Sampling for nematodes near Engle, NM

NMSU nematologist Jacki Beacham collects soil samples from vineyard near Engle, NM

She will elutriate the samples to quantify nematodes prior to applying treatments for their control.  

Link to soil salinity research and preliminary results from soil survey of New Mexico vineyards

Click on the link below to access a recent article on research that is on-going in California. We here in New Mexico are constantly faced with soil salinity issues...the article outlines how this issue is likely to be exacerbated by climate changes.
Salt Tolerant Grape Rootstocks



Results of statewide vineyard soil survey are displayed below in these graphics. I collected the soil samples and they were analyzed at FGL Environmental Labs in Santa Paula, CA. Dr. Ciro Velasco-Cruz our visiting statistics research professor, generated the graphs using SAS software. Take a moment to survey the results and compare them to your soil in your vineyard. How does your vineyard soil compare to the averages in your region of the state? I will be writing some more on the implications of each nutrient in the coming days and weeks.

Phenology continues

Grapevine phenology continues at the Fabian Garcia, ASC, Las Cruces,NM
The most widely accepted and used descriptions of growth stages were developed by Eichhorn and Lorenz and fully described and articulated by Australian researcher, B. G. Coombe in 1995, cited below.  Graduate student, Jacque Cormier is tracking phenology of her Malbec vines exposed to different cover crops as part of her field research project.

From B.G. Coombe, 1995, Adoption of a system for identifying grapevine growth stages, Australian Journal of Grape and Wine Research 1:100-110.

March 24, 2020: budburst, E-L stage #4, Malbec at Fabian Garcia ASC experimental vineyard, Las Cruces, NM (photo credit: (Jacque Cormier)

March 27, 2020: 3-leaf, E-L stage #9,  Malbec at Fabian Garcia ASC experimental vineyard, Las Cruces, NM (photo credit: (Jacque Cormier)

Planting Port

Preparing to receive Touriga National vines later this week. 

Vine row that was treated with Forfeit 280 on March 17th.. The active ingredient in Forfeit 280 is glufosinate. It is a contact herbicide, and one can see it is beginning to have an affect on the weeds in the vine row, as they are wilting and turning brown. 

Take a close look...some small weeds towards the left side of the photo are green and growing despite the application of Forfeit 280 as seen in the photo above. This portion of the  vine row was hoed the day before the application of the herbicide. Because the weeds were cut off below the soil surface the plants' green tissue did not come in contact with the herbicide. Consequently, these "protected" weeds (or more exactly their roots) are giving rise to new growth...growing back quite vigorously. One should allow the weeds to die once the herbicide has been applied. Notice the wilting weed in the upper part of the photo.

Carl (forefront) and Jose (rear) dig and prepare planting holes in anticipation of planting some Touriga Nacional vines at  at the NMSU Los Lunas ASC experimental vineyard.

According to Wikepedia   https://en.wikipedia.org/wiki/Touriga_Nacional

Touriga Nacional is a variety of red wine grape, considered by many to be Portugal's finest. Despite the low yields from its small grapes, it plays a big part in the blends used for ports, and is increasingly being used for table wine in the Douro and Dão. Touriga Nacional provides structure and body to wine, with high tannins and concentrated flavors of black fruit. Jancis Robinson has compared its relationship with Touriga Francesa to the partnership between Cabernet Sauvignon and Cabernet Franc, the former providing structure, the latter filling out the bouquet.  

Always good to see an earthworm...when you are digging a hole. Not sure what role they play in terroir

 

History and Genetic Diversity of Wine Grapes adapted from recent article

Here is a short synopsis of an excellent review article by Patrice This in the journal, Trends in Genetics . The article covers how modern wine grapes were developed over time and the current status of research aspects of the genomics of the grapevine. 

The following is adapted and primarily sourced from the article cited below. Other references are listed at the end of the article.

https://www.sciencedirect.com

Historical origins and genetic diversity of wine grapes
Patrice This1, Thierry Lacombe1 and Mark R. Thomas2
1 INRA, UMR Diversite ́ et Ge ́ nomes des Plantes Cultive ́ es, 2 place P. Viala, 34060 Montpellier, France 2 CSIRO Plant Industry, PO Box 350, Glen Osmond, SA 5064, Australia

