Diallel analysis of nitrogen fixation in the rhizosphere of rice

1983 ◽  
Vol 30 (2) ◽  
pp. 129-135 ◽  
Author(s):  
S Iyama ◽  
Y Sano ◽  
T Fujii
1980 ◽  
Vol 60 (2) ◽  
pp. 509-518 ◽  
Author(s):  
B. R. PINCHBECK ◽  
R. T. HARDIN ◽  
F. D. COOK ◽  
I. R. KENNEDY

In this genetic study of symbiotic nitrogen fixation in the tropical legume Spanish clover (Desmodium sandwicense E. Mey), it was established that the quantitative variance found within several estimates of nitrogen fixation had a genetic basis. The diallel analysis suggested that genetic variation was present and that a major portion of this variation was attributable to differences between the parents and their F1 crosses. The within-cross genetic variation was due solely to general combining ability suggesting the presence of heritable genetic variation. Genotype by environment interactions were also found to be significant. The analysis of the data from a cross between two lines suggested that the four nitrogen fixation estimates measured were highly correlated and this variation could be represented by one principal axis of variation. Significant differences among population means were found for all analyses. Plants with larger cotyledons and juvenile leaves fixed significantly more nitrogen than did plants with smaller cotyledons and juvenile leaves. This difference was attributed to juvenile plant vigor which may assist the onset of nodulation. Analysis of the population means suggested that non-heritable variation accounted for the predominant portion of the genetic variance when the nitrogen fixation estimates were unadjusted for differences due to juvenile plant vigor. However, when the nitrogen fixation estimates were adjusted for the effects of juvenile plant vigor the genetic variation was totally heritable. Such heritable variation is of agricultural importance.


2015 ◽  
Vol 525 ◽  
pp. 41-51 ◽  
Author(s):  
PLM Cook ◽  
V Evrard ◽  
RJ Woodland

Author(s):  
S.F. Ledgard ◽  
G.J. Brier ◽  
R.N. Watson

Clover cultivars grown with ryegrass were compared in an establishment year under dairy cow grazing. There was no difference in total annual productton but summer production was greater with Pawera red clover and with Kopu or Pitau white clovers. Clovers differed little in the proportion of nitrogen fixed, except during summer when values were highest for Pawera. Pawera was less prone to nematode attack than white clover cultivars but was more susceptible to clover rot. Resident clovers and high buried seed levels (e.g., 11-91 kg/ha) made introduction of new clover cultivars difficult. Sown clovers established best (50-70% of total clover plants) when drilled into soil treated with dicamba and glyphosate. Keywords: white clover, red clover, nematodes. nitrogen fixation, pasture renovation


GIS Business ◽  
2019 ◽  
Vol 14 (6) ◽  
pp. 425-431
Author(s):  
Subin Thomas ◽  
Dr. M. Nandhini

Biofertilizers are fertilizers containing microorganisms that promote plant growth by improving the supply of nutrients to the host plant. The supply of nutrients is improved naturally by nitrogen fixation and solubilizing phosphorus. The living microorganisms in biofertilizers help in building organic matter in the soil and restoring the natural nutrient cycle. Biofertilizers can be grouped into Nitrogen-fixing biofertilizers, Phosphorous-solubilizing biofertilizers, Phosphorous-mobilizing biofertilizers, Biofertilizers for micro nutrients and Plant growth promoting rhizobacteria. This study conducted in Kottayam district was intended to identify the awareness and acceptance of biofertilizers among the farmers of the area. Data have been collected from 120 farmers by direct interviews with structured questionnaire.


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