Optimization of In Vitro Germination, Viability Tests and Storage of Daylily ( Hemerocallis spp.) Pollen.

Abstract

Daylily ( Hemerocallis spp.) are perennial herbaceous flowers with high ornamental and medicinal value. Currently, the breeding of new daylily cultivars was mainly achieved through hybrid breeding, but issues such as self-incompatibility, hybridization barriers, and asynchronous reproductive phenology severely hinder the breeding process. Understanding pollen viability was essential for daylily breeding and cultivar improvement. In this study, we systematically investigated the effects of pollen viability determination methods, collection time, medium combinations, culture temperature and storage conditions on the pollen germination characteristics of daylily, using five daylily cultivars introduced in the Zhanjiang region of China as materials. Comparing the Iodine-potassium iodide (I 2 -KI) staining and Acetocarmine staining, the results of 2,3,5-Triphenyltetrazolium Chloride (TTC) staining showed a significant positive correlation ( p -1 sucrose + 0.1 g/L -1 H 3 BO 3 + 0.06 g/L -1 KNO 3 + 0.2 g/L -1 Ca(NO 3 ) 2 . The temperature experiment showed that the optimum temperature for pollen germination was 24.1-26.7 °C, and the optimum range for pollen tube growth was 24.1-25.7 °C, and the high temperature significantly inhibited the elongation rate of pollen tube. Storage experiments showed that low temperature (-40 °C) combined with drying treatment could significantly prolong pollen life, and the "Water Dragon" variety still maintained 41.29% vigor after 60 days of dry storage. This study provides theoretical basis and technical support for the introduction and domestication of daylily in South China, hybridization and garden application.

Plant phenotyping relevance

花粉の生存性・発芽性という植物形質の測定法を比較・最適化し、培養条件や保存条件による測定性能を体系的に評価しているため、測定法開発・検証が研究の中心です。

Code and data availability

The article reports pollen viability/germination measurements for five daylily cultivars, but no public phenotype dataset, images, analysis code, or trained models are deposited. The Data Availability Statement says raw data are available only on request, and the supplementary materials link (mdpi.com) is not among the

No evidence-backed public reproduction asset is currently recorded.