Cross-compatibility of different lily hybrid cultivars

Conventional cross-breeding is still the main method to obtain new cultivars around the world. Here, crossing was made by a normal pollination technique to study the intra- and interspecific cross-compatibility of 46 lily cultivars. One hundred and twenty-nine crosses were designed among 46 cultivars (including Lilium Asiatic hybrids (A), Lilium Oriental hybrids (O), Lilium Longiflorum hybrids (L), hybrids of Longiflorum × Asiatic (LA) and hybrids of Oriental × Trumpet (OT)), which differ in flower color, flower spots, flower type, fragrance and plant height. A total of 1699 flowers were pollinated. Thirty-one crosses obtained tissue culture progeny that could be used as good breeding material. Results demonstrated that most of the crosses in the same hybrid group were compatible. Fruits and embryos were obtained easily in intraspecific crosses of Asiatic hybrids (fruits were obtained in 32 out of 38 crossing types, and embryos were obtained in 24 crossing types) Six of 11 A × LA, 17 of 21 LA × A and eight OT × O combinations had fruits and even embryos for the bridging function of Asiatic and Oriental hybrids. However, interspecific pollinations of A × L, A × O and O × A were less compatible, resulting in low percentage of setting seeds. We obtained five segregating populations with different color and spot traits, and three segregating populations with different plant heights from crosses of high seed setting rate and embryo numbers. Based on these results, we provide a new reference for lily crosses selection.