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West Paris Me.

A grower in another post mentioned that the 1476 Hopkins line tends to be mildew resistant. I am wondering what other lines tend to show this trait. thanks

2/1/2015 5:55:43 PM

Midway, UT

My 1220 Johnson seed seems to have powdery mildew resistance. It is 1421 Stelts x 220 DeBacco.

2/2/2015 8:31:12 PM

Connecticut

In the greenhouse with my many clones the 1421.5 Stelts clones (specifically that grew the 1663 Zoellner '10) showed mildew resistance.

This is part of the reason why I bred the 335 Scherber '11 (F: 1421.5 Stelts [1663 Zoellner] x M: 1161 Rodonis [1725 Sweet]) with the 1734.5 Steil ’13 (F: 220.3 DeBacco ’13 “Snowball” x self) in hopes of getting both size and some diseases resistance all on one seed. I would say the 1220 Johnson is along the same line of thought.

The 1421.5 Stelts seems to be one of the more consistent powdery mildew resistant seeds that I am aware of. Overall, it is difficult to determine true diseases resistance but the 1421.5 Stelts would be a good starting point.

2/3/2015 8:35:50 PM

Brooklyn Corner, Nova Scotia

I resisted, but can someone smarter than me please explain how one AG has powdery mildew resistance when it's counterpart of similar genetic background does not. 1421 Stelts, great cross, but no infusion of powdery mildew resistant material that I know of. Plant vigor, good feeding/biological program leading to better results. Genetically speaking, there isn't any reason to expect that one cross will fare any better than another. This also applies to so-called heat resistant crosses. Environment, not genetics will combat mildew, insects, heat and any other external factors. Until someone introduces a hybrid capable of accomplishing the above noted, grower experience and prowess will determine the outcome. IMHO

2/3/2015 9:37:57 PM

Mission Viejo, CA

Interesting post Andy. I've got no experience growing multiple plants so I haven't had the opportunity to observe trends. But if I had say 8 plants growing at the same time. Same soil, same weather, same ferts and water, etc. All identical treatment. And if one plant stood out as having far less PM, what would you attribute it to?

2/3/2015 10:04:12 PM

Menomonie, WI (mail@gr8pumpkin.net)

Voodooo

2/4/2015 7:27:56 AM

Are all kids by the same parents the exact same? Tons of combinations and does it not depend on what markers are stronger or weaker than others ?

2/4/2015 7:37:45 AM

Bethlehem CT

It is exciting to think that some crosses may have mildew tolerance, or even better have mildew resistance. I would have to see it proven many times in order for me to believe it though. So many different environmental factors can affect the appearance of the disease. One plant may have it bad, while 10' away a plant may not be as bad. Factors such as air circulation, humidity, and temperature all play a part.

2/4/2015 8:00:30 AM

Western NY

Different nutrient / fertility situations will also affect how well a particular plant can manage infection.

2/4/2015 9:39:28 AM

Springfield, Missouri

To actually prove mildew resistance you need to inoculate leaf disks in lab conditions, with a living culture. My 1357 Stevens (1476 Hopkins x Self) showed some PM tolerance, not resistance. Infection on that plant was delayed, and less severe.

PM resistance/tolerance is a quantitative trait, meaning many genes and the environment produce a continuous range of phenotypes; like height in humans. It is possible for a trait like this to go unnoticed due to heavy spraying or inattention of PM severity from plant to plant. The three major genes(I know of) that contribute to PM resistance are dominant.

If one parent of the 1421 (1385x904) had just 1 copy of one of the three major genes you would expect only half of the 1421s to have it. Of the resistant 1421s half of their progeny so on and so forth. We usually grow only the "Hot" seeds, could be easy for a gene to go extinct in these conditions.

2/4/2015 8:16:36 PM

Connecticut

Andy H-

I will attempt to explain how it is possible for one AG to have a trait when other crosses with a similar background can not.

Step 1: Vocabulary-
-There is a difference between "tolerant" (as the name implies the plant can be slower to be infected by a particular disease) and "resistant" (what we all want, a plant that is resistant to a problem).
-Then there is genotype (genetics, the actual DNA sequence) and phenotype (how the plant looks).

Step 2: Crosses-
-Most cells are diploid meaning they contain a copy of DNA from mom and one from dad. Since only one cop can be expresses there is a dominate trait and a recessive trait. In the case both traits are recessive (which is not a bad thing in some cases) it does not matter which on is expressed. However, what this means is that there are genes that are essentially "hidden". The genetic code is there but it is not expressed in a way we can see it.

