35 Years of the SAAGA Yearbook: A Review1 Rob Blakey2 Nigel Wolstenholme3 Foreword This review includes the SAAGA Yearbooks from 1977 to 2012 – 35 yearbooks in total (there was no volume in 1980). The annual SAAGA Research Symposium is held in the first quarter of the year for the presentation of the preceding year’s research results. The objectives of this review were: (i) to consolidate and summarise the more important information in the yearbooks for the benefit of researchers and growers, and (ii) to translate the articles written in Afrikaans into English to make this information available to a wider audience. Multi-year projects have been combined. Many research projects are multi- or cross-disciplinary, necessitating cross-referencing. We recommend that you use the search function in an electronic copy of the review if you are searching for a specific topic. This manuscript does not report on or imply current best practice. Similarly, South African research published in journals, booklets, bulletins or newsletters other than the SAAGA Yearbook is not included. For a broader overview of international avocado research and production, please refer to the second edition of “The Avocado: Botany, Production and Uses” by Schaffer et al. (2013). The original SAAGA Yearbook articles are available online at www.avocadosource.com courtesy of the Hofshi Foundation. 1 This review was published in 2014 2 Westfalia Technological Services, [email protected] 3 University of KwaZulu-Natal, [email protected] 1 Table of Contents Foreword ......................................................................................................................... 1 Introduction ..................................................................................................................... 6 The Golden Avocado ...................................................................................................... 11 1. International Production.......................................................................................... 12 1.1. Australia ..................................................................................................................... 12 1.2. Brazil .......................................................................................................................... 12 1.3. Israel........................................................................................................................... 12 1.4. Mexico ........................................................................................................................ 12 1.5. New Zealand ............................................................................................................... 12 1.6. Spain .......................................................................................................................... 13 1.7. United States .............................................................................................................. 13 2. Orchard Management.............................................................................................. 14 2.1. Soil ............................................................................................................................. 14 2.2. Site Selection & Preparation ........................................................................................ 15 2.3. Orchard Floor Management......................................................................................... 16 2.4. Irrigation ..................................................................................................................... 18 2.5. Nutrition & Fertilisation .............................................................................................. 20 2.5.1. Nutrient deficiencies ..................................................................................................... 20 2.5.2. Micro-nutrients ............................................................................................................. 21 2.5.3. Macro-nutrients ............................................................................................................ 23 2.5.4. Liming ............................................................................................................................ 23 2.5.5. Leaf sampling ................................................................................................................ 24 2.6. Growth Control ........................................................................................................... 25 2.6.1. Pruning .......................................................................................................................... 26 2.6.2. Phloem disruption ......................................................................................................... 27 2.6.3. Chemical growth control ............................................................................................... 28 2.6.4. Fruit size manipulation .................................................................................................. 29 2.7. Yield Estimation .......................................................................................................... 30 2 3. Pathology ................................................................................................................ 31 3.1. Tree Pathology ............................................................................................................ 31 3.1.1. Phytophthora root rot ................................................................................................... 31 3.1.2. Trunk cankers ................................................................................................................ 42 3.1.3. Avocado sunblotch viroid (ASBVd) ................................................................................ 42 3.1.4. Viruses ........................................................................................................................... 44 3.1.5. Avocado black streak .................................................................................................... 45 3.2. Flower Pathology ........................................................................................................ 45 3.3. Fruit Pathology ............................................................................................................ 45 3.3.1. Pre-harvest pathology ................................................................................................... 45 3.3.2. Post-harvest pathology ................................................................................................. 50 3.3.3. Biocontrol ...................................................................................................................... 53 3.3.4. Application machinery .................................................................................................. 56 4. Genetic Resources ................................................................................................... 57 4.1. ARC Breeding Programme ........................................................................................... 57 4.1.1. Scion cultivars ............................................................................................................... 57 4.1.2. Rootstock cultivars ........................................................................................................ 58 4.2. Rootstock Selection ..................................................................................................... 59 4.3. Scion Selection ............................................................................................................ 63 5. Anatomy & Physiology ............................................................................................. 66 5.1. Flowering .................................................................................................................... 67 5.2. Phenology ................................................................................................................... 69 5.3. Tree Physiology ........................................................................................................... 70 5.4. Plant Hormones .......................................................................................................... 73 5.5. Hass Small Fruit Phenotype ......................................................................................... 74 5.6. Pinkerton Problem ...................................................................................................... 75 6. Post-harvest ............................................................................................................ 78 6.1. Fruit Maturity ............................................................................................................. 78 6.1.1. Maturity methods ......................................................................................................... 78 6.1.2. Maturity standards ....................................................................................................... 80 6.1.3. Near-infrared spectroscopy .......................................................................................... 83 6.2. Picking & Handling ...................................................................................................... 84 3 6.3. Cold Storage ...............................................................................................................