Miller Magazine Issue: 152 August 2022

55 MILLER / AUGUST 2022 NEWS the team first calculated the potential yield from a total of 28 commonly used wheat varieties grown at these sites, assuming the best possible cultivation conditions for each one. This gave harvests of less than four tons in Australia and Kazakhstan - com- pared with 14 tons of wheat produced per hectare in New Zealand. Next, they designed ‘idealized’ local varieties within their model, which optimised several plant traits that contribute to yield and whose un- derlying genetics will allow them to be improved by plant breeders. Simulations were based on extensive data on the natural genetic variation underpinning the traits. These included tolerance and response to drought and heat stresses, the size and orientation of the light-capturing upper leaves, and the timing of key life cycle events. The results showed that by optimizing these key traits, genetic yield gaps could be anywhere from 30-70% across different countries, with a global average genetic yield gap of 51%. Therefore, global wheat production could be doubled by exploiting this existing genetic yield gap towards achieving global food security in a sustainable way. “Not unsurprisingly, the countries with the low- est current yields could gain the most from closing their genetic yield gaps,” said Dr. Senapati. “That said, even improvements in those countries with a medium genetic yield gap of 40 to 50%, but with a large proportion of global wheat harvest area - such as the leading producers India, Russia, China, USA, Canada, and Pakistan - would have a substantial ef- fect on global wheat production due to the larger wheat cultivation areas involved.” Before this study, the size of these genetic yield gaps at country and global scales were unknown. The genetic yield gap idea contrasts with the lon- ger-understood concept of traditional yield gap due to sub-optimal management where harvests are smaller than the best-case scenario as a result of factors such as pest or diseases, lack of nutrients, or sowing or harvesting at the wrong time. “Our analysis suggests that such genetic yield gaps due to sub-optimal genetic adaptation could, in relative terms, be as large as the tra- ditional yield gap due to imperfect crop and soil management,” said Dr Semenov. “Wheat was first domesticated about 11,000 years ago, but despite this – and not to mention the sequencing of its entire genome in 2018 – the crop is still some way from being at its ‘genetic best’,” he added. Also involved in the study were leading wheat experts from Australia, Denmark, France, Germany, The Netherlands and Mexico.