Almond Genetic Linkage Map and Quantitative Trait Loci for Flowering Time in a (Nonpareil x Lauranne) Population

Almond (Prunus dulcis) is the only nut crop of the Rosaceae. As one of the earliest species to bloom in spring, almond trees can experience severe crop loss due to late frosts and unfavourable climatic conditions. The Australian almond breeding program is one of the world's major almond breeding programs and has developed a genetic linkage map. One of the objectives of the project is to investigate the inheritance of flowering time. The flowering time of a 'Nonpareil' x 'Lauranne' population was evaluated for two years. The proportion of buds and flowers at seven stages of bud and flower development were recorded for each tree using the same procedures in each of two years. A proportional odds logistic model was used to analyse the data, considering the timing of development of buds and flowers as a latent variable that was estimated for each tree on each occasion recorded. These estimates of flower timing were then used in QTL analysis of flowering time. The goal of this project is to identify genetic markers useful in breeding for altered flowering time in almond.