 six single tree reps of 21 rootstocks were planted at the UC Kearney Ag Center with Fuji as the scion variety. There were no new tree deaths in 2002 and all the trees appeared healthy. There was a substantial reduction in flowering in 2002 compared to 2001, especially with the most dwarfing rootstocks. Even though the trees had grown larger, there was about half as many flower clusters per tree compared to the year before. The greatest reduction occurred with CG41, which had 204 clusters/tree in 2001 but only 58 in 2002. Other rootstocks did not show such a dramatic decrease, such as CG179, which dropped from 187 to 143 clusters/tree. All of the rootstocks had good fruit size in 2002, averaging about 200 g/fruit. This is considerably greater than fruit size in 2001 when the average was about 150 g. Although there were no significant differences among treatments, the M9 clone had the largest size with 231 g/fruit and one of the largest yields at
10.2 kg/tree. Yield on the dwarfing stocks varied between 4.9 and 12.3 kg/tree, with CG41 and the three Supporter stocks having the lowest yields. Only marketable fruit was included in the yield data. Many fruit were thrown out that were sunburned, cracked, damaged by codling moth or abnormally small. This amounted to at least 25% on all rootstocks and reached as high as 45% on the Supporter stocks. For the semi-dwarfing rootstocks, there was less variability in yield, fruit size and unmarketable fruit. Although CG30 (both N and T) looked very productive in 2001, it was very similar to the controls (M26 and M7) in 2002. Cherry: In April 1998 eight replicates of 16 rootstocks were planted near the UC Davis campus. These items have been collected from various countries around the world and have promise for California because of dwarfism, precocity and disease resistance. By the fifth year (2002), a fair number of trees of certain rootstocks have died so good information is being
obtained on survivability. There are also big differences in tree size. Several of the experimental rootstocks such as Gi 195-20 and Gi 209-1 appear to be much more precocious than standard cherry rootstocks. Peach: An ongoing evaluation program for peach rootstocks is now entering its final stages of evaluation. Initially, over 80 items were evaluated for compatibility, productivity, dwarfism and root sucker production. Ten rootstocks showed promise and were put into a replicated trial at two different spacings with two different scion varieties. Three selections have continued to meet the criteria for commercial peach rootstocks and are now being put into grower trials for evaluation. All three are semi-dwarfing rootstocks with no root suckering, compatibility with a range of scion varieties and good productivity. A NC-140 peach rootstock trial was planted in 2001. These three rootstocks plus 12 others were planted in California and about 15 other states for evaluation. An ongoing
breeding program for stone fruit rootstocks will continue with the objective of combining tree size control with resistance to important diseases and pests including nematodes.
Impacts
California fruit growers are very interested in new rootstocks that impart dwarfism and disease resistance to their trees. Having shorter trees can lead to substantial economic savings because of reduced ladder work for pruning, thinning and harvesting. Greater disease resistance can reduce pesticide use and thus save money as well as minimize environmental impacts.
