ASSESSING THE GENETIC VARIATION OF INDIAN WHEAT CULTIVARS BY BIOCHEMICAL AND MOLECULAR MARKERS
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Date
2013
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MPUAT, Udaipur
Abstract
The present study was carried out with 20 genotypes of Triticum sp. to characterize them through molecular and biochemical markers for assessment of genetic diversity.
In microsatellite analysis 10 primers linked with different biotic and abiotic stress resistant genes produced 56 bands, in which 44 were polymorphic and average polymorphism was 78.57%. Different attributes of diversity analysis were calculated and found that Primer Xgwm312, barc108 and Xwmc170 possess high Nei’s index, Shannon index as well as high PIC value and discrimination index could be useful for diversity study. The Jaccard’s similarity coefficient values lies from 0.3864 to 0.8621.
In seed storage protein profiling 32 bands were obtained from them 24 were polymorphic with 75% polymorphism. The size of Polypeptides resolved ranged from 6.5KDa to 129.0KDa. Polypeptides having molecular weight 119.85KDa, 52.0KDa, 45.3KDa, 34KDa (absent in Raj3765), 61.4KDa (absent in Raj3765 and Raj1482) were found only in T. aestivum whereas, polypeptide of 56.8KDa, 54.5KDa, 47.6KDa, 39.8KDa, 36.2KDa and 22.14KDa weight were found only in T. durum. Further analysis of result revealed that polypeptide having molecular weight 129KDa, 96KDa and 77.6KDa were unique for four T. durum varieties viz., HI8498, MACS1967, PDW274, Raj6496 and MACS9 whereas, polypeptide having 106KDa molecular weight were found only in two varieties of T. aestivum named HD2684 and Raj1972. Results exhibits the importance of protein profiling in diversity studies. The Jaccard’s similarity coefficient values between different genotypes ranged from 0.3214 to 1.000.
Isozyme extracted from young plants were used to produce zymograms based on Rm value for three enzyme systems viz. esterase, peroxidase and α- amylase. A total of 15 putative isozyme alleles were generated from these systems. Wherein, both esterase and peroxidase had 6 alleles and α- amylase had 3 alleles. Among these three enzymes system only peroxidase exhibited 100% polymorphism. The difference was also observed in terms of intensity and size of bands and esterase and peroxidase showed high intensity bands in Triticum aestivum. Consequently, population diversity analyses showed that peroxidase with highest diversity index were found useful for discriminating the genotypes. The similarity indices between different genotypes ranged from 0.3571 to 1.000.
Different marker systems viz. microsatellite, seed storage protein profiling and isozyme analysis showed that variation was mainly distributed among the genotypes rather than within genotypes and explaining the low value of estimate of gene flow. Based on dendrogram analysis, all genotypes mainly divided into two clusters according to their ploidy levels and found that Triticum aestivum are more diverse than Triticum durum.
Combined cluster analysis revealed that clustering between durum and aestivum genotypes was found similar with that of all three marker systems. Genotypes viz., HD2684, Raj1972, PBW502, WH896 and HI8498 were found diverse from other varieties of their ploidy group and could be efficiently used for future crop improvement programmes.
Critical analysis of genetic diversity based on biochemical and molecular analysis it revealed that microsatellite based marker system exhibit considerably high genetic diversity and proved better as compared to isozyme and seed protein analysis in fingerprinting of Triticum sp. genotypes and can be precisely used in overcoming the environmental factors as evident from the value so obtained in terms of variability.
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Studies on the Assessing the genetic variation of Indian wheat cultivars by biochemical and molecular markers
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Citation
Chandra and Sharma, 2013