Collection, Estabushment, and Evaluation of A
Total Page:16
File Type:pdf, Size:1020Kb
COLLECTION, ESTABUSHMENT, AND EVALUATION OF A GERMPLASM COLLECTION OF PACIFIC ISLAND BREADFRUIT A DISSERTATION SUBMITTED TO THE GRADUATE DIVISION OF THE UNIVERSITY OF HAWAII IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY IN HORTICULTURE DECEMBER 1991 BY Carol Diane Ragone Dissertation Committee: Richard Manshardt, Chairperson James Brewbaker Yoneo Sagawa Isabella Abbott Gerald Carr We certify that we have read this dissertation and that, in our opinion, it is satisfactory in scope and quality as a dissertation for the degree of Doctor of Philosophy in Horticulture DISSERTATION COMMITTEE I ' QyuJy-Zlt u Copyright 1991 by Carol Diane Ragone ui ABSTRACT Approximately 400 accessions of breadfruit {Artocarpus altilis (Parkin.) Fosberg, A. m ariannensis Trecul, and A. cam ansi Blanco) were collected from 17 Pacific Island groups (Fiji, Rotuma, Solomon Islands, Vanuatu, Belau, Kiribati, Mariana Islands, Marshall Islands, Pohnpei, Truk, Yap, Cook Islands, Marquesas, Samoa, Society Islands, Tokelau, and Tonga) for a germplasm collection. Micronesian accessions included interspecific hybrids between A. mariannenis and A. altilis. A total of 145 accessions were propagated and 185 trees of 135 accessions were added to a germplasm collection on Maui, Hawaii, at the Kahanu Gardens of the National Tropical Botanical Garden. The collection now consists of 226 trees of more than 100 cultivars from 17 island groups. The collection was evaluated using gel electrophoresis. Six enzyme systems (AGO, ADH, IDH, LAP, MDH, and PGM) were polymorphic, and 204 accessions were reduced to 90 unique zymotypes using cluster analysis. Only 12 zymotypes occurred in more than one island group, and one, a Polynesian triploid cultivar (A. altilis) was found in 11 island groups in Polynesia and Micronesia. Seventy-four accessions were observed to have this zymotype. The greatest isozyme variation occurred in Melanesia with 71% of the accessions uniquely characterized. Micronesia and Western Polynesia had relatively high rates of zymotypic variation with 59% and 51% variation, respectively. Only two zymotypes were found in Eastern Polynesia. Chromosome numbers for A. cam ansi and A. mariannensis are reported here for the first time as 2n = 56. Counts of 2n = 56 and 2n = 84 were observed for A. altilis. Most seeded cultivars of A. altilis had counts of 2n = 56, but seedless diploid cultivars were also observed. The majority of interspecific hybrids were seedless with counts of 2n = 56. Triploid interspecific hybrids were also observed. IV TABLE OF CONTENTS Abstract........................................................................................................................................................ iv List of Tables............................................................................................................................................viii List of Figures.............................................................................................................................................ix Preface......................................................................................................................................................... xi Chapter I Literature Review...................................................................................................................1 Traditional importance of breadfruit................................................................................................ 1 Melanesia...........................................................................................................................................1 Polynesia...........................................................................................................................................2 Micronesia........................................................................................................................................ 2 Nutritional value of breadfruit.....................................................................................................3 Storage and preservation methods........................................................................................... 4 General uses of the breadfruit tree............................................................................................6 Present status of breadfruit................................................................................................................. 6 Changing Pacific subsistence economies................................................................................ 6 Effects of storms and drought.....................................................................................................7 Breadfruit diseases......................................................................................................................... 8 The need for germplasm conservation.....................................................................................8 Taxonomy and Geographic Distribution........................................................................................ 9 Genus description.......................................................................................................................... 9 Distribution and description of Artocarpus cam ansi.........................................................12 Distribution and description of Artocarpus altilis ...............................................................14 Distribution and description of Artocarpus m ariannensis ...............................................16 V Distribution and description of A. a ltilis and A. mariannensis hybrids........................17 Morphology...........................................................................................................................................24 Description of trees and leaves................................................................................................ 24 Description of inflorescences....................................................................................................25 Description of fruit.......................................................................................................................27 History of breadfruit collections in the Pacific Islands.............................................................28 Regional survey and collection by the South Pacific Commission................................28 Establishment of a regional collection in Western Samoa................................................28 Collections in other Pacific Islands......................................................................................... 30 Collections in Hawaii.................................................................................................................. 30 Summary of collections..............................................................................................................32 Chapter II Collection and Establishment of Germplasm.............................................................33 Introduction...........................................................................................................................................33 Materials and Methods.......................................................................................................................36 Collection of breadfruit...............................................................................................................36 Field preparation of propagating material.............................................................................39 Propagation procedures.............................................................................................................39 Field planting................................................................................................................................41 Results and Discussion......................................................................................................................41 Field collection of germplasm.................................................................................................. 41 Establishment in greenhouse................................................................................................... 41 Establishment of permanent collection................................................................................. 42 Chapter III Evaluation of Breadfmit Using Gel Electrophoresis...............................................55 Introduction...........................................................................................................................................55 Materials and Methods.......................................................................................................................59 Results.....................................................................................................................................................62 Isozyme phenotypes and their geographic distribution................................................... 77 Geographic patterns of isozyme variability.......................................................................... 80 vi Multivariate analysis of isozyme d ata.................................................................................. 84 Discussion.......................................................................................................................................... 89 Cultivar identification................................................................................................................90