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ニュースリリース|2014

2014年01月27日

Breeding solutions to today’s challenges
Working to solve the problem of downy mildew that threatens European producers.
Sakata is first to develop a downy mildew resistant variety of ornamental cut flower Helianthus.
 An innovative new variety that reduces the production cost and labour of ornamental cut flower Helianthus.

Sakata Seed has developed the world’s first downy mildew resistance ornamental cut flower Helianthus, and this spring will run large-scale trials of this new innovation in Europe’s main production area.

Downy Mildew is a serious threat in Helianthus production. When the crop is affected, a yellowish green lesion is visible on the leaves. If symptoms get worse, the stock will shrink and cannot reach sufficient plant height, resulting in production losses. In recent years, downy mildew damage is becoming a more serious problem for both oilseed and ornamental cut flower Helianthus production in Europe. In the Dutch fields, where downy mildew damage has been severe, worst-case scenarios have resulted in the loss of over 50% of plants. Therefore thorough disease control is a serious business. It is a costly process, but taken seriously because the costs of the disease are also highly significant.

The answer to the issue of disease control is clearly a mildew resistant variety. Sakata is the first breeder to develop an innovative new variety of ornamental Helianthus that solves these problems. The variety is easy to grow and can produce high quality cut flowers. Resistance trials were held in a public experimental station in 2013 in Heidelberg, Germany and also at our Kakegawa research station in Japan. Both came out with proof that Sakata’s new variety has a strong resistance to downy mildew.


The picture shows an inoculation test at our Kakegawa research station. (January 2014)
The existing varieties left and right are infected with downy mildew and cannot reach enough plant height. In the middle is Sakata’s downy mildew resistant variety.

Background
Ornamental cut flower Helianthus production is popular in Europe and South and Central America. According to data from FloraHolland, the worlds largest flower auction, 48 million stems (13 million euro ) of cut flower Helianthus are distributed throughout the year in The Netherlands only, (2012), this is the 3rd of all seedling cut flowers. This data clearly shows that cut flower Helianthus is an important item.

In recent years, downy mildew has become an increasingly serious problem in Northern Europe. Helianthus downy mildew is caused by an oomycete pathogen Plasmopara halstedii. When affected, yellowish green lesions appear on the leaves, and white spores are formed on the underside of the leaves. More severe symptom is stunted growth. Infected plants cannot reach sufficient heights. It tends to outbreak under cool and water saturated soil conditions during the growth period of the seedling. If the germ remains in the soil, it will become a constant source of infection and risk of recurrence will increase. Initially, chemical spraying was effective, but continued use has resulted in resistance to chemicals. There are several physiological races in the pathogen..

In the Dutch fields, where downy mildew damage has been severe, worst-case scenarios have resulted in the loss of over 50% of plants. Therefore, thorough disease control is undertaken. Spraying of chemicals, in addition to the cost of labour, spraying machines and other related costs can be very substantial. These costs and labour are becoming a burden to producers.

For all of these reasons and more, a downy mildew resistant cut flower variety is strongly desired in production areas where damage is severe. A variety that is not only resistant to downy mildew, but also a high quality ornamental cut flower Helianthus.

Sakata’s first downy mildew resistance ornamental cut flower Helianthus offers a solution to these problems. The resistance trials were conducted in the public experimental station in Heidelberg, Germany in 2013 and also at our Kakegawa research station. Both came out with strong resistance to downy mildew. This variety is resistant to most of more than 10 races of Helianthus downy mildew. Moreover, it is easy to grow and can produce high quality cut flowers. More extensive trialling will take place in the European production areas in the Spring of 2014.

The Way Forward
Sakata Seed Corporation’s commitment is to provide attractive and high quality seeds for producers. At the same time, our goal of excellence and innovation, as demonstrated with this first downy mildew resistance cut flower Helianthus, drives the breeding challenge that is committed to lightening the burden of producers and improving the management of our environment.

Inoculation trial with downy mildew at our Kakegawa reserch station

Yellowish green lesion appear to current variety’ surface of leaf due to infection of downy mildew


Situation of plant growth
(Both sides are current varieties, center is Sakata’s downy mildew resistance (DMR) varieties)

 
Spores are formed on the underside of leaves (Both sides are current varieties, the center is Sakata’s DMR variety)

After 36 days from sowing seeds.
Photographing day : 1/7/2014


Reference material : LVG Public trial field at Heidelberg, Germany

「Internal variety trial of Helianthus Cut Flowers: Sensitivity to downy mildew (2013)」

■Cutivation outline

Sowing : 3 times (Set1 : week 18, Set2 : week 21, Set3 : week 24)
Sowing space : 15 seeds/㎡
Sowing quantity : 60 seeds (30 seeds * 2 reputation) per sowing and crop
However only downy mildew resistance variety are sowed 180 seeds (90 seeds * 2 reputation)
Irrigation: Drip tube
Chemical spraying ( to avoid infection of Downy mildew) : none

※Right after 2nd sowing, there was heavy rain. Therefore, only 1st and 3rd result are recorded due to low germination in 2nd sowing

Downy mildew infection rate
 

 

■Infection summary: Marketability lot ratings (1st and 3rd sowing)

  Set 1 Set 3
  Rating Cw 28 Rating Cw 31 Rating Cw 28 Rating Cw 31
  Plot1 Plot2 Plot1 Plot2 Plot1 Plot2 Plot1 Plot2
Variety A 5 5 5 5 3 5 4 5
Variety B 2 2 2 2 3 2 5 5
Variety C 5 5 5 5 5 5 5 5
Variety D 2 3 2 3 3 4 5 5
DMR Variety 0 0 0 0 0 1 0 0

Degree of infection is measured by 0-5
0: no downy mildew infection in lot
1: 1-5 small DM spots (a DM spot is less than 1 cm diameter) in the worst infected plant.
2: 5-10 small DM spots (a DM spot is less than 1 cm diameter) in the worst infected plant.
3: between level 2 and level 4
4: The largest DM spot is bigger than 5 cm diameter
5: One of the infected plants is not marketable due to DM.
 

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