Gayathri Suravaram, V P L (2012) Heterosis and combining ability studies for grain iron and zinc contents in sorghum (sorghum bicolor l. Moench). Masters thesis, Acharya N.G. Ranga Agricultural University.
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|Ashok Kumar, A||ICRISAT|
The present investigation was undertaken in grain sorghum to estimate the heterosis and to study the nature of gene action and combining ability for grain iron and zinc contents as well as to understand the correlations of grain iron and zinc contents with grain yield and other important characters and the direct and indirect effects of these traits on grain iron and zinc contents in sorghum. Two separate experiments were conducted by using parents with varied levels of grain iron in one experiment and those with diversified contents of grain zinc in another experiment. In the first experiment, four parental lines (IS 2263, IS 13211, IS 10305 and SPV 1359) were crossed among each other in a full-diallel fashion and the resultant twelve crosses along with four parents and standard check (ICSR 40) were evaluated during two postrainy seasons, 2010-2011 and 2011-2012 in Randomized Block Design (RBD) with three replications. Significant variation was observed among the genotypes, environment and genotype x environment interaction for all the characters studied (plant height, days to 50 % flowering, 100-grain weight, grain yield and grain zinc) except 100-grain weight. Heterosis for grain iron varied from -9.07 % to 12.89 % over mid-parent, from -14.72 % to 8.55 % over better parent and from -7.19 % to 30.57 % over standard check across the seasons. Heterosis was found to be non-significant over mid-parent and better parent, indicating that additive gene action had a predominant role in the inheritance of this trait. Most of the hybrids recorded significant heterosis over standard check. The combined analysis of variance for combining ability revealed significant differences among parents, direct crosses and reciprocal crosses indicating the existence of wider variability in the material under study for all the characters. However, direct crosses did not show significant variation for grain iron. The ratios of GCA/SCA variances revealed that additive gene action was predominant in the inheritance of all the characters studied barring days to 50 % flowering. Predictability ratio revealed that grain iron content was found to be governed by additive gene action. IS 2263 and IS 13211 were found to be promising general combiners for grain iron based on gca effects and SPV 1359 X IS 13211, IS 10305 X IS 13211, IS 10305....
|Item Type:||Thesis (Masters)|
|Subjects:||Mandate crops > Sorghum
Others > Genetics and Genomics
|Depositing User:||Mr Sanat Kumar Behera|
|Date Deposited:||03 Jul 2012 03:32|
|Last Modified:||03 Jul 2012 03:32|
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