VARIATION, ASSOCIATION AND PATH ANALYSIS OFGRAIN QUALITY ATTRIBUTES IN BLACKGRAM

(VIGNA MUNGO L. HEPPER)

A. Ghosh and S. Panda

Department of Genetics,Bidhan Chandra Krishi Viswavidyalaya, Mohanpur - 741252, India

ABSTRACTSeven blackgram (Vigna mungo L. Hepper) genotypes were tested for 10 physical characters

which determine seed quality. There were significant variations between genotypes for 100 seedweight and volume before and after soaking, hydration capacity, swelling capacity, hydration indexand swelling index. Variation of soaked seed density was low. TU-94-2 exhibited best seed qualityamong the genotypes. Swelling index was positively and significantly correlated with dry seed densityand swelling capacity. Swelling capacity was also positively associated with 100 seed weight aftersoaking and hydration capacity. Path analysis, however, showed that swelling capacity and hydrationcapacity had high positive direct effect on swelling index, important for cooking quality. The studysuggested that selection of swelling capacity and hydration capacity must be given preference alongwith optimum dry seed density in breeding for grain quality improvement.

INTRODUCTIONThe importance of blackgram (Vigna

mungo L. Hepper) in Indian economy canhardly be over emphasized. It is a major foodlegume in terms of rich source of protein (24%)and a factor so important for seed health. Anumber of sweets and recipes are preparedfrom blackgram. It is reported that seed weight,volume, density, hydration capacity, swellingcapacity and swelling index are importantattributes, affecting grain nutritional quality aswell its cooking quality (Waldia et al., 1995;Waldia et al., 1996 and Ram Kumar et al.,1998). However, information on the grainquality characters in blackgram is meagre. Thepresent study is aimed to assess the nature andextent of variability for cooking quality andphysical characters of blackgram genotypes.Subsequently, correlation and path analysis willestablish the extent of association within thecharacters and bring out relative importanceof their direct and indirect effects on swellingindex, the important attribute for cookingquality improvement.

MATERIAL AND METHODSGrain sample of seven blackgram

genotypes namely TU-99-852, Sarada, TU-

94-2, B-76, TU-99-843, TU-99-6-1 and B-108 were grown in the form of yield trial atBidhan Chandra Krishi Viswavidyalaya,Gayeshpur farm and the seed harvested wasused for the present study. During the earlyAugust, 2003 one hundred seeds wereweighed in gram to get 100 seed weight. Thesame seeds were taken to find 100 seedvolume and seed density. The physico-chemicaltests like hydration capacity (ml/seed) andswelling index were determined by the methodsused by other workers (Williams et al., 1983and Ram Kumar et al., 1998). All the testswere carried out in triplicates and the meanvalues were used for statistical analysis. Thederived physical characters were taken as givenbelow :

1. Seed weight: 100 dry seed wereweighed and allowed for 24 hours soaking inwater. After soaking again the seed weight wastaken.

2. Seed volume (dry seed): Inmeasuring cylinder some water was taken andvolume was recorded (V

1 ml). Then 100 dry

seeds were put in the cylinder and the raisedvolume (V

2 ml) was recorded .The 100 dry seed

volume would be = (V2 - V

1) ml.

Legume Res., 29 (1) : 43 - 47, 2006

3. Seed volume (after soaking):Some water was taken in measuring cylinderand volume was recorded (V

3 ml). Then 24

hours soaked dried seeds were put in the

cylinder and the raised volume (V4 ml) was

recorded. The 100 soaked seed volume wouldbe = (V

4 - V

3) ml.

Dry seed weight (100 seed)4. Density (dry seed) =

Dry seed volume (100 seed) in g ml-1

100 seed weight (soaked)5. Density (after soaking) =

100 seed volume (soaked) in g ml-1

(100 seed weight after soaking - dry seed weight)6. Hydration capacity =

100

Hydration capacity (100 seed)7. Hydration index = x 100

100 seed weight (dry)

100 seed volume after soaking - 100 seed volume before soaking

8. Swelling capacity per seed = 100 seed

Swelling capacity (100 seed)9. Swelling index =

100 seed weight (dry seed)

The correlations were estimated asper Panse and Sukhatme (1961) and directand indirect effects using the proceduresuggested by Dewey and Lu (1959).

