Rainbow knock out and Brite Eyes ，also inherits rdr4 from radtee?(reposting post)

[Eric]

The website did not provide an answer

Some of the peerless beauty varieties carry a new anti black spot gene Rdr4, which can resist all black spot bacteria that have not been planted in peerless beauty areas. It will take some time for black spot bacteria to conquer Rdr4 on a large scale.
Radr4 is a gene with simple inheritance. Using modern blue * brine eyes, 50% of offspring are immune to black spots.

Although elegance francaise has good resistance to black spots, its actual performance is not as impressive as Herzogin Christiana. I don’t know how many anti black spot genes Herzogin Christiana has, but it has only one dominant gene that is easy to inherit
What is the principle of 50% genetic inheritance? The probability of Rrrr being generated by Rrrr * rrrr
Rrrr has a 3/6 probability of producing Rr gametes
The 2010 Earth kind test discovered some cultivated varieties that can resist black spot bacteria 3, 8, and 9, all of which are Knock Out cultivated by Williams Radle.
The red highlighted varieties of immune 3, 8, and 9 and the recognized disease resistant Rosa Wichuraiana, New Dawn, The Fairy in the picture

[Eric]

The varieties of Riko with black spots 3, 8, and 9 in this picture, including Grouse, Paprika, and Peachy Cream, are not extinct lines. Among them, Peachy Cream is still a descendant of Grouse. It seems that the family also has an rdr4 gene library
Not necessarily RDR4.

Brite eyes=RADtee * Abel, like Knock Out, is also a fertile 4-fold, and is therefore used for mating studies.

There is a 1/2 chance to obtain Rrrr by multiplying rrrr by Rrrr. Genetic simplicity, Knock Out is easy to use.

Strangely enough, Sunny Knock Out is not resistant to disease, but actually caused by Brite eyes

sunny knock out =brite eyesradsweert=(radteeABRAHAM DARBY)*radsweet。 Except for the ABRAHAM DARBY parents, none of them have yellow color. Obviously, Sunny knock out inherited the ABRAHAM DARBY yellow color and also inherited the gene that is not resistant to black spots.

Red Knock Out略微翻转，表明它不含RDR4。众所周知，含有rdr4的英国人的眼睛仍然只对第12种黑斑真菌敏感。值得一提的是，Lemon Fizz的表现非常好，只对7号黑斑真菌敏感。
“有趣的是，Brite EyesTM和Lemon FizzTM在国际比赛系列中只对一场比赛敏感（分别为第12场和第7场）。”
一些育种者说，红色敲除不容易使用，抗性后代的比例受到另一个父母的很大影响，而不是50%。

That is to say, existing experiments can only confirm that Brite eyes carry the rdr4 gene, and the other variety most likely to contain the rdr4 gene is Rainbow Beauty. Rainbow Knock Out and Brite Eyes both have a common parent, radtee, while their other parents, Carefree Celebration and ABRAHAM DARBY, are known to be resistant to dark spots.

Whether Rainbow Knock Out carries RDR4 has not been confirmed

[Mingwei]

I found that even Knock Out [RADrazz] can get blackspot according to my observation in Shanghai Botanical Garden. It seems that no garden roses are absolutely immune to blackspot.

我在上植的月季园观察发现，即使是在那篇文章中能抗三个菌株的红色绝代佳人，也有零星感染黑斑病。似乎没有绝对免疫黑斑病的园艺品种。

[MidAtlas]

I’m not surprised that you have observed this; I would be skeptical of any claims of absolute immunity to blackspot. Now, in a rose with good horizontal resistance to the disease, you wouldn’t expect to see a total absence of symptoms–just a low level of symptom development that results in a decent-looking plant most of the time. Maybe this is merely what Knock Out looks like after its vertical resistance to certain strains of the fungus has been overcome. Were the blackspot symptoms extensive, or only mild?

Stefan

[Mingwei]

@MidAtlas

Were the blackspot symptoms extensive, or only mild?

The symptom is very mild, I only find a few spotted leaves on the lower part of the canopy. These are mature plants grow in nearly full sun but beside a row of heavily spotted climbers. On individuals grown in semi-shade, more spotted leaves can be found on upper part of the plant, though the plant still looks healthy overall. Anyway, KO is still the healthiest modern rose I seen. KO’s F1 offsprings, like ‘Cherry Bonica’, ‘Sweet Sprint’, ‘Yueding’, are also very healthy but (at least ‘Yueding’) are not as healthy as KO itself, better then “drift” series and ‘The Fairy’.

