Disease update: CGMMV

We would like to share our latest information on Cucumber Green Mottle Mosaic Virus (CGMMV).

On this page, we would like to share our latest information on Cucumber Green Mottle Mosaic Virus (CGMMV), give an explanation about the resistance and introduce our CGMMV resistant varieties to you.

CGMMV is an important disease in Cucurbits in Protected Heated (Glasshouse) growing environments and is increasingly present and severe. We estimate that in the leading markets more than 50% of growers have economic damage related to CGMMV.

CGMMV explained
CGMMV is a virus in the genus of Tobamovirus, which includes also the well-known Tomato Mosaic Virus (ToMV) and Tobacco Mosaic Virus (TMV). CGMMV is especially problematic, because it is easily transmitted by contact and has long viability in plant debris, soil, greenhouse equipment surfaces, etc. There are many fine articles on the internet with information about CGMMV; see the end of article for some suggested links.

CGMMV Resistance explained
There are varieties available with resistance to CGMMV. The resistance functions by reducing virus multiplication and spread in the plant – it does not prevent infection but can prevent or slow down symptom development on plant and/or fruit. CGMMV resistance is not “black and white”, but more like shades of grey. There is a difference between varieties in the expression of the resistance, and there may be difference of infection due to environmental factors, disease pressure, growing conditions, growing region, etc.

CGMMV Resistance Code explained
Within Euroseeds (Working Group Pathology) the leading seed companies align the disease claims to be consistent across the industry to give customers clear and comparable information. CGMMV resistance is a relatively new resistance, and the present claims of the seed companies are not yet harmonized. As a result, for a similar resistance level, some seed companies are claiming High Resistance (HR) and other companies are claiming Intermediate Resistance (IR). For specific information about HR and IR resistance levels please see ISF definitions. We include the PDF at the end of this document.

In 2018, NAKTuinbouw coordinated trials with varieties from different seed companies to review CGMMV resistance level claims. We are now waiting for the final results and expect that harmonization will occur in 2020.

CGMMV resistance of De Ruiter varieties
Even in resistant varieties, the virus can cause economic damage. De Ruiter claims Intermediate Resistance (IR) level for CGMMV. However, we have great confidence in the CGMMV resistance level of our varieties. From earliest stages of selection, De Ruiter varieties are screened for their resistance to CGMMV in grower trials in the East of the Netherlands. These trials are conducted in a summer crop cycle (from June to August) each year, with at least 3 replications per variety and 4 observations made per plot on fruit and plant during the crop cycle.

In the graph below the variety performance is compared to those of the leading varieties in the market. We have chosen to compare the weighted average of 2017-2019 trials. The correlation of resistance level over the years is very good, so we have no doubt that this is a fair comparison. From the graph we can conclude that De Ruiter varieties have CGMMV resistance levels at, or above, the levels of the main competing varieties in the market. Not only is this confirmed in our own trials, but also by Research Institutes such as CVETMO (Trial station, Orléans, France) and grower assessments.

De Ruiter GCMMV portfolio

For North-West Europe

GOTJA: Umbrella Summer & High-wire Summer/Autumn
HR  CVYV/Ccu    IR  CGMMV/Cca    

High yield potential in pieces and kg/m2, especially suited for Summer crops in umbrella and high wire crop systems. Very good  fruit quality and fruit colour, with fruit weight of 370-430g in Umbrella-Summer cropping system. Average fruit length of 30cm (27-33cm). Nicely balanced, quite open variety with medium generative habit.

GETTY: Umbrella Summer/Autumn
HR   Ccu    IR   CGMMV/CVYV/Cca

High yield potential in pieces and kg/m2, especially suited for Autumn Crops. Very good fruit quality and fruit colour with fruit weight of 370-450g in Summer & Autumn crops. Average fruit length 31cm (27-35cm). Quite vigorous plant which is nicely balanced plant; more selective than Gotja and therefore more suitable for Autumn or challenging Summer conditions.

GARPO: Umbrella Summer & High-wire Summer/Autumn
HR   CVYV/Cca/Ccu    IR   CGMMV/CMV/Px

Has become a standard in High-wire crops because of strong resistance package and consistent yield potential of high quality fruit. The fruit weight is 370-450g with an average fruit length of 31cm (28-35cm). Can be successful in umbrella summer crops in generative growing circumstances due to strong vigour.

DRCE1317 - NEW: Umbrella Summer & Autumn
resistance to be confirmed – includes IR Px/CGMMV

Seeds available for trials in 2020. Expected to have higher yield potential than Garpo. The fruit weight is 370-430 g with an average fruit length of 30cm (27-33cm). Variety excelled in fruit size uniformity and colour in 2019 trials, with a more labour-friendly plant type in Umbrella cropping than Garpo. In 2020, to try on larger(r) scale in Umbrella crops and on smaller scale in High-wire crops.

For France, Canada

DAVIDA: Umbrella Summer & Autumn
HR   CVYV/Cca/Ccu/Px    IR   CGMMV/CMV

Very good fruit quality and fruit color with a fruit weight of 450-500 g and an average fruit length of 33cm (30-35cm). Higher or similar yield potential than other varieties available on the market. Short plants, vigorous with excellent endurance under normal growing and climatic conditions. Davida is quite generative and requires adapted growing regime to get best results. Suitable for umbrella summer crops.

GEORGIA  - NEW: Umbrella,High-wire Summer & Autumn
HR   CVYV/Ccu/Px    IR   CGMMV/Cca    

Seeds available for trials in 2020 and variety is still in pre-commercial phase. Georgia has higher resistance to Px and CGMMV than Davida. Expected to have higher yield potential than Garpo. The resistance to Px and CGMMV was very good in our trials. Georgia fruit  had very good fruit size uniformity and color in 2019 trials, with an average fruit weight of 470 g and an average fruit length  of 33cm (31-37cm). Short and open plants. More labour friendly plant type in Umbrella cropping. To try in High-wire crops in 2020.

Links about CGMMV