Genetic variability and the association of grain Fe and Zn-contents with other agronomic traits were studied in 1,394 accessions from core germplasm maintained at the ICRISAT gene bank. A large variability for grain Fe and Zn contents were observed. The grain Fe and Zn contents of the accessions with white grains were marginally higher than those with colored grains and these white grain sorghums originated mostly from India and Zimbabwe. The Fe and Zn contents of the accessions with testa and without testa were comparable. However, endosperm texture and grain size appeared to influence grain Fe and Zn contents. Strong positive correlation between grain Fe and Zn contents and their weak association with the agronomic and grain traits indicated possibility to breed simultaneously for high grain Fe and Zn traits in varied plant agronomic backgrounds that might be suitable for different agro-climatic regions across the world

Ashok Kumar, A

Ramesh, S

Reddy, B V S

Sahrawat, K L

Sanjana Reddy, P

Venkateswara Rao, P

ICRISAT Open Access Repository

      www.IndianJournals.com            Members Copy, Not for Commercial Sale     Downloaded From IP - 220.227.242.220 on dated 29-Apr-2011280 P Sanjana Reddy, Belum VS Reddy, A Ashok Kumar, S Ramesh, KL Sahrawat, P Venkateswara RaoIndian J. Plant Genet. Resour. 23(3): 280-284 (2010)* Author for Correspondence: E-mail: sanjana.reddy@cgiar.orgAssociation of Grain Fe and Zn Contents with Agronomic Traits in SorghumP Sanjana Reddy1*, Belum VS Reddy1, A Ashok Kumar1, S Ramesh2, KL Sahrawat1 and P Venkateswara Rao11International Crops Research Institute for the Semi-Arid Tropics, Patancheru-502 324, Andhra Pradesh2University of Agricultural Sciences, Bangalore, KarnatakaGenetic variability and the association of grain Fe and Zn-contents with other agronomic traits were studied in1,394 accessions from core germplasm maintained at the ICRISAT gene bank. A large variability for grain Fe andZn contents were observed. The grain Fe and Zn contents of the accessions with white grains were marginallyhigher than those with colored grains and these white grain sorghums originated mostly from India and Zimbabwe.The Fe and Zn contents of the accessions with testa and without testa were comparable.  However, endospermtexture and grain size appeared to influence grain Fe and Zn contents. Strong positive correlation between grainFe and Zn contents and their weak association with the agronomic and grain traits indicated possibility to breedsimultaneously for high grain Fe and Zn traits in varied plant agronomic backgrounds that might be suitable fordifferent agro-climatic regions across the world.Key Words: Iron, Micronutrient, Variability, ZincIntroductionSorghum (Sorghum bicolor (L.) Moench) is a staplefood grain in many semi-arid tropical (SAT) and tropicalareas of the world because of its good adaptation toharsh environments and its good yield (Dicko et al.,2006). More than 35% of sorghum is grown for directhuman consumption. The rest is used primarily for animalfeed, alcohol production and industrial products (FAO,1995). Micronutrient malnutrition is primarily the resultof diets poor in bio-available vitamins and minerals,mostly iron (Fe) and zinc (Zn) (Dar et al., 2006). Cropvarieties selected and/or bred for this purpose througha plant breeding approach will complement the existingapproaches (such as other fortified foods and medicalpills), and at a fraction of the cost