Inheritance of Symbiotic Nitrogen Fixation in Two Peanut Crosses1

1989 ◽  
Vol 16 (2) ◽  
pp. 66-70 ◽  
Author(s):  
T. D. Phillips ◽  
J. C. Wynne ◽  
G. H. Elkan ◽  
T. J. Schneeweis

Abstract Symbiotic nitrogen fixation in peanut (Arachis hypogaea L.) may be improved by genetically manipulating the host plant. This requires an understanding of the inheritance of the traits involved in nitrogen fixation. The objectives of this study were to determine the inheritance of several N2 fixation-related traits for two peanut crosses based on Mather and Jink's fixation-related traits for two peanut crosses based on Mather and Jink's additive-dominance model, and to determine if epistasis was important in the inheritance of these traits. A generation means analysis usingparents, reciprocal F1s and F2s, and two back-cross generations was conducted for both crosses. Plants of different generations were grown in modified Leonard jars in the greenhouse for about 60 days at which time nodule number and dry weight, shoot dry weight, nitrogenase activity, and specific activity were measured. Means of the traits for the generations from both crosses (Robut 33-1 x NC 4 and Robut 33-1 x Argentine) showed significant differences. Reciprocal differences were found for most traits measured in the cross of Robut 33-1 x Argentine, a cross of Virginia x Spanish botanical types. Lack of fit of the additive-dominance model indicated significant epistasis for inheritance of nodule number, nodule weight, top dry weight, and nitrogenase activity in both crosses. Three types of digenic interactions (additive x additive, additive x dominance and dominance x dominance) were found. The presence of nonadditive genetic effects suggests that early generation selection would be ineffective.

1986 ◽  
Vol 13 (2) ◽  
pp. 86-89 ◽  
Author(s):  
S. Arrendell ◽  
J. C. Wynne ◽  
G. H. Elkan ◽  
T. J. Schneeweis

Abstract Improvement of the host contribution to nitrogen fixation has been proposed as a method of increasing nitrogen fixation. Significant variability and generally high broad-sense heritability estimates (.60 ± .27 to .82 ± .26 for nitrogenase activity and .53 ± .29 to .85 ± .26 for shoot dry weight) have been reported for F2-derived families from a cross between the Virginia (Arachis hypogaea L. ssp. hypogaea var. hypogaea) cultivar NC 6 and the Spanish (ssp. fastigiata Waldron vulgaris Harz.) breeding line 922, indicating selection for increased nigtogen fixation should be effective in this population. Lines from this population were chosen randomly from F2-derived families selected for high and low nitrogenase activity and high and low shoot dry weight after evaluation at three dates and two locations in each of 2 years (F5 and F6 generations). This study's objectives were to evaluate the N2-fixing ability of the selected lines and to evaluate the association between plant growth habit and N2 fixation. Twenty-four lines in each of the four selection groups and the parents, NC 6 and 922, were evaluated at two sampling dates and two locations. Mean nitrogenase activity of lines selected for increased nitrogenase activity was significantly greater than the mean of the lines selected for low nitrogenase activity. Improved nitrogenase activity was associated with increased fruit weight. The fruit weight mean of the group selected for increased fruit weight. The fruit weight mean of the group selected for increased nitrogenase activity was 39% greater than the mean of the group selected for low nitrogenase activity. Mean shoot dry weight of lines selected for increased shoot dry weight was significantly greater than the mean of the lines selected for low shoot dry weight; however, the fruit weight means of these two groups did not differ. It was hypothesized that selection for increased N2 fixation in a population derived from a cross between Virginia and Spanish types would eliminate genotypes with Spanish growth habit. Groups selected for high nitrogenase activity and for high shoot dry weight had longer and wider leaflets, longer cotyledonary laterals and greater main stem height than did their respective low selection groups. However, these traits chosen to characterize plant growth habit were inadequate in discriminating parental growth habits. Consequently, the data neither substantiated nor refuted the hypothesis.


