Common bean (Phaseolus vulgaris L., Fabaceae), landraces of Lushai hills in India: Nutrients and antioxidants source for the farmers

Indian Journal of Traditional Knowledge Vol. 15(2), April 2016, pp. 313-320 Common bean (Phaseolus vulgaris L., Fabaceae), landraces of Lushai hills in India: Nutrients and antioxidants source for the farmers S K Dutta 1 *, Dibyendu Chatterjee 2, D Sarkar 3, S B Singh 1, T Boopathi 1, Rukuosietuo Kuotsu 2, K Vikramjeet 2, R S Akoijam 1, S Saha 1, Vanlalhmangaiha 1, Malsawmzuali 1, S Chowdhury 1 & Lungmuana 1 1 Indian Council of Agriculture Research, Research Complex for North Eastern Hill Region, Mizoram centre, Kolasib, Mizoram-796081; 2 Indian Council of Agriculture Research, Research Complex for North Eastern Hill Region, Nagaland centre, Jharnapani, Nagaland-797106; 3 Indian Council of Agriculture Research, Research Complex for North Eastern Hill Region, Manipur centre, Lamphelpat, Manipur-795004 E-mail: sudipiari@rediffmail.com Received 24 March 2015, revised 05 May 2015 Incredible diversity is found in the pod and seed morphology of the climbing type common bean landraces of Lushai hills of Mizoram, India. Twenty three such pole-type common bean landraces, consumed locally for seeds and pods, were collected from different districts of Lushai hills during 2008-13. Seeds were multiplied and evaluated for nutrients and antioxidant diversity. A significant diversity was found for seed N, P, K, Cu, Zn, Mn, Fe, ash content, total phenol, diphenyl-2-picrylhydrazyl (DPPH) and azinobisethylbenzothiazoline-6-sulphonic acid (ABTS) radical scavenging activity. Correlation analysis indicated numerous significant positive and negative correlations among nutrients. Principle component analysis (PCA) assessed the patterns of variation by taking all the nutrients variables together. The first four PCs accounted for 74% of the total variation. PC1 (26%) and PC2 (21%) showed the highest variability among all the PCs. Landraces MZFB-47, MZFB-41, MZFB-83, MZFB-116, MZFB-52, MZFB-28, MZFB-116 and MZFB-85 were found to be the most promising ones with highest N, P, K, Cu, Zn, Mn, Fe and ash content while, total phenol, DPPH and ABTS radical scavenging activity were found maximum in MZFB-97. The study generated information about the nutritional importance of this precious, yet unstudied diversity of landraces which can be conserved, promoted and utilized for selecting and improving superior nutritious common bean lines. Keywords: Nutrients, Antioxidant, Common bean, Phaseolus vulgaris, Landraces, Lushai hills IPC Int. Cl. 8 : C09K 15/00, A47G 19/26, A47J 39/02, A61K 36/00 Common bean (Phaseolus vulgaris L., Fabaceae) is the most important grain legume for direct human consumption and is an extremely diverse crop in terms of morphological variability, uses and cultivation 1. High mineral variability 2 and antioxidant activities 3 observed in the seeds of common bean could be useful for the selection of cultivars with higher nutrition value and for the improvement of seed nutrition quality traits. The North-eastern hill region (NEH) of India is one of the hot-spots of agro-biodiversity in the Indian gene centre, and has rich ethnic diversity and traditional culture. Mizoram is one of the eight states of North-eastern (NE) India. The state has the highest (94.8%) proportion of tribal population in India 4. Traditional shifting cultivation (Jhum) is the major source of rural economy and a part of cultural requirement for the tribes. In general, the land type of Corresponding author Mizoram is characterized by inaccessibility, marginality, fragility, ethnicity, rich bio-diversity and low crop productivity. Diversity of pole-type common bean landraces in Mizoram is remarkable. Here, common bean is produced under rainfed conditions in the traditional production system that include intercropping of climbing beans with maize, and growing in backyards and kitchen gardens. The green pods are consumed as fresh vegetable and dried seeds are used as pulse and for seed purposes, while the foliage is used as fodder and to restore soil fertility. Only tender and fibreless podded landraces are preferred by the farmers which are consumed as a stew kind of dish locally known as Bai. Mizos considered pole type landraces as suitable for Bai which were very tasty and fibreless. In contrast, the bush type bold seeded common bean landraces locally called Farash bean having high fibre content, are found scarcely, preferred as pulse substitute.

