Breeding for yellow vein mosaic disease resistance and export standard fruit quality in okra (Abelmoschus esculentus (L.) Moench)

Hybridization and selection of okra was carried out during 2016-2018 at the Kanchanaburi Agriculture Research and Development Center. Yellow vein mosaic disease (YVMD) resistant cultivars which possess export standard fruit quality were required. YVMD is a major problem for okra production as it has dramatically reduced yield and fruit quality. The pedigree selection method was applied and selection populations were obtained from hybrids between susceptible commercial cultivars (desire fruit quality) and YVMD resistant cultivars. The selection procedures were conducted in a disease outbreak field by growing selected lines and a susceptible cultivar ('PC03') in a 2:1 ratio. The progenies showed segregation characteristics in early generations but they became more stable after successive rounds of selection. In the F-6 generation, seven promising lines namely; KC5902-1-1-4-3-1, KC5915-2-18-15-20-10, KC5929-3-30-24-32-27, KC5930-2-31-28-38-31, KC5932-2-38-35-42-37, KC5944-2-54-44-46-38 and KC5950-1-60-55-52-40, were selected. They were completely resistant to YVMD in the disease outbreak field throughout crop production, while all 'PC03' plants showed disease symptoms 44 days after sowing (DAS). In addition, fruit quality was improved and met export standard criteria: five locules, green color, 7-12 cm fruit length, and downy pubescence. The desired plant height of 100-150 cm was obtained, along with 2-3 branches plant(-1), which leads to easy fruit harvesting. In addition, early flowering was observed at 35-42 DAS.