1980 ◽  
Vol 7 (2) ◽  
pp. 114-119 ◽  
Author(s):  
V. M. Reddy ◽  
J. W. Tanner

Abstract Effects of irrigation, inoculants and fertilizer nitrogen (N) on N2(C2H2) fixation in peanuts were studied in 1976 and 1977 at Delhi, Ontario. Inoculant application increased nodulation and N-fixation in both years. Powdered peat and granular formulations containing the same strains of rhizobia resulted in almost the same amounts of nodulation and N-fixation (80 kg/ha on average). Differences in nodulation from inoculants containing different strains of rhizobia were not consistent over the two years. However, 60% difference in N-fixation resulted from the inoculants containing different strains of rhizobia in both years. Nitrogen application decreased the nodule number, nodule dry weight, and N-fixation of all the inoculated peanuts. Irrigation increased the N-fixation of the peanuts treated with granular inoculant in 1976 by an average of 45% and all the inoculated peanuts in 1977 by an average of 54% but had no effect on nodulation in either year.


1983 ◽  
Vol 10 (2) ◽  
pp. 107-110 ◽  
Author(s):  
A. K. Osman ◽  
J. C. Wynne ◽  
G. H. Elkan ◽  
T. J. Schneeweis

Abstract The effect of varying levels of leaf defoliation on the nodulation and nitrogen fixation of a Virginia and a spanish-type peanut (Arachis hypogaea L.) cultivar was investigated in the greenhouse. Five leaf defoliation treatments - (a) control (no leaflet removal), (b) 25%, (c) 50%, (d) 75%, and (e) 100% - were carried out every 3 to 5 days throughout the growing period. All nitrogen fixation measurements were affected by the defoliation (leaflet removal) treatments. Increased leaf defoliation reduced nodule formation and N2 fixation. The reduction in plant dry weight, nodule number, nodule dry weight, and nitrogenase activity was most severe for the 100% defoliation treatment. Correlation coefficients (r) of N2 fixation measurements and leaf areas and weights were highly significant. The defoliation effect was similar in both experiments and cultivars; however, the Virginia type achieved higher values for all N2 fixation measurements.


1985 ◽  
Vol 65 (1) ◽  
pp. 9-21 ◽  
Author(s):  
J. BERTHOLET ◽  
K. W. CLARK

Field studies were conducted to determine if trifluralin [α,α,α-trifluro-2,6,-dinitro-N,N-dipropyl-p-toluidine] and metribuzin [4-amino-6-tert-butyl-3-(methylthio)-a5-triazin-5(4H)one] affect the growth and nitrogen self sufficiency of faba bean (Vicia faba L.). Metribuzin applied at 0.42 kg/ha as a pre-plant incorporated treatment resulted in substantial crop injury in 1981. Compared to the inoculated control, overall reductions averaged over the entire growing season, in plant dry weight, nodule dry weight, nitrogenase activity, and yield due to metribuzin were 59, 85, 92, and 65%, respectively. In 1982 metribuzin at 0.4 kg/ha was not as phytotoxic. Averaged over the season, the reductions recorded in plant dry weight, nodule dry weight, nitrogenase activity, and yield were 25, 33, 49, and 9%, respectively. The differences in phytotoxicity in the 2 yr at the two sites were attributed to differences in soil organic matter, and both the degree and timing of rainfall. During both years trifluralin did not cause any significant reductions in the parameters investigated. Reductions in nodulation and nitrogen fixation as a result of metribuzin application were evident only when the crop was injured and the plants were under stress from herbicide application. Trifluralin at 1.1 kg/ha reduced the phytotoxicity caused by metribuzin when the two chemicals were tank mixed. In 1981 there was a 23% yield improvement with the tank mix compared to metribuzin applied alone. In 1982, non-significant decreases in phytotoxicity with the tank mix were evident for the parameters studied. This reduced phytotoxicity may be explained on the basis of lateral root inhibition attributable to the trifluralin in the tank mix as was evident in the growth room study. The tank mix of trifluralin and metribuzin at 1.1 and 0.4 kg/ha, respectively, caused a 56% reduction in total root length compared to the inoculated control one week after emergence. Conversely, the total root length of the plants receiving only the 0.4 kg/ha rate of metribuzin did not differ significantly from the control. This may allow for greater herbicide uptake in the plants treated with only metribuzin leading to a greater level of injury.Key words: Faba bean, growth, symbiotic nitrogen fixation, trifluralin, metribuzin


