Mapping QTLs for popping ability in a popcorn × flint corn cross
2006
Babu, R. | Nair, S. K. | Kumar, A. | Rao, H. S. | Verma, P. | Gahalain, A. | Singh, I. S. | Gupta, Eca. Esa
Popping expansion volume (PEV) in popcorn (Zea mays L.) is a distinct heritable character and defined as the ratio of the volume after popping to the volume before popping. PEV is quantitatively inherited and 3–4 genes/quantitative trait loci (QTLs) have been implicated. In the present study, we have dissected the quantitative PEV into two component traits, viz., flake volume (FV) and percent unpopped kernels (UPK), and mapped QTLs using SSR markers for all three traits with 194 F₃ families derived from a popcorn (A-1-6) × flint corn (V273) cross. Heritability (broad sense) estimates for PEV, FV and UPK based on F₃ mean bases were 0.72, 0.54 and 0.68, respectively. The QTL analyses for the three traits based on combined environment data were performed by composite interval mapping using QTL cartographer. Four QTLs were identified for PEV on chromosomes 1, 3, 8 and 10, which together explained 62% of the phenotypic variance (σ²p). Four QTLs were found on chromosomes 1, 5, 9 and 10 for FV (explaining 44% of σ²p) and five QTLs for UPK on chromosomes 1, 3, 4, 5 and 9 (explaining 57% of σ²p). The relative efficiency estimates of marker-based selection in comparison to phenotypic selection for PEV (1.10), FV (1.22) and UPK (1.11) indicated that marker-based selection could be relatively more efficient. The QTL on chromosome 1S for PEV was found to be most significant, where QTLs for hard endosperm starch concentration had been detected earlier.
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