Derera, John.Gasura, Edmore.Kolanisi, Unathi.Siwela, Muthulisi.Palacios, Natalia.Qwabe, Fikile Nozipho Pricilla.2020-01-162020-01-1620182018https://researchspace.ukzn.ac.za/handle/10413/16783Doctor of Philosophy in Plant Breeding. University of KwaZulu-Natal, Pietermaritzburg, 2018.Diets of most people in sub-Saharan Africa are composed of mainly cereals that frequently lack most nutrients, such as Vitamin A. Vitamin A deficiency is the leading cause of preventable childhood blindness and increases the risk of death from common childhood illnesses, such as diarrhea. According to The World Health Organization, it affects 48% of children less than 5 years, in sub-Saharan Africa. This global challenge could be alleviated by breeding orange pro-Vitamin A maize hybrids, among other strategies. However, there was need to determine acceptance, adaptation and adoptability of these hybrids by the poor communities, in KwaZulu-Natal, and potential for improvement through breeding. Bio-fortification of maize with orange pro-vitamin A (PVA) changes maize grain colour, organoleptic properties (mainly flavor) and various agronomic traits due to effects of different genetic backgrounds. This study aimed at (i) establishing perception of consumers towards fresh PVA maize, (ii) determining agronomic performance of PVA hybrids across major production environments in South Africa, (iii) determining combining ability and gene action among a set of PVA germplasm and, (iv) identifying traits associated with high yield in PVA germplasm. Sensory evaluation and focus group discussions were conducted, in KwaZulu-Natal province, of South Africa. Results indicated acceptance of orange PVA maize by the end-users and reflected the effects of both age and gender. There were more women (79%) and men (76%) preferring boiled and roasted green mealies, respectively. Interestingly, the youth (18-35 years) had a higher acceptance of PVA maize compared to middle aged (36-60 years) and the elderly (61-75 years). However, focus group discussions revealed that farmers had concerns of agronomic adaptability, economic value, and food value of the PVA maize. The study showed potential for PVA maize in its fresh form for utilization as a food and cash crop. To understand the genetics of PVA maize, crosses among 10 PVA inbred materials with 10 inbred materials from diverse genetic backgrounds were conducted using a lines by tester mating scheme. The resultant 100 single cross hybrids were evaluated using a 10 x 10 α-lattice design with two replications across four environments in South Africa. There were significant differences among hybrids for grain yield and agronomic traits. The lines and testers main effects, and line x tester interaction effects, as well as their interactions with the sites were significant (P< 0.05) for grain yield and associated traits. The predominant additive gene action for most traits including grain yield allowed selection of desirable inbred lines. The significant (P<0.05) genotype plus genotype x environment interaction enabled identification of stable and high yielding hybrids. The agronomic performance of a set of PVA hybrids were compared to white and yellow maize counterparts to understand the yield gap among them. Generally, PVA hybrids had yields that were lower than that of the white and yellow maize types, indicating opportunity for further breeding gains. Although several traits such as longer ears, high shelling percentage, and resistance to diseases were correlated with yield, the lower grain yield of PVA hybrids was associated with high root and stem lodging. There is need to take advantage of the predominant additive gene action to develop inbred lines that can produce stable and high yielding hybrids through fixing lodging related traits in PVA. Overall the study confirmed the opportunity for deploying orange pro-vitamin A maize hybrids and contribute to alleviation of Vitamin A deficiency in KwaZulu-Natal.enVitamin A deficiency.Pro-vitamin A maize.Bio-fortification.Consumer acceptance.Genetic analysis.Orange maize.Combining ability.Thesis