Morphological Characterization of Hybrids Derived from the Pollination of <i>Hoya deleoniorum</i>

Horticultural significance in <i>Hoya</i> hybrids stems from their distinctive foliage and flowers. Morphological characterization of hybrids aids in understanding genetic diversity and in forming the basis for breeding new varieties that meet market demands and enhance sustainable horticultural practices through a diversity of attributes. In this study, two first-generation offspring, GTX-021 (<i>H. deleoniorum</i> × <i>H. peninsularis</i>), GTX-067 (<i>H. deleoniorum</i> × <i>H. subquintuplinervis</i>), and their respective parents underwent phenetic examination. This encompassed the assessment of 13 vegetative traits, including aspects of leaf shape, size, and indumentum, as well as 23 reproductive traits, which included features related to inflorescence, corolla, and corona. The traits were analyzed using the UPGMA clustering method, employing the Jaccard similarity coefficient for qualitative traits and the Euclidean distances for quantitative traits. Polymorphism appeared in 14 out of 24 qualitative traits, with significant variations in all quantitative metrics except corona height (<i>p</i> < 0.05). Cluster analysis revealed that GTX-021 exhibited an intermediate overall morphology, comprising both qualitative and quantitative traits, falling between its parents. Notable traits include shared corolla pubescence with <i>H. peninsularis</i> and a distinct corona column similar to <i>H. deleoniorum</i>. Furthermore, GTX-067 resembled its pollen father, <i>H. subquintuplinervis</i>, exhibiting less twinning, horizontal stem growth, and reflexed corolla lobes. Morphometrically, it clustered close to the seed parent, with corona measurements distinguishing it from the pollen parent. This characterization emphasizes the hybrids’ distinctiveness, suggesting their potential as ornamental plants. Additionally, their contribution to enhanced genetic diversity is crucial for developing future varieties, benefiting the horticultural industry with more robust and diverse plant options.