STUDIES ON CHARACTERIZATION AND EVALUATION OF FRENCH BEAN (Phaseolus vulgaris L.) GERMPLASM OF HIMACHAL PRADESH
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Date
2017
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UHF,NAUNI
Abstract
ABSTRACT
Knowledge of genetic diversity is important for selection of parents in the crop improvement
programmes and to develop a sustainable conservation strategy. The present investigation entitled “Studies on
characterization and evaluation of French bean (Phaseolus vulgaris l.) germplasm of Himachal Pradesh” was
conducted in the years 2014, 2015 and 2016 to decipher the French bean diversity of Himachal Pradesh through
varietal characterization and also aimed to evaluate the performance of different French bean genotypes for seed
yield and other agronomical attributes. In total 26 geographically diverse French bean genotypes collected from
different agro-climatic zones of Himachal Pradesh and two check varieties viz., Baspa and Jawala were utilized in
the study. The genotypes were subjected to preliminary seed morphometric characterization in the Laboratory and
field evaluation in the Experimental farm using qualitative and quantitative traits. Analysis of seed morphometric
traits revealed ample amount of variability with respect to seed coat colour, seed shape, 100 seed weight, seed
length and seed width. The field experiment was laid out in Randomized Complete Block Design with three
replications for studying the extent of variability and performance of each genotype. Observations were recorded
on eleven qualitative and fifteen quantitative traits. Amongst the qualitative traits, French bean genotypes observed
variability w.r.t. plant growth habit, stem pigmentation, hairiness on the stem, flower colour, pod colour at
immature stage and pod shape. Analysis of variance for quantitative traits showed significant differences among all
the genotypes for all the characters studied. The genotypes RL-19 and RL-20 gave higher seed yield and performed
better for many of the horticultural traits over all the checks. The genotypic variance was low to high for different
traits studied, which resulted in low to high heritability and genetic gain values. High heritability coupled with high
genetic gain was observed for plant height at final harvest, number of branches per plant, number of pods per plant,
100 seed weight and seed yield /plant which suggests their improvement through simple selection method.
Correlation analysis revealed that all the traits except pod width had significant positive correlation with seed yield
per plant at both phenotypic and genotypic level. Further, path coefficient analysis indicated that pod length had the
highest positive direct effect on seed yield/plant followed by number of seeds per pod, number of pods per plant,
days to 50% flowering, number of branches per plant, leaflet width, harvest duration, plant height at final harvest
and 100 seed weight. Therefore, main emphasis should be given on these characters, while making selection in
French bean genotypes. D2 Mahalanobis analysis divided the genotypes into three clusters and revealed that the
cluster I and II were most divergent and there will be more chances of getting better segregants in F2 and
subsequent generations from the crossing of genotypes from cluster I and II. Thus, hybridization between the
genotypes of these groups can be very effective for further improvement in French bean. Moreover, 15 RAPD
primers were used for deducing the diversity at DNA level. The French bean genotypes produced 79 PCR
fragments, of which 59 were polymorphic with an average of 3.93 polymorphic bands per primer. The level of
polymorphism with different primers ranged between 42.86-100%. The average Jaccard similarity index among
genotypes ranged from 0.48 to 0.98, thereby showing sufficient genetic variability. Dendrogram generated via
RAPD information separated majority of the genotypes in two sub clusters (Ia and Ib) sharing approximately 68%
similarity between each other. Further, genotype RL-21 followed by RL- 18, RL-17 and RL-22 came as an outliner
falling individually in distinct indexing pattern. Geographical affiliations and morphological associations were
observed while studying the genotypic patterns within each group i.e. A, B, C and D, thereby conforming the
usefulness of PCR based approach in diversity assessment. Thus, the present study indicated that the collected
landraces had sufficient variability both at morphological and molecular level. Such variability is desirable in
breeding programs.
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