RESULTS AND DISCUSSIONSeed quality variation: A perusal of

the Table 1 revealed considerable variation forall the characters related to nutritional qualityand cooking quality studied. The seven varietiestaken for this experiment had 100 seed weightranging from 4.0 g (Sarada and B-108) to 4.6g (TU-94-2) with mean seed weight 4.31 g.100 seed volume varied from 3.2 ml (Saradaand B-108) to 4.3 ml (TU-99-6-1). The volumeincreased to more than double after soakingin all the varieties except TU-99-6-1 which hadmaximum volume. Hydration capacity, a

measure of intake of water by the grains wasthe highest for the genotype TU-94-2 (0.044ml/seed). Dry seed density varied from 1.07g/cm3 (TU-99-6-1) and 1.30 g/cm3 (TU-99-852). The seed density decreased, as expected,after soaking by about 10%, though thisdecrease varied with the variety. The coefficientof variation of soaked seeds was very low. Theswelling capacity, hydration index and swellingindex were found to be highest in TU-94-2.Similar studies were conducted by Williams andSingh (1987), Waldia et al. (1996) and RamKumar et al. (1998) and all these workers hadreported considerable variation for the qualitytraits though in somewhat different crops.Based on the present studies, the variety TU-94-2 was found very good for physical and

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Table 1. Grain quality characters in different genotypes of blackgram

S. No. Genotypes 100 100 seed 100 Hydration Density Density Swelling Hydration Swelling seed volume ml seed capacity (Dry) (Soaked) capacity index index weight weight per (ml/g) (g) Before After after seed soaking soaking soaking

1. TU-99-852 4.3 3.3 7.3 7.9 0.036 1.30 1.08 0.040 0.837 0.9102. Sarada 4.0 3.2 6.8 7.6 0.036 1.25 1.12 0.036 0.900 0.9003. TU-94-2 4.6 3.6 8.3 9.0 0.044 1.28 1.08 0.047 0.957 1. 0224. B-76 4.2 3.7 7.3 8.2 0.040 1.14 1.12 0.036 0.952 0.8575. TU-99-843 4.5 3.5 7.5 8.4 0.039 1.29 1.12 0.040 0.867 0.8896. TU-99-6-1 4.6 4.3 8.0 8.2 0.036 1.07 1.03 0.037 0.783 0.8047. B-108 4.0 3.2 6.8 7.6 0.036 1.25 1.12 0.036 0.900 0.900

X 4.31 3.54 7.43 8.13 0.0381 1.226 1.096 0.0389 0.8851 0.9002S 0.26 0.39 0.56 0.49 0.0031 0.087 0.035 0.0040 0.0621 0.0670σ 0.24 0.36 0.52 0.46 0.0029 0.081 0.032 0.0037 0.0575 0.0621C.V. 5.61 10.11 7.04 5.61 7.4800 6.568 2.921 9.575 6.497 6.8951

X = Mean; S = Sample standard deviation; σ = Population standard deviation.

physico-chemical characters as well in respectof cooking quality and therefore, could be usedas donors for further improvement throughhybridization. Considering the variationspresent in the ten characters furthercorrelations and path analysis were conductedto estimate degree of association among thecharacters as well direct and indirect effectsfor the cooking quality traits.

Correlation study: Correlationcoefficients among the different grain qualitycharacters were presented in Table 2. Swellingindex was positively and significantly correlatedwith dry seed density (0.7655) and swellingcapacity per seed (0.8144). Dry seed densityand volumes were negatively associated.Swelling capacity was positively associated with100 seed weight after soaking (0.8281) andhydration capacity (0.77). This was inaccordance with the results obtained by Waldiaet al. (1991) in desi and Kabuli chickpea.Subsequently, 100 soaked seed weight waspositively associated with 100 dry seed weightand hydration capacity as observed by Waldiaet al. (1995) in kabuli chickpea. Beside that100 seed weight at dry was also found to benegatively correlated with soaked seed density.

The result suggested that for

improving swelling index dry seed density,swelling capacity/seed should be butter alongwith higher 100 soaked and dry seed weightas well hydration capacity. In other word, seeddensity, swelling capacity, hydration capacity,100 soaked and dry seed weight were foundto be important attributes, affecting cookingquality and cooking time (as determined byswelling index) to a greater extent than theother measured traits. The results were inconformity with the findings of Waldia et al.(1996) in chickpea and Zia-Ur-Rehman andShah (1998) in kidney beans.

Path analysis: The correlations werepartitioned into direct and indirect effects bythe path coefficient analysis (Table 3). Swellingcapacity per seed (1.3188) and hydrationcapacity (0.9934) were observed to have highpositive direct effect on swelling index whiledensity of dry seeds recorded negative directeffect through the indirect positive effect ofswelling capacity of seed, 100 seed volumebefore soaking, hydration capacity and 100seed weight before soaking. Hydration indexexhibited high negative direct effect on swellingindex through hydration capacity, 100 seedweight before soaking and swelling capacityper seed.

