Characterization of one new non-S-RNase of Armeniaca cathayana

Armeniaca cathayana, a new species described in 2010, belongs to gametophytic self-incompatibility (GSI) system which is under S-allele control. One new non-S-ribonuclease (non-S-RNase) was found in A. cathayana through comparing its nucleotide and amino acid sequences with sequences of the S-allele in Genbank. The BLAST analysis showed that the one new non-S-RNase S68-RNase (GenBank Accession No. MH155952) had the highest 96% nucleotide sequence homology with Prunus webbii non-S-RNase PW₁ (EU809938.1). Alignment of deduced amino acid sequences of A. cathayana S68-RNase shared 83% similarity with P. webbii PW₁. The new non-S-RNase determined in this study will provide new information to GSI of Rosaceae.

Application of DNA fingerprinting for the classification of selected almond [Prunus dulcis (Miller) D. A. Webb] cultivars

Almond cultivars developed in Australia are thought to have descended from 2 breeding lines, 1 from hard-shelled Spanish/Jordan types, and the other from paper-shell Californian types. However, the precise derivation of many individual Australian cultivars is uncertain. Randomly amplified polymorphic DNA (RAPD) was used to estimate the genetic similarities between 50 accessions of almond cultivars derived from Australia, California, Europe and the Middle East, and individual accessions of Prunus orientalis (Miller) D. A. Webb and Prunus webbii (Spach) Vieh. Amplification products were analysed using the simple matching coefficient and the unweighted pair group method with arithmetic averages to cluster individuals into a dendrogram. Cultivars known to have originated in Europe or the Middle East clustered in a different group from those known to have originated in California confirming the 2 suspected breeding lines. The origin of some common Australian commercial cultivars was inferred by their placement on the dendrogram, and the possible parentage of some Australian selections is discussed.

523 PB 489 INCORPORATION OF USEFUL TRAITS FROM NATIVE ALMOND SPECIES INTO CULTIVATED ALMOND VARIETIES. II. GENE INTROGRESSION

Breeding lines have been developed incorporating introgressed genes from three native almond species Prunus fenzliana, Prunus webbii and Prunus argentea. Selected traits include self-fertility and autogamy, late bloom, smaller tree size, early nut maturity, improved cropping potential, and a well-sealed shell (endocarp) with high kernel/shell crack-out percentages. Fertility barriers, while present were easily overcome though linkage to introgressed genes with undesirable phenotypes remains an important obstacle to commercial use. Current breeding results, however, support a general conclusion that the wide diversity present within the range of species related to the cultivated almond (Prunus dulcis) provides an valuable gene pool for variety improvement.

034 INCORPORATION OF USEFUL TRAITS FROM NATIVE ALMOND SPECIES INTO CULTIVATED ALMOND VARIETIES

Approximately twenty native almond species have been described. Representative germplasm from seven of these are present in UC collections and have been used in crossing. Three specific breeding lines utilizing these species are described. One (1980 series) involved increasing yield potential through selection of high blossom density following gene introgression from Prunus fenzliana. A second involved incorporation of self-fertility, late bloom, smaller tree size, early maturity, high blossom density, and desirable nut characters from Prunus webbii into commercial breeding lines. A self-fertile selection resembling `Nonpareil' has been obtained from this material. The third line involves transmission of a unique thin, netted-surfaced, hard-shell phenotype from Prunus argentea.