Current status of grape genomic resources

            What is the heck is “genomics” anyway? How is it different from “genetics”?  Genetics and genomics are two terms that are often incorrectly used interchangeably. Genetics is the study of single genes and their role in the way traits or conditions are passed from one generation to the next. Genomics describes the study of all parts of an organism's genes. This distinction/definitions are found at: https://www.healio.com/cardiology/genetics-genomics/news/online/%7B6cdf2745-8257-40e4-ae0c-4f1fa7193d03%7D/genetics-vs-genomics

            At any rate, the two terms differ. Although “back in day”, plant breeders I knew and worked for seldom dealt with a single gene. Most had to account and allow for the role of multiple genes when developing new varieties. However, here we defer to the term: genomics: the study of multiple genes and their interactions and as “study of all parts of an organism’s genes”, in our case, we are concerned with genes of the grapevine and its close relatives.

Historical overview

            Human culture has been associated with the grapevine since ancient times. Wine has captured humankind’s attention …devotion even, over the centuries. The ancient’s gods, Dionysus and Bacchus were gods of wine. The Italian cultivar, Sangiovese translated from Latin sanguis Jovis, means the “the blood of Jupiter” (Wikipedia).

             The Vitis genus within the Vitaceae family has 60 inter-fertile species (species is a community of individuals that can interbreed with one another, but not with members of other populations), see Figure 1. Vitis vinifera, or the ‘wine-bearer’, the species that originated in Eurasia about 65 million years ago, is most used in today’s worldwide wine industry.

             There are about 10,000 modern grape varieties and these cultivars are hermaphroditic, which in the case of grape means they possess perfect flowers with male and female reproductive structures and are self-fertile. However, hermaphroditic vines also “out-cross” easily. A few varieties dominate the wine industry: Airen, Grenache, Carignan, Merlot, Chardonnay, Cabernet Sauvignon, Pinot Noir, Tempranillo, Aligoté, Riesling, Rkaziteli, Sangiovese, Sauvignon Blanc, and Chenin Blanc. Grapes are classified by their end use as: table grapes, wine grapes, juice grapes (think Welch’s, made from the Vitis labrusca variety, Concord) or raisins. Most known cultivars are not planted commercially and exist only in germplasm collections, although there is some recently renewed interest in old landraces and local cultivars. 

Figure 1. Grapevine family tree with various species of the family Vitaceae and within the
   genus Vitis or Muscadinia. Note the single European species, Vitis vinifera, “the winebearer”.

            When the grape was domesticated, and likely made into wine, it was also selected for sugar production, yield, and regular production from year to year. The wild grapevine has/had a dioecious (Greek dis = double, oikos =house) flowering habit, meaning functionally male or female flowers occur on different individual plants. Cultivated types have functionally perfect flowers…the aforementioned hermaphroditic types. The grapevine’s seeds also changed and this characteristic is important when researching the age of seeds found in archaeological remains. The question arises…did these changes occur over a long period of time via natural sexual crosses and human selection, or in a short time with mutations noticed and propagated with cuttings by observant and enterprising humans?

            Wild grapes probably originated in the Near East, with early wine production in Iran near Hajii Firuz Tepe about 7400-7000 BP (before present). Although the earliest evidence of a functioning winery has been documented in Armenia (Barnard et al. 2010). Seeds of domesticated grapes dated from ~8000 ago have been found in Georgia and Turkey, and in bronze-age sites in France. From these sites, grape culture likely spread to Egypt, Lower Mesopotamia and on to the Phoenicians, Greeks, and Romans among others, and eventually to China and Japan. The Romans spread V. vinifera to Germany and throughout their empire. As Roman influence faded, the Catholic church spread wine and grape culture, and the Islamic faith spread table grape culture.

After the Renaissance, V. vinifera was carried to the new world, and missionaries introduced it to the Americas. Cuttings were spread to South Africa, Australia and New Zealand in the 19^th century. By the end of the 19^th century, the fungal diseases: powdery mildew, downy mildew, and black rot and the root louse phylloxera were carried to Europe from North America and spread across the continent devasting its vineyards. Sadly, there are few surviving native or wild grapevines in Europe today. European viticulture was salvaged and began to thrive again when American, non-vinifera, Vitis species were used as rootstocks and for breeding disease resistant, inter-specific hybrids (see Table 1, from Keller, the Science of Grapevines)

 
Figure 2. Wild Vitis (above) and fairly modern wine grapes (below): Muscat Blanc 9middle) and Muscat Noir (bottom).
Images from Kew Science website: http://www.plantsoftheworldonline.org/taxon/urn:lsid:ipni.org:names:325876-2

