USING CENTRAL ASIAN GERMPLASM TO IMPROVE FRUIT QUALITY AND ENHANCE DIVERSITY IN CALIFORNIA ADAPTED APRICOTS

Abstract

Fifty years of apricot breeding efforts at the Agricultural Research Service in Parlier, California has led to the development of ten new fresh market and processing varieties. During this period, consumer comments indicated that increased sugar and aroma would be desirable improvements in California produced apricots. In the early 1990's, numerous sources of Central Asian apricot germplasm, both clonal and seedling-derived, were imported and utilized in the breeding program to introduce genetic diversity and improve fruit quality. These Central Asian apricots were generally not well adapted to California's environment, but some accessions did display significantly increased Brix levels, long fruit development periods, diverse fruit colors and shapes as well as other novel characteristics. As a group, Central Asian apricot germplasm is far too small-fruited for fresh markets in North America. First generation hybrids between California adapted apricots and Central Asian accessions were generally more productive than their Central Asian parents, but were still too small in fruit size to be directly usable. Second generation hybrids, obtained through intercrossing elite F1s or through backcrosses to California adapted hybrids, are very diverse in both fruit and tree characteristics. Fruit sizes adequate for fresh marketing are obtainable in the second generation, and large-fruited clones having significantly elevated Brix levels are also observed. The fruit-ripening season has been extended by two week through breeding with Central Asian apricots, and forthcoming seedlings may extend the fruit ripening period even later. Seedlings obtained to date as a result of breeding with Central Asian apricot germplasm demonstrate that significant gains in fruit quality traits can be obtained in two generations.