Boosting Durian Productivity RIRDC Project DNT - 13A Project funded by: Rural Industries Research Development Corporation (RIRDC) Northern Territory Department of Primary Industry and Fisheries © 2009 Rural Industries Research and Development Corporation. All rights reserved. ISSN 1440-6845 Boosting Durian Productivity Publication No. 97/001W Project No. DNT-13A The information contained in this publication is intended for general use to assist public knowledge and discussion and to help improve the development of sustainable regions. You must not rely on any information contained in this publication without taking specialist advice relevant to your particular circumstances. While reasonable care has been taken in preparing this publication to ensure that information is true and correct, the Commonwealth of Australia gives no assurance as to the accuracy of any information in this publication. The Commonwealth of Australia, the Rural Industries Research and Development Corporation (RIRDC), the authors or contributors expressly disclaim, to the maximum extent permitted by law, all responsibility and liability to any person, arising directly or indirectly from any act or omission, or for any consequences of any such act or omission, made in reliance on the contents of this publication, whether or not caused by any negligence on the part of the Commonwealth of Australia, RIRDC, the authors or contributors. The Commonwealth of Australia does not necessarily endorse the views in this publication. This publication is copyright. Apart from any use as permitted under the Copyright Act 1968, all other rights are reserved. However, wide dissemination is encouraged. Requests and inquiries concerning reproduction and rights should be addressed to the RIRDC Publications Manager on phone 02 6271 4165. Researcher Contact Details Dr T K Lim L Luders Horticulture Division Department of Primary Industry and Fisheries GPO Box 990 Darwin NT 0801 Telephone: 08 8999 2222 Fax: 08 8999 2049 In submitting this report, the researcher has agreed to RIRDC publishing this material in its edited form. RIRDC Contact Details Rural Industries Research and Development Corporation Level 2, 15 National Circuit BARTON ACT 2600 PO Box 4776 KINGSTON ACT 2604 Phone: 02 6271 4100 Fax: 02 6271 4199 Email: [email protected]. Web: http://www.rirdc.gov.au Printing by Union Offset Printing, Canberra Electronically published by RIRDC in March 2009 First published in July 1997. ii EXECUTIVE SUMMARY Durian has immense potential to be developed into viable fruit crop in northern Australia. The market potential for durian has not been tapped despite a sizeable Asian Pacific minority and European migrant population. There are many production and market impediments that have to be surmounted before it can developed into a viable horticultural industry in northern Australia. Some of these can be summarised as the lack of high-yielding adaptable cultivars, erroneous identification of cultivars, a long juvenile period of 9-12 years, inadequate knowledge of the crop phenology and poor fruit set and development. This project attempts to find solutions to surmount some of the above constraints. The primary objective is to boost durian productivity in northern Australia. More specifically, this project aims to: i) increase durian productivity by introducing more adaptable, high-yielding and compatible clones; ii) improve our understanding of the crop phenology and reproductive biology of durian with regards to pollination so as to rationalise cultural practices such as assisted pollination and fertilisation; iii) improve fruit yield, size, quality and uniformity by practical cultural measures and proper fertilisation based on soil and foliar nutrient monitoring; and iv) reduce the juvenile period using various precocious rootstock-scion combinations and propagation techniques with introduced Durio species and clones. From the overseas trips to Sarawak and Peninsular Malaysia a total of 440 plants and seeds of 45 plant species were brought back besides durian cultivars and Durio species. Besides achieving our objectives, the trip served as the catalyst and springboard for the establishment of collaborative research and exchange of germplasm with the Department of Agriculture, Sarawak. As a prelude to correct identification a novel method using polygonal graph analysis was developed to correctly characterised and identify cultivars based on leaf parameters. Polygonal graph analysis of leaf characters can be used to differentiate among durian cultivars instead of using reproductive characters which entails a long waiting period of 10-12 years for seedling trees and 6-8 years for grafted trees. Additionally a multiple linear regression model was developed to estimate leaf area in durian based on non-destructive measurements of leaf length and mid width which are commonly employed as indices of growth and development in crop physiological studies and in horticulture. The crop phenology model developed for durian provided a holistic approach to optimising crop management inputs and cultural practices in particular with respect to the development of assisted pollination methods and sound fertilisation scheduling programs. Assisted manual pollination can be done in early evening instead of later in the night. Manually assisted cross-pollination gave significantly higher fruit set of 31% in contrast to <10% for selfing. Selfing resulted in more fruit drop, lower yields and poorer fruit quality. The maternal parent was found to influence the following fruit traits of flesh colour, taste, flavour, basic fruit shape and spine length. The pollen had a metaxenia effect on fruit weight, size (length), rind weight, number of locules with fertilised ovules, number of well-formed arils per locule, number of arils per fruit, percent flesh recovery and sweetness (Brix). This stresses the importance of mixed clonal plantings. Diagnosis of crop nutrient demand should be assessed from leaf and soil sampling done in November. Fertiliser scheduling is to be adjusted in accordance to the crop phenology, the crop nutrient requirement and the crop load (yield) produced. Nutrient norms developed on the sufficiency range basis and m-DRIS approaches are to be used as guidelines for nutrition programs. Objective four is only attainable after 4-5 years from implementation. Basically it involves using multiple rootstocks especially of precocious and dwarf Durio species or durian cultivars to obviate the long juvenile period and enhance precocity. Other advantages include better root development and support against wind-throw, and resistance to soil borne diseases by using resistant rootstocks. iii CONTENTS EXECUTIVE SUMMARY ................................................................................................................................... iii ACKNOWLEDGMENTS .................................................................................................................................... vii CHAPTER 1 ........................................................................................................................................................... 1 1.1 Introduction................................................................................................................................................... 1 CHAPTER 2 ........................................................................................................................................................... 7 2.1 Introduction of Durian Varieties and Durio Species..................................................................................... 7 2.2 Characteristics of Durian Cultivars............................................................................................................... 9 2.3 Comparisons Of Different Leaf Parameters For Leaf Area Prediction Models In Durian ......................... 33 Results............................................................................................................................................................... 35 Discussion......................................................................................................................................................... 38 2.4 Polygonal Graph Analyses Of Durian Cultivars Using Leaf Characters .................................................... 40 CHAPTER 3 ......................................................................................................................................................... 51 3.1 Durian Crop Phenology and Reproductive Biology ................................................................................... 51 3.2 Durian Pollination And Incompatibility Studies......................................................................................... 58 Materials and methods ...................................................................................................................................... 58 3.3 Pollen Germination And Viability Studies ................................................................................................. 69 CHAPTER 4 ......................................................................................................................................................... 76 4.1 Seasonal Changes In Durian Leaf And Soil Mineral Nutrient Content. ..................................................... 76 4.2 Preliminary M-DRIS Norms And Indices For Selected Macronutrients For Durian In The Northern Territory, Australia ..........................................................................................................................................