b'Breeding for the futureRijk Zwaans breakthrough in 1997 withvariety than spend time and money ona breach can be detected quickly. Using lettuce aphid-resistant varieties markedspraying. Not to mention the high valueDNA markers, we are constantly looking for a turning point for growers, endingthat consumers place on food safety. new resistances, and we cross them into concerns about harvest losses. Similarly,existing varieties in advance. This means we controlling downy mildew remainsResistance against aphidshave resistances ready if there is a breach. crucial. We cross in new resistancesgives certainty We just dont know for sure whether they will before new variants have even emerged,The introduction of lettuce varietieswork against future variants, but they often while looking for broader resistance atresistant to the aphid Nasonovia ribisnigrido. Thats what enables us to introduce new the same time, says Johan Schut,(Nr:0) in 1997 was revolutionary. Althoughvarieties so quickly.Breeding Manager Lettuce.Johan wasnt with Rijk Zwaan at the time, he recalls its signifi cant impact: TheseGiving growers worldwide Growing importance ofvarieties reduced the need for sprayingpeace of mindresistant varietiesand provided growers with certainty. WeveThe breeding team is now diving even The search for resistances has been asince incorporated this trait into 90 per centdeeper into the genetics to look for priority since the 1960s, and its importanceof our lettuce types, to allow all markets toresistances to Bremia. We found that some still continuous to grow every day. Johanbenefi t from it. In the 25 years since then,hundred-year-old varieties have broader explains: Diseases and pests cause majorwe still havent discovered precisely why theresistance. Its quite extraordinary. Its harder crop losses. Lettuce aphids can make aresistance works so well. The aphid piercesto pinpoint exactly why, because it involves growers entire crop unsaleable. The samethe lettuce once, but then doesnt feed on it.multiple genes with relatively small eff ects. goes for an outbreak of downy mildewIt doesnt die, but it just doesnt seem to likeBut were applying ever-more advanced (Bremia). And Fusarium in the soil can eventhe lettuce anymore. research techniques to understand this. force growers to switch to a diff erent cropThey are also working on Fusarium and or cultivation system. Stricter regulationsFuture-proof varietiesregional issues, such as introducing twoespecially in Europeare another reason:In the case of Bremia, it is much moreINSV-resistant varieties to the Salinas Valley These increasingly restrict the use ofcommon for new variants to breach ain 2023. Johan: This is one example of how chemicals. But even if growers may still useresistance. Thanks to alert growers who sendwe try to give lettuce growers worldwide them, they would rather choose a resistantaff ected lettuces to Rijk Zwaan for analysis,peace of mind, both now and in the future.Sharing knowledge with stakeholdersRZN-seedworld-wt5-240916.indd 7 16/09/2024 13:46'