b'YIELD AND RESISTANCESThe task of breeding is to provide growers with a variety that satisfies not only quantitative, but also qualitative prerequi-sites, says Aust. However, quality fruit yield is one of the main parameters that is increasingly related to disease resistance and cucumber resistance to abiotic influences in the environment. The earliness yield curve during vegetation and overall plasticity of the variety are then monitored. However, we must not forget about one of the most impor-tant characteristics of cucumbers for the end consumer, such as the taste and consistency of the flesh. This applies to all types of cucumbers, he adds. For Bal and his company, it is important to make the world more sustainable. So, we are constantly looking at the actual disease and pest pressure for our crop. Fusarium is an impor-tant threat in mid tech situations like Spain and Greece, and he proudly adds that last year his company launched their first variety with Fusarium resistance in these countries.Abad explains that cucumber is basically a producing machine where yield and regular quality are main factors, and therefore a breeder needs to build the main chassis by prioritiz-ing these factors. Of course, when diseases are a limiting point, resistances are becoming a must.Gonzlez-Cabezuelo concurs that these are the main objec-tives of the cucumber breeding program in all its typologies. The minimum requirements for a variety launched on the market are increasing year after year. Therefore, new varieties must be totally up to date with the needs that may arise in any growing area. Flowering cucumbers in the greenhouse. Source: Rijk ZwaanOne of the big challenges for all growers will be to grow sustainable crops, says Kraan. One way to reach that is to com- several new products with resistance to ZYMV, CMV, CCu, pow-plement genetic resistances with crop protection programs.dery mildew and tolerance to downy mildew, we can talk about Our main breeding goal is still on resistances and yield. Onthe increasing in yield of 30-40 per cent in real conditions.the other hand, we see a big increase in demand towards differ-ent cucumber types. For example, the snack cucumbers wereREGIONAL DIFFERENCESbarely present in supermarkets the world over, and nowadaysFor Suelmann, it is new diseases that make it difficult to we see them everywhere. We develop snack cucumber varietiesestimate and compare yield over different areas. that are adapted to different growing systems.Often big jumps in yield are obtained when changing He says yield will always be a top priority in their breeding,growing systems, such as in the Netherlands and Canada where but not necessarily as extra kilosmore from the perspectivegrowers move from the so called traditional system to the high-of economic yield, like extra resistance that will lower the dis- wire system. The area where yield increase probably is the most ease pressure.visible is the German pickling cucumber market.This lowers the costs for the grower and probably increasesYes, there are regional differences in yield increase, espe-the economical yield. cially in areas where non-parthenocarpic mixed flowering varie-ties are changed for parthenocarpic, female varieties. Examples YIELD INCREASES are the development of gherkin in U.S. and India, says Bal.This was an interesting point of self-evaluation and assessmentAust concurs, explaining that tracking revenue by region of their breeding, especially when looking at the tremendoustoday is not a simple task due to many influencing factors that yield of some old varieties, says Abad.are different for different regions. Today it is more a recommen-We have been focused on regularity and reliability duringdation of a suitable variety for the area and use. these years more than on a massive increase in yield. There isHowever, we can observe that with the warming of the cli-still room for improvement and big possibilities when using newmate, cucumbers can now be successfully grown in areas where technologies. it was not possible before. In contrast, in classical cucumber Bal estimates an increase of maximum one per cent per yearareas, it is necessary to respond to a higher incidence of pests as breeding effect on the yield increase. Further increases inand higher infectious pressure of cucumber diseases. Here we yield are realized by technical developments (like high wire withpromote new resistant varieties.assimilation light and higher CO2 level) and movement fromYield ratio is usually sensitive to both different locations flat outdoor cultivation to vertical to indoor (tunnel) f.i. Asianand different crop cycles. That is why the variety selection pro-bicolour.cess carried out by Meridiem Seeds is conducted by testing them The total yield of cucumbers depends on many factors andin different areas and different seasons, for several years before is greatly influenced by the technology of cultivation, technologygoing to market, to ensure stable behaviour, says Gonzlez-of protection and harvesting and the quality of human labourCabezuelo. during harvest, says Aust. As part of our breeding program, we regularly compare yields, especially field trials, with several repetitions, even among our breeding stations. If we compare the yields in theMake sure to check out Part 2 of this series on page 18.basic types of gherkins over the last 10 years, when we include 8IEUROPEAN SEEDIEUROPEAN-SEED.COM'