@MidAtlas

I would be skeptical of any claims of absolute immunity to blackspot. Now, in a rose with good horizontal resistance to the disease, you wouldn’t expect to see a total absence of symptoms–just a low level of symptom development that results in a decent-looking plant most of the time.

I understand that, so I think maybe I should give up the thought to breed a rose absolutely immune to blackspot. Instead, I’m planning to create something with good growth rate to outgrow blackspot and keep the plant healthy overall. In my region, ‘Old Blush’ is extremely prone to blackspot, but they tend to grow new leaves quickly to take place the sick, dropped old ones, so OB looks better than some more resistant ones like ‘Angela’.
R. multiflora and polyanthas I observed are very healthy and vigorous, with almost no or very mild blackspot. Maybe I can introgress the reblooming gene to R. multiflora to create a very healthy polyantha-liked rose.
In addition, KO and Double KO can be very prone to mildew in some situations (heavy shade, cool, dry weather in spring.

[jeekinlau]

Just chiming in here. If you look at my paper you will see that even “resistant” Brite Eyes over time can get some black spot. Look at figure 2 which is atttached here. Frontiers | QTL discovery for resistance to black spot and cercospora leaf spot, and defoliation in two interconnected F1 bi-parental tetraploid garden rose populations

The black square on the x axis of is blackspot rating. and the density curves shows the distribution of the disease ratings of the populations. In 2019, Brite Eyes and it’s progeny show some resistance and even Brite Eyes has little to no blackspot. However, into 2020 and 2021 it seems like this resistance is lost? From my time working in roses, I have found that at least in Central Texas where we do screening for blackspot at Texas A&M University, things that have the vertical resistance genes, all the Rdr genes seem to break down over time. Not sure if it is the race of black spot that we have, or if the pathogen has evolved to unlock the vertical resistance. Would interested to hear if anyone has any other explanations?

Best,

Jeekin

[Eric]

Thank you for replying to my post. Do Brite Eyes and Rainbow Knock Out inherit the rdr4 gene? Compared to who is more resistant to disease? After reading your comment, my understanding is that when this plant was first cultivated, it was resistant to diseases. As the breeding years increased, the resistance to diseases gradually decreased. But why is this the reason? Based on my understanding, its resistance should continue to decline as the number of generations of planting increases. I think this should be due to the asexual reproduction of the toxin in the plant itself. As its algebraic iteration increases, the accumulation will become more and more, leading to the degradation of some traits. I understand it this way, only after tissue culture detoxification. Same shape as before.

Can you list the roses that you think are the most resistant to diseases?I hope to quickly cultivate offspring that are resistant to diseases. The offspring of Brite Eyes and Rainbow Knock Out are indeed resistant to diseases.

Next year, we will test whether Lemon Fizz’s offspring are resistant to diseases. Lemon Fizz’s resistance to diseases seems to come from Rosa Wichuaiana, but it has been proven that the strength of resistance is not related to the concentration of Rosa Wichuaiana’s bloodline. Rosa Wichuaiana’s bloodline concentration does not necessarily mean resistance to diseases.Double Knock Out and Pink Double Knock Out have shown average resistance to disease here, and I am disappointed that they may even be infected with anthrax and have poor growth.

[Eric]

Thank you for replying to my post. Do Brite Eyes and Rainbow Knock Out inherit the rdr4 gene?
Can you list the roses that you think are the most resistant to diseases?I hope to quickly cultivate offspring that are resistant to diseases. The offspring of Brite Eyes and Rainbow Knock Out are indeed resistant to diseases.Two disease resistant varieties may not necessarily produce disease resistant children, and Knock Out genes may be different, which can stably inherit disease resistance.
Next year, we will test whether Lemon Fizz’s offspring are resistant to diseases. Lemon Fizz’s resistance to diseases seems to come from Rosa Wichuaiana, but it has been proven that the strength of resistance is not related to the concentration of Rosa Wichuaiana’s bloodline. Rosa Wichuaiana’s bloodline concentration does not necessarily mean resistance to diseases.Double Knock Out and Pink Double Knock Out have shown average resistance to disease here, and I am disappointed that they may even be infected with anthrax and have poor growth.