1988 ◽  
Vol 110 (2) ◽  
pp. 321-329 ◽  
Author(s):  
R. Rai

SummaryHigh-temperature-adapted strains RAU 1, RAU 2 and RAU 3 ofAzospirillum brasilenseC 7 were isolated from stepwise transfer to higher temperature (30 to 42 °C). One of the strains (RAU 1) showed more growth, greater nitrogenase and hydrogenase activities at 30 and 42 °C than parental and other temperature-adapted strains. This strain also showed growth and more nitrogenase activity from pH 6·5 to 8·0. Strain RAU 1 showed cross-resistance to penicillin (300/µg/ml) but not to streptomycin, kanamycin, viomycin and polymixin B at 30 and 42 °C. It was demonstrated in field plots in calcareous soil that seed inoculation with RAU 1 enhanced mineral uptake of cheena. Inoculation with RAU 1 led to a significant increase in associative nitrogen fixation, dry weight of roots, grain and straw yield of cheena compared with the uninoculated control with or without applied N, but the effect of seed inoculation with high-temperature-adapted strains was variable with different genotypes of cheena.


2006 ◽  
Vol 54 (4) ◽  
pp. 469-485 ◽  
Author(s):  
G. Singh ◽  
D. Wright

Effects of one pre-emergence herbicide (terbutryn/terbuthylazine) and one post-emergence herbicide (bentazone) along with unweeded and hand-weeded controls on weeds and on the nodulation, nitrogenase activity, nitrogen content, growth and yield of pea (Pisum sativum) were studied. Terbutryn/terbuthylazine was applied pre-emergence @ 1.40, 2.80 and 5.60 kg/hawhereas bentazone was sprayed 6 weeks after sowing @ 1.44, 2.88 and 5.76 kg/h. Terbutryn/terbuthylazine controlled all the weeds very effectively, whereas bentazone did not control some weeds such as Polygonum aviculare, Poa annua and Elymus repens. The herbicides decreased the number of nodules, the dry weight of nodules, the nitrogenase activity, the shoot dry weight, the nitrogen content in the straw and seeds, and the seed yield of peas, the effects generally being higher at higher rates of application. The adverse effects of herbicides on these parameters might be due to their effects on plant growth, as both the herbicides are known to adversely affect photosynthesis. Nitrogenase activity did not correlate well with plant-N content or shoot dry weight. However, there was a strong relationship between plant biomass and plant-N content, which suggests that researchers can rely on these parameters for studying the effects of treatments on nitrogen fixation, rather than measuring nitrogenase activity.


2019 ◽  
Vol 32 (9) ◽  
pp. 1196-1209
Author(s):  
Zaiyong Si ◽  
Qianqian Yang ◽  
Rongrong Liang ◽  
Ling Chen ◽  
Dasong Chen ◽  
...  

Little is known about the genes participating in digalactosyldiacylglycerol (DGDG) synthesis during nodule symbiosis. Here, we identified full-length MtDGD1, a synthase of DGDG, and characterized its effect on symbiotic nitrogen fixation in Medicago truncatula. Immunofluorescence and immunoelectron microscopy showed that MtDGD1 was located on the symbiosome membranes in the infected cells. β-Glucuronidase histochemical staining revealed that MtDGD1 was highly expressed in the infection zone of young nodules as well as in the whole mature nodules. Compared with the control, MtDGD1-RNA interference transgenic plants exhibited significant decreases in nodule number, symbiotic nitrogen fixation activity, and DGDG abundance in the nodules, as well as abnormal nodule and symbiosome development. Overexpression of MtDGD1 resulted in enhancement of nodule number and nitrogen fixation activity. In response to phosphorus starvation, the MtDGD1 expression level was substantially upregulated and the abundance of nonphospholipid DGDG was significantly increased in the roots and nodules, accompanied by corresponding decreases in the abundance of phospholipids such as phosphatidylcholine, phosphatidylethanolamine, and phosphatidylinositol. Overall, our results indicate that DGD1 contributes to effective nodule organogenesis and nitrogen fixation by affecting the synthesis and content of DGDG during symbiosis.