of existing approaches.Current research focuses on identifying varieties withhigh Fe and Zn meeting specific agricultural and foodrequirements from the greater biodiversity of sorghumsfor their direct use and/or introgression of the traitsinto breeding lines to ensure health. In a set of 84 breedinglines evaluated at the International Crops ResearchInstitute for the Semi-Arid Tropics (ICRISAT), Patancheru,the Fe content varied from 20.1 to 37.0 mg kg-1 grainand Zn content varied from 13.4 to 31.0 mg kg-1 grain,indicating limited variability (Reddy et al., 2005). Hence,a need was felt to explore the germplasm to identifylines with high grain Fe and Zn contents and studytheir associations with agronomic traits before utilizationin the breeding programs.Materials and MethodsA total of 2,974 accessions from the core collectionmaintained at the ICRISAT genebank representing thevariability of the entire germplasm collection (about36,774 accessions) were evaluated on Vertisols in anAugmented Design at the ICRISAT center farm, Patancherualong with four checks viz., ICSV 745, IRAT 204, LaddeSamrudhi and Paccha Jonna known for their high grainFe and Zn contents. The material was sown on 30thNovember 2005. The experimental site is located at analtitude of 545 m above mean sea level with latitudeof 17.53o N and longitude of 78.27o E. The site receivesan average annual rainfall of 887.56 mm (average of31 years from 1974 to 2004).For the sake of convenience, while collecting dataon plant growth and grain yield and its component traits,harvesting and processing of grain samples for Fe andZn contents estimation, the accessions were evaluated(in contiguous blocks) as three separate groups classifiedbased on days to 50% flowering (early: d” 65 days;medium: 66 to 80 days; late: > 80 days) in AugmentedDesign. The early group consisted of 1,095 accessionsalong with 4 checks, each repeated 11 times; the mediumgroup consisted of 1,128 accessions along with the 4checks, each repeated 12 times; the late group consistedof 751 accessions along with 4 checks, each repeated8 times. Each accession was sown in one row of 2      www.IndianJournals.com            Members Copy, Not for Commercial Sale     Downloaded From IP - 220.227.242.220 on dated 29-Apr-2011Indian J. Plant Genet. Resour. 23(3): 280-284 (2010)Fe and Zn Contents in Sorghum 281m length. One week after seedling emergence, the plantswere thinned to maintain 10 cm spacing between plants.A fertilizer dose of 80 Kg N (half as basal and remaininghalf at 30 days after sowing) and 40 Kg P2O5 (entireas basal) was applied. Apart from this, the recommendedcrop production and protection packages were followedto raise a healthy crop. In each accession, the borderplants were left for open-pollination and all the middleplants were selfed.The data were collected on the traits such as daysto 50% flowering, plant height (m), grain yield(t ha-1), 100-grain weight (g), grain color (LB= lightbrown, Br= brown, DB= dark brown, Cr= cream,CW= chalky white, G= gray, R= red, W= white, Y=yellow), grain shape (C= circular, E= elliptic, NE=narrow elliptic), Grain endosperm texture (0 = 0%corneous or 100% farinaceous to 100%= 100% corneousor vitreous), Germ size (S= small, M= medium, L=large), plant agronomic aspect (taken on a 1 to 5scale, where 1= most desirable and 5= least desirable),panicle shape (taken on a 1 to 5 scale, where 1=reverse pyramid, 2= panicle broader in the upper part,3= symmetric, 4= panicle broader in the lower partand 5= lower part pyramidal), panicle compactness(C= compact, SC= semi-compact, SL= semi-loose,L= loose and VL= very loose), glume color (Bl=black, Br= brown, G= green, Lr= light red, P= purple,R= red, S= straw), glume coverage (0% to 100%)and presence/absence of seed sub-coat.  