ISSN 2375-074X
African Journal of Plant Breeding ISSN 2375-074X Vol. 6 (3), pp. 001-010, March, 2019. © International Scholars Journals
Full Length Research Paper
Sampling strategies for proper quantification of carotenoid content in cassava breeding
Darwin Ortiz, Teresa Sánchez, Nelson Morante, Hernán Ceballos*, Helena Pachón, Myriam C. Duque, Alba Lucía Chávez and Andrés Felipe Escobar
International Center for Tropical Agriculture (CIAT), National University of Colombia, Palmira Campus, Apartado Aéreo 6713, Cali, Colombia.
Accepted 21 December, 2018
Abstract
Rapid-cycling recurrent selection has been implemented to produce cassava varieties that deliver pro-vitamin A carotenoids to human populations that are affected by vitamin A deficiency. Rapid-cycling selection relies on quantification in just one plant per genotype. This study was conducted to assess the reliability of single- plant evaluations and the effect of age of the plant on carotenoid content in cassava roots. Variation in aliquot quantifications from the same root was negligible indicating a reliable experimental procedure. A large source of variation for carotenoids was due to differences among genotypes. Root- to-root variation from the same plant in some cases was surprisingly high and accounted for an average of 25% of the total variation. Plant- to-plant variation was not as high and accounted for 20% of the total variance. Carotenoid content was shown to vary depending on the age of the plant. Single-plant evaluations for carotenoid content in cassava, which is a requirement for rapid-cycling recurrent selection is acceptable considering that it reduces in half the time required for evaluation and selection. However, it is suggested that 2 to 3 roots per plant be combined together in a sample to represent each genotype at a standard plant age.
Key words: Plant age, environmental influence, rapid cycling, genetic gains, -carotene, repeatability.