Step 3: Hybrids-
-While we are not developing a true hybrid with the crosses we make there are some genetic outliers with-in a population that will be created. Growing multiple plants in the same conditions allows for a general comparison to be made and when traits are seen across multiple growers in multiple years we can share this information and increase the probability that we select a seed that has the traits we desire.

Step 4: Hopefully this answers your question and does not add more confusion;-)

2/4/2015 9:15:02 PM

norway , maine

Thank you Matt and Logan for the clarification

2/4/2015 10:38:31 PM

Torrance, Ca.

When I spray with " Pristien " they become really resistant ;)

Its like magic.

2/4/2015 11:06:22 PM

Mill Bay, British Columbia

All my plants seem to be powdery mildew resistant ..... Thanks to a few applications of Infuse...

2/5/2015 11:18:17 AM

Torrance, Ca.

Lol Northshore;)

That one is in the rotation!

When all else fails, create your own resistance.

2/5/2015 12:53:43 PM

Connecticut

No to sound negative, but Powdery Mildew has become resistant to more than one fungicide so it is a constant game of survival through adaptation for the fungi.

This is a good presentation to take a look at and provide some good winter reading...

https://cals.arizona.edu/crops/presentations/Matheron-ImperialCountyMtg-melonPM.pdf

2/5/2015 9:01:01 PM

Connecticut

*Not to sound negative, but Powdery Mildew has become resistant to more than one fungicide so it is a constant game of survival through adaptation for the fungi.

This is a good presentation to take a look at and provide some good winter reading...

https://cals.arizona.edu/crops/presentations/Matheron-ImperialCountyMtg-melonPM.pdf

2/5/2015 9:01:43 PM

Brooklyn Corner, Nova Scotia

Thanks Logan and Matt for your posts, much appreciated. I tend to lean towards Logan's supposition that the hot seeds get planted leaving previous speculation regarding mildew tolerance/ resistance in the dust.

Matt, your post, Step 3 Hybrids, hits the nail on the head. The need for better testing over a period of time to prove or disprove the hypothesis that these traits can be carried on to the next generation.

2/5/2015 9:28:44 PM

President - GPC

Not to be negative either, but I stopped getting clones Matt because I got a super PM virus right out of the box, this held true for CoJoe as well, two years in a row...

I have never had PM in May before they even hit the hoopers...probably due to cold shipping temps....Moved across the entire patch... even using EAGLE...I couldnt get rid of... just a thought

2/6/2015 2:44:51 PM

That State Up North

C. maxima resists more PM than c. pepo; but within our general breeding material there is a range of resistance level. Keeping note of grower observation to this is very useful.
1421.5 and some associated genetics is on the list

any others?

I have observed resistance related to 866 Mombert, but I am dating myself with any such observations that aren't too relevant within today's competitive material

2/6/2015 10:58:55 PM

West Paris Me.

Thanks for all of the replies, very interesting.

2/7/2015 11:20:03 AM

Partlow,Va

Good stuff here.Thanks for the link Matt

2/7/2015 3:56:14 PM

Connecticut

SkyWiZzzy-

When I first get the plant material (in the fall) I have a very hard time getting it clean of powdery mildew initially. Once I get by the first month typically the mildew pressure decreases going into winter. I have noticed (just as you did) that initially once planted in the field (in spring) the powdery mildew would show up again very early in the season. To combat this I would apply a quick rotation of fungicides that would stop it and then I was clean again until the more typically time of powdery mildew (mid-summer).

The advantage early in the season is that there is not a lot of natural inoculum around so rotating fungicides just on the clone plants was quick, easy and effective. While the clones did prove to be effective despite the small sample size the work is quite extensive to prepare them and then to ship them. I shifted to producing seeds during the winter that has also proven to be effective. The hard part with this process is timing as spring comes quick when you grow in the winter;-)

I want to thank everyone who took a chance on some of the ideas I have come up with and made available to growers. I know some of my ideas have been unconventional but supported by science. I could not have shown the effectiveness of any of these ideas just by myself, so thank you to all that have supported my experiments in various ways!

2/7/2015 6:38:24 PM

Torrance, Ca.

Our next mountain Matt,,,,,,,,,,,,,,,,,,

Mosaic and I need some real help with that one..........


Looking forward to what your plan is!