Trait	Eurasian Species	American Species
Fruitfulness	Good	Poor or highly variable
Fruit quality	Good	Poor
Usefulness	Highly diverse products	Niche products
Propagate capacity	Good	Variable
Lime tolerance	Good	Highly variable
Phylloxera tolerance	Poor	Good or variable
Disease tolerance	Poor	Good or variable

Table 1. Viticultural traits of American and Eurasian grapevine species. Table from Keller, 2010, The Science of Grapevines

Hybrids were popular until the 1950’s, but are scarce today because hybrids seldom have produced fruit and wine that satisfies most European winegrowers or the hopes of the breeders themselves. As M. Keller explains in his comprehensive textbook, The Science of Grapevines, “the only unequivocal success story thus far has been the grafting of phylloxera-susceptible European wine grape cultivars to rootstocks that are usually hybrids of tolerant American Vitis species”.

From the wild grapevine to varieties

            Wild European grapevines provide clues to the origin of modern cultivars. The question is: are they true-to-type wild vines, i.e. Vitis silvestris types, or simply escapes from vineyards or out-crossed hybrids between wild and cultivated types. Modern genetic techniques such as DNA analysis can help determine whether the collected individual vines are truly wild or whether they possess some genetic contribution from cultivated types. Wild ancestors and modern varieties differ in: sugar content, flower sex, berry and bunch size.

             

Early domestication and propagation by seed

            Early on, grapes were spread and distributed by seed. Seedling plants result from sexual crosses with new combinations of genes that could then be spread by cuttings (vegetative propagation) when desirable traits occurred. Patrice This and her co-authors, in the source article: Historical origins and genetic diversity of wine grapes, reminds us that the Pinot and Gouais varieties produced progeny maintained and adapted to the environment in northeast France and exist to this day. But they go on to explain that it is unlikely that there is gene mixing between wild and cultivated types, as the flowering times of the two are not the same.

Was there a single domestication event or many domestication events?

            Was there more than one genetic pool that generated modern varieties? The Muscat group of varieties, with their distinct flavors and aromas, support the likelihood of multiple genetic sources. Some researchers maintain a difference between European and Near Eastern grapes. For example, Chardonnay, considered a French variety from a cross of Pinot and Gouais of Croatian origin, demonstrates a mix of genes from different regions. Syrah, another example, long thought to be of eastern origin, has been determined to be of French origin.

How old are modern grape varieties?

            Speculation about the historical origins of current cultivars is common in popular publications but no evidence supports the notion that varieties from antiquity or the middle ages exist today, although the analysis of ancient DNA has been much improved lately. For instance, grape seeds from between 2600 and 1700 years ago have been successfully analyzed. Seeds are important as they can be a result of crosses, and coupled with the analysis of ancient wood, can characterize the identity of old cultivars and provide comparison with modern cultivars. The old variety, Mission, that is believed to be the first grape of European origin grown in New Mexico was brought to the Americas by the Spanish missionaries as seeds. It is believed that the Mission variety found in South America in the 16^th century was vegetatively propagated and transported as cuttings to various American countries where it was renamed with local names such as: Païs, Criolla chica, Rosa del Peru, and Negra corriente. Vegetative propagation of grapevines to plant new vineyards and move vines from region to region has been common for many hundreds of years. However, despite the importance of vegetative propagation, recent genetic characterization of cultivars has shown mutations frequently have had a role in generating genetic diversity.

The role of mutations

Figure 3. Pinot Noir with somatic mutation evident on individual berries

            Sexual crossing and natural mutations have driven grapevine evolution. The appearance of hermaphrodite flowers, the most important genetic development, seems to be the result of a mutation. It is not known when this trait was found and first used by humans. However, it is assumed that the adoption of such uniformly flowering and fruiting plants was rapid. Another mutation, berry skin color, was quickly made use of in development of modern cultivars. Because wild grapes are believed to have had black berries, white berries were probably selected and maintained during domestication.

            Somatic mutations that do not originate from sexual gene mixing but from vegetative tissue, can be stably maintained and vegetatively propagated over time. The Pinot family is notorious for many vegetative and floral mutants. Pinot noir has a black berry, Pinot gris a grey berry, and Pinot blanc has a white berry, all likely from a mutation.

            The seedless trait in Thompson Seedless, Emperor Seedless and Chasselas apyrène all probably occurred separately. Humans selected this seedless trait for their table grapes.

