Genetic variability and inter-relationship of kernel carotenoids among indigenous and exotic maize (Zea maysL.) inbreds

Abstract

Carotenoids play vital role in growth and development of human beings. Yellow maize kernel contains carotenoids that possess provitamin A and antioxidant activity. Multilocation based analyses of 105 maize inbreds of indigenous and exotic origin revealed wide genetic variation for lutein (0.2-11.3 µg/g), zeaxanthin (0.2-20.0 µg/g) and β-carotene (0.0-15.0 µg/g). For β-cryptoxanthin, low variation (0.1-3.3 µg/g) was observed. Carotenoids were quite stable over environments that played minor role in causing variation. The heritability (>90%) and genetic advance (>75%) were high for all the carotenoid components. Zeaxanthin showed positive correlation with lutein and β-cryptoxanthin, while β-carotene, the major provitamin A carotenoid, did not show correlation with other carotenoids. Kernel colour was positively correlated with lutein (0.25), zeaxanthin (0.47) and β-cryptoxanthin (0.44), but not with β-carotene (0.04). This suggested that visual selection based on kernel colour will be misleading in selecting provitamin A-rich genotypes. Inbreds with provitamin A and non-provitamin A carotenoids identified in the present study will help in development of biofortified maize hybrids.

Genetic analyses of kernel carotenoids in novel maize genotypes possessing rare allele of β-carotene hydroxylase gene

“…Though β-carotene showed significant location × cross interaction, the proportion of sum of squares to total sum of square, was of quite low magnitude (0.05%), thereby also suggesting that β-carotene is not much influenced by environments. Similar results of low effects of environment on carotenoid concentration have been observed in our earlier study while evaluating a set of 95 diverse inbred lines across three locations (Muthusamy et al 2015a). Negligible effect of environment on kernel carotenoids was also reported in tropical inbred lines (Menkir et al 2008), as well as temperate-inbreds (Kurilich and Juvik 1999) and hybrids (Egesel et al 2003).…”

“…Negative correlation of β-carotene with other carotenoids revealed in the study could be due to genetic nature of the material used in the study, where all the genotypes possessed crtRB1 favourable allele, which blocks the conversion of β-carotene to further carotenoids in the pathway, viz. β-cryptoxanthin and zeaxanthin making them negatively correlated (Muthusamy et al 2015a). Neutral association of carotenoids with grain yield offers possibility of enhancing kernel carotenoids in high yielding genotypes.…”

“…In traditional maize genotypes, β-carotene and β-cryptoxanthin possessing provitamin A activity are present in minor fraction, while non-provitamin A carotenoids, viz. zeaxanthin and lutein are the predominant fraction (Vignesh et al 2012;Muthusamy et al 2015aMuthusamy et al , 2015b.…”

Accruing genetic gain in pro-vitamin A enrichment from harnessing diverse maize germplasm

“…Extensive studies were conducted to characterize concentrations of carotenoids in diverse tropical and temperate maize germplasm and found considerable natural genetic variations in accumulation of provitamin A and other carotenoids (Blessin et al 1963;Kurilich and Juvik 1999;Egesel et al 2003;Berardo et al 2004;Islam et al 2004;Chander et al 2008;Vallabhaneni and Wurtzel 2009;Burt et al 2011;Muthusamy et al 2015). To assess the extent of variation in carotenoid composition and content in adapted germplasm available for breeding, we also evaluated 421 tropical-adapted yellow to orange endosperm maize inbred lines in several independent trials (Menkir et al 2008).…”

Recurrent selection method for improvement of lutein and zeaxanthin in orange waxy corn populations

“…Color parameters have been suggested as an alternative selection method for high carotenoids (Mcguire, 1992;Hyman et al, 2004;Kljak and Grbe, 2014) and anthocyanin (Harakotr et al, 2015) in kernels in large corn populations. Although the method is simpler than other methods, it is not reliable for selection of high provitamin A in corn (Muthusamy et al, 2015). The information on the relationship between color parameters and carotenoids in waxy corn population is still lacking.…”