314 INDIAN J TRADIT KNOWLE, VOL. 15, NO. 2, APRIL 2016 Nevertheless, the landraces are being lost because of replacement by other high value crops, drought and forest fire. There exists a lot of diversity in seed shape, size and colour among the genotypes 5, similarly a considerable amount of macro and micro-nutrient diversity in this landraces may exist and that has to be explored and can be used for breeding purposes to evolve nutrients rich varieties. They will also be useful to evaluate whether the enhancement of one mineral influences the concentration of another or not 6. Until now there is no information available on the nutrients content of the common bean landraces of Lushai hills of India. Therefore, current investigation was initiated with an objective to examine the genetic variation in macronutrients (N, P and K), micronutrients (Cu, Zn, Mn and Fe), ash content and antioxidant activity of these landraces. This work will help to identify lines, which could be used to improve the nutritional quality of common bean in India and/or to provide information to the breeders interested in common bean genetic resources of Lushai hills of India. Methodology Survey was conducted and seeds of indigenous common bean landraces were collected from all the eight districts of Lushai hills (Mizoram, India) during 2008-13. Major common bean growing areas of the whole state was surveyed and 23 landraces were collected which are grown largely by the farmers. Only those distinct landraces were selected which are preferred by the farmers due to their tenderness, taste, cooking quality etc. All the passport data, viz. date of collection, source, frequency, site of collection, latitude, longitude and altitude were recorded (Table 1). The genotypes were sown in raised beds (3 m 1 m) using a randomized completely blocked design with three replicates per genotype at the Research Farm, ICAR Research Complex for North Eastern Hill Region, Mizoram centre, Kolasib, Mizoram, India. All the genotypes were grown with a spacing of 15 cm between plants within a row and 45 cm between rows. All plots were treated identically with standard agricultural practices. Table 1 Passport data of common bean landraces of Lushai hills Sl. No. Local Ref No. Date of collection Source Frequency Village District Latitude (N) Longitude (E) Altitude (m) 1. MZFB-28 March 2008 Sel. from IC-611100 Frequent Vengthar Kolasib 24º12 33 92º40 33 645 2. MZFB-29 March 2008 Sel. from IC-611101 Frequent Vengthar Kolasib 24º12 33 92º40 33 645 3. MZFB-32 April 2008 Sel. from IC-611102 Frequent Kawnpui Kolasib 24º13 55 92º40 39 677 4. MZFB-41 October 2008 Sel. from IC-611103 Frequent Theiva Saiha 22º23 57 93º00 52 1110 5. MZFB-42 October 2008 Sel. from IC-611104 Frequent Theiva Saiha 22º23 57 93º00 52 1110 6. MZFB-43 October 2008 Sel. from IC-611105 Frequent Theiva Saiha 22º23 57 93º00 52 1110 7. MZFB-45 April 2010 Sel. from IC-595238 Rare Vengthar Kolasib 24º12 33 92º40 33 645 8. MZFB-47 April 2008 Sel. from IC-611106 Frequent Kawnpui Kolasib 24º13 55 92º40 39 677 9. MZFB-48 April 2010 Sel. from IC-595238 Rare Vengthar Kolasib 24º12 33 92º40 33 645 10. MZFB-50 March 2010 Sel. from IC-611108 Frequent Sihphir Aizawl 23º48 49 92º44 18 1214 11. MZFB-51 March 2010 Sel. from IC-611109 Frequent Sihphir Aizawl 23º48 49 92º44 18 1214 12. MZFB-52 March 2010 Sel. from IC-611110 Frequent Bilkhawthir Kolasib 24º20 01 92º43 05 438 