Vitis vinifera germplasm and genetic diversity

            Molecular geneticists tell us that sexual and asexual multiplication and mutations have helped expand and diversify the grapevine. As mentioned earlier, the number of varieties in various germplasm collections around the world is likely ~10,000. Nearly every wine growing country has its own grapevine germplasm collection that maintains quarantines and the material in the field as living plants. Many variety names are applied to the same cultivar as explained with the example, Mission. But often it works the other way around, and the same name can be applied to different cultivars, adding to the confusion. This is where microsatelitte (a bit of the DNA strand that repeats itself, https://en.wikipedia.org/wiki/Microsatellite) marker studies, available since the 1990s, are very useful and effective in identifying and differentiating varieties and determining the true extent of genetic diversity. With new genetic tools, it is estimated that the number of vinifera varieties will prove to be closer to 5,000 than it is to 10,000 (This et al., 2006)

            This et al. (2006) also point out that collections around the world need to cross correlate all their information to accurately identify cultivars. This burgeoning effort is available at http://www.montpellier.inra.fr/vassal. Additional data and coding are being accomplished and will assist in the development of an international database that will aid estimation of diversity in Vitis and V. vinifera: http://www.genres.de/eccdb/vitis.

            Somatic mutations and vegetative propagation have increased the genetic diversity in grapevine. The use of mutations in genomic studies will help assign roles to specific genes. Identifying and maintaining these mutants is crucial and the collection at Vassal, France has been doing this for many years and has cataloged over 200 mutants (This et al. 2006).

Conclusion

            Various collections can be defunded, and varieties can be lost. DNA profiling and a common database are needed to determine the true number of varieties, their relationships, genetic diversity and identification of unique individuals. Such data is also helpful for historical investigation of domestication.

            Wild grapevines are poorly characterized, and extensive analysis of wild individuals from a broad geographical area are crucial to understand the role of Vitis silvestris in the domestication process. Recent DNA studies and application of genomic techniques has increased characterization of the genes and genetic control of important traits. This detailed genetic analysis should help us understand the biology of the grape, and if properly and thoughtfully utilized in the field, can improve viticulture around the world.

References

Barnard, H., Dooley, A. N., Areshian, G., Gasparyan, B., and K.F. Faull. 2010. Chemical evidence for wine production around 4000 BCE in the Late Chalcolithic Near Eastern highlands. Journal of Archaeological Science. 1-8. http://www.elsevier.com/locate/jas

Keller, M. 2010. In the Science of Grapevines: Elsevier Inc., London, UK.

This, P., Lacombe, T., and M.R. Thomas. 2006. Historical origins and genetic diversity of wine grapes. Trends in Genetics. Vol 22. 9:511-519.  https://www.sciencedirect.com

Preparing for table grapes

Table grape trial 2020... to be installed at Alcalde, Los Lunas and Farmington ASCs

Daniel Goodrich, NMSU Viticulture Program Coordinator, uses a handi-jack to remove old end posts from a plot located at the Alcalde ASC north of  Espanola, NM
(photo credit: Ms. Jacque Cormier) 

Malbec on the move at Las Cruces..photo taken last week (photo credit: Ms. Jacque Cormier)

On Monday March 16th Jacque Cormier and Daniel Goodrich manually dug out all the PVC sprinkler heads,  and the next day used a hand cranked ratchet to rip out the trellis anchors. Apparently the sprinklers had to be removed by hand because if he used the tractor ripper it would splinter them and has in the past popped the liquid filled tires.

Apparently the vines were put in in the 90’s and the anchors looked like they were averaging about 14 inches of concrete about 6 inches below the soil surface. Even after all that time they were pretty solid. The vines themselves were no longer in great shape many of them were desiccated and some showed trunk rot when cut in half where the cordons met at the head. 

Practical viticulture take three: spring weed control

These Jonquils in front of the Los Lunas ASC have escaped the winter and other threats...to successfully bring in spring...the first official day of spring this year was yesterday, March 19, 2020

Per the vineyard...it is time to apply some herbicide and control winter weeds. Forfeit 280 active ingredient glufosinate, was applied today. Find some information on the label for Forfeit 280 at the link below

label information for Forfeit 280 herbicide

Practical Viticulture Take Two..correctly tying the vines to the trellis

Tying down a cane to the fruiting wire...with the use of lightweight plastic tape dispensed from a "Tapener" hand held device (shown below and no endorsement implied or intended) that staples the tape in place. It is loose enough to provide expansion and growth by the cane. 

