Performance of sexually derived tetraploids for parental development of triploid hop cultivars in New Zealand
Hop (Humulus lupulus L.) is a dioecious perennial vine, with the female being the plant of commerce. The New Zealand hop breeding programme produces commercial cultivars of triploid genetic constitution. Created from crosses between diploid and tetraploid parents, these triploid genotypes have the advantage of being seedless as well as high yielding. Population improvement procedures are used independently in both diploid and tetraploid populations, from which parental material is derived. Recently the New Zealand programme has increased the number of sexually derived tetraploids to widen the gene pool. This paper summarises the latest population of tetraploids in terms of the genetic variability for various resin and oil chemistry traits and gender of plants. We also report gender segregation ratios from recent triploid seedling populations derived from diploid (female) × tetraploid (male) and tetraploid (female) × diploid (male) crosses. The statistical analysis of the triploid seedling female genotypes from these populations is also presented for several commercially important traits. Future strategies for breeding triploid hops are discussed.
Stephens, M., Alspach, P. and Beatson, R. (2019). Performance of sexually derived tetraploids for parental development of triploid hop cultivars in New Zealand. Acta Hortic. 1236, 145-152
Humulus lupulus L., recurrent selection, polyploid breeding