The grainsamples from some of the accessions could not becollected due to severe bird damage and in fewaccessions the available grains were not sufficientfor estimation of Fe and Zn contents. The grain samplesharvested from selfed panicles of 698 accessions ofearly maturity, 459 accessions of medium maturity,and 237 accessions of late maturity (making a totalof 1,394 accessions), and the grain samples harvestedfrom open-pollinated panicles of 118 accessions ofearly maturity, 66 accessions of medium maturity,and 30 accessions of late maturity (making a totalof 214 accessions) where sufficient quantities wereavailable. The contents of Fe and Zn in the groundgrain samples (one replication per sample, randomsamples were duplicated) were determined by usingthe triacid digestion method and the Fe and Zn contentsin the aliquot was determined by atomic absorptionspectrometer (Sahrawat et al., 2002).Results and DiscussionGenetic variabilityThe Fe and Zn contents of the checks although varied,the variability was minimal as the CV% was below15. Assuming that the variability of the check varietieswas same as that of the test varieties, the trait-valuesof the accessions were adjusted and reportedhere under. A large variability for grain Fe (7.7 to 132.6mg kg-1) and Zn (15.1 to 91.3 mg kg-1) contents wasobserved among the 1394 core accessions. The variabilityobserved in core germplasm collection was much higherthan that reported earlier, based on screening of 86genotypes consisting of germplasm lines, hybrid parentsof released/marketed hybrids and popular varieties. Ingeneral, sorghums used as human food have whitepericarp, tan plant color, straw color glumes and producegrain with medium to hard endosperms. Sorghums withbrown or red color, including those with pigmented testa,are often used to produce malt and local alcoholicbeverages and porridges (Rooney and Waniska, 2000).Interestingly, grain Fe and Zn contents of accessionswith white grains (43.6 mg kg-1 Fe and 35.1 mgkg-1 Zn), which are used for human consumption inIndia, were marginally higher than those with coloredgrains (Fe content ranged from 40.4 to 42.6 ppm andZn content ranged from 30.9 to 34.0 ppm) (Table 1).The Fe and Zn rich, white or cream colored grainsorghums originated mostly from India, Zimbabwe,Sudan and Yemen apart from other countries while thosewith low Fe and Zn in similar grain color backgroundhad India, Algeria, Cameroon and Sudan origin.  TheFe and Zn rich, brown colored grain sorghums originatedfrom USA, India, Spain, China, Angola and Tanzaniawhile those with low Fe and Zn in similar grain colorbackground had Kenya, Uganda, Mexico, Australia, Maliand Korea origin (Table 2). The Fe and Zn contentsof accessions with testa (42.5 ppm Fe and 34.2 ppmZn) and without testa (42.9 ppm Fe and 33.2 ppm Zn)were comparable (Table 1).  