Publications
- No publications reported this period
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Progress 01/01/01 to 12/31/01
Outputs
Apple: In March, 1999 six single tree reps of 21 rootstocks were planted at the UC Kearney Ag Center with 'Fuji' as the scion variety. There were no new tree deaths in 2001 and all the trees appeared healthy. The trees are starting to separate out in size as measured by tree height and trunk circumference. In the dwarf planting, Supporter 1, 2 and 3 are the smallest and are significantly smaller than M9, while CG13 is the largest, significantly larger than M26. In the semi dwarf planting Supporter 4 and CG707 are the smallest and similar in size to M26 while CG210 is the largest, substantially larger than M7. The trees flowered abundantly in 2001 with most trees having close to 200 clusters per tree. CG935 stood out from the others with an average of 374 clusters. This translated into significantly higher yields even though attempts were made to thin all trees to similar fruit loads. Since average fruit weight and tree growth were both better than average, it suggests
CG935 shows promise as a productive dwarfing rootstock under California conditions. In the semi dwarf planting, CG30 appears to have the greatest potential as a productive rootstock. It had over 3 times the yield of either M26 or M7 with comparable fruit size. Cherry: In April 1998 eight replicates of 16 rootstocks were planted near the UC Davis campus. These items have been collected from various countries around the world and have promise for California because of dwarfism, precocity and disease resistance. By the fourth year (2001), a fair number of trees of certain rootstocks have died so good information is being obtained on survivability. There are also big differences in tree size. Several of the experimental rootstocks such as Gi 195-20 and Gi 209-1 appear to be much more precocious than standard cherry rootstocks. Peach: An ongoing evaluation program for peach rootstocks is now entering its final stages of evaluation. Initially, over 80 items were evaluated for compatibility,
productivity, dwarfism and root sucker production. Ten rootstocks showed promise and were put into a replicated trial at two different spacings with two different scion varieties. Three selections have continued to meet the criteria for commercial peach rootstocks and are now being put into grower trials for evaluation. All three are semi-dwarfing rootstocks with no root suckering, compatibility with a range of scion varieties and good productivity. A NC-140 peach rootstock trial was planted in 2001. These three rootstocks plus 12 others were planted in California and about 15 other states for evaluation. An ongoing breeding program for stone fruit rootstocks will continue with the objective of combining tree size control with resistance to important diseases and pests including nematodes.
Impacts
California fruit growers are very interested in new rootstocks that impart dwarfism and disease resistance to their trees. Having shorter trees can lead to substantial economic savings because of reduced ladder work for pruning, thinning and harvesting. Greater disease resistance can reduce pesticide use and thus save money as well as minimize environmental impacts.
Publications
- No publications reported this period
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Progress 01/01/00 to 12/31/00
Outputs
Apple: In March, 1999 six single tree reps of 21 rootstocks were planted at the UC Kearney Ag Center with 'Fuji' as the scion variety. Most of these rootstocks are from the Cornell breeding program and have been selected for dwarfism and resistance to fire blight and other diseases, which will be very valuable to growers in California. During the year 2000 a heavy rain occurred towards the end of bloom which caused a serious outbreak of fire blight. There were several fire blight strikes in every tree and these were immediately cut out. Only one tree (on Supporter 1 rootstock) has died so far whereas all of the Cornell rootstocks have survived. The trees bore very little crop in 2000 but put on extensive vegetative growth, so there will be a substantial crop in 2001. All of the experimental rootstocks had no or very few root suckers. Some of these same rootstocks with 'Gala' as the scion variety were planted in 3 separate grower trials in 2000 and another planting
with 'Pink Lady' will be established in 2001. Cherry: In April 1998 eight replicates of 16 rootstocks were planted near the UC Davis campus. These items have been collected form various countries around the world and have promise for California because of dwarfism, precocity and disease resistance. By the third year (2000), a fair number of trees of certain rootstocks have died so good information is being obtained on survivability. There are also big differences in tree size. In 2000, data were collected on flower density. Several of the experimental rootstocks such as Gi 195-20 and Gi 209-1 appear to be much more precocious than standard cherry rootstocks as they had 2 to 3 times greater flower density than Mazzard or Mahaleb. Fruit production was very low in 2000 as low chill conditions prevailed. Peach: An ongoing evaluation program for peach rootstocks is now entering its final stages of evaluation. Initially, over 80 items were evaluated for compatibility, productivity, dwarfism
and root sucker production. Ten rootstocks showed promise and were put into a replicated trial at two different spacings with two different scion varieties. Three selections have continued to meet the criteria for commercial peach rootstocks and are now being put into grower trials for evaluation. All three are semi-dwarfing rootstocks with no root suckering, compatibility with a range of scion varieties and good productivity. A NC-140 peach rootstock trial is planned for 2001. These three rootstocks plus at least 15 others will be planted in California and 8 to 12 other states for evaluation. An ongoing breeding program for stone fruit rootstocks will continue with the objective of combining tree size control with resistance to important diseases and pests including nematodes.
Impacts
New fruit tree rootstocks that impart dwarfism and disease resistance will be very important to California fruit growers. Having shorter trees can lead to substantial economic savings because of reduced ladder work for pruning, thinning and harvesting. Greater disease resistance can reduce pesticide use and thus save money as well as minimize environmental impacts.