Another option to properly secure canes is this wire twist tie, similar to that found on bread wrappers. the device and various grades of tying material used with it are pictured below...some are designed to bio degrade readily and others will last longer.  The pictured tying material does not biodegrade very readily and one must be careful when applying it as they will be in place for an extended period.







  Go to the following link to check out some more tips on tying vines properly
 Michigan State vine tying tips

What is going on here? This vine is presenting Crown Gall...caused by the bacterium, Agrobacterium vitis...The likely reason crown gall is showing up is winter cold injury. Grafted vines are especially susceptible to this condition. 

Practical Viticulture...and another small 'illogical' take on vineyard cover crops

March 17, 2020 in the vineyard at Los Lunas ASC

A wire tie that has been left on too long and appears to
have girdled this cane

The same cane from the photo above... with the tie removed...

Does it make sense?  Take a look down the row...notice that the weeds that appear be thriving in the vine row to the right are not so prevalent when encountering some competition from the winter wheat planted in row middles. This photo was taken today, March 17, 2020, in the vineyard at the Los Lunas ASC experimental vineyard. No irrigation has been applied since late October 2019. 

Unusual is the usual in New Mexico, and... it looks like spring!..

Unusual flowering habit for a grapevine!...old yucca flower structure and old grapevines near Engle, NM appear somewhat 'sympatico'.

Winter wheat cover crop in row middles at the Los Lunas, ASC vineyard on Miller Road ...looks like it is greening up nicely. The cover crop has had no applied water since late October 2019. Do cover crops' benefits out weigh their costs? 

Time for bud break? and How a Bud Becomes a Bunch

What is going on with this bud? Notice anything significant? This photograph was taken today by NMSU Viticulture graduate student Ms. Jacqueline Cormier.  

Of Buds and Bunches

Adapted from: “What causes a bud to produce a bunch… or not?”  by Devin Carroll, Advanced Agricultural Services, Inc. Hanford, CA., Practical Winery and Vineyard, Nov-Dec. 2009.

This short piece, adapted from the more detailed article cited above covers some vine processes and factors that affect bud formation and fruitfulness. The original article also covers the phenomenon of plant mediated bunch necrosis or PMBN. We will not cover that here.

Fruitfulness depends on the percentage of buds on a grapevine that produce flower clusters. Flower initiation, formation, bloom and fruit set, fruit development and ripening require a two-year cycle. The developing buds contain tissues that form primordial flower clusters and require a favorable environment to flower and fruit. There are several steps to achieve a desired level of fruitfulness: flower initiation and minimal bud necrosis. Bud necrosis is caused when the vine “decides” that to carry the bud to fruitfulness is not worth the metabolic costs. It takes more energy than the vine can afford and the bud is aborted. In this case, secondary buds within the compound bud will grow and allow the vine to survive but not bear fruit, or bear much less fruit. Injury to the vine can also cause bud necrosis…pathogens, heat, water stress or frost can damage or kill a bud. Bud mites, can infest buds and move from old to new buds during the early weeks after bud break and multiply from there. Hundreds of these mites can inhabit one bud and damage the inflorescence (flower cluster).

Inflorescence initiation

Grape flowers and fruit clusters are borne on new shoots that come from dormant buds.  Each dormant bud is formed at each node and leaf axil on a shoot the previous season and is actually a compound bud that contains three separate buds. The primary bud within the compound bud, for most Vitis vinifera varieties, under most growing conditions, will produce 1 to 3 clusters with 2 clusters being typical. However, this shoot may remain vegetative on young vines and the number of inflorescences is also variety dependent. For instance, Chambourcin (a hybrid) and Petit Verdot (Vitis vinifera) often have more than two clusters per shoot. The secondary bud can have a fruit cluster but not always, and the third bud typically produces vegetative growth (shoots and leaves) only. Regardless of flower clusters, each simple bud contains a 6-12 node shoot that is compressed and complete with primordial leaves, flower clusters (if present) and tendrils. This complete shoot is within each bud. Compound buds develop from the base of the shoot towards to the shoot tip. This process takes from two to three months beginning as soon as the node appears in the spring. After formation, the bud stops growing and becomes dormant until it breaks and grows the following spring. Grapevines do not form terminal buds as many temperate zone fruit crops do. The shoot tip will die back in the winter to a fully ripened (lignified) portion of the shoot that has a mature dormant bud. Cluster initiation for next year begins in midsummer and are fully formed within the dormant bud by the end of the growing season. Final development of the flowers occurs as the shoot emerges the following spring. The flowers are fully formed by bloom time when the shoots are about 18-24 inches long. Grapes generally flower late… about 4 to 5 weeks after bud break, later than most tree fruit crops. Grapes are wind pollinated for the most part and warm, sunny conditions at bloom favor fruit set. Note that the most fruitful buds are located at bud number 4 to 10 on the cane. Thus, when spur pruning (leaving only the number 1 to 4 buds) some degree of fruitfulness or total possible crop is sacrificed. If spur pruning, the buds left on spurs are formed before bloom. These represent next year’s entire crop. If canes are used, some crop will come from buds closer to the shoot tip, and they are exposed to environmental conditions that existed later than the buds near the base of the shoot.

