Genetic Improvement for Yield and Yield Related Traits by Introgressive Hybridization in Sweet Corn

Proper choice of source populations contributes to the ultimate success of selection for genetic improvement. The source population should possess the most desirable alleles at as many loci as possible for intra population improvement. Such desirable alleles can be intensified by introgression of exotic germ plasm into locally adapted ones through hybridization followed by selection. The objectives of this study were to determine the mean performance, genetic variability $({\sigma}^2G)$ and heritability of fresh ear yield and other important traits within two sweet corn source populations, $BC1-10{\times}Syn-II$ and BC2-10. One hundred selfed progenies from each of the two source populations were evaluated in a $10\times10$ lattice design, at the Institute of Bioscience (IBS) Farm, University of Putra Malaysia (UPM) following the recommended cultural practices. Significant differences among selfed progenies within $BC1-10{\times}Syn-II$ were observed for all traits, while differences among selfed progenies within BC2-10 were noted for fresh ear yield, ear length, ear diameter, number of kernels per row, ear height, days to tasseling and days to silking. Progenies developed from $BC1-10{\times}Syn-II$ population had higher estimates of ${\sigma}^2G$ than did progenies from BC2-10 population for number of kernel rows per ear, total soluble solids, plant height, days to tasseling and days to silking, showing that selection to improve these traits would be more effective in selfed progenies of $BC1-10{\times}Syn-II$ than that in BC2-10. On the other hand, progenies developed from BC2-10 population had higher estimates of ${\sigma}^2G$ for ear length, ear diameter and ear height, indicating that progenies from this population would have better genetic gain than $BC1-10{\times}Syn-II$. Comparable estimates of genetic variance were found for fresh ear yield, and number of kernels per row, indicating that genetic improvement of the two source populations is expected to produce similar genetic gains for these two traits. Therefore, selfed progenies developed from both source populations could be used to improve the two populations for various traits and thereby develop superior genotypes for immediate use in the production system.