genetic divergence and association studies in field

Crop Improvement 34 (2) : 179-82 (2007)

GENETIC D I V E R G E N C E A N D ASSOCIATION STUDIES IN FIELD PEA (PISUM SATIVUM L.) INDERJIT SINGH, PRITPAL SINGH AND J.S. SANDHU Department of Plant Breeding, Genetics & Biotechnology Punjanb Agricultural University, Ludhiana-141 004 ABSTRACT One hundred twenty genotypes were evaluated for 10 characters to study genetic diversity and association between yield and its components. The study indicated presence of considerable genetic divergence among the genotypes. The genotypes were grouped into six clusters. To get the desirable segregants the hybridization among the genotypes of cluster III and VI, cluster V and VI and cluster I and VI as the inter cluster distance was greater between these clusters. Association studies indicated that pods per plant, clusters per plant, seeds per pod and days to 50% flowering were significantly correlated with grain yield. Pods per plant, 100-seed weight, seeds per pod and days to maturity had positive direct effect on grain yield, while plant height, pods per cluster and pod length had negative direct effect on grain yield.

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Index Words : Field pea, genetic divergence, correlation, path analysis

Field pea is a cool season crop grown for food, feed and vegetable. It is a high protein (20%) crop having all the essential amino acids and phosphorus important for normal activity of living organisms. It is also considered an efficient biological nitrogen fixing crop. In India, it occupied 0.79 m ha during 2004-05 (Anonymous, 2006). Productivity-wise it ranks first (993 kg/ha) among all the pulses grown in the country. Plant breeders have mainly concentrated on three characters viz. tendrils, dwarf plant type and powdery mildew resistance in field pea. Besides these, characters like thick stem, early maturity, bold and green seed and off course the seed yield are also important. Genetic variation provides an opportunity for i m p r o v e m e n t of a u t o g a m o u s crop plants through hybridization and heterosis is known to depend on the extent of genetic diversity between the parents. Selection of parents with desirable characters for utilization in hybridization programme is very important. Keeping this in mind, an effort was made to evaluate 120 diverse germplasm lines for different characters of economic importance to study genetic diversity among them and to study association among different traits. MATERIAL AND METHODS The experimental material consisted of 120 diverse germplasm lines. The material was grown in augmented

design during Rabi 2005-06 at the Punjab Agricultural University, Ludhiana. Each line was sown in a single row plot of 4 m length with inter and intra row spacings of 30 and 10 cm, respectively. Recommended package of practices were followed to raise healthy crop. Data were recorded on five raise healthy crop. Data were recorded on five randomly selected plants for each genotype for days to 50% flowering, days to maturity, plant height (cm), clusters per plant, pods per cluster, pods per plant, pod length (cm), seeds per pod, seed yield per plant (g) and 100-seed weight (g). Estimates of error mean squares and adjusted mean values of all the traits were worked out as per Federer and Raghavarao (1975). Adjusted mean values were used for principal component analysis to transfer the inter-dependent variables into a set of independent variables (Mardia, 1971). Different clusters were generated through a non-hierarchical method of cluster analysis through SPAR 1 (Beale, 1969; Spark, 1973). The correlation coefficients as per method devised by Pearson and Lee (1902-03) and path analysis was carried out as per procedure given by Dewey and Lu (1959). RESULTS AND DISCUSSION Genetic Diversity: The 120 germplasm lines were grouped into six clusters (Table 1). Cluster I had 33

[Vol. 34 No. 2

Inderjit Singh et al.

180

Table 1. Distribution of field pea genoypes in different clusters. Cluster No. of Genotypes genotypes LFP 28,29,33,331,334,335,336,338,351,353,360,361,368,369,370 and LEP 418, IM 92019-19. KPMR 522. HFP 9405, HFP 9506, KPMR 5 9 1 , DDR 7, DDR 49, Pant P 17, DDR 40, DDR 44, DDR 65, EC 383137. EC 5 0 7 7 7 1 , IC 267161 and IC 29667. LFP 5, LFP 24.LFP 42, 332,345,346,347,348,354,356,357,358,359, LFP 368, KPMR 526, HUDP 20, IM 9214, DDR 50, KPMR 593, P 9-40,IPED 205, EC 356344, EC 414483 and IC 310833.

