No abstract

The use of corn wastes should increase production efficiency. The objective of this study was to evaluate anthocyanin content, phenolic content and antioxidant activity in kernel, cob, silk, and husk of purple waxy corn. Three varieties of purple waxy corn and a commercial check were planted in a randomized complete block design with three replications. Data were recorded for anthocyanin content, anthocyanin yield, phenolic content and antioxidant activity determined by 2,2-diphenyl-1-picrylhydrazyl radical scavenging ability (DPPH) and Trolox equivalent antioxidant capacity (TEAC) methods at edible stage (20 days after pollination; DAP) and seed stage (35 DAP). Significant differences between kernel maturity stages and among corn varieties and ear components were observed. Seed stage had significantly higher anthocyanin content, phenolic content and antioxidant activity than edible stage. KKU-OP and commercial check had the highest anthocyanin content, anthocyanin yield, DPPH and TEAC at edible and seed maturity stages. Corn silk had high anthocyanin content, DPPH and TEAC at seed stage, but corn cob had the highest anthocyanin content per unit of area. KKU-OP had the highest anthocyanin content, DPPH and TEAC at both maturity stages, whereas KKU-OP and KKU-WX111031 had the highest anthocyanin yield at edible and seed stages, respectively. Corn silk and corn cob had anthocyanins and can be used as a source of anthocyanins in food industry. KKU-OP and KKU-WX111031 had high anthocyanins and antioxidant activity and could be used as an alternative source of bioactive compounds for the functional food industry and a germplasm source for high anthocyanins.

Selection of purple waxy corn genotypes for high and stable anthocyanin content in corn cobs is important for breeding programs and anthocyanin production. The objectives of this study were to evaluate the effects of location, genotype and their interaction on anthocyanin content and antioxidant activities and to identify purple waxy corn genotypes with high and stable anthocyanin content. Five purple waxy corn and a white waxy corn genotypes were evaluated in a randomized complete block design with three replications at four locations with different elevations in Thailand. Location (L), genotype (G) and GxL interaction were significant for all characters. Waxy corn grown in Nakhon Ratchasima had the highest total anthocyanin content (TAC), cyanidin 3-glucoside (C3G), pelargonidin 3-glucoside (Pg3G), and peonidin 3-glucoside (Pn3G), DPPH radical scavenging activity of phenolics (DPPH) and Trolox equivalent antioxidant potential (TEAC). Genotype KNDM4 had the highest TAC, Pg3G, Pn3G and DPPH. Its regression coefficient (b i ) was close to one but it had the highest Sd 2 , indicating specific adaptation to favorable environments. KNDM4 genotype performed better than other genotypes at unfavorable environments for all studied traits. This information is useful for breeding programs and anthocyanin production from purple waxy corn.

The use of combinations of two or more genes controlling carbohydrate characters of corn is an attractive way to improve table quality of sweet corn. Poor seed quality of the inbred lines hinders the progress of this strategy for hybrid seed production. The objective of this study was to evaluate sweet corn inbred lines with combinations of double and triple recessive genes for germination percentage, seed vigor, total sugar content, and starch content. Eleven sweet corn genotypes including seven inbred lines (F6 generation) with different combinations of genes controlling carbohydrate characters and four F1 hybrids were used. The germination experiment was conducted under standard test between papers (BP) and accelerated aging (AA) test. The data were recorded for germination percentage, germination speed, normal and abnormal seedling, seedling length, and seedling dry weight. The seeds were analyzed for total sugar and starch content in endosperm at maturity stage. The results showed that single recessive genotype (sh2sh2) had high germination percentage and seedling vigor. The combinations of bt or sh2 gene with wx gene resulted in low germination percentage and poor seedling vigor. However, combinations of triple recessive genes (btbt sh2sh2 wxwx) had good germination in BP test but they performed poorly in AA test.

Vegetable corn with an excellent, balance proportion of kernel carbohydrates in relation to good eating quality appeals to consumers. Sweet-waxy corn hybrid is proposed to improve palatability of traditional cooked waxy corn, well known as synergistic corn. We determined genetic effects of sugars, phytoglycogen, total starch, and amylopectin and estimated general combining ability of parents for these traits. Three sweet corn lines assigned as female were crossed with eight waxy corn lines as male following the North Carolina II. About 11 parents, 24 F1 progenies, and 3 checks were evaluated in randomized complete block design with three replications in two seasons between 2017-2018. Then, entry means of 38 genotypes was clustered with dendogram. Additive effect was important for favored kernel carbohydrates except for phytoglycogen. Two sweet corn lines 101LBW and 101LTSC-10 were proposed as broad-based testers for total sugar and sugar fractions, whereas a waxy corn line KVMON for total starch and amylopectin. Cluster analysis based on amylopectin, total sugar, and phytoglycogen was reliable to discriminate corn genotypes into seven major groups, and two sweet-waxy corn F1 hybrids 101LTSC-10/C13-1 and 101LTSC-10/KV3473 corresponding to our selection criteria were identified. Implications in plant breeding and suggestions for further investigations are discussed.