Scion Clones Research Articles

Growth of Cut-Grafting Robusta Coffee Seeds Utilizing Orthotropic and Plagiotropic Rootstocks with Application Bacillus and Pseudomonas Mixture

Vegetative propagation by cut-grafting has the advantage of being able to obtain seeds that inherit two superior traits from two scion clones in a relatively short time. The purpose of this research is to determine the effect of using orthotropic and plagiotropic rootstocks applied by Bacillus and Pseudomonas on the early growth of robusta coffee seedlings from cut grafting. The method used was by using a completely randomized factorial design with 2 factors and was repeated 3 times. The first factor was the use of rootstock cuttings which consisted of 2 levels, which were S1 (orthotropic stem) and S2 (plagiotropic stem). The second factor was the concentration of Bacillus and Pseudomonas which consisted of 5 levels, which were B0 (0 ml/L), B1 (20 ml/L), B2 (40 ml/L), B3 (60 ml/L) and B4 (80 ml/L). The results showed that (1) there was no interaction between the use of variatic rootstock and the application of the biological agent (2) The use of orthotropic rootstock increased plant growth, that is the number of primary roots and the number of leaves and (3) Application of the biological agent of Bacillus and Pseudomonas with concentrations of B4 increased seedling growth on all observed parameters except the number of shoots. Based on the results of this research, the benefit for coffee planters is to obtain alternative planting materials, namely from orthotropic branches. For further research, the use of orthotropic branch planting material as a scion plant can be investigated.

Successful Grafting of Two Indonesian Clones of Piper nigrum L. with P. colubrinum Link.: Effects of IBA and NAA on Rooting and Effects of BA on Grafting

<p>This study aimed to investigate the effects of auxin types and their concentrations on rooting of the rootstock cuttings and BA on grafting. First, IBA, NAA or IBA+NAA, each at 0, 1000, 2000, and 3000 ppm were used as treatments to study rooting of <em>P</em><em>iper colubrinum</em>. In the second experiment, BA (0 and 50 ppm) was applied to <em>P. nigrum</em> scion clones of Natar-1 and Petaling-2, before being grafted to the rootstocks. Results showed, that all types of auxins (IBA, NAA or IBA+NAA) induced rooting and shoot growth, and the increase of auxin concentrations led to the increase of rooting. However, their effectiveness was different. NAA and IBA+NAA were superior to IBA, and at 2000 ppm, IBA+NAA resulted in the best plant growth, as indicated by higher values of both rooting and shoot growth parameters. Compared to control, BA treatment on scions resulted in higher grafting success (80% vs. 93%) for Natar-1, and (73% vs.100%) for Petaling-2 clones. BA treatment on scions also induced more calluses in the graft union and better shoot growth. To our knowledge, this is the first report on the use of BA to increase success of grafting between <em>P. nigrum</em> and<em> P. </em><em>colubrinum</em>.</p>

Cocoa Clones Reveal Variation in Plant Biomass, Root Nitrogen Uptake, and Apparent Nitrogen Recovery at the Seedling Stage

We aimed to investigate variation in growth, biomass, macro-nutrient uptake, and nitrogen (N) use efficiency indices of cocoa (Theobroma cocoa L.) scion clones under two different nitrogen conditions. Ten clones were top-grafted onto 4-month-old rootstocks clone MCC 02. Each seedling received either 0 or 4.6 g of nitrogen applied as urea fertilizer. The design was arranged as a two-factor experiment with four replicates in a factorial randomized block design. We measured stem diameter, biomass, nutrient concentration, and calculated nutrient uptake, nitrogen use efficiency (NUE), agronomic efficiency (AE), apparent nitrogen recovery (ANR), and physiological efficiency (PE). We found that clones significantly affected stem diameter and shoot biomass of both rootstocks and scions. Clones differed in root magnesium (Mg) and shoot calcium (Ca) concentration, root N, and shoot Mg uptake. Furthermore, a significant clone effect was observed on ANR, with local clones showing higher ANR than introduced clones. Nitrogen application significantly improved stem diameter and biomass. Compared to unfertilized plants, a significantly higher N concentration was observed in roots, resulting in higher N uptake in both roots and shoots. Nitrogen application increased shoot Ca concentration and uptake but decreased shoot phosphorus (P) and Mg concentrations. Our results suggest genotypic variability in nitrogen uptake efficiency in clonal cocoa. Clones with high nitrogen uptake efficiency are valuable genetic resources for breeding cocoa clones that efficiently use available N and, therefore, grow better under N-deficient conditions.