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Table 2. Estimates of phenotypic correlation coefficients of differentgrain quality characters in 7 genotypes of blackgram

Genotypes 100 100 100 100 Hydration Density Density Swelling Hydration seed seed seed seed capacity (Dry) (Soaked) capacity index weight volume volume weight per (g) before after after seed soaking soaking soaking

Swelling Index 0.0940 -0.5097 -0.1057 0.4370 0.6192 0.7655* 0.1375 0.8144* 0.5784

100 seed weight - 0.7032 0.3236 0.8395* 0.4950 -0.1731 -0.7556* 0.6540 -0.2911

100 seed volume before soaking - - 0.4778 0.4565 0.1340 -0.8214* -0.7478 0.0261 -0.4194

100 seed volume after soaking - - - 0.4748 0.4850 -0.4167 -0.0289 0.1173 0.2858

100 seed wt. after soaking - - - - 0.8876** 0.0189 -0.4614 0.8281* 0.2750

Hydration capacity - - - - - 0.1770 -0.0974 0.7700* 0.6866

Density (Dry) - - - - - - 0.4225 0.4750 0.3102

Density (Soaked) - - - - - - - -0.3326 0.5231

Swelling capacity per seed - - - - - - - - 0.2826

• = Significant at 5% probability level;** = Significant at 1% probability level.

Table 3. Estimation of direct (diagonal values) and indirect effects betweenswelling index and other physical characters of grains in 7 genotypes of blackgram

Genotypes 100 100 100 100 Hydration Density Density Swelling Hydration seed seed seed seed capacity (Dry) (Soaked) capacity index weight volume volume weight per (g) before after after seed soaking soaking soaking

100 seed weight -1.228 -0.7895 -0.3634 -0.9427 -0.5558 0.1944 0.8484 -0.7344 0.3269

100 seed volume before soaking 0.2597 -0.3694 -0.1765 -0.1686 -0.0495 0.3034 0.2762 -0.0096 0.1549

100 seed volume after soaking 0.0058 0.0086 0.0180 0.0086 0.0087 -0.0075 -0.0005 0.0021 0.0051

100 seed wt. after soaking 0.1705 -0.0927 -0.0964 -0.2031 -0.1803 -0.0038 0.0937 -0.1682 -0.0559

Hydration capacity 0.4917 0.1331 0.4818 0.8818 0.9934 0.1758 -0.0968 0.7649 0.6821

Density (Dry) 0.0464 0.2200 0.1116 -0.0051 -0.0474 -0.2678 -0.1132 -0.1272 -0.0831

Density (soaked) 0.0002 0.0011 0.0013 0.0011 0.0012 0.0008 0.0014 0.0010 0.0090

Swelling capacity per seed 0.8630 0.0333 0.1535 1.0919 1.0151 0.6261 -0.4376 1.3188 0.3639

Hydration index 0.2401 0.3458 -0.2357 -0.2268 -0.5662 -0.2558 -0.4314 -0.230 -0.8246

Correlation with swelling index 0.0940 - 0.5097 -0.1057 0.4370 0.6192 0.7655 0.1375 0.8144 0.5784

Residual effect = 0.0025.

Based on the information of pathanalysis on swelling index, preference may begiven to characters like swelling capacity and

hydration capacity of the seeds along withoptimum dry seed density and hydration indexin breeding for cooking quality.

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REFERENCESDewey, D.R. and Lu, K.H. (1959). Agron. J., 51: 515-518.Panse, V.G. and Sukhatme (1961). Statistical Methods for Agricultural Workers, ICAR, New Delhi.Ram Kumar et al. (1998). Legume Res., 21: 33-36.Waldia, R.S. et al. (1991). Int. Chickpea Newsl., 24: 15-17.Waldia, R.S. et al. (1995). Int. Chickpea and Pigeonpca Newsl., 2: 40-42.Waldia, R.S. et al. (1996). J. Food Sci. Technol. Mysor., 33: 397-402.Williams, P.C. and Singh, U. (1987). Nutritional quality and the evaluation of quality breeding programmes. In: The

Chickpea. (Saxena, M.C.; Singh, K.B. eds). CAB International. The International Centre for AgricultureResearch in Dry Areas, Syria, Pp. 339-350.

Williams, P.C. et al. (1983). J. Sci. Food Agric., 34: 472-496.Zia-Ur-Rehman and Saha, W.H. (1996). Pakistan J. Scientific and Industrial Res., 39: 195-199.

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