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ANALYSIS OF HETEROTIC POTENTIALITY AND MOLECULAR PROFILING OF LATE FLOWERING INBRED LINES OF MAIZE (Zea mays L.)

KrishiKosh

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Title ANALYSIS OF HETEROTIC POTENTIALITY AND MOLECULAR PROFILING OF LATE FLOWERING INBRED LINES OF MAIZE (Zea mays L.)
Ph.D.
 
Creator MARUTHI R T
 
Contributor Gadag, R.N.
 
Subject maize, genetics, inbred lines, biological phenomena, yields, crossing over, grain, hybrids, genotypes, seasons
 
Description Analysis of Heterotic Potentiality and Molecular Profiling of Late Flowering Inbred Lines of Maize (Zea mays L.)
ABSTRACT
Greater emphasis on late maturity hybrids is required to exploit full productive potential of maize crop. Medium to late maturing maize hybrids are ideal for commercial production because of their high yield potential and profitability. Maize in the tropics is continuously exposed to different kinds of stresses viz., drought, flood, nutrient (e.g. nitrogen) etc. Until recently, the research efforts in public sector institutions was concentrated mostly in development of early maturing hybrids, in fact they were quite successful in development of early maturing maize cultivars. However, public bred hybrids with late maturity and high productivity are very few. Hence, greater emphasis and necessary strategies towards development of full season maturity hybrids are required. Therefore, present study was undertaken to analyze the heterotic potentiality and molecular diversity of late flowering inbred lines of maize.
62 promising late-flowering maize inbred lines were obtained from Maize Genetics Unit, Division of Genetics, IARI, New Delhi. The genotypes were characterized for 23 morphological traits to understand their genetic relatedness during kharif-2010 at IARI experimental field. According to principal component analysis, eight principal components (PC) had Eigen values >1 which accounted for 73.46 per cent of the total variability with ear diameter, ear length and plant height being the most important characters in PC1. Based on cluster analysis, the 62 genotypes were separated into three major groups with each having two or more subgroups. Based on the results 24 inbred lines were selected from cluster 1 and 3 as they were more divergent. Further, crossing can be made between these lines with the better prospects of getting more heterotic combinations.
Two inbred lines selected were grouped into two sets on the basis of their agronomic superiority and late maturity and were used in crossing programme by following 10 x 10 half diallel and 14 x 3 line x tester mating designs. Experimental crosses of 10 x 10 half diallel were generated at Winter Nursery Centre, Directorate of Maize Research, Hyderabad during rabi 2010-11. Similarly, 14 x 3 Line x Tester was generated at the IARI experimental farm, New Delhi during Kharif 2011.The diallel set, comprising of 10 parents and their 45 F1’s and two commercial hybrid checks (PMH-1 and PMH-3) were evaluated at two locations viz., New Delhi and Dharawada in two seasons viz., kharif 2011 and rabi 2011-12. The analysis of variance revealed significant differences among the genotypes over the environments for all the characters under investigation indicating existence of sufficient variation in the material studied. The lines P5, P6 for both kharif and rabi season were identified as good general combiners for grain yield whereas line P9 was identified as good general combiner for both grain yield and late-flowering trait. Similarly, evaluation of hybrids for all the 11 traits revealed P9xP10, P4xP5 and P3xP6 for kharif season, while P2xP6, P6xP8 and P3x P5 for rabi season as the best specific combiners for grain yield. Based on the estimates of specific combining ability effects (SCA), mid-parent heterosis (MPH) and mean per se performance of crosses for grain yield (kg plot-1) ten late-flowering inbred lines were classified into four heterotic groups. To understand the molecular diversity among the lines 35 SSR primers were employed. The molecular diversity analysis has grouped based on genetic similarity matrix the ten late-flowering inbred lines in three major clusters. However, heterotic grouping of inbred lines based on combining ability analysis did not agree well with the genetic similarity matrix/clustering based on SSR markers.
In another experiment 42 F1 crosses were generated by line x tester mating scheme and their parents along with two hybrid checks (PMH-1, PMH-3) were evaluated in separate trials at two locations namely New Delhi (rabi 2011-12 and kharif 2012) and Dharawada (rabi season 2011-12) The ANOVA for line x tester method revealed significant environment x test cross interaction, environment x tester interaction effects, environment x line x tester effects for grain yield and yield related traits. The presence of significant environmental interaction implied that genotypes should be tested widely across different locations to identify stable hybrids. The lines L6, L14 from rabi season data and L5, L8 from kharif data were identified as a potential lines for development of high yielding hybrids and open pollinated synthetic varieties. The best specific combinations for grain yield were L12xT2, L4xT1 and L9xT2 for kharif, while L12xT2, L14xT2 and L2xT1 for rabi season. The cross L12xT2 was found to be stable across seasons and locations. 14 late-flowering maize inbred lines were classified into three heterotic groups; Group A, B and AB, using testers BML-10 and HKI-163, while SSR based UPGMA clustering
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analysis divided the 14 late-flowering maize inbred lines into seven clusters which did not agree grouping of inbred lines with the combining ability analysis.
Thus combining ability analysis and SSR analysis helped in classifying the lines into different heterotic groups. The inbred lines in each group can be effectively used in hybrid breeding schemes. Further, to broaden the genetic base of heterotic groups formed there is need to incorporate new inbred lines continuously
 
Date 2016-03-09T14:42:13Z
2016-03-09T14:42:13Z
2013
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/65006
 
Language en_US
 
Format application/pdf