2015 Open4st MBP and Nursery Summary
Post date: Oct 19, 2015 9:35:54 PM
The Open4st - 2015 Bell Nursery season was busy with significant progress in our goal to produce vigorous, good rooting, and diverse aspens. The primary 2015 focus was to propagate, test and select clones derived from earlier Phase 3-4 breeding efforts. Below is a summary of the year's progress:
We planted 3463 total aspens representing a variety of stock types with 2206 aspens surviving in the 2015 nursery. Final tallies include 319 unique clones via 453 test replications with a mean survival rate of 61% and 153 "Plus Trees" noted for their outstanding performance. The stock type distributions are listed below:
The 2015 nursery contains 319 clones represented by 57 different families, 43 of which are from recent McGovern Breeding Program (MBP) crosses and 14 are from the wild or outside programs that include clones. See the Phase 4 Breeding Matrix for details on the most recent MBP families.
There were significant germination differences within families listed on the Phase 4 Breeding Matrix that may illustrate selection potential for selecting less fertile trees. For example the male F1 hybrid 9AG105 and female Plaza AG had combined 8 cross progeny germination rates under 25%. There are many variables to germination rates such as parental combining characteristics, branch health/age and seed age that can impact germination rates. However, it may worthwhile to investigate if specific crosses can produce selections with desirable traits including effectively sterile progeny to prevent interbreeding with native populations.
The ODC and ODC1-0 dormant cuttings planted in the 2015 nursery had 57% mean survival rate (1603 trees).
There were 146 aspen clonal selections from the 2015 nursery that will be carried forward to 2016. These selections had a 65% average survival rate for the DC and ODC1-0 stock types. Note that most of this material was planted with 6" cuttings and diameters ranging from 13 - 4 milometers. We speculate that aspen field grade cuttings of 10-12" will have much higher survival rates.
The ODC1-0 stock types consisted of 5 - 6 ortet 6" cuttings planted with the ortet 1-0 mini-stool. The cuttings were scored with survival and median collar diameter, along with the 1-0 mini-stool collar diameter. These metrics were combined to form the stool vigor survival metric (Stool VS). The replicated DC 6" stock types also had their survival rates and median collar diameter tabulated to form the Vigor Survival (VS) values. The hypothesis is that if the VS and Stool VS nursery metrics are recorded then later field trial patterns may show useful correlations. Below are the basic formulas.
end_quantity / td.start_quantity AS survival_rate,
(end_quantity / td.start_quantity) * td.collar_median_dia_mm AS vigor_survival,
(end_quantity / td.start_quantity) * td.stool_1_1_collar_mm AS stool_vigor_survival
The online r4st Postgres database contains several 2015 Nursery views that list the details, selections and selection summaries. The vw_nursery_2015_selections table has the column, new_old_clones_ranked_vs_stoolvs that lists older and new (1 yr ODC1-0) clones. These clone names were used to assist with clonal selection for the 2016 materials.
The older clone names contain the syntax: <CloneName~VigorSurvivalMetric-VigorSurvivalPlusTreeMetric>.
The new one year clones have the format: <CloneName-StoolVSMetric-StoolVSPlusTreeMetric_1_ODC1-0>.
Three unrooted 6' aspen whips were field planted at 10" deep in the Spring of 2015Planted field trial at one site (see: 2B16 2015 Unrooted Whips). All 3 whips survived with healthy stems that had about 18" of growth. The 2B16 clone has a 3 year nursery 6" cutting survival rate of 54%.
A 3 year old CAG x T clone was observed with Bronze Leaf Disease (BLD). This was not unexpected since native but rare, T x G families are highly susceptible to BLD. This may provide an interesting opportunity to study the disease and observe if different family/parent combinations would produce resistant strains.
Created the Hybrid Aspen Research and Deployment Strategies document to outline important research areas.
TBD - 3 year 5/3 DOT field trial measurements.
TBD - CSSE Measurements...