Respuestas fisiológicas y morfológicas de raíces en diferentes combinaciones de patrones e injertos de cacao al déficit hídrico

Grafting is a common practice in cacao cultivation, but it has not been reported whether rootstock-scion combinations respond differently in terms of water transport, growth, or nutrient uptake under varying soil water availability conditions. The effects of water deficits on water potential (Ψf), basal diameter (db), root growth, chlorophyll and leaf concentrations of nitrogen (N) were evaluated in 16 rootstock-scion combinations that resulted from four rootstocks and four scion clones. Grafted seedlings were subjected to two water regimes: 21 days without irrigation (WD) and continuous irrigation (I). Under WD conditions, Ψf tended to be lower when using the EETP800 clone with the four rootstocks, indicating that this clone may have a higher rate of transpiration. The greater Ψf (p <0.05) obtained with the EET400 and EET399 rootstocks-scion combinations indicate higher water uptake capacity by the root systems of these rootstocks, which permits the maintenance of adequate transpiration rates and higher Ψf. The higher db, chlorophyll content and leaf N content obtained in the combinations of scions with the EET400 rootstock under WD impart on this rootstock a more favorable degree of adaptability for tolerating water deficits. However, this tolerance is not associated with increased root growth, which indicates that higher efficiency of water uptake is related to metabolic and physiological processes rather than a larger root surface.

Combination of two analytical techniques improves wine classification by Vineyard, Region, and vintage

Three important wine parameters: vineyard, region, and vintage year, were evaluated using fifteen Vitis vinifera L. ‘Pinot noir’ wines derived from the same scion clone (Pinot noir 667). These wines were produced from two vintage years (2015 and 2016) and eight different regions along the Pacific Coast of the United States. We successfully improved the classification of the selected Pinot noir wines by combining an untargeted 1D 1H NMR analysis with a targeted peptide based differential sensing array. NMR spectroscopy was used to evaluate the chemical fingerprint of the wines, whereas the peptide-based sensing array is known to mimic the senses of taste, smell, and palate texture by characterizing the phenolic profile. Multivariate and univariate statistical analyses of the combined NMR and differential sensing array dataset classified the genetically identical Pinot noir wines on the basis of distinctive metabolic signatures associated with the region of growth, vineyard, and vintage year.

Reproducibility of elemental profile across two vintages in Pinot noir wines from fourteen different vineyard sites

The reproducibility of elemental profile in wines produced across vintages of 2015 and 2016 has been studied using grapes from a single scion clone of Vitis vinifera L. cv. Pinot noir. Grapevines were grown on fourteen different vineyard sites, from Oregon to southern California in the U.S.A., which span distances from approximately hundreds of meters to 1450 km, while elevations range from near sea level to nearly 500 m. The number of elements quantified in the wines made from the 2016 vintage was thirty, by using inductively coupled plasma mass spectrometry (ICP-MS). These data were compared with the twenty-seven elements quantified and previously reported in wines made from 2015 vintage, including twenty-four elements reported in both vintages. The composition of each element was analyzed by analysis of variance with main effect of vineyard. Wines were classified according to vineyard origin and environmental growing site with a combination of factors correlated with the wine elemental profile. The low variability (< 25%) of certain elements in wines from at least eight sites across both vintages, including Group 1 (Cs, K, Na and Rb), Group 2 (Ba, Ca, Mg and Sr), Group 3B (Eu), Group 13 (Al, B and Ga), Group 15 (As and P) and Co, Fe, Mn, Ni and V, demonstrated the reproducibility over the seasons analyzed (2015 and 2016). The comparison of elemental profile of wines across growing seasons demonstrates the opportunity to reproduce one key aspect of wine chemistry across vintages.

