Unveiling the sweetness: evaluating yield and quality attributes of early generation sweet corn (Zea mays subsp. sachharata) inbred lines through morphological, biochemical and marker-based approaches.

Abstract

Sweet corn is gaining tremendous demand worldwide due to urbanization and changing consumer preferences. However, genetic improvement in this crop is being limited by narrow genetic base and other undesirable agronomic traits that hinder the development of superior cultivars. The main requirement in this direction is the development of potentially promising parental lines. One of the most important strategies in this direction is to develop such lines from hybrid-oriented source germplasm which may provide diverse base material with desirable biochemical and agro-morphological attributes. The study was undertaken to carry out morphological and biochemical evaluation of 80 early generation inbred lines (S2) of sweet corn that were developed from a cross between two single cross sweet corn hybrids (Mithas and Sugar-75). Moreover, validation of favourable recessive alleles for sugar content was carried out using SSR markers. The 80 sweet corn inbreds evaluated for phenotypic characterization showed wide range of variability with respect to different traits studied. The highest content of total carotenoids was found in the inbred S27 (34μgg-1) followed by the inbred S65 (31.1μgg-1). The highest content for total sugars was found in S60 (8.54%) followed by S14 (8.34%). Molecular characterization of 80 inbred lines led to the identification of seven inbreds viz., S21, S28, S47, S48, S49, S53, and S54, carrying the alleles specific to the sugary gene (su1) with respect to the markers umc2061 and bnlg1937. Comparing the results of scatter plot for biochemical and morphological traits, it was revealed that inbreds S9, S23, S27 and S36 contain high levels of total sugars and total carotenoids along with moderate values for amylose and yield attributing traits. The inbred lines identified with desirable biochemical and agro-morphological attributes in the study could be utilized as source of favourable alleles in sweet corn breeding programmes after further validation for disease resistance and other agronomic traits. Consequently, the study will not only enhance the genetic base of sweet corn germplasm but also has the potential to develop high-yielding hybrids with improved quality. The inbreds possessing su1 gene on the basis of umc2061 and bnlg1937 markers were also found to possess high sugar content. This indicates the potential of these lines as desirable candidates for breeding programs aimed at improving sweet corn yield and quality. These findings also demonstrate the effectiveness of the molecular markers in facilitating marker-assisted selection for important traits in sweet corn breeding.