Location: Tropical Crops and Germplasm Research
Project Number: 6090-21000-061-016-T
Project Type: Trust Fund Cooperative Agreement
Start Date: Oct 1, 2023
End Date: Dec 31, 2025
Objective:
Mango represents 27% of the global tropical fruit trade (FAO 2022). In the United States, mango production is concentrated in Florida, Puerto Rico, and Hawaii with a market value of $15.7 million in Florida and $25 million for Puerto Rico. However, anthracnose caused by species of Colletotrichum is one of the most important pre- and post-harvest diseases that affect production and shelf life in mango exports. This disease has been associated with yield losses of up to 60% in different countries. Anthracnose is characterized by black sunken lesions that can totally rot mangoes in less than 8 days limiting its marketing. Several control methods including biological, cultural, and chemical practices as well as the use of tolerant cultivars have been proposed to control this disease. Investigating resistance to anthracnose have been focused on M. indica cultivars however, other genetic pools in the Mangifera genus need to be explored. This proposal has as main objective to identify new sources of resistance to mango anthracnose. Incoming funds will be used to: 1) test susceptibility of commercial mango varieties/species and; 2) evaluate resistance of mango anthracnose in a population of crosses between promising mango species/cultivars.
Approach:
Test resistance of commercial varieties and mango species to mango anthracnose using Colletotrichum inoculations in the laboratory.
Representative isolates of Colletotrichum spp. will be identified using morphological parameters and by PCR amplification of four nuclear genes. Colletotrichum spp. will be inoculated on eight species of mango (Mangifera casturi, M. indica, M. lalijiwa, M. laurina, M. odorata, M. rubropetala, M. Sylvatica, M. zeylanica) and two M. indica cultivars (Keitt, Sunny). Pathogenicity will be tested using Koch's postulates. Disease severity will be evaluated 8 days after inoculations using a 0-6 scale where 0 (resistant cultivar) = 0-4% 1 (strongly tolerant) = 5-10% 2 (tolerant) = 11-30% 3 (moderately tolerant) = 31-45% 4 (moderately sensitive) = 46-74%, 5 (sensitive) = 75-100% 6 (highly sensitive).
Evaluate resistance of mango anthracnose in a population of crosses between best mango species/cultivars. For this purpose, mango fruits from a population of 67 mango trees obtained from crosses between promising mango species and cultivar will be inoculated with Colletotrichum spp. Forty-eight healthy mango fruits provided by Martex Farms will be used to conduct experiments. Protocols of fungi inoculations, evaluations and pathogenicity test will be used as is described above.
