Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 18, 2013
Publication Date: December 2, 2013
Citation: Volk, G.M., Henk, A.D., Richards, C.M., Forsline, P.L., Chao, C.T. 2013. Malus sieversii: a diverse Central Asian apple species in the USDA-ARS National Plant Germplasm System. HortScience. 48(12):1440-1444. Interpretive Summary: Wild apples grow in the forests of the Central Asian countries of Kazakhstan, Kyrgyzstan, Tajikistan, as well as Western China. The USDA-ARS National Plant Germplasm System (NPGS) has sponsored four trips to Kazakhstan and neighboring countries to collect seeds from these forests of Malus sieversii for inclusion in our gene bank. Seeds from these collection trips have been planted in the orchards in Geneva, NY. In addition, trees from related Malus taxa including M. sieversii var. kirghisorum, M. sieversii var. turkmenorum, M. pumila, and M. pumila var. niedzwetzkyana are also represented in the USDA NPGS. This research uses both genetic and trait data to compare the accessions represented by the various taxa in the NPGS and determines that the genepools for the accessions are very similar. Information about novelty of species and varieties can be used to identify gaps in the NPGS collections.
Technical Abstract: There are several Central Asian Malus species and varieties in the USDA-ARS National Plant Germplasm System (NPGS) apple collection. Malus sieversii is the most comprehensively collected species native to Central Asia. Other taxa such as M. sieversii var. kirghisorum, M. sieversii var. turkmenorum, M. pumila, and M. pumila var. niedzwetzkyana have primarily been donated to the collection by other institutions and arboreta. We sought to determine if genetic and/or phenotypic differences among the individuals that make up the gene pools of these taxa in the NPGS exhibit unique characteristics. Genetic data, based on microsatellite analyses, suggested that the diversity within each taxa is significantly greater than that among taxa. Trait data also revealed very few differences among taxa, the primary characteristic being the dark red fruit coloration and tinted flesh color of the accessions assigned to M. pumila var. niedzwetzkyana, resulting from a known single-gene mutation in anthocyanin production. We found that M. sieversii is a highly diverse species with a range in genetic and phenotypic trait variation that includes the characteristics of the other Central Asian taxa of interest. We conclude that the gene pools that comprise the accessions within the NPGS Central Asian Malus collection are highly overlapping with respect to both phenotypic traits and genotypic characters.