The Journal of Research ANGRAU
Contents of 41(1) 2013 - acharya ng ranga agricultural university
Contents of 41(1) 2013 - acharya ng ranga agricultural university
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<strong>Research</strong> Notes<br />
J.Res. <strong>ANGRAU</strong> 41(1) 109-113, 2013<br />
GENETIC DIVERGENCE STUDIES FOR YIELD AND PHYSIOLOGICAL<br />
ATTRIBUTES IN GROUNDNUT (Arachis hypogaea L.)<br />
D. NIRMALA, V. JAYALAKSHMI, B. NARENDRA and P. UMAMAHESHWARI<br />
Deptartment <strong>of</strong> Genetic & Plant Breeding, Agricultural College, <strong>ANGRAU</strong>, Mahanandi – 518 503<br />
Date <strong>of</strong> Receipt : 07.06.2012 Date <strong>of</strong> Acceptance : 26.12.2012<br />
Selection <strong>of</strong> genotypes from the available<br />
genetic variation is crucial for any crop improvement<br />
programme. Estimating genetic diversity available in<br />
the existing germplasm provides clue to the choice<br />
<strong>of</strong> most desirable parents for use in hybridization<br />
programmes. Selections based on physiological traits<br />
that confer water use efficiency have been suggested<br />
for improving drought tolerance in Groundnut. In the<br />
present investigation an attempt was made to identify<br />
most diverse groundnut genotypes for practical plant<br />
breeding programmes utilizing physiological traits like<br />
SPAD Chlorophyll Metre Reading (SCMR), specific<br />
leaf area, crop growth rate (CGR), relative growth rate<br />
(RGR) etc.<br />
Thirty genotypes <strong>of</strong> Groundnut were<br />
evaluated during Kharif 2011 at Agricutural College<br />
Mahanandi, A.P. <strong>The</strong> experimental material was<br />
procured from the Groundnut Breeding Station,<br />
RARS, Tirupati comprising <strong>of</strong> diverse breeding<br />
material generated in All India Coordinated Groundnut<br />
Improvement Programme. <strong>The</strong> experiment was laid<br />
out in a Randomized Block Design replicated thrice.<br />
Each genotype in a replication was grown in two rows<br />
<strong>of</strong> 4.2 m length with a spacing <strong>of</strong> 30 cm between the<br />
rows and 10 cm within a row. All the recommended<br />
package <strong>of</strong> practices were followed to raise a good<br />
crop. Observations were recorded on five randomly<br />
chosen plants in each genotype in a replication for<br />
19 characters. <strong>The</strong> data collected was analyzed as<br />
per the standard procedures described by<br />
Mahalanobis’s (1936) and Rao (1952).<br />
Analysis <strong>of</strong> variance for both quantitative and<br />
physiological traits in all the 30 genotypes under study<br />
revealed significant differences for all the characters<br />
indicating the wealth <strong>of</strong> variability available in the<br />
germplasm. Further the data was subjected to D 2<br />
analysis and the results were presented in<br />
Table 1 to 3.<br />
Based on D 2 analysis all the 30 genotypes<br />
were grouped into 14 clusters with a variable number<br />
<strong>of</strong> entries in each cluster revealing the presence <strong>of</strong> a<br />
considerable amount <strong>of</strong> genetic diversity in the<br />
material (Table 2). Cluster I had maximum number<br />
<strong>of</strong> 10 genotypes followed by cluster II with 6<br />
genotypes and cluster X with 3 genotypes. Remaining<br />
all other clusters possessed one genotype each.<br />
Cluster I alone had one-third <strong>of</strong> the total genotypes<br />
studied indicating that the genotypes under study had<br />
narrow genetic diversity among them. Similarity in<br />
the base population from which they have been<br />
evolved might be the cause <strong>of</strong> genetic uniformity.<br />
However, the uni-directional selection potential for<br />
one particular character or a group <strong>of</strong> linked traits in<br />
several places may produce similar phenotypes which<br />
can be aggregated into one cluster irrespective <strong>of</strong><br />
geographical diversity. Sudhir Kumar et al (2010),<br />
Awatade (2007) and Garajappa et al. (2005) reported<br />
that there is no correlation between genetic diversity<br />
and geographical diversity in the groundnut genotypes<br />
studied by them.<br />
Average inter cluster and intra cluster D 2<br />
values among the 30 genotypes were furnished in<br />
Table 2. <strong>The</strong> maximum intra cluster distance was<br />
recorded for cluster X (6.31) followed by cluster II<br />
(5.13) and cluster I (4.95) revealing substantial<br />
diversity within the clusters. Maximum inter-cluster<br />
values were observed between cluster III and cluster<br />
XII (12.35) followed by cluster V and cluster XIII<br />
(12.10) indicating maximum divergence between the<br />
genotypes included in these clusters.<br />
Cluster means for all the traits were given in<br />
Table 2. Cluster means for different characters<br />
indicated that none <strong>of</strong> the clusters contained genotype<br />
with all the desirable characters and so recombinant<br />
breeding between genotypes <strong>of</strong> different clusters is<br />
needed. Cluster XII showed higher cluster means for<br />
email: veera.jayalakshmi@gmail.com<br />
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