Grafting influence on productivity and drought tolerance of tea clones

AbstractGrafting of fresh cuttings using drought-susceptible and low-yielding clones as scions on drought-tolerant clones as rootstocks offers the possibility of raising composite plants with improved productivity and drought tolerance. Hence, the study was aimed to widen the choice of compatible composites and to delineate the underlying factors responsible for productivity and drought tolerance in grafted plants. One year-old composite plants of TRF-1, TRF-2 and UPASI-28 cleft-grafted on the rootstocks of UPASI-2, UPASI-9, ATK-1 and TRI-2025 were field planted along with their respective controls and evaluated. The results indicated that productivity and drought tolerance of scion clones varied significantly with the rootstocks used. Significant increases in yield and yield components were noted in the following graft combinations compared with their corresponding self-rooted scion clones: TRF-1 grafted on UPASI-9 and ATK-1, TRF-2 grafted on all four rootstocks, and UPASI-28 grafted on UPASI-9, TRI-2025 and UPASI-2. The findings clearly emphasize the scion–rootstock interaction as the critical determinant of productivity in grafted plants compared with vigour, drought tolerance and yield potential of scion and rootstock clones. Further, high-yielding capacity of grafts over the ungrafted scions and rootstocks was largely dependent on the yield potential of the scion clone and the degree of scion–rootstock compatibility. Higher field survival and enhanced yield observed during the drought period in the compatible grafts demonstrated their better drought tolerance compared with their respective self-rooted scions.

Influence of top working on growth and flowering of tea clones

Abstract To study the impact of the top working method of grafting on flowering behavior in tea clones and its applicability in tea breeding two field experiments were carried out. Field established plants of the clone UPASI-9 was used as the rootstock in both the experiments. Recently released clones TRF-1, TRF-3 and TRF-4 were used as scions to study the influence of top working on flowering. One-year-old rooted plants of the clones used as scions field planted in the same year served as standards for comparison. Precocious flowering was noticed in all the top worked clones by eight months from grafting. In self- rooted plants of the scion clones only sparse flowering was noticed after eighteen/nineteen months. Similarly, the duration of flowering and total number of flowers were significantly higher in top worked plants compared to self-rooted plants. The top worked scions were significantly more vigorous than the corresponding self-rooted plants, except TRF-3. In the second experiment by top working the scions of two different clones on the same rootstock; four sets of combinations were tried. The clone TRF-4 was used as one scion in all the four sets and the clones TRF-1, SA-6, Yabukita and SMP-1 served as the other scions in each set. Early flowering as well as synchronization of flowering was observed in both the scion clones in three of the tested pairs. However, the growth and flowering of the common scion clone TRF-4 varied significantly in each set depending on the other clone used as a scion.

Effect of monoclonal and assorted seedling rootstocks on long term growth and yield of Hevea clones

Abstract Seven Hevea brasiliensis clones were evaluated on two types of rootstocks, assorted seedling rootstocks (AR) and monoclonal rootstock (MR) over 19 years. Influence of rootstock on scion growth and rubber yield was assessed based on juvenile height, circumference of the main trunk (cm), number of branches, branching height and cumulative dry rubber yield (g per tree per tapping, conventionally abbreviated gt-1 t-1). Highest cumulative yield (g per tree per tapping) over the 12 years for which the trees were tapped was obtained from clone RRII 105 (MR: 1076 g per tree per tapping and AR: 497 g per tree per tapping), followed by RRII 203 (MR: 661; AR: 538), RRII 208 (MR: 477; AR: 486), RRII 118 (MR: 497; AR: 452). Gl 1 yielded the least, 219 g per tree per tapping (MR) and 378 g per tree per tapping (AR); GT1 produced 335 g per tree per tapping (MR) and 375 g per tree per tapping (AR). RRII 118 had the greatest circumference at age 19 (91.4 cm on MR) 88.8 on AR, followed by RRII 105 (MR: 87.4 cm AR: 89.2 cm) and GT 1 (MR: 88.5 cm; AR: 84.4cm). Effect of scion clone was significant (p&lt;0.01) only for trunk circumference at opening, but not for cumulative rubber yield at age 11 (4 years after opening) or cumulative rubber yield at age 19 (12 years after opening). Most importantly, rootstock and clone × rootstock interaction did not significantly affect rubber yield or tree circumference at any evaluation time. There was no evidence to suggest that growth and yield of clones was influenced significantly by rootstock type.

Keberhasilan sambungan pada beberapa jenis batang atas dan famili batang bawah kakao (Theobroma cocoa L.). (Grafting performance of some scion clones and root-stock family on cocoa (Theobroma cocoa L.)

