Malus sieversii, the main progenitor of the cultivated apple exhibits its maximum diversity in mountainous areas in southeast Kazakhstan. To represent this species better in the USDA-ARS germplasm collection, maintained in Geneva, NY, a co-operative project was initiated with the Republic of Kazakhstan to assess and collect that country's wild populations of M. sieversii and to develop more secure in situ reserves to complement ex situ holdings in the USA and Kazakhstan. Three collecting expeditions have been undertaken since 1989, in seven different regions. Disease screening of seedlings has revealed potentially novel variation for resistance to three important apple diseases: apple scab, cedar apple rust, and fireblight. An isozyme analysis of maternal half-sib families from four regions representing the first two expeditions indicates that over 85% of total genetic variation was due to differences among families and none due to differences among regions. The 1995 collections targeted regions that were more ecologically diverse, including a site at 47.5° N, the northern limit for M. sieversii. Both seeds and scions were gathered from selected trees with superior horticultural phenotypes. Considerable variation existed for a number of important traits including: tree growth habit and size; fruit size, colour, aroma and firmness and apparent damage due to pests and diseases. Seedlings germinated from the 1995 collections are being characterised for DNA markers.
|Original language||English (US)|
|Number of pages||7|
|State||Published - Dec 1 1998|