Genetic stability evaluation of caladium somaclonal variants by morphological, cytological, and SSR analysis in three successive generations

Abstract

Somaclonal variants with valuable agronomic traits play a crucial role in crop breeding, provided that they are stably passed down in subsequent generations. Although numerous somaclonal variants have been identified and studied among in vitro regenerated plants in the foliage plant caladium (Caladium × hortulanum Birdsey), no research has been carried out to evaluate their genetic stability in subsequent generations. This study aimed to evaluate the genetic stability of three types of diploid caladium somaclonal variants, previously derived from in vitro callus cultures, over three successive tuber-propagated generations. The analysis of quantitative morphological characteristics revealed a greater degree of variation among the established plants in the first generation (G1) compared to the second (G2) and third generations (G3). Seven plants exhibiting distinct leaf coloration changes were identified in the G1 generation and were found to be stably passed down to the subsequent G2 and G3 generations. These findings indicate a wide range of morphological variation in the G1 generation, followed by relative stability in subsequent generations. A comprehensive cytological and molecular analysis revealed that five of the seven newly observed variants displayed notable differences in relative nuclear DNA content, chromosome number, or SSR (simple sequence repeat) banding patterns compared to their corresponding normal counterparts. The findings of this study will be instrumental in developing new cultivars with distinctive plant morphology through the exploitation of somaclonal variation in caladium.

Keywords

• caladium breeding
• chromosome number
• nuclear DNA content
• somaclonal variation
• tuber generations