Yield and herbage quality of North American alfalfa varieties in Estonian climatic conditions.
Within the framework of cooperation programme between USA and Baltic states 18 varieties of USA and 12 of Canadian origin were tested at the Jõgeva Plant Breeding Institute in 1993…1998, aiming at investigation of their winter survival, yield capacity and forage quality. The trial was established in five replications, sown in wide-apart (60 cm) rows. Forage was cut once in seeding year and three times in a year thereafter. To investigate the forage quality, crude protein content was assessed both in the entire herbage and crop fractions. The winters during the testing period were favourable for alfalfa, except the winters 1993/94 and 1998/99 when the stands of North American alfalfa varieties were injured, in the latter case even in an extent which resulted in termination of the trial one year earlier than planned.
Only two varieties were found among the American ones in the trial which turned out to be competitive in comparison with Estonian local varieties when dry matter yield and longev-ity of the stand, derived from winterhardiness were considered. These were variety 'MN GRN-14', originating from Minnesota state (mean dry matter yield of five production years accounted for 105.2%, compared with standard variety 'Jõgeva 118') and variety 'Denali' originating from Alaska (96.6%). Crude protein content and yield for both the varieties remained lower than that with of Estonian varieties.
Among the 12 Canadian varieties in the trial, six turned out to be outstanding by winter survival, persistence of the stand and dry matter yield. These were 'Alouette' (bred in the province of Quebec, mean dry matter yield of five production years accounted for 109.0%, compared with standard variety 'Jõgeva 118'), 'Caribou' (Ontario, 108.7%), 'Oac Minto' (Ontario, 103.5%), 'Apica' (Quebec, 103.3%), 'Peace' (Alberta, 102.3%) and 'Algonquin' (Ontario, 97.7%). Crude protein yields of the varieties 'Caribou', 'Alouette' and 'Peace' were equal to standard variety, the crude protein yields of the three remaining abovementioned Canadian alfalfa varieties were exceeded by the variety 'Jõgeva 118'.
Estonian variety 'Karlu', bred for grazing resistance, revealed to have superior winter-hardiness, productivity and yield stability. As an average of five years of use, it surpassed the dry matter yield of standard variety 'Jõgeva 118' by 7.3% and crude protein yield by 11.5%. The pasture varieties, sent from the American continent to the trial and characterized by vegetative spreading ability, significantly overcame by yield in Estonian conditions.
Assessed on the base of crude protein content in the herbage dry matter, the