13. MZFB-53 March 2010 Backyard of farmer Frequent Sihphir Aizawl 23º48 49 92º44 18 1214 14. MZFB-80 September 2013 Backyard of farmer Frequent Cherkawn Serchhip 23º11 20 93º01 05 863 15. MZFB-82 September 2013 Backyard of farmer Frequent Bungtlang Serchhip 23º11 30 92º54 01 820 16. MZFB-83 September 2013 Road side market Frequent Hnahthial Lunglei 22º57 30 92º55 98 821 17. MZFB-85 September 2013 Backyard of farmer Rare Tuipui-D Lunglei 22º54 19 92º55 93 225 18. MZFB-97 September 2013 Backyard of farmer Frequent Sihtlangpui Lawngtlai 22º25 03 92º56 16 819 19. MZFB-101 September 2013 Backyard of farmer Frequent Sihtlangpui Lawngtlai 22º25 03 92º56 16 819 20. MZFB-116 September 2013 Road side market Frequent Lengpui Mamit 23º49 59 92º37 34 416 21. MZFB-119 September 2013 Road side market Frequent Lengpui Mamit 23º49 59 92º37 34 416 22. MZFB-121 September 2013 Backyard of farmer Frequent Champhai Champhai 23º27 23 93º19 41 1328 23. MZFB-126 September 2013 Backyard of farmer Frequent Champhai Champhai 23º27 23 93º19 41 1328

DUTTA et al.: NUTRIENTS AND ANTIOXIDANTS DIVERSITY OF COMMON BEAN OF LUSHAI HILLS 315 Characterization of soil and seed samples was done following the methods described by Tandon 7. The surface (0-15 cm) soil samples from each plot were collected, ground and passed through 2-mm sieve and characterized for physicochemical properties. The ph in soil water suspension (1:2.5) was measured in a digital ph meter (Cyberscan ph tutor, Eutech Instruments, Singapore). The electrical conductivity was measured in the supernatant liquid of the soil water suspension (1:2.5) with the help of Conductivity Bridge (Model 611, EI Products, Panvanoo, Himachal Pradesh, India), expressed in ds m -1 at 25 C. Mineralizable nitrogen in soil was determined by alkaline- KMnO 4 method. Available phosphorus in soil was determined Bray-Kurtz No. 1 method, followed by colour development by ascorbic acid method measured in a UV VIS spectrophotometer (Model Systronics-117, Systronics India Limited, India). Available potassium was extracted by 1N neutral NH 4 OAc and determined by flame photometer (Flame photometer-128, Systronics Limited, India). Zinc, copper, iron, and manganese were extracted by DTPA TEA buffer (0.005 M DTPA+ 0.01 M CaC1 2 + 0.1 M TEA) and concentrations in the DTPA extract were determined in an Atomic Absorption Spectrophotometer (Thermo Electron Corporation, Cambridge, United Kingdom). Mizoram has red soil in the order of Entisol, Inceptisol and Ultisols. The characteristic of the soil where experiment was conducted were: ph = 6.28±0.17; EC (ds m -1 ) = 0.984±0.016; Organic C (%) = 1.57±0.25; N (mg/kg) = 74.2±4.20; P (mg/kg) = 23.4±0.59; K (mg/kg) = 123.0±8.50; Cu (mg/kg) = 1.12±0.08; Zn (mg/kg) = 2.51±0.11; Mn (mg/kg) = 42.1±1.90 and Fe (mg/kg) = 21.9±0.07. After drying at ambient temperature, the seeds were ground in a mill. The ground seeds were stored in 4 C until the analyses. Then, the composite seed samples were digested in diacid mixture (concentrated HNO 3 and HClO 4 in the ratio of 9:4 by volume) for analysis of phosphorus and potassium content, while digestion with concentrated H 2 SO 4 was executed for nitrogen content by modified microkjeldahl method. Total phosphorus content was analyzed by following vanado-molybdate phosphoric acid yellow colour method and total potassium content by flame photometer (Flame photometer-128, Systronics