2/7/2015 7:51:11 PM

Springfield, Missouri

Chris, besides preventing mosaic with pesticides there is't a lot to do besides pull the plant. If we are talking clones, mosaic can be removed by tissue culturing "ahead" of the virus. (Quickly growing vine tips are usually not infected)

There are also cultivars of C.maxima resistant to mosaic.

2/8/2015 2:39:51 AM

Connecticut

So.Cal.-

Does not seem like I ever run out of things to work on related to pumpkins;-)

I have a basic plan together and I am constantly refining in at the moment. The key (at least in my situation) is to determine when I first saw mosaic symptoms in my plants. I suggest you try and estimate the same "week" so that the most effective prevention plan can be put in place. I know there is a short time-frame that the dirty bugs seem to come in and I am trying to target this time for maximum prevention.

Logan-

I am aware of some of the resistant cultivars but there are multiple species of virus. While I have lab tests confirming I have gotten hit by the common ones Watermelon Mosaic-2 and Zucchini Yellow (WMV-2 and ZYMV), my goal is to target the insect vectors. If I can eliminate the insects from entering the pumpkin patch, I essentially get wide spread control of multiple viral species. I have also had a dagger nematode screen done showing levels below detection (essentially none) so the problems I am dealing with are nonpresistent.

The concept of culturing ahead of the virus does work but in my case and So.Cal's case we are talking about field grown "mature" plants. For which there is no cure, only prevention.

2/8/2015 10:25:21 AM

Torrance, Ca.

Thanks Matt and I'll pinpoint the exact date when I get home this afternoon. I'm pretty bad and take notes a few times a day during the growing period.

Yes, in the field and plants are usually in the 300 sq. ft. range every time I'm infected..... Its very, very frustrating....

I'll email my dates Matt.

And thanks so much!

2/8/2015 12:37:01 PM

Springfield, Missouri

Hey Matt,

We were taking clones up on Wiz's post,,, just trying to cover all the bases.

The endless list of improvements keeps things fun and interesting, doesn't it? As viruses go I'm aware of the different species/strains. The USDA has observed resistance to WMV-2 and CMV in a C.maxima line I'm using. I'm also working with multiple wild species that have been reported with resistance mosaic viruses; amongst other things.

I think the work you are doing is important, as growers have a responsibility to prevent the spread of disease. There are times (topic of diseases seems to be inherently negative) when prevention doesn't work due to the complex network of vectors and hosts, it is then that all options should be explored... I'm working with some good people this summer, hopefully we can introduce a few beneficial traits.

2/8/2015 6:26:44 PM

Connecticut

Logan-

No problem, I look forward to seeing what your crosses produce. I see this as one big team effort which is nice to see with-in the pumpkin community. This was the basic idea behind "Team-Pumpkin".

Sometimes things can get too interesting, especially when talking about diseases;-) Zucchini Yellow mosaic virus resistance would be appreciated by a few growers and I know it is not an easy task, but just thought I would mention it.

2/8/2015 8:07:38 PM

Springfield, Missouri

For sure... way too interesting! We'll try not to disappoint, although you have really set the bar with your winter breeding project :)

2/8/2015 9:05:58 PM

Torrance, Ca.

Yes, thank you all for such amazing work!

The passion some have for this hobby blows my mind!

2/8/2015 10:14:14 PM

Partlow,Va

This thread has made me re-evaluate my fungicide program. The U of Arizona study was also very informative I want to share with you my conclusions. It is clear the 2 frontrunning products were Procure(triflumizole)and Quintec(quinoxyfen). They were head and shoulders above the rest in % control over the 10 year study. It is also clear that putting either at the front of a rotation will increase the effectiveness of your other products that did not fair as well by themselves in the testing.

Last year I rotated Daconil(chlorothanil 53% effective), Eagle20(myclobutanil 79%) and Honor Gaurd(propiconazole-not tested).I had decent mildew control but by mid-August all the leaves were 50% infected.
Next year my rotation will be something like this Quintec 93% effective, Eagle 20 79%, Quintec, Procure 94%, Daconil, Quintec, Eagle20, Procure, etc.

It is very humid here and mildew is a big problem for me every year. I estimate that my new fungicide program will be at least 30% more effective and get me another 200lbs by itself, 6-8lbs/day or so from mid-August on until the weigh-off. It is exciting to learn and I look forward to hopefully seeing great looking leaves on Labor Day!

2/15/2015 9:56:01 AM

Connecticut

Awesome info

6/19/2015 3:04:05 PM