title: Shielding Flowers Developing under Stress: Translating Theory to Field Application.
abstract: Developing reproductive organs within a flower are sensitive to environmental stress. A higher incidence of environmental stress during this stage of a crop plants' developmental cycle will lead to major breaches in food security. Clearly, we need to understand this sensitivity and try and overcome it, by agricultural practices and/or the breeding of more tolerant cultivars. Although passion fruit vines initiate flowers all year round, flower primordia abort during warm summers. This restricts the season of fruit production in regions with warm summers. Previously, using controlled chambers, stages in flower development that are sensitive to heat were identified. Based on genetic analysis and physiological experiments in controlled environments, gibberellin activity appeared to be a possible point of horticultural intervention. Here, we aimed to shield flowers of a commercial cultivar from end of summer conditions, thus allowing fruit production in new seasons. We conducted experiments over three years in different settings, and our findings consistently show that a single application of an inhibitor of gibberellin biosynthesis to vines in mid-August can cause precocious flowering of ~2-4 weeks, leading to earlier fruit production of ~1 month. In this case, knowledge obtained on phenology, environmental constraints and genetic variation, allowed us to reach a practical solution.
authors.affiliation: The Institute for Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food And Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel. noamchayut@gmail.com.
authors.forename: Noam
authors.initials: N
authors.lastname: Chayut
authors.affiliation: The Institute for Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food And Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel. shiri.naft@gmail.com.
authors.forename: Shiri
authors.initials: S
authors.lastname: Sobol
authors.affiliation: The Institute for Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food And Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel. nahum@dalton-winery.com.
authors.forename: Nahum
authors.initials: N
authors.lastname: Nave
authors.affiliation: The Institute for Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food And Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel. alon.samach@mail.huji.ac.il.
authors.forename: Alon
authors.initials: A
authors.lastname: Samach
keywords: Passiflora edulis; cytokinins; flower development; flowering time; gibberellins; off-season flowering; temperature