Limited, India) directly. Micronutrients were analyzed in diacid extract with suitable dilution using an Atomic Absorption Spectrophotometer (Thermo Electron Corporation, Cambridge, United Kingdom). Ash content was measured by loss on ignition using a muffle furnace NSW 101 (Narang Scientific Works Private Limited, New Delhi 64, India) and heated at 550 600 C for 6 hrs 7. For Total Phenol and Antioxidant assay, ten gm of ground seeds were shaken separately in methanol for 72 hrs on an orbital shaker at room temperature. Extracts were filtered using a Buckner funnel and Whatman No. 1 filter paper. Each extract was suspended in methanol to make 50 mg/ml stock solution. Total phenolic content of all the extracts was evaluated with Folin-Ciocalteu method 8. The phenolic concentration of extracts was evaluated from a gallic acid calibration curve using UV-VIS spectrophotometer (Specord 200 plus, Analytikjena, Germany). Total phenolic content was expressed as milligrams of gallic acid equivalent (GAE) per gm of extract. For measuring diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, 2ml of each extract and control at various concentrations (100, 50, 25, 12.5, 6.25, 3.125, 1.625, and 0.812 μg/ml) were added to 3 ml of freshly prepared DPPH solution (50 μm) in methanol 9. The reaction was allowed for 30 min and absorbance was measured at 515 nm using a spectrophotometer (Specord 200 plus, Analytikjena, Germany). The percentage inhibition of DPPH free radical scavenging activity was calculated using the following equation: % inhibition = [(A DPPH A sample )/A DPPH ] x 100 (Eq. 1) where, A DPPH = Absorbance of DPPH; A sample = Absorbance of sample (extract/ascorbic acid) For azinobisethylbenzothiazoline-6-sulphonic acid (ABTS) assay, stock solutions included 7.4mM ABTS solution and 2.6mM potassium persulfate solution 10. The working solution was then prepared by mixing the two stock solutions in equal quantities and allowing them to react for 12 hrs at room temperature in the dark. The solution was then diluted by mixing 1ml ABTS solution with 60ml methanol to obtain an absorbance of 1.1±.02 units at 734 nm using the spectrophotometer. Fresh ABTS solution was prepared for each assay. Seed extracts (150 ml) were allowed to react with 2850 ml of the ABTS solution for 2 hrs in a dark condition. Then the absorbance was taken at 734nm using the spectrophotometer (Specord 200 plus, Analytikjena, Germany). The standard curve was linear between 0.812 and 50 μg/ml of ascorbic acid. The percentage inhibition of ABTS free radical

316 INDIAN J TRADIT KNOWLE, VOL. 15, NO. 2, APRIL 2016 scavenging activity was calculated using the equation same as Eq. 1. Three numbers of replicates were used for the analyses of soil and seed samples. Means were compared using Duncan s multiple-range test (DMRT). Associations among traits were assessed using the Pearson correlation coefficient (r). Grouping of landraces based on mineral composition was performed by principal component analysis (PCA). Analysis of variance (ANOVA) was used to test difference in antioxidant activities of the landraces using total phenol, DPPH and ABTS radical scavenging assay. Statistical Application Software (SAS, Version 9.3) was used for all statistical analyses. Results and discussion Collection area of the common bean landraces was Lushai hills, which covered all the districts of Mizoram state of India with altitude