Differences in performance of grafting seedling were estimated from effect of using the root-stock and scion clones. This research aimed to study the differences of performance of some root-stock and scion clones on grafting seedling. The study used split plot design. First factor was root-stock consisted of ICS 60, Sca 6, Sca 12 and KW 165 and the second factor were 12 scions clones consisted of ICCRI 01, ICCRI 04, ICCRI 05, DR 2, Sulawesi 1, Sulawesi 2, KW 516, KW 514, KW 617, KW 570, KEE 2, and KW 604. There were three replication in each treatment and each replication consisted of 15 samples. Viability, lingkage diameter, ratio of root-stock and scion, hight of shoot, number of leaves and shoot were observed. The study showed that differences of root-stock just affected viability, lingkage diameter, and high of shoot. Scion clones factor affected to all of the characters. Their interaction caused the differences of all characters except of the number of shoot. Root-stock Sca 6 showed the lowest viability and number of the shoot, however root-stock KW 165 and ICS 60 showed the best performance to all parameters. The cluster analysis was done based on growth parameters and viability on lingkage distance of 15. There were three clusters; cluster 1 (KW 570), cluster 2 (ICCRI 04, ICCRI 05, Sulawesi 1, Sulawesi 2, KW 514, KW 165) and cluster 3 (ICCRI 01, DR 2, KW 516, KW 617, KW 604). Correlation analysis showed that main factor which affected the high viability root-stock diameter and diameter ratio of root-stock and scion were used.

Comportamento vegetativo e reprodutivo de clones de cajazeira cultivados na Chapada do Apodi, Ceará

O pomar de cajazeira foi plantado em fevereiro de 2000 na Chapada do Apodi, Limoeiro do Norte, Ceará, com o objetivo de avaliar os efeitos das diferentes combinações porta-enxerto x enxerto no crescimento vegetativo, número de plantas produtivas e produção de frutos de clones de cajazeira. O ensaio foi instalado no delineamento de blocos aleatorizado, em fatorial (5 x 2), com quatro repetições e quatro plantas/parcela. Os garfos (copas) foram obtidos de plantas adultas produtivas de Capuan, Caucaia-CE; Curimatã, Pacajus-CE; Gereau e Ladeira Grande, Maranguape-CE e Lagoa Redonda, Fortaleza-CE e os porta-enxertos de pé franco de cajazeira e de imbuzeiro. Os clones copa Gereau enxertado sobre imbuzeiro e Lagoa Redonda sobre cajazeira tiveram os maiores portes (570 cm) e taxas médias anuais de crescimento, enquanto o Ladeira Grande teve o menor porte em todas avaliações, na última tinha altura de 362 cm. Os clones de maior porte também tiveram os maiores perímetros de caule. Os clones Capuan, Curimatã e Gereau foram os mais tardios, com as primeiras plantas entrando na fase reprodutiva, somente aos 62 meses de idade. O clone copa Lagoa Redonda foi o mais produtivo, tanto na combinação sobre imbuzeiro como na sobre cajazeira. O porta-enxerto e a enxertia não alteraram o padrão de crescimento dos clones, resultando em plantas vigorosas sem indícios de incompatibilidade. O porta-enxerto de imbuzeiro aumentou a precocidade, número de frutos/cacho e produção dos clones copa de cajazeira. O clone copa Lagoa Redonda foi o mais produtivo, notadamente quando enxertado sobre imbuzeiro.

English

&nbsp; Improving drought resistance of rubber trees has become a pressing issue with the extension of rubber plantations and the prevalence of seasonal drought. Root system is vital to water and nutrients uptake of all plants, therefore, rootstocks could play decisive roles in drought resistance of grafted rubber trees on a specific scion clone. To investigate the responses of different clone rootstocks and their grafted trees to water stress and find applicable methods for selecting drought resistant rootstocks, seven related parameters and root hydraulic properties of both seeds originated and grafted saplings of PB86, PR107, RRIM600 and GT1 were measured to assess their drought resistance. It was shown that the rootstock drought resistance and root hydraulic conductance may improve the drought resistance of the grafted rubber trees.&nbsp;Among the four clone rootstocks, GT1, which demonstrated more resistant to drought and higher root hydraulic conductance, was comparatively resistant to drought both for the seed propagation seedlings and grafted saplings.&nbsp;In addition, studies on the grafted saplings with different root hydraulic conductance further validated the possibility of selecting drought resistant rootstocks on the basis of rootstock hydraulic conductance using a high-pressure flow meter. &nbsp; Key words:&nbsp;Rubber tree (Hevea brasiliensis), rootstock, hydraulic conductance, drought resistance, high-pressure flow meter.