It is possible for two buds to form at the same node. This phenomenon is common in Pinot Noir, and has been observed in Cabernet Sauvignon, Syrah, Merlot and Chardonnay. Because these are fairly widely planted varieties, this double bud phenomenon may be due to more reporting, rather than actually something more common to these varieties in particular.

The rachis (specialized stem bearing flowers and fruit) forms branches before the bud goes dormant, but the flowers themselves are formed after winter, at bud break. Therefore, environmental conditions just after bud break influence the final number of flowers. But cluster size contingent on rachis branching is determined by conditions in the prior year.

A non-specific tissue called an “anlage” gives rise to either an inflorescence (flower cluster) or a tendril. The inflorescence can be seen within a bud ten nodes from the shoot tip when the bud is dissected and viewed with a microscope. The vine’s decision to form flower clusters comes much earlier and is correlated with temperature especially in the buds about three nodes from the shoot tip. Therefore, both vine physiology and temperatures the shoot is exposed to in the first weeks following bud break play a role in vine fruitfulness.

Several factors impact flower cluster formation: temperature (hot and cold), light and shading, carbohydrate reserves, water, nitrogen, mineral deficiencies, and plant growth hormones.

Temperatures held at 68^oF immediately following bud break on Muscat grapes greatly reduced the number of flower clusters. Similarly, at temperatures > 95^o F, flower cluster numbers were greatly reduced. However, cold temperatures are likely the most common cause for low fruitfulness in a given variety the following year because temperatures in that range are more common in the spring.

Solar radiation (light) and favorable temperature are two critical climatic factors. Shade can reduce fruitfulness, but shading due to canopy is not the usual case early in the season when leaves are small or not yet emerged. Thus, cloudy, cool days as the shoot emerges and grows in spring can reduce bud fruitfulness. The amount of light falling on a shoot’s leaves is correlated to the number of flower clusters eventually formed in the buds of that shoot. Accumulated light rather than just peak intensity is the important aspect. A short day-length or several hours or days of cloudiness can reduce bud fruitfulness.        

Stored carbohydrates influence the formation of flower clusters in young buds. Carbohydrates in roots, trunk cordons, canes and spurs were stored the year before the buds were differentiated. Thus, growing conditions and vine strength two years ago strongly influence the current year’s fruitfulness. Overall, buds are a weak sink for carbohydrates compared to actively growing shoot tips. Rapid shoot growth will draw carbohydrates from the buds and shading on such vigorously growing vines also reduces fruitfulness.

Excess water will reduce the number of flower clusters on a vine…while water deficit does not. Overwatering and excess growth that promotes canopy shading likely draws carbohydrates away from buds and lowers their fruitfulness.  

Mineral deficiencies that include potassium and phosphorus can reduce bud fruitfulness. Low phosphorous detected around the time of bud break can be linked to cold soil temperatures that prevents uptake by roots despite the mineral being present in the soil. In the case of most New Mexico soils with elevated pH (above 7), phosphorous can be in short supply due to reduced availability. Potassium and phosphorus can be added to the vine via foliar sprays. This should be done shortly after bud break to increase fruitfulness in the first several buds.

Plant growth regulator compounds or hormones, gibberellic acid (GA) and cytokinins interact to regulate inflorescences in grapevines. Early on, GA can favor analage formation that give rise to inflorescences, but that same GA decreases inflorescences by favoring tendril formation. Cytokinins, on the other hand can favor inflorescences over tendrils. Although some kelp-based sprays have been reported to contain cytokinins…it is not clear if such cytokinins are the correct types for grapes.