Publications
- Perry, R., G. Reighard, D. Ferree, J. Barden, T. Beckman, G. Brown, J. Cummins, E. Durner, G. Greene, S. Johnson, R. Layne, F. Morrison, S. Myers, W. R. Okie, C. Rom, R. Rom, B. Taylor, D. Walker, M. Warmund, and K. Yu. 2000. Performance of the 1984 NC-140 cooperative peach rootstock planting. J. Amer. Pom. Soc. 54:6-10.
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Progress 01/01/99 to 12/31/99
Outputs
Apple: In March, 1999 six single tree reps of 21 rootstocks were planted at the UC Kearney Ag Center with Fuji as the scion variety. Most of these rootstocks are from the Cornell breeding program and have been selected for dwarfism and resistance to fireblight and other diseases which will be very valuable to growers in California. All the trees grew well in the first year with subtle differences in tree size starting to show up among rootstocks. Some of these same rootstocks will be put in grower trials in the year 2000. Cherry: In April, 1998 eight replicates of 16 rootstocks were planted near the UC Davis campus. These items have been collected form various countries around the world and have promise for California because of dwarfism, precocity and disease resistance. By the second year (1999), a fair number of trees of certain rootstocks have died so good information is being obtained on survivability. There are also big differences in tree size. In 2000, data
will start to be collected on precocity, productivity (flower density, fruit set and yield), fruit size, cropping efficiency, disease susceptibility, uniformity of growth habit and size, and other horticultural characteristics. Peach: An ongoing evaluation program for peach rootstocks is now entering its final stages of evaluation. Initially, over 80 items were evaluated for compatibility, productivity, dwarfism and root sucker production. Ten rootstocks showed promise and were put into a replicated trial at two different spacings with two different scion varieties. Three selections have continued to meet the criteria for commercial peach rootstocks and are now being put into grower trials for evaluation. All three are semi-dwarfing rootstocks with no root suckering, compatibility with a range of scion varieties and good productivity. A NC-140 peach rootstock trial is planned for 2001. These three rootstocks plus at least 15 others will be planted in California and at least 12 other
states for evaluation.
Impacts
Apple: In 1999, an apple rootstock planting was established with 21 different rootstocks. These will be evaluated for disease resistance and horticultural characteristics under California conditions. Cherry: A rootstock trial of 16 items planted in 1998 shows a few with potential for dwarfism and disease resistance. Peach: Three rootstocks from an ongoing evaluation program show promise as dwarfing stocks for peaches and nectarines. These are now being put in larger commercial trials.
Publications
- No publications reported this period
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Progress 01/01/98 to 12/31/98
Outputs
Apple: The 1993 planted NC-140 apple rootstock plot of Cornell-Geneva (CG) selections was removed in 1998. A new planting to replace it will be established in spring of 1999. The scion variety will be Fuji and 17 different rootstocks will be tested including 13 fireblight resistant CG selections and 4 Supporter selections from Germany. These selections range in size from M27 (very dwarfing) to M111 (standard). Some of the most promising stocks are CG16 (M9 size), CG935 (M26 size) and CG30 (M7 size). Cherry: In the spring of 1998 a new cherry rootstock trial was established in Winters. The scion variety is Bing and 16 different rootstocks are being tested including 7 Giessen selections and 6 Weiroot stocks. Several of the Weiroot selections did not survive well at planting but otherwise the trial is growing well. Peach: 1998 was the third year for the peach rootstock block. Both Loadel and Flavorcrest had substantial yields and big differences in tree growth and vigor
were observed on the various rootstocks. Several of the rootstocks are showing incompatibility but three still look very promising as semi dwarfing rootstocks for the California peach industry. These three, K119-50, P30-135, and K146-43, are being propagated for larger trials with commercial growers.
