b'MYTH: HYBRIDS ARE STERILEMYTH: GENETIC DIVERSITY IN PLANT VARIETIES FACT:Hybrid crops are wrongfully believed to be sterile. InSUFFERS FROM HYBRIDIZATIONfact, hybrid crops can produce fertile seeds and generate fertileFACT:Genetic diversity in varieties is perceived to decrease, and offspring. Seeds harvested from a hybrid plant will segregate.sometimes associated with the spreading use of hybrid varieties. And this means that the offspring (the F2 generation) will loseTo set the scene, it should be realized that crop domes-some of the benefits of the original F1 hybrid. So, farmers cantication, which depending on the species, took place between still save seeds from their hybrid plants, but the next generation3,000 and 12,000 years ago, was the process in which humans will not likely be the same as the original F1 generation. Hence,selected for desired crop traits. And in that process a lot of crop in case farmers wish to maintain the same crop performancediversity has been lost, particularly for genes that were targeted they will need to buy new seed every season. Therefore, hybridsby the domestication, such as seed shattering or fruit abscission. are not sterile, but because of the segregation they do offer a sortStudies have shown to sometimes up to 60 per cent, or even of natural protection of the germplasm against infringement. more, of the nucleotide diversity within that species was lost, as well as a significant decrease in gene expression. MYTH: HYBRIDS ARE ONLY SUITABLE FORWhen discussing modern day genetic diversity in varieties, INTENSIVE FARM SYSTEMS one way to approach the issue is to make a distinction between FACT:Hybrids are suitable for all types of cultivation and usedin situ, ex-situ and on-farm genetic diversity in varieties. In in all types of farm systems. Farmers, including organic farmers,situ refers to genetic diversity within that species in nature. Ex may prefer hybrids because crop performance is likely higher,situ refers to genetic diversity in a species outside nature in while the risk of crop failure is lower thanks to heterosis andgene banks or breeders collections. Ex situ diversity increases trait stacking. Thanks to breeding efforts, hybrids can be morethrough collection missions in nature or traditional farming resilient to pests, diseases, and harsh environmental conditions,systems in primary or secondary centres of diversity of a crop. compared to conventional varieties. Strong genetics may alsoEx-situ diversity is incredibly important for plant breeding and allow for the reduced use of inputs, for example a wide set ofhence, breeding is a major driver of these efforts. On-farm refers resistance genes will (strongly) lower the need to use crop pro- to diversity in varieties in farmer fields. tection products. In the past years, breeding companies haveMany research papers have looked at the genetic diversity expanded their organic hybrid seed portfolios to meet growingof varieties, including a meta-analysis based on data from 44 market demand: many vegetables grown from hybrid seed arepublished papers (van de Wouw et al, 2010). This study on agri-organically certified. In the future, the importance of hybridscultural field crops, addressed diversity trends in released crop will likely continue to increase across farm systems, as climatevarieties of eight different field crops in the 20th century. The change roughens growing conditions around the world and thestudy encompassed variety diversity in many countries in the shift towards a more sustainable agriculture requires farmersworld, not only in Europe and North America. Wheat was the to reduce the use of inputs.most represented crop, with 26 out of the 44 papers. For wheat, the lowest diversity occurred in the period from the 1960s until MYTH: HYBRIDS ARE TOO EXPENSIVE FORthe 1980s. This decrease was 6 per cent compared to the first SMALLHOLDERS half of the century and was significant. However, a recovery of FACT:Smallholders in developing countries are also growingdiversity was observed in the 1990s. For seven other major crops hybrids. For home-consumed or subsistence crops, hybrid seed(barley, maize, oat, flax, soybean, pea, rice), a dip in diversity is uncommon. However, for commercial crops like maize andwas also observed in the 1960s, but the recovery was earlier tomato with large established markets, many smallholders arecompared to wheat. willing and able to invest in hybrids. Organisations like One AcreA similar and even stronger increase in genetic diversity Fund or Fair Planet are raising awareness amongst smallholderscan be seen in vegetable crops, for example tomato. A recent regarding the impact of quality seed on their yield. Moreover,study (Schouten et al, 2019) looked at the diversity dynamics of they train farmers in good agricultural practices to maximizegreenhouse tomato varieties in NW Europe over the last seven returns on this investment. Smallholders may also adopt hybridsdecades. The study provided compelling evidence that plant to be able to tweak their production planning. Smallholders tendbreeding has in fact increased the diversity of tomato varieties to produce the same crop at the same time and hence, they alleight-fold since the 1960s. sell when the market is flooded, and prices are low. Hybrids with strong resistance against fungal diseases or a shorter growingIN CONCLUSION:the concern that modern plant breeding is cycle enable them to grow their crop slightly earlier or later,decreasing diversity among varieties, is not at all supported by fetching a (much) higher price.scientific evidence. In contrast, a tremendous increase in diver-sity was observed, both at the genotypic and phenotypic level. Since more and more varieties are F1-hybrids, it can also be concluded that hybridization per se has no negative effect on genetic diversity. EUROPEAN-SEED.COMIEUROPEAN SEED I 15'