However, endosperm textureand grain size appeared to influence grain Fe and Zncontents. While the accessions with 100% corneousendosperm had 56.2 ppm Fe and 44.3 ppm Zn contents,those with 0% to 75% corneous endosperm had lessthan 44.8 ppm Fe and 35.0 ppm Zn (Table 1). However,further studies are needed to confirm this. The textureof endosperm has significance in food preparations. Thegrains with 50% corneous endosperm are useful for      www.IndianJournals.com            Members Copy, Not for Commercial Sale     Downloaded From IP - 220.227.242.220 on dated 29-Apr-2011282 P Sanjana Reddy, Belum VS Reddy, A Ashok Kumar, S Ramesh, KL Sahrawat, P Venkateswara RaoIndian J. Plant Genet. Resour. 23(3): 280-284 (2010)Table 1. Relationship of grain traits (colour, testa presence/absence and endosperm texture) with grain Fe and Zn contents in sorghum coregermplasm collection, 2005 post-rainy season, Patancheru  Trait # of                         Fe (mg kg-1)                           Zn (mg kg-1)lines Range Mean SD Range Mean SD1. Colour of the grain     Light Brown 29 28.8 to 63.6 41.2 8.6 21.6 to 44.4 31.8 5.7Brown 604 7.7 to 132.6 42.6 13.4 15.8 to 91.3 34.0 8.5Dark Brown 30 27.7 to 51.7 40.4 6.0 21.7 to 55.8 32.2 7.5Cream 244 12.9 to 96.0 42.0 11.3 15.9 to 66.0 33.7 8.9Chalky White 139 21.8 to 90.5 42.1 9.1 15.1 to 56.8 31.2 7.8Gray 8 33.1 to 53.8 42.4 7.6 27.9 to 41.0 33.1 4.4Light Red 11 31.5 to 48.1 41.6 4.8 19.8 to 29.5 30.9 9.4Red 133 12.4 to 84.4 41.9 9.1 20.3 to 64.9 33.8 7.7White 138 18.9 to 71.0 43.6 10.4 17.6 to 59.9 35.1 9.1Yellow 58 22.1 to 65.6 40.9 10.6 15.7 to 52.7 30.9 8.32. Testa        Present 728 7.7 to 132.6 42.5 11.7 15.7 to 66.0 34.2 8.3Absent 666 17.6 to 128.9 42.9 11.7 15.1 to 91.3 33.2 8.73. Texture of the endosperm       0 % corneous 299 20.8 to 112.4 43.4 13.2 15.8 to 91.3 34.9 9.125% corneous 703 7.7 to 132.6 41.7 10.3 16.0 to 63.7 33.2 7.750% corneous 329 15.0 to 96.0 43.2 11.3 15.1 to 66.0 33.8 9.475% corneous 53 24.8 to 88.6 44.8 12.4 20.0 to 55.1 35.0 8.8100% corneous 10 48.1 to 73.9 56.2 7.8 35.1 to 53.0 44.3 5.54. Grain size        Bold grain (>3.5 g 100-1) 384 12.4 to 83.1 40.8 13.9 15.1 to 58.3 32.2 9.1Medium grain (>2.5 g to3.5g 100-1) 564 19.0 to 108.4 42.6 10.2 15.9 to 66.0 33.5 8.3Small grain (<2.5 g 100-1) 446 7.7 to 132.6 44.4 9.3 15.8 to 91.3 35.9 7.7Overall 1394 7.7 to 132.6 42.3 11.6 15.1 to 91.3 33.5 8.5Table 2. Origin of germplasm lines with high and low grain Fe and Zn contents in varied grain color backgroundsImportant  Line*grain color Micronutrient High LowCream Fe IS 8078 (Japan); IS 6413 (India), IS 30655 (Cameroon); IS 916 (Algeria),IS4622 (India), IS 2263 (Sudan) IS 4116 (India), IS 31697 (Algeria)Zn IS 2248 (India); IS 26012 (Mali), IS 5273 (India); IS 916 (Algeria);IS 28084 (Yemen); IS 27108 (Zimbabwe) IS 23453 (India), IS 20607 (Sudan)White Fe IS 25386 (Kenya); IS 30056 (Zimbabwe); IS 16054 (Cameroon); IS 29012 (Yemen);IS 6975 (Sudan); IS27906 (S. Africa) IS 9918 (Sudan); IS 20537 (Sudan)Zn IS 3790 (Taiwan); IS 24895 (Zimbabwe); IS 20537 (Sudan); IS 20552 (Sudan);IS 30056 (Zimbabwe); IS 23879 (Yemen) IS 22381 (Sudan); IS 20502 (Sudan)Light Red Fe IS 19053 (Sudan); IS 26280 (Togo); IS 22231 (Australia); IS 14433 (Lesotho);IS 22356 (Botswana); IS 20435 (Niger) IS 20298 (Niger); IS  14869 (Cameroon)Zn IS 26280 (Togo); IS 22356 (Botswana); IS 14869 (Cameroon); IS 22231(Australia);IS 22756 (Somalia); IS 20435 (Niger) IS 3158 (S. Africa); IS  20298 (Niger)Red Fe IS 31906 (Yemen); IS 2885 (Italy); IS 16546 (Cameroon); IS 26513(Benin);IS 28376 (Yemen); IS 26200 (Togo) IS 13885 (S. Africa); IS 25713 (Mali)Zn IS 31906 (Yemen); IS 18088(Lebanon); IS 13585 (Uganda); IS 18745(USA);IS 31984 (Yemen); IS 26200 (Togo) IS 9571 (S. Africa); IS 271 (Unknown)Yellow