ranging from 225 to 1328 meters above mean sea level. Fig. 1 (A) shows the variations in seed morphology of common bean landraces. Passport data of indigenous common bean landraces (Table 1) depicts that the landraces were collected in three batches, first during March-October 2008, second during March-April 2010 and third during September 2013. Statistical analysis showed that the landraces differed significantly (P<0.0001) in all macro and micro-minerals and also had considerable variation in ash content. Mean seed N content (Table 2) for all landraces was 0.56% with a 1.54-fold variation and maximum was found in MZFB-47 (5.40 %). P content (Table 2) varied 5.9 fold with a mean P content of 0.48% and maximum was found in MZFB-41 (0.71 %). K content was maximum in MZFB-83 (2.52%) and varied 2.5 fold with a mean K content of 1.84% (Table 2). Micro element content (Table 2) analysis showed that the mean Cu and Zn concentrations in the 23 landraces were 10.74 mg/kg and 56.61 mg/kg, while they varied 5.3 and 1.5 fold respectively. Maximum Cu and Zn content were found in landraces MZFB-116 (19.76 mg/kg) and MZFB-52 (67.18 mg/kg), respectively. The mean Mn and Fe concentrations of all the landraces were 15.60 mg/kg and 92.27 mg/kg, with a variation of 5.8 and 2.9 fold, respectively. Highest Mn and Fe Table 2 Nutrients (N, P, K, Cu, Zn, Mn and Fe) and ash content (%) of common bean landraces Genotypes N (%) P (%) K (%) Cu (mg/kg) Zn (mg/kg) Mn (mg/kg) Fe (mg/kg) Ash (%) MZFB-28 3.84 fgh 0.65 c 1.92 dfe 17.01 bac 65.21 ba 40.03 a 152.68 ba 17.36 jk MZFB-29 4.35 efcd 0.22 hi 1.75 gfe 18.37 ba 58.09 bdac 19.31 cde 59.90 ij 12.23 ml MZFB-32 3.97 efgh 0.61 d 2.20 bc 13.46 d 48.11 fh 15.00 fge 53.96 j 13.10 ml MZFB-41 4.03 efg 0.71 a 1.74 gfe 15.46 bdc 60.61 bac 15.02 fge 78.03 gifh 29.82 c MZFB-42 5.02 ba 0.67 bc 1.69 gf 4.96 hg 65.24 ba 17.51 fde 139.43 b 16.39 k MZFB-43 3.55 gh 0.30 f 2.02 dce 5.51 hg 64.27 ba 12.61 ifghj 94.86 dfce 21.37 g MZFB-45 4.75 bcd 0.58 d 1.92 dfe 6.96 fheg 54.53 fdecg 6.86 j 106.26 c 12.43 ml MZFB-47 5.40 a 0.26 g 0.98 i 5.46 hg 62.10 bac 13.77 ifghe 88.53 gdfce 11.73 m MZFB-48 3.96 efgh 0.58 d 1.74 gfe 9.21 e 57.15 fbdec 12.32 ifghj 88.00 gdfce 11.61 m MZFB-50 3.67 gh 0.19 i 1.92 dfe 5.81 fhg 65.14 ba 22.43 cd 94.47 dfce 13.29 l MZFB-51 5.13 ba 0.54 e 1.85 dgfe 14.31 dc 57.73 bdec 24.34 cb 93.16 dfce 16.87 k MZFB-52 5.13 ba 0.64 c 2.06 dc 4.66 hg 67.18 a 8.09 ij 61.08 ihj 27.54 d MZFB-53 4.42 ecd 0.68 ba 2.21 bc 6.16 fheg 57.10 fbdec 7.70 ij 79.33 gfh 31.81 b MZFB-80 4.23 ef 0.31 f 1.88 dgfe 7.86 feg 61.77 bac 14.90 fge 83.90 gfe 20.47 hg MZFB-82 4.99 ba 0.60 d 2.38 ba 17.01 bac 54.29 fdecg 8.46 ihj 103.60 dc 23.85 f MZFB-83 3.50 h 0.22 hi 2.52 h 13.71 dc 56.12 fbdecg 16.61 fgde 100.43 dce 33.72 a MZFB-85 5.35 a 0.12 j 1.85 dgfe 3.68 h 48.76 fheg 15.31 fge 79.70 gfh 33.98 a MZFB-97 4.31 efd 0.24 hg 2.24 bc 16.96 bac 59.912 bac 10.91 ighj 86.53 gdfe 19.86 hi MZFB-101 3.97 efgh 0.64 c 2.23 bc 9.46 e 50.52 fhde 12.26 ifghj 71.06 gihj 33.13 ba MZFB-116 4.82 bc 0.60 d 1.11 i 19.76 a 47.40 hg 28.44 b 159.93 a 25.35 e MZFB-119 3.70 gh 0.57 d 1.12 ih 8.86 fe 53.74 fdecg 14.43 fghe 75.78 gifh 19.38 hi MZFB-121 4.21 ef 0.60 d 1.63 g 18.11 ba 44.40 h 14.56 fghe 88.88 gdfce 18.43 ji MZFB-126 3.67 gh 0.59 d 1.36 h 4.26 h 42.76 h 7.96 ij 82.86 gfe 17.39 jk Within each nutrients, means followed by different letters are significantly different (P< 0.05; DMRT).