2016 ◽  
Vol 46 (9) ◽  
pp. 1594-1600
Author(s):  
Giovanna Moura Calazans ◽  
Christiane Abreu de Oliveira ◽  
José Carlos Cruz ◽  
Walter José Rodrigues Matrangolo ◽  
Ivanildo Evódio Marriel

ABSTRACT: Cratylia argentea is a leguminous shrub native to the cerrado, which has great potential for forage production and recovery of degraded areas. This study aimed to isolate, characterize, and select efficient rhizobial strains in symbiosis with Cratylia argentea . Rhizobacteria were isolated from the nodules of 12-month-old plants and cultivated in pots containing cerrado soil. Twenty-five bacterial strains were obtained, which displayed extensive variability with respect to morphological and symbiotic characteristics. Cratylia argentea seeds were planted in pots containing 5kg of cerrado soil and maintained in the greenhouse. The treatments consisted of 25 rhizobial isolates, two controls (without nitrogen and without inoculation), with or without nitrogen fertilization (5mgN·plant-1·week-1), and four replications. Plants were cultivated for 150 days after planting seeds to evaluate nodule number, nodule dry weight, shoot and root dry weight, shoot and root N content, and relative and symbiotic efficiency. Thirteen isolates improved shoot dry weight (up to 65.8%) and shoot nitrogen concentration (up to 76%) compared with those of control treatments. Two isolates, 4 (CR42) and 22 (CR52), conferred higher symbiotic efficiency values of approximately 20%. Therefore, these two rhizobial isolates displayed the highest potential as beneficial inoculants to optimize the symbiotic efficiency for Cratylia and to increase the incorporation of nutrients and biomass into the productive system in the cerrado.


1980 ◽  
Vol 7 (2) ◽  
pp. 101-105 ◽  
Author(s):  
T. G. Isleib ◽  
J. C. Wynne ◽  
G. H. Elkan ◽  
T. J. Schneeweis

Abstract Manipulation of the host genotype has been proposed as a method of increasing biological nitrogen fixation by rhizobia in symbiosis with the peanut (Arachis hypogaea L.). The F1 generation of a diallel cross of 10 South American cultivars was evaluated in the greenhouse in an analysis of gene action for traits related to nitrogen fixation. The parents represented five secondary centers of diversity and effects in the diallel model were partitioned into among- and within-center components. Variation of center effects was significant for several characters but was smaller in magnitude than within-center variation. Specific combining abilities were significant and accounted for more variability than general combining abilities for nodule number, nodule mass, specific nitrogenase activity, shoot weight, and total nitrogen, indicating non-additive types of gene action. Maternal effects were observed for the same characters. The parents with the highest general combining abilities (GCA's) for nitrogen fixation were both fastigiate types, while Virginia-type parents had generally low GCA's. Correlations between parental and GCA effects were nonsignificant for all traits, so simple evaluation of lines for nitrogen-fixing capacity may not identify superior parents for use in breeding programs.


1979 ◽  
Vol 25 (3) ◽  
pp. 298-301 ◽  
Author(s):  
Ilona Barabás ◽  
Tibor Sik

In two out of three pleiotropic mutants of Rhizobium meliloti, defective in nitrate reductase induced by amino acid utilization in vegetative bacteria and in symbiotic nitrogen fixation, nitrogenase activity could be restored completely by purines and partially by the amino acids L-glutamate, L-aspartate, L-glutamine, and L-asparagine. The compounds restoring effectiveness in nitrogen fixation did not restore nitrate reductase activity in vegetative bacteria. The restoration of effectiveness supports our earlier conclusion that the mutation is not in the structural gene for a suggested common subunit of nitrogenase and nitrate reductase.


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