Characterization of maize inbred lines for high plant density amenable traits
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Date
2024
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Punjab Agricultural University
Abstract
In temperate maize, breeding for stress tolerance including a higher number of plants per unit area has been extensively used for productivity enhancement in commercial hybrids but this strategy has not been exploited in tropical maize. The increase in the number of plants per unit area through the adoption of high density planting (HDP) is one of the alternative strategies to achieve high productivity in tropical/subtropical maize. Narrow leaf angle, shorter anthesis silking interval, and moderate plant height were delineated as major architectural traits for tolerance to HDP in parental lines. The lines harboring these traits coupled with high grain yield potential under HDP were identified and recommended to use as parents for the HDP breeding program. These are following inbred lines identified for HPD traits CML 451, 221520, EML108, EML113, EML129, PML1112, PML115, PML1194, PML1239, PML133, PML162, PML163, PML164, PML18, PML2, PML80, PML81, SN485145 and VL174449.The inheritance study of leaf angle resulted as the expected number of intermediate, broad leaf angle and narrow leaf angle plants for 9:6:1 was 405, 250 and 607, respectively, giving a chi-square value of 1.097 (< 5.991) hence giving a perfect fit to 9:6:1. Thus, Chi-square analysis revealed that the narrow leaf angle is controlled by two recessive gene. A cross between broad leaf angle (PML1126) and narrow leaf angle (CML451) inbred line was used to raise an F2 mapping population for the construction of two contrasting bulks namely, broad leaf angle (BLA) and narrow leaf angle (NLA). These bulks along with both the parents were sequenced using whole genome resequencing and analysed using the SNP-index method for identifying the narrow leaf angle associated region.
Identification of QTLs associated with narrow leaf angle in the material under study based on sequence based bulked segregant analysis and use of QTLseqr software was done. It was observed that the ∆SNP-index values in the region 48.72mb to 55.13mb on chr 6, 44.63mb to 45.74mb; 46.21mb to 50.86mb on chromosome 7, 48.22mb to 54.56mb on chromosome 9 lied outside the statistically calculated confidence interval at 99% level of significance. The findings of the present study will facilitate in genetic dissection of candidate gene(s) responsible for the narrow leaf angle gene. This study will also help in the development of SNP-based markers which would facilitate marker-assisted transfer of narrow leaf angle gene in maize inbred line.
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Meena, Tarun Kumar (2024). Characterization of maize inbred lines for high plant density amenable traits (Unpublished M.Sc. thesis). Punjab Agricultural University, Ludhiana, Punjab, India.