ABSTRACT
In this study, we developed a mutagenesis protocol specifically designed for chrysanthemum cv. "Candid" in order to introduce genetic variation. By subjecting chrysanthemum shoots to different doses of physical and chemical mutagens, we successfully generated a total of 24 mutants, each with unique genetic compositions. We observed that the mortality rate was lowest when the shoots were exposed to 10 Gy gamma irradiation and 1.00% EMS. To assess the diversity and relatedness among the mutants, we employed RAPD and SSR markers. The combination of these markers allowed us to construct a dendrogram that effectively categorized the mutant population into distinct clusters based on the specific mutagen treatments. Interestingly, the mutants induced by 10 Gy gamma irradiation exhibited greater genetic diversity in terms of flower colors. On the other hand, mutants created with 1.00% EMS displayed a higher level of variation and yielded more viable mutants. To determine the optimal markers for studying genetic diversity, we analyzed the polymorphic information content (PIC) of different markers. Among the tested markers, OPA-07 (RAPD) and JH47 (SSR) showed the highest PIC values, indicating their effectiveness in capturing genetic variability within the mutant population. Conversely, the PIC values of OPD-07 and JH20 demonstrated the lowest among the markers tested. Our results revealed a percentage of polymorphism ranging from 81.81% to 100% for RAPD markers and 66.66% to 100% for SSR markers. These findings indicate that physical mutation induced by 10 Gy gamma irradiation can be clearly distinguished from chemical mutation induced by EMS at concentrations of 1% and 0.75% in chrysanthemum cv. "Candid.â³ Overall, this study provides valuable insights into the genetic composition of the generated mutants and highlights their potential for enhancing chrysanthemum-breeding programs. The identified markers, particularly, OPA-07 and JH47, can serve as valuable tools for future studies aimed at exploring and exploiting the genetic diversity within the chrysanthemum population.
ABSTRACT
Besides apple mosaic virus (ApMV), apple necrotic mosaic virus (ApNMV) has also been found to be associated with apple mosaic disease. Both viruses are unevenly distributed throughout the plant and their titer decreases variably with high temperatures, hence requiring proper tissue and time for early and real-time detection within plants. The present study was carried out to understand the distribution and titer of ApMV and ApNMV in apple trees from different plant parts (spatial) during different seasons (temporal) for the optimization of tissue and time for their timely detection. The Reverse Transcription-Polymerase Chain Reaction (RT-PCR) and Reverse Transcription-quantitative Polymerase Chain Reaction (RT-qPCR) was carried out to detect and quantify both viruses in the various plant parts of apple trees during different seasons. Depending on the availability of tissue, both ApMV and ApNMV were detected in all the plant parts during the spring season using RT-PCR. During the summer, both viruses were detected only in seeds and fruits, whereas they were detected in leaves and pedicel during the autumn season. The RT-qPCR results showed that during the spring, the ApMV and ApNMV expression was higher in leaves, whereas in the summer and autumn, the titer was mostly detected in seeds and leaves, respectively. The leaves in the spring and autumn seasons and the seeds in the summer season can be used as detection tissues through RT-PCR for early and rapid detection of ApMV and ApNMV. This study was validated on 7 cultivars of apples infected with both viruses. This will help to accurately sample and index the planting material well ahead of time, which will aid in the production of virus-free, quality planting material.