Viticultural terroirs in Stellenbosch, South Africa. II. The interaction of Cabernet-Sauvignon and Sauvignon Blanc with environment

&lt;p style="text-align: justify;"&gt;&lt;strong&gt;Aims&lt;/strong&gt;: A terroir can be defined as a grouping of homogenous environmental units, or natural terroir units, based on the typicality of the products obtained. Terroir studies therefore require an investigation into the response of grapevines to the natural environment.&lt;/p&gt;&lt;p style="text-align: justify;"&gt;&lt;strong&gt;Methods and results&lt;/strong&gt;: A network of plots of Sauvignon blanc and Cabernet Sauvignon were delimited in commercial vineyards in proximity to weather stations and their response monitored for a period of seven years. Regression tree methodology was used to determine the relative importance of the environmental and management related variables and to determine regression trees for each dependent variable. Excepting for scion clone, which had a high relative importance for bunch mass of Sauvignon blanc and yield to pruning mass index of Cabernet Sauvignon, no other nonenvironmental variable included in the analyses appeared to have a strong effect on grapevine performance and wine character. The performance of Cabernet-Sauvignon was related to the potassium content of the subsoil and climate (temperature and rainfall) of the season. The performance of Sauvignon blanc appeared to be related to soil texture, wind exposure and temperature of the site and season, both during the green berry growth stage and the month prior to ripening.&lt;/p&gt;&lt;p style="text-align: justify;"&gt;&lt;strong&gt;Conclusions&lt;/strong&gt;: From the results presented, it appears that environmental parameters have an overriding effect on the performance of both Cabernet Sauvignon and Sauvignon blanc but that these two cultivars react differently to environmental stimuli.&lt;/p&gt;&lt;p style="text-align: justify;"&gt;&lt;strong&gt;Significance and impact of study&lt;/strong&gt;: These results should contribute to the identification of viticultural terroirs with specific agronomic potential for Cabernet-Sauvignon and Sauvignon blanc.&lt;/p&gt;

Graft survival and promotion of female and male strobili by topgrafting in a third-cycle slash pine (Pinus elliottiivar.elliottii) breeding program

A total of 2561 slash pine ( Pinus elliottii Engelm. var. elliottii) grafts were topgrafted in the winter of 2003 and evaluated in January of 2004. The objectives of this study were to understand the effect of the genetic material and crown position on survival and flowering response of topgrafts. Also, the effects of geographic direction, branch order, and scion age on topgraft response were assessed. Topgrafting was an effective tool for promoting both female and male strobili. The genetic material (scion and interstock clones) and the crown position had large effects on the promotion of female flowering and topgraft survival. More than 23% of the total variation in female flowering and 16.3% of the total variation in topgraft survival were due to differences among scion clones and among interstock clones, respectively. The highest survival rate was reached by grafting in the mid-top followed by the top crown position. Grafting in the top of the crown was highly superior in promoting female strobili followed by the mid-top position. First-order branches showed a significantly superior production of female strobili. Chronologically older scions, from selections made in the first and second generations of the tree improvement program, produced more female and male strobili than third-cycle forward selections.

The effects of scion maturation on growth and reproduction of grafted slash pine

Establishment of the University of Florida Cooperative Forest Genetics Research Program's clone banks provided an opportunity to look at scion maturation effects on growth and reproduction of many grafted slash pine clones. In 1988 and 1989, clone banks were established in nine locations in the Southeastern United States. Over 460 scion clones varying from 5 to greater than 40 years old from time of seed germination (chronological age) were grafted into the clone banks. Comparisons of diameter growth, height growth, lateral branch number and female and male strobili production were made annually for six years after grafting. Within slash pine clone banks, there were significant effects due to scion chronological age. Chronologically older scions (backward selections) grew less, had fewer branches and produced only a few more female strobili than chronologically younger material (forward selections). Forward selections produced significantly more catkin clusters than backward selections. By year six, there was no significant difference in numbers of female strobili per tree between backward and forward scions, but forward selections produced about 2.5 times as many catkin clusters as the backward selections. Similar effects on growth and reproduction due to chronological age were also found among clones within the forward selections, with older selections growing more slowly and producing fewer catkin clusters. The size and breadth of this study lends strong support to the idea that these patterns of growth will occur for grafted slash pine in any location throughout its native range.

