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Authors: Zargar, Mohd Amin
Advisor: Tak, G M
Title: Genetic analysis of yield and yield components in sesame (Sesamum indicum L.)
Publisher: SKUAST Kashmir
Language: en
Type: Thesis
Agrotags: Plant Breeding & genetics
Sesamum indicum
Genetic analysis
Keywords: Sesamum indicum, Genetic analysis
Abstract: Sesame (Sesamum indicum L.) was one of the important kharif crops of small/ marginal farmers of Kashmir before the cultivation of temperate fruit plants got a boon in the Kashmir valley. Vast areas of rainfed Karewa lands have been brought under cultivation of these fruit crops. This shift in the cropping systems from the traditional low input and low value crops to high input and high value crops like apple resulted in the erosion of genetic variability of adapted local sesame cultivars, and some of elite genotypes have been lost. Some area under small/ marginal category still exists in this rainfed ecosystem of Kashmir valley that has the potential to grow a crop like sesame instead of maize and other crops that are badly affected by the moisture stress during the critical crop growth stages. With this background into consideration the present investigation was taken into hand and so as to identify some of the high yielding and early maturing lines of sesame which could be used per se improving the local adapted germplasm through introgression or generating useful recombinants through hybridization. In the present study twelve diverse parents were used to generate 66 F1’s in a half diallel fashion. The parents + F1's were evaluated in RBD at two different locations during Kharif 1998. Observations were recorded for various maturity, morphological and yield component traits. Significant variation was observed for all the traits which was also reflected in high genotypic coefficient of variation for seed yield/ plant, capsules/ plant, capsule bearing nodes and branches/plant. Significant contribution from G x E variance was observed in days to flowering and maturity and seeds/ capsule. Significant G x E Interaction was observed for most of the traits. Interrelationship measured in terms of correlation at genotypic level in the non-segregating generations revealed that seed yield was positively and significantly correlated with capsule bearing nodes and capsules/ plant whereas, length of capsules indicated significant and negative correlation. The variance due to sca were higher in magnitude than the corresponding gca variances resulting in very high values of σ2s than σ2g, which when translated into genetic components of variance revealed that variance due to dominance deviation ¬(σ2D) was more important than additive genetic variance (σ2A) in controlling the inheritance of these traits. The average degree of dominance was in range of over- dominance for almost all the traits. Less than unity value of 2σ2g/ 2 σ2g + σ2s indicated that performance of a particular single cross can not be predicted on the basis of the general combining ability of parents alone. None of the parents could be Identified to possess good combining ability for all the attributes however, the parents ES-49, TC-25, SI-242-2, RT-54, RT-157, RT-214 and TC-328 were found to possess good attributes for most of the traits. Based on the results of specific combining ability the crosses for early maturity were ES-4-5 x RT-54, ES-72-1x ES-4-5 and ES-49 x ES-127, for seed yield/plant ES-72-1 x SI-242-2, ES-49 x TC-25, RT-157 x TC-328, SI-153 x ES-127 and SI-153 x TC-328 and for oil content RT-54 x ES-127, RT-214 x RT-157 and TC-25 x RT-54. Component analysis revealed that both the components of dominance deviations (H1 and H2) were higher in magnitude than the additive genetic component (D), with proportion of positive alleles contributing to dominance to be more than the negative alleles. h2 (net dominance) estimates were less than H1, or H2 for most of the traits indicating unidirectional dominance and presence of correlated gene distribution which was also confirmed from the value of H2/4H1, that confirmed asymmetrical gene distribution. The value of KD/ KR was more than one in most of the cases indicating presence of excess of dominant genes than the recessive genes. The regression value 'b' significantly deviated from unity confirming presence of epistasis which when considered alongwith h2/H2 confirmed that the epistasis was having significant contribution from complementary and/ or duplicate gene action. Average degree of dominance was in the range of over dominance which confirmed the estimates obtained from combining ability analysis and graphical analysis in most of the cases. Significant t2 values in some cases indicated that some of the assumptions for diallel analysis were not fulfilled. For a meaningful breeding methodology diallel selective mating system would be ideal in the present materials which would slow down the process of homozygosity and present ample chances for recombination of some good lines from the release of latent genetic variability hidden in the heterozygous polygenic blocks
Description: PhD Thesis submitted to SKUAST Kashmir
Subject: Genetics and Plant Breeding
Theme: Genetic analysis of yield and yield components in sesame (Sesamum indicum L.)
These Type: Ph.D
Issue Date: 2000
Appears in Collections:Thesis

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