DUTTA et al.: NUTRIENTS AND ANTIOXIDANTS DIVERSITY OF COMMON BEAN OF LUSHAI HILLS 317 Table 3 Correlation coefficients between seed nutrients and ash content in a collection of 23 common bean landraces N P K Cu Zn Mn Fe Ash content N 1 0.25 0.25-0.33-0.03 0.12 0.47 0.19 P 1 0.33-0.63 0.10 0.51 0.23 0.99** K 1-0.79* 0.41 0.30 0.15 0.34 Cu 1-0.46-0.54-0.09-0.63* Zn 1 0.71* -0.11 0.12 Mn 1 0.20 0.52 Fe 1 0.42 Ash 1 P < 0.05, P < 0.01. Fig. 1-(A) Variations in seed morphology of some common bean landraces and (B) clustering of the common bean landraces in PCA biplot concentration were found in landraces MZFB-28 (40.03 mg/kg) and MZFB-116 (159.93 mg/kg), respectively. There was a 2.9 fold variation in ash content with maximum in MZFB-85 (33.98%) and the mean ash content was 20.92%. These results indicate the existence of a significant degree of genetic variability for Cu, N, P, K, Cu, Zn, Mn, Fe, and ash content. Until now, majority of common bean studies in India were restricted to genetic diversity analysis of bush type local and commercial genotypes 11. In the present study, for the first time the seed mineral content of this local North-East Indian pole type common bean landraces were analyzed. We have found significant genetic variation in the common bean landraces for macronutrients (N, P and K), micronutrients (Cu, Zn, Mn, and Fe) and ash content, which was in confirmation with the studies of Pinheiro et al. 2, who found a high degree of variability in seed P, Fe, Zn, Cu, Mn, Ca and protein content among Portugeese common bean germplasm. There are also reports of high variability in Fe and Zn concentration in Mesoamerican and Andean landraces 12. The mineral characteristics of the crop plants depend on genetic, environmental and geneticenvironment interaction factors. In the present study the plants were grown in soil mediums with uniform characteristics, so the variations within the genotypes were due to only genotypic effect. The genotypic variation in common bean landraces provides good opportunities for improvement of cultivated common bean. Also, genotypes with high micro-and macronutrient levels as discussed earlier might be suitable for studying mechanism of nutrient transport and accumulation in beans seeds. This information is potentially important for breeding programs, since some accessions have high values of N, P, K, Cu, Zn, Mn, Fe, and ash content. There is possibility of genetic erosion in this crop due to continuous biased selection of farmers towards the economic characters. Unconscious selection by local farmers could also have affected common bean diversity in mineral uptake. There is an urgent need of conservation of these genotypes. As a part of conservation effort, these genotypes have been mass multiplied at ICAR RC NEH Region, Mizoram Centre, Kolasib, Mizoram and deposited to National Bureau of Plant Genetic Resources (NBPGR), New Delhi for long time conservation. The correlation coefficients among the different mineral and ash contents in the 23 landraces (Table 3) indicated many significant positive (P < 0.01 and 0.05) and negative correlations, but the result with r-values greater than 0.4 are discussed here. Significant positive correlation were found in P-ash content (P < 0.01) and Zn-Mn content (P < 0.05).

318 INDIAN J TRADIT KNOWLE, VOL. 15, NO. 2, APRIL 2016 Contrastingly significant negative correlation was evidenced in K-Cu (P < 0.05) and Cu-ash content (P < 0.05). It is very interesting to note that beside Fe-Zn 6, P-Cu, P-protein and Ca-Mn 2, Zn-Ca, Zn-P 13 positive correlation previously reported in common bean, we found significantp-ash content and Zn-Mn positive correlation. Chatzav et al. 14 opined that correlation between grain concentrations of different mineral nutrients may indicate the existence of one or more common genetic physiological mechanisms involved in mineral absorption or uptake by the root system, translocation and redistribution within the plant tissues, remobilization to the grain and accumulation in the developing grain. The positive association of Zn with other minerals demonstrates that selection for high Zn concentration may indirectly select for higher levels of other macro-and micronutrients. Correlations between various nutrients can be caused by genetic linkage or pleiotropical effects. Thus, the correlation found in the study may be considered while breeding for grain fortification. PCA was used to assess the patterns of variation by taking all the nutrients variables together. Also, eigenvectors, eigenvalues, differences, proportions, and cumulative percentages of variation were explained by principal components (PC). The first four PCs accounted for 74% of the total