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GENETIC ANALYSIS OF GRAIN IRON AND ZINC CONCENTRATIONS IN SORGHUM (Sorghum bicolor L. Moench)

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Title GENETIC ANALYSIS OF GRAIN IRON AND ZINC CONCENTRATIONS IN SORGHUM (Sorghum bicolor L. Moench)
 
Creator TIRUMALA RAVI KIRAN, K
 
Contributor RADHIKA, K
 
Subject GENETIC, ANALYSIS, GRAIN, IRON, ZINC, SORGHUM
 
Description The present investigation was carried out in sorghum to study the gene action involved in the inheritance of grain iron and zinc concentrations using generation mean analysis, to estimate the nature and magnitude of genetic effects and to understand the correlations of grain iron and zinc concentrations with grain yield and other agronomic traits. Two crosses (IS13205 × SPV1359 and IS13205 × IS23464) using diverse parents with varied levels of grain iron and zinc concentrations were made to generate six generations i.e., P1, P2, F1, F2, B1 and B2. These six generations were evaluated in post-rainy season, 2012-13 at ICRISAT, Patancheru. Observations were recorded on important agronomic traits as per standard procedures, and grain iron and zinc concentrations were estimated using Inductively Coupled Plasma Optical Emission Spectometry (ICP-OES).
Analysis of variance showed significant differences among the generations of both the crosses for almost all the traits studied except days to 50% flowering, panicle width and 100-grain weight. Only one cross each showed significant difference between generations for days to 50% flowering (IS13205 × SPV1359) and 100-grain weight (IS13205 × IS23464). Panicle width exhibited non-significant difference between the generations of both the crosses. The phenotypic coefficient of variation was moderately higher than genotypic coefficient of variation for all the traits under study except days to 50% flowering, which suggested moderate influence of environment on these traits. Grain zinc concentration showed higher estimates of PCV % and GCV % than iron concentration in both the crosses and the gap between PCV % and GCV % was higher for grain zinc concentration than grain iron concentration which implies that the accumulation of this micronutrient suffered less from environment than that of grain zinc accumulation. High heritability coupled with high genetic advance was obtained for plant height, grain yield, grain iron and zinc concentrations indicating that these traits were governed by additive gene action and that selection will be effective. Average heterosis was negative for most of the traits
studied with significant negative heterosis over mid-parent obtained for panicle length and panicle width in the cross IS 13205 × IS 23464, significant average heterosis for grain yield which was negative in the cross IS 13205 × IS 23464 and positive in the cross IS13205 × SPV 1359 and was positive for iron and zinc concentrations in both the crosses. Significant residual heterosis over mid parent was obtained for plant height for both the crosses and for panicle width in the cross IS13205 × IS23464. Heterobeltiois was negative for almost all the traits studied. Significant negative heterobeltiosis obtained for grain yield for both the crosses, for days to 50 % flowering and plant height in the cross IS 13205 × IS 23464. Heterobeltiosis was non-significant for grain iron and zinc concentrations in both the crosses. Inbreeding depression was significant for plant height in the cross IS 13205 × IS 23464 and grain iron concentration in the cross IS13205 × SPV1359.
Correlation studies showed highly significant positive correlation between grain iron and zinc concentrations in both the crosses, indicating the possibility of simultaneous improvement of both the traits. Grain iron and zinc concentrations did not show any significant association with grain yield plant-1 and other agronomic traits except panicle length in the cross IS13205 × SPV1359.
Generation mean analysis showed that three scaling tests viz., A, B and C were significant for all the traits studied, except for days to 50% flowering in the cross IS13205 × IS23464, with significance of atleast one scaling test (for grain yield and grain iron and zinc concentrations in both the crosses and for 100-grain weight in the cross IS13205 × SPV 1359) to three scaling tests (plant height and panicle length in the cross IS13205 × SPV 1359) which indicated the presence of digenic non-allelic interactions in the inheritance of these traits. For grain yield plant-1 both direct and epistatic effects were significant in the cross IS13205 × SPV 1359 whereas in the cross IS13205 × IS23464 additive and additive × additive were significant. For 100-grain weight, only additive × dominance interaction was significant which needs further investigation. For grain iron and zinc concentrations mostly digenic epistatic interactions were significant and direct effects were non-significant which indicated the predominance of epistatic interactions. In general, dominance component was higher in magnitude over additive component where as dominance × dominance component was of higher value than the remaining interactions, and also magnitudes of interactions were higher than their respective direct effects. Epistasis was duplicate type in all the cases except for plant height in the cross IS13205 × IS23464 where it was of complementary type. Recurrent selection, biparental mating and diallel selective mating system may be profitable to exploit both additive and non-additive components for bringing about improvement in grain yield and its attributes, grain iron and zinc concentrations.
 
Date 2016-06-14T12:22:43Z
2016-06-14T12:22:43Z
2013
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/67342
 
Language en
 
Relation D9325;
 
Format application/pdf
 
Publisher ACHARYA N.G. RANGA AGRICULTURAL UNIVERSITY