Fe IS 7881 (Nigeria); IS 22022 (India); IS 21761 (Sudan); IS 24632 (Lebanon);IS 22311 (Botswana); IS 25331 (Ethiopia) IS 18333 (India); IS 15697 (Cameroon)Zn IS 5522 (India), IS 7881 (Nigeria); IS 21761 (Sudan); IS 24632 (Lebanon);IS 10973 (USA); IS 22311 (Botswana) IS 15697 (Cameroon); IS 24561 (Lebanon)Brown Fe IS 28 (USA), IS 613 (USA); IS 6335 IS 9058 (Kenya), IS 902 (Mexico);(India); IS 13211 (Spain) IS 22227 (Australia); IS 30520 (Korea)Zn IS 6335 (India), IS 20888 (Angola); IS 8891(Uganda), IS 9058(Kenya);IS 30310 (China); IS 12701 (Tanzania) IS 8084 (Uganda); IS 12380 (Mali)*The origin of the germplasm line is given in the parentheses      www.IndianJournals.com            Members Copy, Not for Commercial Sale     Downloaded From IP - 220.227.242.220 on dated 29-Apr-2011Indian J. Plant Genet. Resour. 23(3): 280-284 (2010)Fe and Zn Contents in Sorghum 283Table 3. Estimates of correlation of agronomic and grain traits withgrain Fe and Zn contents in sorghum core germplasmcollection, 2005 postrainy season, PatancheruTrait Fe (mg kg-1) Zn (mg kg-1)Days to 50% flowering 0.088** 0.207**Plant height (m) 0.220** 0.380**100-grain weight (g) -0.130** -0.143**Grain yield (t ha-1) -0.161** -0.200**Panicle shape1 0.063* 0.083**Panicle compactness2 0.214** 0.125**Glume color3 -0.038 -0.173**Glume coverage%4 0.278** 0.292**Grain color5 -0.016 0.002Grain shape6 -0.156** -0.179**Grain endosperm texture7 0.071* 0.032Germ size8 0.009 0.032Zn (ppm) 0.604** -n-2 = 1392; r at 5% = 0.062; r at 1% = 0.0811Panicle shape (taken on a 1 to5 scale, where 1= reverse pyramid, 2= panicle broader in the upper part, 3=symmetric, 4= panicle broader in the lower part and 5= lower part pyramidal),2panicle compactness (taken on a 1 to 5 scale, where 1= compact, 2= semi-compact, 3= semi-loose, 4= loose and 5= very loose), 3glume color (takenon a 1 to 7 scale, where 1= green, 2= straw, 3= brown, 4= light red, 5= red,6= purple, 7= black), 4glume coverage (taken on a 1 to 4 scale, where 1=25%, 2= 50%, 3= 75% and 4= 100%), 5grain color (taken on a 1 to 9 scale,where 1= white, 2= chalky white, 3= cream, 4= yellow, 5= gray, 6= red, 7=light brown, 8= brown and 9= dark brown), 6grain shape (taken on a 1 to 3scale, where 1= narrow elliptic, 2= elliptic and 3= circular), 7Grain endospermtexture (taken on a 1 to 5 scale, where 1= 0% corneous, 2= 25%, 3= 50%,4= 75% and 5= 100%) and 8Germ size (taken on a 1 to 3 scale, where 1 =small, 2= medium, 3= large).preparation of ‘roti’ or ‘chapati’ (unleavened bread),the most popular food forms of sorghum grains in India,and for ‘ingera’ (leavened bread), the most popularfood forms of sorghum grains in some parts ofAfrica. Grains with more than 75% corneous endospermare useful for preparation of ‘to’ the most popular foodforms of sorghum grains in some parts of Africa (Anglani,1998). The accessions with small grains (< 2.5 g100-grain weight) had higher grain Fe (44.4 ppm) andZn (35.9 ppm) contents than those with mediumgrain weight of 2.5 g to 3.5 g 100-grains (42.6 ppmFe and 33.5 ppm Zn) and those with large grain weightof >3.5 g 100-grains (40.8 ppm Fe and 32.2 ppm Zn)(Table 1).Association of grain Fe and Zn contents with othergrain traits and agronomic traitsCorrelation of grain Fe and Zn contents with agronomicand grain traits in 1394 core germplasm lines wereestimated (Table 3). Fairly high correlation (r=0.6)between grain Fe and Zn contents suggests ample scopefor simultaneous improvement