Selecting and breeding grain legumes for enhanced nitrogen fixation

Enhancing crop legume N2 fixation through selection and breeding

“…An extension of this approach can be found in the program at USDA Beltsville which aims to develop cultivars of soybean that bypass the native soil rhizobia and only nodulate with highly effective inoculant strains (Cregan and Keyser, 1986). The second approach is to ignore specificity and to screen plant genotypes in a field soil containing high numbers of effective rhizobia or screen under glasshouse or field conditions using strain(s) known to be highly effective with a wide range of genotypes (Betts and Herridge, 1987;Bliss and Miller, 1988;Herridge and Rose, 1994;Kueneman et al, 1984;Nangju, 1980;Phillips and Teuber, 1985). This approach has merit.…”

“…They did not consider that the xylem ureide method was appropriate for assessing N 2 fixation in the program, mainly because of lack of familiarity with the method rather than for technical reasons (Bliss and Miller, 1988), The xylem ureide method was essentially developed for soybean (Herridge, t982, 1984;McClure et al, 1980) but was subsequently extended to other crop legumes. In a preliminary experiment, the relative abundance of ureide-N in root-bleeding (xylem) sap of common bean was shown to vary as the plants' proportional dependence on N2 fixation and mineral N varied .…”

Ecophysiology of Nitrogen Fixation Ability on 3 cultivars Common Bean (Phaseolus vulgaris L.) with some types of Inoculants which contain different strains of Rhizobium leguminosarum; bv.phaseoli

“…Now the rhizosphers bacteria are using for biological fertilizers in many countries. Some researchers believe that nitrogen fixation is a hereditary trait and common bean varieties are genetically different in biological nitrogen fixation (Bliss and Miller., 1986, Graham and Rosas., 1997, Barron et al, 2000.…”

Avaliação agronômica da disponibilização de nitrogênio à cultura de feijão sob sistema de semeadura direta

“…Além disso, variabilidade genotípica que afeta componentes de produtividade como, massa e número de nódulos, ou atividade da nitrogenase foi observada dentre as espécies de leguminosas (Wani et al, 1995). Assim sendo, quando existe a presença de uma numerosa população indígena no solo, a seleção de rizóbios pode esconder qual é o mais efetivo, entre uma gama extensiva de genótipos (Bliss & Miller, 1988;Herridge & Rose, 1994). Quando os níveis iniciais de N no solo são baixos, a planta terá um demorado período de "demanda" por N podendo reduzir o rendimento, nodulação e fixação de N 2 (Eaglesham et al, 1983).…”