Co-Authors:
Juvik, J.A., Dept. Nat. Rsrc. and Environ. Sci., University of Illinois, Urbana, IL 61801, United States
Yousef, G.G., Dept. Nat. Rsrc. and Environ. Sci., University of Illinois, Urbana, IL 61801, United States
Han, T.-H., Dept. Nat. Rsrc. and Environ. Sci., University of Illinois, Urbana, IL 61801, United States
Tadmor, Y., Agricultural Research Organization, Newe Ya'ar Research Center, P.O. 31999 Haifa, Israel
Azanza, F., Dept. Nat. Rsrc. and Environ. Sci., University of Illinois, Urbana, IL 61801, United States
Tracy, W.F., Department of Agronomy, University of Wisconsin, Madison, WI 53706, United States
Barzur, A., Agricultural Research Organization, Newe Ya'ar Research Center, P.O. 31999 Haifa, Israel
Rocheford, T.R., Department of Crop Sciences, University of Illinois, Urbana, IL 61801, United States
Abstract:
This study was conducted to identify the chromosomal location and magnitude of effect of quantitative trait loci (QTL) controlling sweet corn (Zea mays L.) stand establishment and investigate the impact of dry kernel characteristics on seedling emergence under field conditions. Genetic and chemical analysis was performed on two F2:3 populations (one homozygous for suI and segregating for seI, the other homozygous for sh2 endosperm carbohydrate mutations) derived from crosses between parental inbreds that differed in field emergence and kernel chemical composition. A series of restriction fragment-length polymorphism (RFLP) and phenotypic markers distributed throughout the sweet corn genome were used to construct a genetic linkage map for each population. F2:3 families from the two populations were evaluated for seedling emergence and growth rate at four locations. Mature dry kernels of each family were assayed for kernel chemical and physiological parameters. Composite interval analysis revealed significant QTL associations with emergence and kernel chemical and physiological variables. Improved emergence was positively correlated with lower seed leachate conductivity, greater embryo dry weight, and higher kernel starch content. QTL affecting both field emergence and kernel characteristics were detected in both populations. In the suI seI population genomic regions significantly influencing emergence across all four environments were found associated with the scI gene on chromosome 2 and the RFLP loci php200020 on chromosome 7 and umc 160 on chromosome 8. In the sh2 population the RFLP loci umc 131 on chromosome 2 and bn19.08 on chromosome 8 were linked to QTL significantly affecting emergence. Since seedling emergence and kernel sugar content have been shown to be negatively correlated, undesirable effects on sweet corn eating quality associated with each emergence QTL is discussed. Segregating QTL linked to RFLP loci in these populations that exert significant effects on the studied traits are candidates for molecular marker-assisted selection to improve sweet corn seed quality.