Flowering Phenology and Mating System of a Red Skin Pitaya (Hylocereus spp.) Germplasm Collection in Taiwan
Tran Dinh Ha *
Department of Agronomy, Thai Nguyen University of Agriculture and Forestry, Quyet Thang Commune, Thai Nguyen City, Vietnam
Le T. Kieu Oanh
Department of Agronomy, Thai Nguyen University of Agriculture and Forestry, Quyet Thang Commune, Thai Nguyen City, Vietnam
Chung-Ruey Yen
Department of Plant Industry, National Pingtung University of Science and Technology, 1 Shuefu Road, Neipu, Pingtung, Taiwan
*Author to whom correspondence should be addressed.
Abstract
Flowering Phenology and Mating System of a Red Skin Pitaya (Hylocereus spp.) Germplasm Collection in Taiwan
Aims: To Investigate flowering phenology and mating systems of 30 red skin pitaya genotypes
Study Design: Around ten-years-old pitaya genotypes were used in this study. The pitaya plants were grown on concrete posts/pillars with 1.5 m height and spacing of 2 m between plants and 3 m between rows. One-two plants were used for intercropping with each other.
Place and Duration of Study: At the NPUST’s Orchard between May and December 2014.
Methodology: From 1 to 2 plants for each genotype was verified for flowering characteristics, fruit set and fruit weight. Hand self-pollination and hand cross-pollination method was applied. Fruit weights were compared using Duncan’s multiple range test at a significance level of P ≤ 0.05.
Results: The natural flowering season of the pitayas occur from June to October with early comings in higher temperatures. Mostly red or magenta pulp pitayas have genotypes for a longer flowering season than white flesh ones. A number of flowering flushes and flowers/season/plant highly varies with 3 – 6 waves and 9 - 40 flowers. The floral and fruit stages spend 14 – 18 days and 27 – 33 days, respectively. Full self-compatibility (F-SC) in 3 white flesh and 3 magenta flesh, partial self-compatibility in 2 magenta flesh, and complete self-incompatibility (C-SI) in 22 red or magenta flesh was found. Hand cross-pollination gave high fruit set percentages (72.7 ‒ 100%) in all and larger fruits than hand self-pollination in almost all genotypes except for VN-White producing smaller fruits that performed strong SC mechanism.
Conclusion: A diversity in reproductive biology was found in the pitaya collection. VN-White, Chuchi Luu, D4, Chaozhou large, Chaozhou 5 and F4 that exhibited good reproductive characteristics could be further multiplicated for commercial cultivation and the one which have extended flowering season should be induced for off-season fruits. The breeding system types of cultivars help to design desired planting system orchards that achieve the most effective fruit production.
Keywords: Red pitayas, flowering phenology, mating systems, fruit set, pollination