Exploiting natural variation in exotic germplasm for increasing provitamin-A carotenoids in tropical maize uri icon

abstract

  • The nutritional value and health benefits derived from carotenoids have prompted increased investment in breeding crop varieties with elevated carotenoid levels for areas where crops like maize with low nutrient density are consumed in large quantities. Twelve exotic donor lines of high beta-carotene were crossed to seven elite tropical yellow or orange lines and the F1s were backcrossed to the same or different elite line. Ninety-eight lines derived from these backcrosses (BC), seven recurrent parents, and 24 adapted lines derived from other source populations were included in a trial grown at Ibadan in Nigeria for three years. Carotenoid analyses of samples harvested from this trial found significant differences in accumulating provitamin-A and other carotenoids among lines, which were consistently expressed across years. The lines also displayed distinct carotenoid profiles. Among the best 25 inbred lines containing 5.0-16.6 mu g g(-1) beta-carotene and 8.0-17.4 mu g g(-1) pro-vitamin A, 24 were BC-derived lines and one was derived from a bi-parental cross of tropical yellow elite lines. The best BC-derived lines accumulated 23-313 % more beta-carotene and 32-190 % more provitamin-A than the recurrent parents. These BC-derived lines may be valuable resources for favorable alleles to develop maize varieties with high provitamin-A and for genetic studies to understand the underlying mechanisms regulating carotenoid biosynthesis. These results illustrate the effectiveness of exploiting natural allelic diversity existing in exotic lines through backcrossing combined with visual selection for bright yellow to orange kernel color with semi-flint to flint kernel texture in boosting provitamin-A to a new level in tropical maize.

publication date

  • 2015
  • 2015
  • 2015