Impacts
(N/A)
Publications
- No publications reported this period
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Progress 01/01/97 to 12/01/97
Outputs
Apple: The 1993 planted NC-140 apple rootstock plot of Cornell-Geneva (CG) selections had yields in 1997 lower than in 1996. This is partly due to excessive fruit drop which occurs with 'Liberty' apples under the hot conditions of the San Joaquin Valley. In the dwarf planting, none of the experimental rootstocks surpassed the standard M.9 EMLA and M.26 rootstocks in terms of yield and fruit numbers. In the semi-dwarf planting CG.13 had slightly higher yield than the standard M7 EMLA/M.7a rootstock. CG.30 has performed very well in other locations but has not been impressive under california conditions. In the vigorous planting, all of the experimental rootstocks are quite vigorous and had greater yields than the standard M.111 rootstock. Peach: Growth in both the Loadel and Flavorcrest portions of the block was good with clear differences in tree growth and vigor developing between most of the rootstocks. The experimental rootstocks are producing trees that range from
50-90% of the control trees on Nemaguard. Unfortunately some trees on three of the experimental rootstocks (Sapalta, Alace, 145-5) are beginning to show what may be signs of delayed incompatibility. Almost all trees on the other rootstocks appear healthy and exhibit characteristics that are encouraging for meeting the goal of identifying acceptable size controlling rootstocks for the California peach industry.
Impacts
(N/A)
Publications
- AUTIO, W.R., HAYDEN, R.A., MICKE, W. C., and BROWN, G.R. 1996. Rootstock affects ripening, color, and shape of 'Starkspur Supreme Delicious' apples in the 1984 NC-140 cooperative planting. Fruit Varieties Journal 50(1):45-53.
- ROM, R. C., ET AL. NC-140. 1996. Performance of the NC-140 cooperative apple rootstock planting: I. Survival, tree size, yield and fruit size. Fruit Varieties Journal 50(1):6-11.
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Progress 01/01/96 to 12/30/96
Outputs
Apple: The 1993 planted NC-140 apple rootstock plot of Cornell-Geneva (CG) selections had yields ranging from 10 to 40 kg/tree in 1996. In the dwarf planting, none of the experimental rootstocks had yields greater than M.9 EMLA. However, a large number of both M.9 EMLA and M.26 rootstock trees have died, apparently from fireblight. None of the experimental trees have succumbed to this disease. In the semi-dwarf planting, the standard rootstocks (M.7a and M.7 EMLA) again out-produced all the experimental rootstocks. CG 30 has shown great promise in all the other test sites of this project, but does not seem to perform as well in California. For the vigorous planting, all the experimental rootstocks produced greater yields than the standard M.111. Some of the most productive rootstocks include CG 707 and CG 760. CG 239 also produced well but 50% of the trees have broken off at or near the graft union. Peach: From an original pool of 80 potential rootstocks planted in
1987, 8 have been selected for further testing. These are all semi-dwarfing and show some degree of disease resistance. After budding to Flavorcrest and Loadel peach in 1995, replicated plots were established at the Kearney Agricultural Center in 1996. Both high and moderate density systems were planted. These plots will be evaluated over the next few years for yield, yield efficiency, fruit quality, suckering and tree size.
Impacts
(N/A)
Publications
- ROM, R. C., ET AL. NC-140. 1996. Performance of the NC-140 cooperative apple rootstock planting: I. Survival, tree size, yield and fruit size. Fruit Varieties Journal 50(1):6-11.
- AUTIO, W.R., HAYDEN, R.A., MICKE, W. C., and BROWN, G.R. 1996. Rootstock affects ripening, color, and shape of 'Starkspur Supreme Delicious' apples in the 1984 NC-140 cooperative planting. Fruit Varieties Journal 50(1):45-53.
