Characterisation of Australian almond cultivars and comparison with Californian cultivars by isozyme polymorphism

Abstract

Australian-derived almond cvv. Baxendale, Bruce, Chellaston, IXL Seedling, Johnston's Prolific, Keane's Seedling, Pethick's Wonder, Somerton, and White Brandis were identified by means of isozyme polymorphisms at 8 genetic loci: AAT- 1, GPI-2, LAP- 1, PGM-1, PGM-2, IDH, G6PD, and SKDH. The same genetic markers were used to compare Australian almond cultivars with commonly grown Californian cvv. Carmel, Davey, Drake, Fritz, Mission, Ne Plus Ultra, Nonpareil, Peerless, Price, and Thompson. The assignment of alleles at the various loci was aided by an examination of the inheritance of these markers by crossing Nonpareil with pollen from 17 Australian and Californian cultivars. This demonstrated, for the first time, null genes in Price at LAP- 1 and in Drake at AAT-1. The Australian cultivars differed from the Californian at several loci. These differences arise from the separate development in Australia of almond cultivars from what is believed to be largely Spanish 'Jordan' types, before a shift to larger irrigated orchards using Californian methods and Californian-Australian cultivars.