of both the micronutrients.Though correlation of grain Fe and Zn contents withdays to 50% flowering (0.1 for Fe and 0.2 for Zn),plant height (0.2 for Fe and 0.4 for Zn) was significantand positive, the lower magnitude of the correlationsuggests near-independence of the crop growth traitsand grain micronutrients contents. The results indicatedthat sorghum grain Fe and Zn contents can be improvedin different maturity and plant stature backgrounds.Similarly, significant negative but lower magnitude ofcorrelation of grain Fe and Zn contents with grain yield(-0.2 Fe and -0.2 Zn) and grain size (-0.1 Fe and -0.1 Zn) suggested that it is possible to enhance grainFe and Zn contents in high yielding backgrounds withlarge grain. Significantly high and positive correlationswere observed for grain Fe (0.9) and Zn (0.8) contentsestimated from grain obtained from open-pollinated andselfed panicles.A large variability for grain Fe and Zn contentswas observed among 1394 core collection accessions.Strong positive correlation between grain Fe and Zncontents and their weak association with the agronomicand grain traits indicated possible positive outcomesfrom breeding simultaneously for high grain Fe andZn traits in varied plant agronomic backgrounds thatmay be suitable for different regions across the world.The accessions with high grain Fe and Zn contents areneeded to be evaluated again for confirmation andsimultaneously involved in the development ofmicronutrient-enriched cultivars with farmer-preferredtraits.AcknowledgmentsThis study was financially supported by ChallengeProgram on HarvestPlus for “Development ofmicronutrient and ß-carotene-dense sorghums”. We arethankful to Dr HD Upadhyaya, Principal Scientist,ICRISAT Genebank, for providing the seed of germplasmlines.ReferencesAnglani C (1998) Sorghum for human food – a review. Plant FoodHum. Nutr. 52: 85-95.Dar WD, BVS Reddy, CLL Gowda and S Ramesh (2006) Geneticresources enhancement of ICRISAT mandate crops. Curr. Sci.91(7): 880-884Dicko MH, H Gruppen, AS Traore, AGJ Voragen and WJH VanBerkel (2006) Sorghum grain as human food in Africa: relevanceof content of starch and amylase activities. Afr. J. Biotechnol.5: 384-395.      www.IndianJournals.com            Members Copy, Not for Commercial Sale     Downloaded From IP - 220.227.242.220 on dated 29-Apr-2011284 P Sanjana Reddy, Belum VS Reddy, A Ashok Kumar, S Ramesh, KL Sahrawat, P Venkateswara RaoIndian J. Plant Genet. Resour. 23(3): 280-284 (2010)Food and Agricultural Organization (FAO). (1995) Sorghum andmillet in human nutrition. FAO Food and Nutrition Series No.27. ISBN 92-5103381-1. Consulted on 10 September2 0 0 5 a t : h t t p : / / w w w. f a o . o r g / D O C R E P / T 0 8 1 8 e /T0818E00.htm#ContentsReddy BVS, S Ramesh and T Longvah (2005) Prospects ofbreeding for micronutrients and b-carotene-dense sorghums.Int. Sorghum Millets News.l. 46: 10-14.Rooney LW and Waniska RD. (2000) Sorghum food and industrialutilization. In: Smith CW and Frederiksen RA (eds) Origin,History, Technology and Production. John Wiley and Sons,New York, USA, pp 689-729.Sahrawat KL, G Ravi Kumar and JK Rao (2002) Evaluation oftriacid and dry ashing procedures for determining potassium,calcium, magnesium, iron, zinc, manganese and copper in plantmaterials. Commun. Soil Sci. Plant Analysis 33: 95-102.

Association of Grain Fe and Zn Contents with Agronomic Traits in Sorghum

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