33

II

24

III

22

IV

7

v

25

DDR 41,DDR 42, HBP 1, Rachna, DM R 7, HFP 9232, DMR 38, DMR 39, HFP 8923, HFP 9519, RAU 3-12, KPMR 5 5 1 , IFP 98-9, KPMR 557, LFP 40, LFP 4 1 , EC 502159, EC 334160, EC 356322, IC 381777 and IC 342734. LFP 43,44,341,343,355, IPM 98-7 and EC 389374 DDR 53, KPMR 389, DDR 66, HUDP 25, HFP 89-10, IFPD 206, LFP 412, 413, 414, 415, 416, 417, 419, 420, 421,423,424,425, EC 337188, EC 385246,EC 396745, EC 384890, IC 279013 and LFP 370 A.

VI

LFP 45, 337, 339, 340, 344, 349, 350, LFP 352 and IFP 98-19.

Table 2. lntra(digonal in bold) and inter cluster distances of various clusters in field pea IV II III Cluster I




I II III . IV V VI

2.133

2.99 2.63 3.71 2.03

2.86 3.52 2.15

2.89 2.03

V

VI

2.85 3.06 3.17 3.80 2.22

4.37 3.20 5.70 3.57 5.13 1.94

Table 3. Mean values of clusters for different characters in field pea Cluster/Character

Days to 5 0 % flowering Days to maturity Plant height (cm) No. of clusters per plant No. of pods per cluster Pod length (cm) Pods per plant Seeds per pod Yield per plant (g) 100-seed weight (g)

I

II

III

IV

V

VI

Average

S.E.

C.V.

81.10

83.39

76.06

84.93

73.48

82.39

80.23

1.83

5.59

141.80 72.49 8.86

142.95 81.44 10.61

132.27 157.51 7.14

142.56 72.90 14.35

137.76 70.05 8.07

142.43 74.13 19.24

139.96 88.09 11.38

1.72 13.97 1.88

3.02 38.86 40.56

1.69

1.55

1.58

1.43

1.57

1.78

1.60

0.05

7.56

6.17 15.11 3.51 9.44 16.91

6.23 19.80 3.54 17.44 19.39

5.47 11.98 2.76 8.46 18.40

5.30 23.70 2.45 12.09 17.14

7.54 14.82 2.72 11.31 23.74

6.08 35.39 3.47 21.03 18.88

6.13 20.13 3.08 13.30 19.08

0.32 3.49 0.20 2.01 1.01

12.80 42.47 15.78 36.94 12.01

genotypes, cluster II had 24, cluster III had 22, cluster IV

I and VI. Cluster III includes early flowering and early

had 7, cluster V had 25 and cluster VI had 9 genotypes.

maturing genotypes, while cluster VI includes late

The pattern of distribution of genotypes from different

flowering and late maturing genotypes. Similary, cluster

ecogeographical regions into six clusters was at random

VI had genotypes with higher number of pods per plant,

indicating that geographical diversity and genetic diversity

yield per plant, pods per cluster and cluster per plant,

were not related. Similar results were also reported by

while cluster III had early flowering and early maturing

Dobhal and Ram (1985), Saxena etal. (1985) in pea and

tall genotypes. Cluster V had genotypes with early

Rathi etal. (1998) in lentil.

flowering and higher 100-seed weight. Thus, for obtaining

The maximum inter-cluster distance (5.70) was found

desirable segregants the crosses between genotypes of

between cluster III and cluster VI (Table 2) followed by

cluster III and VI, cluster V and VI and cluster I and VI

5.13 between cluster V and VI and 4.37 between cluster

will be effective. The genotypes LFP 337, LFP 349, IFP




Dec. 2007]

181

Genetic divergence in field pea

98-1 and LFP 45 were found promising for clusters per

Association Studies : The correlation coefficients

plant, pods per plant and grain yield per plant in cluster

among the characters are presented in Table 4. Grain

VI (Table 3). The genotypes KPMR 557 and Rachna were

yield per plant was found positively and significantly

found promising for 100-seed weight in cluster III, In

correlated with pods per plant, clusters per plant, seeds

cluster V, genotypes DDR 66, HFP89-16, LFP 415, LKFP

per pod and days to 5 0 % flowering. Positive association

416, LFP 419, LFP 420, LFP 4 2 1 , LFP 422 AND IC

between yield and pods per plant was also reported earlier

279013 were found promising for 100-seed weight. Thus,

by Tyagi and Shrivastava (2002), Sharma et al. (2003)

hybridization involving these genotypes that belong to

and Patel etal. (2006). Plant height was negatively and

different clusters is expected to give desirable segregants.

significantly correlated with grain yield per plant and other

The measures of coefficients of variation (Table 3)

traits except days to 5 0 % flowering and pods per cluster.

indicated that pods per plant, clusters per plant, plant

Days to 50% flowering was positively and significantly

height and seed yield per plant had greater contribution

correlated with pods per plant, seeds per pod and clusters

towards genetic divergence, where as seeds per pod,

per plant and negatively correlated with pod length.

