Effect of six pre-storage rhizome treatments on rhizome vitality and seasonal growth characteristics of three Canna x generalis cultivars

摘要

In a 3-year study, effects of six pre-storage rhizome treatments (thiophanate-methyl, iprodione, dimoxistrobin + boscalide, Trichoderma asperellum, charcoal dust and untreated control) were studied on rhizome bud numbers, disease incidence of rhizome, sprouted plant, leaf numbers and plant height for three Canna x generalis cultivars. The three chemical fungicide treatments showed clear differences from the untreated control for all the five measurements among cultivars and years. Bud numbers on rhizome ranged from 1.8 to 2.6, which were significantly higher in the three chemical control treatments (2.6) than in the untreated control (1.8). Disease incidences of rhizome were significantly lower in the chemical treatments (ranged from 5.4 to 22.9%) than T. asperellum, charcoal dust and untreated control treatments (ranged from 16.2 to 32.1%, from 21.9 to 32.7%, and from 27.8 to 43.3%, respectively). Sprouted plants were significantly higher in all chemical treatments ranged from 76.8 to 96.3% than the untreated control ranged from 43.2 to 62.3% for each year and cultivar. Leaf numbers and plant height were significantly higher in the chemical treatments (ranged from 16.0 to 22.4 and 86.8 to 161.1 cm, respectively) than the untreated control (ranged from 13.7 to 17.6 and 65.8 to 132.3 cm, respectively), for all the three cultivars, in all years. Pearson's correlation analyses revealed four significant relationships among disease incidence of rhizome versus incidence of sprouted plants (r = -0.982, P = 0.0001), leaf numbers versus plant height (r = 0.842, P = 0.007), bud numbers on rhizome versus incidence of sprouted plants (r = 0.773, P = 0.017), and bud numbers on rhizome versus disease incidence of rhizome (r = -0.709, P = 0.033). The two strongest relationships were revealed further by linear regression analysis. Our results showed that pre-storage chemical treatments of C. x generalis rhizomes were essential for reducing diseases of rhizomes during storage as well as had positive effects on sprouted plant, leaf numbers and plant height during the season.