Rootstock effects on scion growth and reproduction in 8-year-old grafted loblolly pine

Contributions of sites, rootstocks, and scion clones (and the interactions between these factors) to scion growth and reproduction were studied in loblolly pine (Pinus taeda L.). Twenty-five full-sib families were used as rootstocks. Six scion clones were grafted on them in all combinations. Study sites were three seed orchards in the southeastern United States; trees were measured 8 years after grafting. Scion elongation, diameter at breast height (DBH) of the main leader, crown diameter, cone counts, and number of male and female strobili were measured at all sites. Crown diameter and tree height were combined into a crown volume index. Highly significant differences existed among scion clones for all traits. When analyzed over all three sites, the only trait with significant rootstock effects was DBH. There were significant rootstock × scion interactions for total scion elongation, crown volume index, and DBH and significant site × scion interactions for strobili counts and cone count. In analyses by clone, rootstock effects were expressed differently in the different clones. There were significant rootstock effects for three traits in each of three clones and no effects at all in two clones. For all traits the largest variance component was for either site or scion clone. Components for rootstocks were small or zero. These results show that the scion clone and site have more control on scion growth and reproduction of grafted loblolly pine than the rootstock. The study did not identify full-sib families that (as rootstocks) would signficantly reduce scion elongation or signficantly increase cone production, for all six scion clones at all three sites.

Scion-rootstock relationships with respect to height growth and foliar concentrations of nitrogen and phosphorus in reciprocal grafts of Pinus caribaea var. hondurensis

Both scion and rootstock clones significantly influenced scion elongation and concentrations of nitrogen and phosphorus in the scion foliage. Scion clone was the more important determinant. Scion clone × rootstock clone interactions were not significant. The ability of a clone to elongate as a scion was not correlated with its capacity to promote or retard scion elongation when used as a rootstock. Genetic differences in foliar nutrient concentrations appeared to reflect levels of nutrient demand, rather than the ability of roots to absorb nutrients. Nutrient demand of the rootstock can also explain negative correlations between nitrogen levels in rootstock clones and levels of both nitrogen and phosphorus in the scions. There was no significant relationship between scion elongation and foliar nitrogen concentrations of either rootstock or scion. The weak relationship between scion elongation and concentration of phosphorus in the rootstock apparently resulted from tissue dilution.

Rootstock and scion effects on carbohydrates and mineral nutrients in loblolly pine

Variation in scion physiology caused by rootstock families, scion clones, and the rootstock–scion interactions were studied in loblolly pine (Pinustaeda L.). Ten full-sib families were used as rootstocks, and six scion clones were grafted on the rootstocks in all combinations. The trees were measured during and after the 2nd year after grafting; the traits measured were needle carbohydrate (starch, sucrose, and hexoses) concentrations and needle N, P, K, Ca, and Mg concentrations. These traits were measured in early fall and early spring. There were highly significant differences among scion clones for all traits. Rootstocks significantly affected hexoses in fall, total sugars in spring, P, K, Ca, and Mg in fall, and Ca and Mg in spring. For most traits the largest variance component was within each rootstock-scion combination; next largest were those for scion clones. Variance components for rootstocks were small or negative for most traits, indicating that the scion has more control than the rootstock on scion physiology of young grafted loblolly pine.

Sources of Resistance to Pierce’s Disease in Vitis1

Abstract Under conditions favoring Pierce’s disease (PD) infection in the vineyards at Leesburg, Florida, 222 Euvitis scion clones, 60 Muscadinia clones, and 49 Euvitis rootstock clones were grown and observed for PD symptoms for 8 or more years. There were 21 PD-resistant scion clones, 20 of which derived their resistance from 1 or more of 4 species: Vitis smalliana Bailey, V. simpsoni Munson, V. shuttleworthi House, and V. aestivalis Michx. There were 22 PD-resistant Muscadinia clones, predominantly of V. rotundifolia Michx. background. There were 15 Euvitis rootstock clones with resistance derived from one of six native species: V. candicans Engelm., V. champini Planch., V. cordifolia Michx., V. shuttleworthi, V. simpsoni, and V. smalliana.

Inheritance of Graft Compatibility in Douglas-Fir

Graft compatibility of genetically related and unrelated rootstock-scion combinations was compared. Scion clones were 75% compatible when grafted on half-related rootstocks but only 56% compatible when grafted on unrelated rootstocks. Most variance associated with graft incompatibility in Douglas-fir appears to be caused by multiple genes.