Genetic variability for early seed vigor traits for enhanced performance under sub-optimum temperatures in sweet corn (Zea mays Convar. saccharata L.)

Abstract

High germination and seed vigor under sub-optimum temperature is desirable for successful stand establishment in Sweet Corn. An
investigation was undertaken to assess the performance of shrunken2 based Sweet Corn hybrids; CMVL Sweet Corn-1 and Pusa Super
Sweet Corn-2 and their parental lines; SWT16, SWT17, VSL16 and VSL4 for early seed vigor parameters under sub-optimum (15⁰C, 20⁰C)
and optimum (25⁰C) temperature conditions. Among the genotypes, hybrids (CMVL Sweet Corn-1 and Pusa Super Sweet Corn-2) were
superior than their parental lines for the seed vigor traits like seedling emergence, germination index, mean germination time (MGT),
vigor indices, root growth parameters and field emergence under sub-optimum temperature. The inbred lines; SWT16 and SWT17
had better performance than VSL16 and VSL4 for seed vigor parameters under sub-optimum temperatures. Seedling root architecture
affected seedling performance and establishment under sub-optimum conditions. In the study, under sub-optimum temperatures
seedling root parameters i.e. the root length, surface area and root volume reduced whereas the root diameter increased in the sweet
corn lines. Vigor index-II (0.87 and 0.78) and MGT (-0.87and -0.54) showed significant correlation with the field emergence of sweet corn genotypes under 15 and 20oC respectively and thus could be the selection indices for identifying sweet corn genotypes with optimum performance under sub-optimum temperature regimes.