Germplasm diversification – a kiwi perspective on tools and strategies

The international ornamentals industry is benefiting from perennial plants developed in New Zealand (NZ) such as begonia Bonfire (TM), limonium Sinzii (TM), and the gentian Showtime (TM) series. The 'Bonfire' series of begonia, with its distinctively new flower shape, was released in the year 2000. While flower and foliage colour were important; architectural form, vigour and floral productivity were key selection criteria. Understanding the underlying physiology of plant architecture (physiologically informed breeding) was key in the introduction of subsequent new cultivars to the series. These screening criteria allowed us to evaluate annually ten times more begonia seedlings per season. Planting of limonium Sinzii continues to expand exponentially: in 2018/19 plantings almost doubled compared with those of the previous year. The limonium Sinzii range resulted from successful hybridisation between Limonium sinuatum and L. perezii. Embryo culture, chromosome doubling, and backcrossing were some of the in vitro and in vivo tools and strategies applied to achieve the current range. The sterile gentian 'Little Pinkie' was another plant developed using wide crosses and embryo rescue. As with other gentians in the Showtime series, a physiologically informed breeding strategy was used. In the case of 'Little Pinkie', an understanding of how crown buds arise was used to generate at least double the number of shoots on propagules. This has underpinned the success of this crop for us, and our industry partners. The preceding examples illustrate how, for each crop species, our breeding programmes have diversified germplasm, through exploiting a diverse skill base within the team. Our conclusion is that our most successful examples of breeding programmes have been those in which plant breeders, plant physiologists, in vitro specialists, horticulturalists, and marketers are all actively engaged.