Aspects Applied Biology 2001 63 13pages Effect Inoculation Rhizobium Seed Chemical Physical...

8/13/2019 Aspects Applied Biology 2001 63 13pages Effect Inoculation Rhizobium Seed Chemical Physical Properties

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Aspects ofApplied Biology 63,2001Plant Microbial Interactions:Positive interactions n relation to cropproduction and utilisationEffect of inoculation with Rhizobium on the seedchemical andphysical properties of legumes

ByEAEELsHEIKHDepartment ofSoil Sciences, aculty ofAgriculture, University of Khartoum, Shambat,Sudan

E-mail: [email protected]

SummaryThe effect of inoculation with Rhizobium on the physical and chemical properties

of legume seeds was reviewed. Inoculation significantly increased the proteincontent and significantly decreased he carbohydrates content of the seed of fababean, chickpea, fenugreek, guar, soybeanand groundnut. In most reports,Rhizobiuminoculation significantly increased he in vitro protein digestibility and decreased heanti-nutritional factors. Properties such as moisture, fat, crude fiber, mineralcomposition, yield, 100 seed weight, total seed defect, hydration coefficient andcookability were found to vary with the type of Rhizobium strain, crop, cultivar andother fertilization treatments.Key words: Grain legumes,Rhizobia, seed quality, inoculum

IntroductionAgricultural resources are subject o a high utilization pressuredue to the steady ncrease n thepopulation. Therefore, means and methods to meet the food shortage and to improve foodquality should be introduced. The proximate analysis of seeds nclude protein, carbohydrates,fats, crude fiber, ash and moisture contents. Anti-nutritional factors, such as tannin, phytic acidand trypsin inhibitor, are undesirable and efforts are directed to minimize their contents in theseeds.The technology of increasing productivity through the application of chemical, organic

and biological fertilizers is practiced throughout the world. Enthusiasm for biological andorganic fertilizers stems from their advantages n increasing yield and being environmentallysafe.Vigorous efforts are directed to improve the food supply by increasing crop productivity,enhancingnutrient composition and availability, and mproving food charaCteristics uchas size,taste, and texture through the use of biotechnology and genetic engineering programmes(Babiker et ai., 1995). Fertilization, genetic engineering and breeding programmes could beused as useful tools to solve this problem. Rhizobium inoculants have beenused to improve theyield of leguminous crops, Most of the reports in the literature tackle yield and other importantagronomic parameters,but very few focus on the chemical and physical properties of the seeds.

This review, hence, directs the attention towards the importance of Rhizobium inoculants inimproving the chemical composition and the physical characteristics of the seedsof leguminouscrops.


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Proximate CompositionProteincontent

CarbohydrateontentGenerally the carbohydrate content in the seeds of leguminous crops was found to decreasewith Rhizobium inoculation (Table I). Inoculation significantly decreased the carbohydratecontent of faba bean seeds compared to the control (Elsheikh, 1998; Elsheikh & Elzidany,1997a; Elsheikh & Ahmed, 2000). According to Elsheikh & Mohamedzein (1998a),Bradyrhizobium sp. strain 1000 decreased he carbohydrate content of groundnut seeds by29.9 compared to the control in the presenceor absenceof nitrogen and phosphorus reatments

(Table 1). Similarly, inoculation significantly decreased the carbohydrate content of guar(Elsheikh & Ibrahim, 1999) and fenugreek seed (Abdelgani et al., 1999) compared to theuninoculatedcontrol. The decrease n the carbohydrate content in the seeds of inoculated plantscould be attributed to the high concentration of nitrogen available to the plant which increasedthe protein content (Table 1), at the expense of the carbohydratecontent.

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Moisture ontentAs shown in Table 1, inoculation with Rhizobium and/or Bradyrhizobium did not affect themoisture content of faba bean (Elsheikh, 1998) fenugreek (Abdelgani et al., 1999) andgroundnut seeds (Elsheikh & Mohamedzein, 1998a). However, a few reports showed asignificant increase in the moisture content of the seeds of inoculated plants (Elsheikh &Elzidany, 1997a; Elsheikh & Ahmed, 2000). The moisture content of guar seeds was affectedneither by the strain of Bradyrhizobium nor by the cultivar (Elsheikh & Ibrahim, 1999). Theeffect of Rhizobium inoculation, nitrogen, sulphur or chicken manure treatments on moisturecontent of faba beanvaried from no response o significant effect (Elsheikh & Elzidany, 1997a).Generally, the moisture content is affected by cultivar, the relative humidity of surroundingatmosphereat harvest andstorage.

AshcontentInoculation with Rhizobium and/or Bradyrhizobium significantly increased the ash content offaba bean (Elsheikh & Ahmed, 2000), guar (Elsheikh & Ibrahim, 1999) and groundnut seeds(Elsheikh & Mohamedzein 1998a). However, contradicting results were also reported in whichthe ash content of faba beanseeds (Elsheikh, 1998)and fenugreekseeds Abdelgani et al., 1999)was not significantly affected by inoculation (Table 2). Treatments such as application ofchicken manure (Elsheikh & Elzidany, 1997a) and mycorrhiza (Elsheikh & Mohamedzein,

1998a) significantly increased he ash content of faba bean seedsand groundnuts, espectively.The ash content of fenugreek seeds was reported to vary from 3.4 (Abdel-Nabey & Damir,1990) o 3.8 (Nour & Magboul, 1986). The ash content of foodstuffs represents he inorganicresidue remaining after the organic matter has beenburnt. The ash obtained is not necessarilyofexactly the same composition as the mineral matter present n the original food as there may belossesdue to volatilization or as a result of some interactions betweenconstituents.

Fat andfibre contentInoculation with Rhizobium and/or Bradyrhizobium significantly increased the fat and thecrude fibre content of faba bean (Elsheikh & Ahmed, 2000), guar (Elsheikh & Ibrahim, 1999)and groundnut seeds (Elsheikh & Mohamedzein, 1998a). However, Elsheikh & Elzidany

(1997a) reported insignificant results for the fat and crude fibre content of inoculated plants(Table 3). According to Abdelgani et at. (1999), Rhizobium inoculation significantly increasedthe fat content and fibre content of fenugreek compared to the uninoculated control. The fatcontent of fenugreek seeds remained within the low fat level, even with inoculation treatmentswhich increased he level of fat significantly. Fenugreekseedsare known to have a low crude oilcontent (El-Shimi et al., 1984; Hemavathy & Prabhaker, 1989). Generally, fats are importantdietary constituents, not only because of their high energy value, but also because of theessential atty acids and vitamins associatedwith the fat of natural foods. The crude fibre is animportant constituent of human food and animal feed. It is needed n reasonable proportions asa bulking agent o maintain diet and help in movement hrough the digestive tract. Crude fibreis generally affected by the environmental conditions, varietal characteristicsand fertilizationtreatments (Elsheikh &Mohamedzein, 1998a).

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Aspects Applied Biology 2001 63 13pages Effect Inoculation Rhizobium Seed Chemical Physical...

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