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GENETICAL STUDIES FOR IMPROVEMENT OF SINGLE CROSS HYBRIDS OF MAIZE (Zea mays L.) THROUGH IDENTIFICATION OF ELITE INBREDS WITH FAVOURABLE ALLELES FOR YIELD AND YIELD COMPONENTS

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Title GENETICAL STUDIES FOR IMPROVEMENT OF SINGLE CROSS HYBRIDS OF MAIZE (Zea mays L.) THROUGH IDENTIFICATION OF ELITE INBREDS WITH FAVOURABLE ALLELES FOR YIELD AND YIELD COMPONENTS
 
Creator SAIDA NAIK, V
 
Contributor MOHAN REDDY, D
 
Subject crossing over, hybrids, yields, environment, maize, heterosis, diseases, biological phenomena, planting, grain
 
Description The present investigation entitled “Genetic studies for improvement of single cross hybrids of maize (Zea mays L.) through identification of elite inbreds with favourable alleles for yield and yield components” was carried out at Sri Venkateswara Agricultural College wetland farm, Tirupati, Andhra Pradesh. The experimental material consisting of ten inbred lines and forty five F1 cross combinations generated by mating these inbreds in all possible combinations excluding reciprocals following a 10 × 10 diallel mating design during kharif, 2009 and Kharif, 2010. The evaluation of ten parents and forty five F1 hybrids was done in separate but adjacent trials during rabi, 2009-10, summer 2010, kharif 2010, rabi 2010-11 and rice fallow 2010-11 in a randomized block design (RBD) with three replications.
The investigation was carried out to identify the elite inbreds with favourable alleles to improve the selected single cross hybrids, to test the combining ability of these inbreds and crosses to determine the gene action, to study the heterosis and stability (AMMI) analysis over seasons with respect to grain yield and other agronomic traits.
The results on the status of favourable alleles in new donor inbreds for improvement of the cross BML 6 × BML 7 (target cross) showed that the donor inbred lines BML 10 and CM 131 had highest frequency of favourable alleles (μG') to further improve its yield performance. Similarly, for other superior crosses, CM 131 × BML 7 the donors CM 211 and CM 131; for CM 211 × BML 7 the donors CM 131 and CM 133; for CM 131 × BML 6 the donors BML 10 and
xxi
CM 119 and for BML 6 × BML 10, the donors CM 131 and CM 119 gave highest frequency of significant favourable alleles. Based on the results, comprehensive breeding plans were also suggested for utilizing the selected donors to either enhance the target cross performance or to develop new single cross using one of the parents of the target cross.
In combining ability analysis, both GCA and SCA variances were significant for all the traits studied in all the five environments and in combined analysis, indicating the importance of both additive and non-additive genetic variances. The combining ability studies over environments clearly indicated that both additive and non-additive genetic effects were greatly influenced by environments for the traits studied. Based on overall combining ability status of all the traits, three parents BML 6, BML 7 and CM 211 and twenty three of the forty five crosses were classified as having ‘high’ status. The hybrid CM 133 × BML 7 and BML 6 × BML 10 recorded highly significant sca effects besides high per se for yield per plant in combined analysis. Hence, it could be suggested that these crosses might be successfully exploited for yield improvement.
The studies on heterosis showed high magnitude of heterosis for grain yield over better parent which ranged from 36.75 per cent to 182.88 per cent across the five environments. Majority of the crosses expressed substantial heterosis in desired direction over better parent for most of the characters studied. The crosses viz., CM 120 × BML 13, CM 210 × BML 210 and CM 131 × BML 10 showed high heterosis for grain yield per plant and other important yield components.
The stability analysis based on AMMI model revealed that, forty five hybrids showed significant differences for genotypes, environments and G × E interaction for all the characters except protein per cent and number of kernel rows per ear. IPCA1 explained most of the proportion of G × E interaction than IPCA2 and IPCA3 for all the characters studied. The results revealed that among all the hybrids, the hybrids 6 (CM 119 × BML 6), 7 (CM 119 × BML 7), 21 (CM 131 × BML 6), 22 (CM 131 × BML 7), 28 (CM 133 × BML 7), 36 (CM 211 × BML 6), 37 (CM 211 × BML 7), 42 (BML 6 × BML 10) and 44 (BML 7 × BML 10) found stable for yield and other important yield attributing traits and hence suggested for exploiting in all the seasons/situations under consideration.
 
Date 2016-06-17T10:32:30Z
2016-06-17T10:32:30Z
2012
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/67504
 
Language en
 
Relation D9361;
 
Format application/pdf
 
Publisher ACHARYA N.G. RANGA AGRICULTURAL UNIVERSITY