Information on phytochemicals in the cob and husk of field corn is important for the use of corn waste in the production of value-added corn products. The objectives of this study were to evaluate the variation in monomeric anthocyanin content (MAC), total phenolic content (TPC), and antioxidant activity, as determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity and Trolox equivalent antioxidant capacity (TEAC) in 53 purple field corn genotypes, and to study the correlations of these traits with color parameters. Fifty-three corn genotypes were planted in a randomized complete block design with three replications in two locations in the dry season of 2015/2016. The effects of genotype, location, and the interaction between genotype and location were significant for most characters. Genotypic variation contributed to a large portion of the total variance for all traits, accounting for 63.9-86.9%. Corn genotypes were classified into six groups based on MAC, TPC, and antioxidant activity determined by the DPPH and the TEAC methods. The highest MAC, TPC, and antioxidant activity were obtained in TB/KND//PF3 and TB/KND//PF8 for husk, and only TB/KND//PF8 for cob. They should be used as parental lines to develop corn varieties with high phytochemicals. Chroma (C*) and hue (H • ) of color parameters could potentially be used as an indirect selection criterion for improving MAC, TPC, and antioxidant activity in cob. The information is useful for the improvement of phytochemicals in cob and husk of field corn.

The objective of this study was to identify the maize inbred lines with good general combining ability (GCA), good specific combining ability (SCA), high heterosis for yield and phytochemicals, and the crosses with high yield of yellow kernels and high anthocyanin content in cobs and husk, which was probably related to the high antioxidant activity. The parental lines including five unpigmented females and five pigmented males were crossed in North Carolina design II. The parents, the resulting 25 hybrids, and 5 controls were evaluated at two locations in the dry season of 2016/2017. Additive and non-additive gene effects controlled the inheritance of grain yield, agronomic traits, and phytochemicals. KKU–PFC2 and KKU–PFC4 had the highest GCA effects for phytochemical traits in husk and cob, whereas Takfa1 and Takfa3 were good combiners for grain yield. F1 hybrids had significantly higher total anthocyanin content (TAC), total phenolic content (TPC), (2,2-diphenyl-1-picrylhydrazyl) (DPPH), and trolox equivalent antioxidant capacity (TEAC) in husk and cob than pigmented control cultivars. The hybrids superior for individual traits were identified, but the experiment was not able to identify superior hybrids for multiple traits. The Takfa3 × KKU–PFC5 and NakhonSuwan2 × KKU-PFC4 had the highest anthocyanin in husk and cobs, respectively. The breeding strategies to develop maize varieties with high anthocyanins and normal yellow kernels and utilization of the hybrids are discussed.

Improvement of anthocyanin levels in husks and cobs of field corn may add economic value to corn coproducts in commercial production. This study aimed to evaluate the response to four cycles of modified mass selection (MMS) for yield, agronomic traits, total anthocyanin yield (TAY), total anthocyanin content (TAC), total phenolic content (TPC) and antioxidant activity determined by 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity assay (DPPH) and trolox equivalent antioxidant capacity assay (TEAC) in corn husk and cob of five purple field corn populations. The improved populations and check varieties were evaluated at two locations for two seasons in 2017/2018. Selection cycle contributed to a large portion of the total variations for TAC, TPC, DPPH and TEAC in corn husk and cob. All tested populations showed progress for days to anthesis, TAY, TAC, TPC, DPPH and TEAC across four cycles of selection. Lack of significant correlation between agronomic traits and anthocyanin concentrations suggested the independent segregation of these traits. MMS was successfully used to develop field corn populations with improved anthocyanin, antioxidant activities and early flowering without significant yield loss. The populations with the highest selection gains for anthocyanin in husk and cob were identified. Visual selection for dark purple husks and cobs boosted anthocyanin levels and antioxidant activity in selected populations.