Abstract: Avocado plant`s fruits have high amounts of fats, proteins and fibre. Phytophthora cinnamomi fungal causes avocado root rot that is devastating to growth. The pathogen combined with flooding leads to asphyxiation, root decay and eventually death. Several studies have evaluated the tolerance of different avocado rootstocks to Phytophthora cinnamomi, there are few studies in Kenya that characterized the pathogen and evaluated the effect of the pathogen on the physiology of avocado rootstocks under flooding. The objectives of this study therefore were to determine physiological responses of avocado rootstocks to the fungus under water logging conditions. Rootstocks; Puebla, Fuerte, Booth7 and Pinkerton were obtained from orchards in Maseno, Nyando, Kisumu East and Budalangi of Western Kenya. The fungus was isolated from the soil by planting on selective medium and by baiting methods. Avocado rootstocks were planted in 10 litre plastic pots containing sand - soil mixture of ratio 1:2 for 3 months, inoculated under flooded and non-flooded conditions. Experiment was laid in a CRD within greenhouse. Data on chlorophyll concentration and chlorophyll fluorescence were collected then subjected to analysis of variance. Means separation and comparison was done using LSD at 0.05. Flooding and inoculation significantly (p≤0.05) reduced chlorophyll a, b, total chlorophyll concentration and, reduced Fv/Fm, ΦPSII and ETR of rootstocks. This was an indication that photosynthetic apparatus were affected. This contributed to the reduction in overall avocado growth. Interactions between treatments and avocado rootstocks were significantly different for the parameters. Puebla rootstocks responded better to flooding and P. cinnamomi inoculation, and were therefore recommended for growing in flood affected regions of Kenya where P. cinnamomi infestation is also a common problem.
Keywords: Avocado rootstocks, Flooding, Phytophthora cinnamomi, Physiological response, Chlorophyll fluorescence.
Title: Effect of Phytophthora cinnamomi inoculation on chlorophyll concentration and chlorophyll fluorescence parameters of four avocado (Persea americana Mill.) rootstocks seedlings grown under water logging conditions.
Author: Shiranda M. A.,Musyimi D. M., Mmayi M. P.
International Journal of Life Sciences Research
ISSN 2348-313X (Print), ISSN 2348-3148 (online)
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