100-seed weight, pods length, pods per cluster, days to

Number of clusters per plant had significant positive

flowering and days to maturity had low contribution

association with pods per plant. Pods per plant was

towards genetic divergence.

positively correlated with seeds per pod. The 100-seed

Table 4. Phenotypic correlation coefficients a m o n g different yield components in field pea Character

Days to maturity

Plant hight

No.fo clusters per plant

No.of pods per cluster

Pod length

Pods per plant

Seeds per pod

Yield per plant

100-seed weight

Days to 5 0 % flowering Days to maturity Plant height (cm) No. of clusters per plant No. of pods per cluster Pod length (cm) Pods per plant Seeds per pod Yield per plant (g)

0.378*

-0.109 -0.271*

0.309* -0.060 -0.204*

-0.049 0.059 -0.074 -0.099

-0.212* 0.134 -0.230* -0.153 -0.056

0.310* 0.015 -0.201* 0.890* 0.145 -0.114

0.285* 0.154 -0.207* 0.171 0.125 0.003 0.190*

0.233* 0.124 -0.228* 0.496* 0.029 -0.071 0.601* 0.203*

-0.094 -0.033 -0.002 -0.144 0.022 0.326* -0.047 -0.219* 0.145

Seeds per pod

100-seed weight

'Significant at P=0.05

Table 5. Direct (blod) and indirect path effects towards seed yield in field pea Character

Days to 5 0 % flowering Days to maturity Plant height (cm) No. of clusters per plant No. of pods per cluster Pod length (cm) Pods per plant Seeds per pod 100-seed weight

Days to 50% flowering

Plant hight

-0.048

0.043

0.011

-0.026

0.005

0.030

0.203

0.039

-0.023

0.233*

-0.018 0.005 -0.015

0.112 -0.030 -0.007

0.027 -0.100 0.020

0.005 0.017 -0.085

-0.006 0.008 -0.010

-0.019 0.033 0.022

0.010 -0.131 0.582

0.021 -0.028 0.023

-0.023 -0.000 -0.035

0.124 -0.228* 0.496*

0.002

0.007

0.007

-0.008

-0.104

0.008

0.095

0.017

0.005

0.029

0.010 -0.015 -0.014 0.005

0.015 0.002 0.017 -0.004

0.023 0.020 0.021 0.000

0.013 -0.075 -0.015 0.012

0.006 -0.015 -0.013 -0.002

-0.142 0.016 -0.000 -0.046

-0.074 0.654 0.124 -0.031

0.000 0.026 0.136 -0.030

0.078 -0.011 -0.053 0.240

-0.071 0.601* 0.203* 0.145

Residual effect= 0.5538, *Significant at P=0.05

No.fo clusters per plant

No.of pods per cluster

Pod length

Pods per plant

Correlation with seed yield

Days to maturity

182

Inderjit Singh et al.

weight was positively and significantly correlated with pod length but its association with seeds per pod was

reason of positive correlation of these characters with grain yield. Seeds per pod also had positive indirect effect

Path coefficient analysis provided information about

through pods per plant. So selection of these characters

direct and indirect contributions of yield components

will also help to improve yield indirectly. Plant height, pods

towards grain yield (Table 5). The pods per plant (0.654)

per cluster and pod length exerted negative direct effect

showed highest direct effect towards yield followed by

on yield indicating that direct selection of these characters

100-seed weight (0.240), seeds per pod (0.136) and days

may not be useful. Negative direct effect of plant height

to maturity (0.112). Positive direct effect of pods per plant

and pods per cluster was also reported by Patel et al.

and 100-seed weight was also reported earlier by Singh

(2006). Path analysis revealed that pods per plant, 100-

etal. (2002), Tiwari etal. (2001) and Patel etal. (2006.

seed weight, seeds per pod, clusters per plant and days

Days to flowering and clusters per plant although had

to 5 0 % flowering should be given more emphasis in

negative direct effect but they had indirect positive effect

selection programme.

Anonymous. (2006). Annual report of All India Coordinated Research Project on MULLaRP, IIPR, Kanpur. lh


Beale, E.M.L.H. (1969). Euclidean cluster analysis. 37 Session of the International Statistical Institute, U.K.


on grain yield through pods per plant which was the main

significantly negative.

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[Vol. 34 No. 2

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