Submitted to: Plant Genetic Resources Newsletter
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 3, 2004
Publication Date: December 1, 2004
Citation: Ledbetter, C.A., Peterson, S.J. 2004. Utilization of Pakistani apricot (Prunus armeniaca L.) germplasm for improving Brix levels in California adapted apricots. Plant Genetic Resources Newsletter. 140:14-22. Interpretive Summary: California produced 30% of the 79,000 tons of apricots used as fresh fruit during 2002. A major consumer complaint of fresh California apricots, however, is that the fruits are tart and lack sugar. Apricots native to the northern part of Pakistan are extremely high in sugars compared to California apricots. Many of the diverse Pakistani apricots were collected and crossed with those adapted to the California environment. Some of the new hybrid apricots have the high sugar content of the Pakistani apricot parent and large fruit size of the California parent. This work will benefit U.S. consumers when they are grown in California orchards, and will increase sales of fresh sweeter apricots.
Technical Abstract: A 1988 plant collection expedition to the Northern Regions of Pakistan led to the introduction of 53 Prunus armeniaca L. seedlots into the United States. Portions of these seedlots were distributed to interested breeders. These Pakistani apricots are characterized as having extremely high Brix when compared to adapted apricot germplasm utilized in California. Thirty seedling families from portions of the 53 seedlots were established in a research orchard in Fresno, California for evaluation and potential breeding purposes. This original Pakistani apricot germplasm was not well adapted to the environment of central California. While only a minority of the seedling trees ever produced fruit, some of the seedlings did have extraordinarily high Brix as compared to California adapted apricot germplasm. Numerous hybridizations were performed between fecund Pakistani seedlings and apricot accessions adapted to the California environment in an attempt to transfer the elevated Brix to California adapted apricots. First generation seedlings were very productive in fruit yield, and were intermediate between their parents for many evaluated characters. Many hundreds of second generation seedlings have now been produced from open pollination, and from backcrossing to California adapted apricots. Evaluations of the F2 trees for fruit quality characteristics are ongoing, and further breeding efforts are warranted based on collected data. The elevated Brix characteristic present in the original Pakistani apricot seedlings has been successfully identified and selected in the F2. Utilization of the Pakistani apricot germplasm in a breeding program with California adapted apricots will lead to enhanced quality in newly developed varieties.