variation (Table 4). PC1 accounted for 26% of total variation, and Mn, Fe and Zn had the highest positive coefficients. PC2 explained 21% of total variation, and Cu, K, Fe and P had the highest positive Table 4 Eigenvalues, differences, proportions and cumulative percentages of variation explained by the first four principal components (PC) of indigenous common bean landraces Eigenvectors Variables PC1 PC2 PC3 PC4 N -0.025-0.048 0.803-0.057 P 0.003 0.318 0.140-0.834 K -0.473 0.387 0.119 0.239 Cu 0.247 0.503-0.271 0.042 Zn 0.376-0.477 0.212 0.100 Mn 0.547 0.283-0.020 0.272 Fe 0.416 0.364 0.371 0.0901 Ash -0.313 0.225 0.251 0.384 Eigenvalue 12.14 21.69 31.12 40.98 Difference 0.45 0.56 0.14 - Proportion 0.26 0.21 0.14 0.12 Cumulative 0.26 0.48 0.62 0.74 coefficients. PCA biplot using PC1 and PC2 clustered the landraces into four groups as evident from Fig 1 (B). Similar correlations have been found between Zn and Ca 15 and between Zn and Fe 16. The amount of total phenol, DPPH and ABTS radical scavenging activity were significantly different among common bean landraces (Table 5). Total phenolic content was estimated by gallic acid (Fig. 2) and expressed as milligrams of gallic acid equivalent (GAE). All the landraces contained a considerable amount of phenolic contents from 14.54 ± 0.48 (MZFB-116) to 62.66 ± 1.31(MZFB-97) mg of GAE/g of extract, depicting 4.3 fold variations. The variation in total phenolic content among the landraces could be attributed to diversity of habitat and microclimatic conditions. Previous studies 17,18 showed that bean hulls contained large amounts of phenolic compounds, and their methanolic extract exhibited substantial antimutagenic activity against Salmonella typhimurium and aflatoxin B1. Our range of total phenol is completely in agreement with previously reported range of 2.2 to 78.2 mg of catechin equivalents per gram of sample 18. Also it is reported that cultivar had the main dominant effect for its major contribution to tannin content of 5 bean cultivars grown in Mexico 19. DPPH and ABTS radical scavenging based antioxidant potential of the landraces and standard ascorbic acid at 25 μg/ml concentration was evaluated using the parameter percent inhibition. Among all the land races, MZFB-97 (42.59 %) revealed the highest DPPH radical scavenging activity after standard ascorbic acid (52.10 %), while MZFB-116 (17.77 %) showed the lowest activity (Fig. 3). ABTS radical scavenging activity ranged from 29.98 % (MZFB-116) to 89.68 % (MZFB-97), while standard Table 5 ANOVA for total phenol, DPPH and ABTS antioxidant assays from 23 indigenous common bean landraces. Source df MS P Total Phenol Landraces 22 318.93 <0.01 Error 46 1.37 DPPH Landraces 22 152.39 <0.01 Error 46 1.49 ABTS Landraces 22 705.92 <0.01 Error 46 4.85 DPPH, diphenyl-2-picrylhydrazyl; ABTS, azinobisethylbenzothi azoline-6-sulphonic acid, P<0.01, significant at 1%.

DUTTA et al.: NUTRIENTS AND ANTIOXIDANTS DIVERSITY OF COMMON BEAN OF LUSHAI HILLS 319 Fig. 2 Total phenol content of 23 common bean landraces. Values expressed are mean ± standard deviation (n = 3). The total phenol contents are expressed as mg of gallic acid equivalent (GAE) per gm of seed extract. Fig. 3 Percent DPPH and ABTS radical inhibition of standard ascorbic acid (AA) and 23 common bean landraces at 25 μg/ml concentration.values expressed are mean ± standard deviation (n = 3) ascorbic acid revealed 98.05 % scavenging activity (Fig. 2). Different techniques have been used to evaluate the antioxidant activity from different bean cultivars. Cardador-Martinez et al. 18 studied the antioxidant potential of methanolic, acetone and ethyl acetate/acetone extracts from common beans by utilizing β-carotene-linoleate and 1, 1-diphenyl-2- picrylhydrazyl (DPPH) in vitro method system and observed antioxidant activity to be correlated with polyphenolic content in a dose dependant manner. The differences in antiradical activities of bean cultivars may be due to the presence and composition of procyanidins, since they are expected to have radical scavenging activity. Conclusion We documented a considerable genetic variation in the seed macro and micro-nutrients content with high antioxidant activity among the common beans landraces of Lushai hills of India. As there has been no record of nutrients diversity of these landraces, this information can be used for breeding new common bean cultivars with high mineral content. Genetic markers associated with specific nutrients may be identified and further studies are needed to establish the quantitative trait loci (QTL) for nutrients accumulation in the seeds. Most importantly efforts should be strengthened for ex-situ conservation of this landraces.

