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Die Bodenkultur - Journal for Land Management, Food and Environment
O. CHLOUPEK, J. BABINEC and M. MALÁ:
Breeding of lucerne for higher symbiotic nitrogen fixation and testing in hydroponics with limited mineral nitrogenl
Two experimental lucerne synthetic populations were developed for higher symbiotic nitrogen fixation. The first one (ZE-N2-I) was developed in five cycles of recurrent phenotypic selection for indirect (root system size, number of nodules, dry herbage weight) and direct selection criteria (nitrogenase activity measured by acetylene reduction) from two varieties: "Palava" and "Zuzana". The second one consisted of 22 plants chosen from progenies of 13 selected clones. Both populations were tested in 17 cuts by a glasshouse experiment in hydroponics with limited levels of mineral nitrogen for three years (1987-1989). The ZE-N2-I gave a significantly higher dry herbage yield (increase of 13 %), significantly lower concentration of crude protein (CP) and significantly higher yield of CP (of 7 %) than the average of the parental varieties. The ZE-N2-II proved a significantly lower concentration of CP and nitrates in herbage than both control varieties. The yield of dry herbage and CP were similar to those of control varieties, Field experiments have been evaluated. Key words: Medicago sativa, breeding, symbiotic nitrogen fixation, yield, nitrates.