Responses of a Supernodulating Soybean Genotype, Sakukei 4 to Nitrogen Fertilizer

Correlation of Leaf Nitrogen, Chlorophyll and Rubisco Contents with Photosynthesis in a Supernodulating Soybean Genotype Sakukei 4

“…1). This phenomenon was also observed in our previous study (Maekawa et al, 2003). Further study is needed to elucidate whether the high photosynthetic effi ciency of Sakukei 4 is attributed only to the increased amount of chlorophyll and Rubisco contents per leaf area, or to an additive increase of the other N compounds in a leaf.…”

“…This genotype, the yield of which can be comparable to Enrei under certain environments, is the only supernodulating soybean cultivar which can be grown practically (Takahashi et al, 2003a(Takahashi et al, , 2003b. Previously, we found that Sakukei 4 has a superior ability to maintain high N content in the leaf and high photosynthetic rate until the later growth stage compared to its parental cultivar Enrei (Maekawa et al, 2003). These observations raise the following question.…”

Nitrogen Utilization in the Supernodulating Soybean Variety “Sakukei 4” and Its Parental Varieties,“Enrei” and “Tamahomare”

“…Sakukei 4 had naturally crossed with Tamahomare, a high-yielding variety, during a period of selection, so that Tamahomare is the true pollen parent of Sakukei 4 (Yamamoto et al, 2004). Reports on the comparation of the growth and yield between Sakukei 4 and its parental varieties have been inconsistent (Maekawa et al, 2003;Takahashi et al, 2005a;Shimamura et al, 2007). Moreover, whether the improved productivity originates from supernodulation of Enrei or from the productivity of Tamahomare is unclear.…”

Effects of High Ground-Water Level on the Growth and Yield of Supernodulating Soybean Cultivar, Sakukei 4II. Effects of High Ground-Water Level on Nitrogen Absorption

“…1). Because Sakukei 4 develops more nodules than Enrei, Sakukei 4 is capable of fi xing more nitrogen, resulting in a higher nitrogen content of leaf, and a higher photosynthetic rate than in Enrei (Maekawa et al, 2003;Takahashi et al, 2003). However, the results of this experiment indicated that a high ground−water level markedly decreases nitrogen fixation by root nodules and the total nitrogen absorption more greatly in Sakukei 4 than in Enrei.…”

“…A soybean variety, Sakukei 4 (currently Kanto 100) which is a supernodulating genotype derived from Enrei and Tamahomare (Yamamoto et al, 2004), can develop a large number of nodules. This variety has a markedly high rate of nitrogen fixation, and a high photosynthetic rate during the growth period (Maekawa et al, 2003;Takahashi et al, 2003). Sakukei 4 also has a higher grain yield than Enrei (Takahashi et al, 2003).…”