320 INDIAN J TRADIT KNOWLE, VOL. 15, NO. 2, APRIL 2016 Acknowledgement This research was supported financially by Indian Council of Agriculture Research (ICAR), New Delhi, India. The authors acknowledge Dr. S.V. Ngachan, Director, ICAR RC NEH Region, Meghalaya for his technical assistance and providing necessary facilities. References 1 Broughton WJ, Hernandez G, Blair M, Beebe S, Gepts P & Vanderleyden J, Beans (Phaseolus spp.) model food legumes, Plant Soil, 252 (2003) 55 128. 2 Pinheiro C, Baeta JP, Pereira AM, Domingues H & Ricardo CP, Diversity of seed mineral composition of Phaseolus vulgaris L. germplasm, J Food Comp Anal, 23(4) (2010) 319-325. 3 Cardador-Martinez A, Castano-Tostado E & Loarca-Pina G, Antimutagenic activity of natural phenolic compounds present in the common bean (Phaseolus Vulgaris) against aflatoxin B1, Food Addit Contam, 19 (2002) 62-69. 4 Lalramnghinglova H, Ethno-medicinal plants of Mizoram, (Bishen Singh Mahendra Pal Singh, Dehra Dun, India), 2003. 5 Dutta SK, Singh AR, Boopathi T, Singh SB, Lungmuana, Malsawmzuali, Dubey S, Singh MC & Ngachan SV, Seeds of pole-type Frenchbean landraces, ICAR News, 19(4) (2013) 20. 6 Welch RM & Graham RD, Breeding for micronutrients in staple food crops from a human nutrition perspective, J Experi Bot, 55 (2004) 353-364. 7 Tandon, H.L.S. (Ed.), Methods of Analysis of Soils, Plants, Waters, Fertilisers and Organic Manures. 2nd edn. Fertiliser Development and Consultation Organisation, New Delhi, India, 2009, 204+xii. 8 Shahat AA, Ibrahim AY & Alsaid MS, Antioxidant capacity and polyphenolic content of seven Saudi Arabian medicinal herbs traditionally used in Saudi Arabia, Indian J Tradit Knowle, 1(1) (2015) 28-35. 9 Susanti D, Sirat HM, Ahmad F, Ali RM & Aimi N, Antioxidant and cytotoxic flavonoids from the flowers of Melastoma malabathricum L., Food Chem, 103 (2007) 710 716. 10 Arnao MB, Cano A & Acosta M, The hydrophilic and lipophilic contribution to total antioxidant activity, Food Chem, 73 (2001) 239 244. 11 Razvi SM, Khan MN, Bhat MA, Ahmad M, Khan MH, Ganie SA & Paddar BA, Genetic diversity studies in common bean (Phaseolus vulgaris L.) using molecular markers, Afr J Biotechnol, 12(51) (2013) 7031-7037. 12 Moraghan JT, Padilla J, Etchevers JD, Grafton K & Acosta-Gallegos JA, Iron accumulation in seed of common bean, Plant Soil, 246, (2002) 175 183. 13 Gelin JR, Forster S, Grafton SK, McClean PE & Rojas-Cifuentes GA, Analysis of seed zinc and other minerals in a recombinant inbred population of navy bean (Phaseolus vulgaris L.), Crop Sci, 47 (2007) 1361-1366. 14 Chatzav M, Peleg Z, Ozturk L, Yazici A, Fahima T, Cakmak I & Saranga Y, Genetic diversity for grain nutrients in wild emmer wheat: potential for wheat improvement, Ann Bot, 105 (2010) 1211 1220. 15 Guzmán-Maldonado SH, Martínez O, Acosta JA, Guevara-Lara F & Paredes-López, O, Putative quantitative trait loci for physical and chemical components of common bean, Crop Sci, 43 (2003) 1029-1035. 16 Pfeiffer WH & McClafferty B, HarvestPlus: Breeding crops for better nutrition, Crop Sci, 47 (2007) 88-105. 17 Gonzalez de Mejıa E, Castano-Tostado E & Loarca-Pina G, Antimutagenic effects of natural phenolic compounds in beans, Mutat Res Genet Toxicol Enviro Mutagen, 44(1b) (1999) 1-9. 18 Cardador-Martinez A, Loarca-Pina G & Oomah BD, Antioxidant Activity in Common Beans (Phaseolus vulgaris L.), J Agric Food Chem, 50 (2002) 6975-6980. 19 De Mejia EG, Guzman-Maldonado SH, Acosta-Gallegos JA, Reynoso-Camacho R, Ramirez-Rodriguez E, Pons- Hernandez JL, Gonzalez-Chavira MM, Castellanos JZ & Kelly JD, Effect of cultivar and growing location on the trypsin inhibitors, tannins, and lectins of common beans (Phaseolus vulgaris L.) growth in the semiarid highlands of Mexico, J Agric Food Chem, 51 (2003) 5962 5966.