Effect of weather parameters and citrus genotypes on the occurrence of citrus canker incited by Xanthomonas citri pv. citri

In the present studies, two experiments were conducted. In first experiment, 43 citrus genotypes, including 36 acid lime and 7 lemons, were screened against natural infection of Xanthomonas citri pv. citri ( Xcc ) during 2018–2020. In the second experiment, the selected genotypes of lime (13), lemon (02) and grapefruit (02) were screened against artificial inoculation of Xcc . Moreover, all the lemon genotypes showed a high level of resistance. However, acid lime cultivars exhibited a variable reaction against Xcc . The range of the average percentage of disease index (PDI) for three years varied from 0.00 to 55.36%. ALC-35 expressed the maximum average PDI (55.36%), closely followed by the genotype ALC-107(51.77%) and ALC-111 (47.22%). Genotype of lemon, Kagzi Kalan showed immune to the canker disease, while LS-5, LS-7 and Konkan Seedless had minimum percentage of disease index under natural infection in the field condition. On the basis of average PDI, ALC-35 and ALC-107 were categorised as highly susceptible, whereas 34 genotypes were classified as susceptible to Xcc . The average of three years area under disease progression curve (AUDPC) ranged from 0.00 to 2653. The genotype ALC-35 proved highly susceptible to Xcc with 2653.00 AUDPC, followed by ALC-107, ALC-111 and ALC-89. The lemon group was found to be highly resistant to Xcc . This study predicates about the effects of various weather parameters, including temperature, relative humidity, rainfall, and wind speed. These variables correlated with PDI and AUDPC during the consecutive three years. A significant positive correlation was observed among different weather parameters and the development of disease through Pearson’s correlation coefficient. Under artificial inoculations also, ALC-35 lime proved highly susceptible (PDI − 60.67%) statistically. ALC-35 and ALC-107 proved similar statistically in respect of AUPDC. Results showed that the values of different weather parameters such as minimum temperature (24 °C), maximum temperature (37 °C), relative humidity (76%), and wind speed (6.4 km/h), conditions were conducive for disease development.