Microsatellite markers based characterization of rice genotypes in relation to drought tolerance
Loading...
Date
2017
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Dr. Rajendra Prasad Central Agricultural University, Pusa (Samastipur)
Abstract
Eighteen genotypes of rice were evaluated for various physio-morphological characters and to investigate the microsatellite markers based polymorphism for their characterization and differentiation using polymorphic and informative markers in order to estimate the extent of genetic diversity among these rice genotypes.Experimental materials were evaluated in randomized block design with three replications during three consecutive years. Molecular characterization was done by targeted amplification of the genomic DNA using a panel of thirty two microsatellite primer pairs covering nine chromosomes. Statistical methods and parameters used for deriving inference were analysis of variance, range, mean values, relative mean performance, drought tolerance indices, variability parameters, correlation andpath coefficients. An analysis of variance revealed significant differences among the genotypes for all the characters evaluated during present study.
Considerable extent of variability existed for all the attributes recorded among the genotypes. The coefficient of variability was recorded moderate to high genetic variability for number of grains per panicle, root length and yield per plant under normal condition consistently over years, whereas for leaf rolling, number of tillers per plant, number of grains per panicle, plant height, harvest index and yield per plant under drought condition. Yield per plant recorded high variability amongst the genotypes evaluated under both conditions.The genotypes RAU-1426-4-3-2-57-2, RAU-1416-4-2-5-2-2 and Sahbhagi Dhan recorded remarkably higher mean performance fornumber of tillers per plant, number of grains per panicle, 1000-grains weight, harvest index and yield per plant, under both drought and normal conditions. Similarly, genotypes like RAU-1397-2-5-8-1-2-5-4, RAU-1453-12, RAU-1451-6-6-1-1-5-2 and Sahbhagi Dhan exhibited superior performance in respect of root length, plant height, dry root weight, relative leaf water content, canopy temperature and number of grains per panicle under both drought and normal conditions. The relative mean performance of genotypes, namely,RAU-1421-12-1-7-4-3, RAU-1415-3-5-7-6-9-5-3, RAU-1401-1-8-1-5, RAU-1478-5-2-2-4-6, RAU-1451-6-6-1-1-5-2, RAU-1416-4-2-5-2-2, RAU-1426-4-3-2-5-7-2, RAU-1453-12 and Sahbhagi Dhan to be relatively more drought tolerant than other genotypes under evaluation.
Root length, plant height, dry root weight, spikelet fertility, number of grains per panicle, 1000-grain weight, harvest index and yield per plant exhibited moderate to high heritability in broad sense coupled with moderate to high estimates for genetic advance as per cent of mean under both drought and normal conditions over years.Correlation studies, revealed that root length, number of tillers per plant, relative leaf water content, spikelet fertility, 1000-grain weight and harvest indexshowed significant positive association with yield per plant under both conditions. However, positively significant association was also observed between yield per plant and number of grains per panicle under drought condition.Path coefficient analysis revealed that the characters, namely, numbers of tillers per plant, root length, dry root weight1000-grain weight and harvest index had considerable positive direct effects on yield per plant more or less consistently across the years under drought as well as normal conditions.Four tolerance indices viz. TOL, SSI, DTE and STI were used. According to TOL, SSI and DTE, 12 genotypes,namely, RAU-1421-12-1-7-4-3, RAU-1415-3-5-7-6-9-5-3, RAU-1401-1-8-1-5, RAU-1478-5-2-2-4-6, RAU-1477-9-7-2-2-5-7-3, RAU-1451-6-6-1-1-5-2, RAU-1416-4-2-5-2-2, RAU-1426-4-3-2-5-7-2, RAU-1463-16, RAU-1471-10, RAU-1453-12 and Sahbhagi Dhan appeared to be relatively more tolerant to drought stress. Among these 12 genotypes, 7 genotypes namely,RAU-1421-12-1-7-4-3, RAU-1415-3-5-76-9-5-3, RAU-1451-6-6-1-1-5-7-3, RAU-1416-4-2-5-2-2, RAU-1426-4-3-2-5-7-2, RAU-1453-12 and Sahbhagi Dhan recorded higher STI valueexhibiting high tolerance to drought condition.
Using a set of thirty two microsatellite primers generated allelic variants ranged from 4 in case of RM 85 to 16 in case of RM 324 and RM518.The primer pair RM 3,RM 18, RM 72, RM 87, RM225, RM 262, RM302, RM 324, RM 327, RM 416, RM 518, RM 520, RM 521, RM1349, RM 5443 and RM 23679generated amplified products due to amplification of more than one microsatellite locus. Altogether 300 allelic variants were detected at 48 microsatellite loci with an average of 6.25 alleles per locus. A total of 174 shared and 126 unique allelic variants were generated. Considering the number of alleles in conjunction with the level of polymorphism detected, the primersRM 231, RM 225, RM 163, RM 555, RM 212, RM 72, RM 3549, RM 1349, RM 521, RM 5443 and RM 302 appeared to be more informative primers.Analysis of divergence pattern based on microsatellite markers allowed differentiation and classification of rice genotypes into two groups. The first multi-genotypic group consisted of twelve genotypes, namely, RAU-1428-6-7-3-6, RAU-1417-2-1-5-7-7,RAU-1421-12-1-7-4-3, RAU-1415-3-5-76-9-5-3, RAU-1401-1-8-1-5, RAU-1428-4-3-2-7-26, RAU-1478-5-2-2-4-6, RAU-1477-9-7-2-2-5-7-3, RAU-1451-6-6-1-1-5-2, RAU-1416-4-2-5-2-2, RAU-1397-2-5-8-1-2-5-4 and RAU-1451-3-5-7-6-9-5-1 whereas the second multi-genotypic group consisted of six genotypes, namely, RAU-1426-4-3-2-5-7-2, RAU-1428-3-1-5-4, RAU-1463-16, RAU-1471-10, RAU-1453-12 and Sahbhagi Dhan.The maximum similarity value of 0.46 was observed between the genotypes i.e. genotype RAU-1477-9-7-22-5-7-3 and RAU-1451-6-6-1-1-5-2 indicating that these were more closely related. The panel of microsatellite markers employed for molecular characterization in the present study showed very high degree of efficiency in discrimination of genotypes in relation to drought tolerance.
Description
Keywords
null