b'carefully examine the regionselect traits at the genomenies, including Bayer, BASF, for any variation that couldlevel that we know, as breed- Syngenta and Enza Zaden are contribute to that trait. Someers, will result in a variety withworking on breeding genetic of the apparent causes aresuperior qualities.resistance. During the last twoKEY FACTS:single nucleotide polymor- A new analysis of geneticmonths of 2020, these com-phisms (SNPs), but thus far,variation among tomatoes bypanies all announced making most have been caused by avan der Knaaps team uncov- progress toward developing1 ToBRFV was structural variant. Knowingered 230,000 previouslytomato varieties with a signifi- originally discovered the structural variants in thehidden large-scale differencescant level of ToBRFV resistance.in late 2014.genome facilitates the discov- in DNA between varieties.Enza Zaden has defined ery of novel genes that controlAll this variation providestwo levels of protection: high2 From the first traits such as resistance ordata that can be analyzedresistance (HR) and interme- discovery in 2014, weight, shape and flavor.by a molecular geneticist todiate resistance (IR). The com- it quickly spread A breeder wants to knowidentify markers. It is usefulpany describes plant varietiesand was found on exactly where these variantsfor developing new varietiesthat highly restrict the growtha tomato in Jordan occur in order take it one stepwithout large, time-consum- and development of ToBRFVin 2015, and then further to figure out what theing field trials. One of theunder normal pathogen pres- subsequently in change is, says University ofmost pressing challenges issure as high HR. These plantsMexico. Georgia plant breeder andto use this new-found geneticmay exhibit some symptoms horticulture researcher Esthervariation to develop varietiesor damage under heavy path- 3 Not only does van der Knaap. The genomewith genetic resistance to theogen pressure. IR varietiesToBRFV affect is linear in higher organisms.Tomato Brown Rugose Fruitwill show less severe damagetomato plants, but it The genes are in a certainVirus (ToBRFV). than susceptible plants whenalso can infect your order in most tomato plants.grown under similar environ- pepper plants as well. In other tomatoes, there is aTomato Brown Rugosemental conditions. region of about 300KB thatFruit VirusSyngenta Vegetable Seeds4 ToBRFV is is inverted. We dont knowAn outbreak of a new diseaseannounced it had launchedfrom a group of how that happened, but it isinfecting tomatoes occurredits first commercial ToBRFVviruses called inverted. As tomato plantsin 2014 in Southern Israel.resistant variety to be avail- Tobamoviruses, evolved, segments of DNAIt was identified as Tomatoable in early 2021. The newwhich also were deleted, duplicated orBrown Rugose Fruit Virusvariety will be released inincludes Tobacco rearranged. These structural(ToBRFV) and has spread toareas where growers faceMosaic Virus and variations in genomes under- most major tomato produc- severe disease pressure fromTomato Mosaic pin the vast diversity amongtion regions. One of the mostthe virus and will supportVirus. However, tomatoes.distinguishing and problem- against crop losses.ToBRFV is known We cross tomato varie- atic characteristics of ToBRFVWith fast developmentto overcome all ties all the time. One pairingis its ability to overcomeand use of molecular markers,genetic resistances might make bigger fruit whilegenetic resistance in toma- Syngenta is able to rapidlyin tomato.another might make moretoes, including the well-knownmake use of this resistance, fruit, but there are hundredsTM-22 gene. The disease candeploying it in a large range of5 Symptoms caused of populations. We wouldcause a 100% yield loss. In thevarieties; spreading the resist- by ToBRFV include need 10 times the greenhouseabsence of genetic resistanceance in our germplasm, saysbubbling and space to evaluate them all.or other effective mitigationPilar Checa, Global Breedingmosaic on leaves of We have to be smart about itmeasures, the virus is of greatLead for Tomato. He explainssusceptible pepper and choose which crosses areconcern to the global produc- that before the utilization ofand fern leaf and going to be the most informa- tion regions. Rugose refersmolecular markers, it couldmosaic of tomato.tive, which ones are going toto the rough and wrinkledtake up to 10 years to developSource: The American give us new genes we dontleaves present on infecteda resistant variety. Seed Trade Association know about yet. With theplants. Bayer announced the final knowledge we create, we canSome private compa- large-scale pre-launch trials of FEBRUARY 2021SEEDWORLD.COM /61'