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Progress 01/01/95 to 12/30/95
Outputs
Apple: The 1993 planted NC-140 apple rootstock plot of Cornell-Geneva (NY) selections had yields ranging from 5 to 10 kg/tree in 1995. Some trees on M.26 and M.9 EMLA were lost, apparently due to fireblight. Rootstocks producing the most suckers were G.65, M.7a, M.7 EMLA, CG.239, CG.8, CG.11, CG.13 and M.9L, all with 6 or more per tree. Trees on G.65 are considerably larger than expected. Sweet cherry: Rootstock trials initiated in 1987 and 1988 as part of the NC-140 project were terminated last year because of tree decline from stem pitting disease. In California, the Gisela rootstocks preferred by growers are 148/1 and 148/2. Studies using water stress to control growth and reduce summer pruning of young trees have shown some promise. Peach: Over 80 potential rootstocks for peach have been evaluated for compatibility, suckering, tree size, yield, fruit size, disease resistance and nematode susceptibility during the past 8 years. Eight of these selections show promise
as semi-dwarfing rootstocks. These were budded to Flavorcrest and Loadel varieties in 1995 and will be planted in a replicated trial at the Kearney Agricultural Center in 1996. Several trees of numerous other scion varieties were also made to test compatibility.
Impacts
(N/A)
Publications
- NO PUBLICATIONS REPORTED THIS PERIOD.
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Progress 01/01/94 to 12/30/94
Outputs
Apple: The 1984 planted NC-140 apple rootstock plot was removed this year and root systems examined. Rootstocks that produced dwarf trees tended to have poor, sparse and often brittle root systems with small lateral roots, especially P.22, P.16, Bud.9, P.2, Mac 39 and CG-24. P.2 roots also showed galling of undermined cause on six of the ten replicates. Rootstocks that produced more vigorous trees usually had extensive root systems. Sweet cherry: Because rainfall precluded harvest in 1994, yield and fruit size was rated. Rootstocks having the heaviest crop ratings for the 'Bing' cultivar were Gi 169/15, Gi 172/7 and Gi 173/9. Those producing the largest fruit size ratings were P. mahaleb, MM46, MM60, MM2, MM97 and 'Colt'. Trees on more dwarfing rootstocks tended to have more uniform and advanced maturity. As reported in 1993 some trees on Gi rootstocks showed spur death and small leaves. This condition worsened in 1994. Of the Gi rootstocks, 148/1 is currently favored
in California. Peach: A large group of potential rootstocks for peach were narrowed down to 30 promising selections. Trees on these rootstocks have been evaluated for tree size, yield, fruit size and compatibility with peach. Several appeared to have potential for reducing tree size by 20 to 40%. Nursery trees of the six most promising of these rootstocks have been budded to several peach cultivars for larger scale replicated test plots.
Impacts
(N/A)
Publications
- NO PUBLICATIONS REPORTED THIS PERIOD.
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Progress 01/01/93 to 12/30/93
Outputs
Apple: Data collection from the 1984 planted NC-140 apple rootstock trial was completed this year. In this California trial no rootstock performed better than M.7 EMLA. Three rootstocks, P.18, M.4 and Ant.313, produced trees larger than those on seedling and were not very yield efficient. Four rootstocks, P.22, P.16, Bud.9 and P.2, produced very small trees that were not suited to California Central Valley growing conditions. Rootstocks in this trial that showed promise and should be tested further include P.1, MAC 39, and possible CG-24 and C.6. A test of new apple rootstocks from the Cornell-Geneva program was planted in 1993 and included subplots of dwarf, semi-dwarf and semi-vigorous rootstocks. Sweet cherry: Of the newer rootstocks Gi 195/2, Gi 148/1 and possibly Gi 169/15 have performed the best overall with generally low root suckering, little bacterial canker and high yield with good fruit size. In 1993 Mahaleb rooted trees increased in yield. Trees on some Gi
rootstocks were beginning to show spur death and small leaves. Colt appeared to impart delayed bloom in 1993. Peach: Eighty potential rootstocks have been screened for peach. Based on compatibility, low suckering, productivity, fruit size and disease and nematode resistance, ten of these showed promise as semi-dwarfing rootstocks. Source trees of these rootstocks are being produced. Citation, while performing poorly in other peach trials, was one of the most promising rootstocks in this study.
Impacts
(N/A)
Publications
- TYLER, R.H. and MICKE, W.C. 1993. Which apple rootstocks are best in California. California Grower 17(9):41-42.
- MICKE, W.C., SOUTHWICK, S.M., and JOHNSON, R.S. 1993. Annual report of NC-140 Cooperative Regional Project, Report to the NC-140 Technical Committee, Unpub.
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