Consumer acceptability, adaptability and genetic analysis of orange pro-vitamin A maize hybrids in KwaZulu-Natal province of South Africa.

Doctor 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

Breeding investigations for development of specialty green maize hybrids.

Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermartizburg, 2011.Green maize (Zea mays L.) provides food security and cash income to rural households in Sub-Saharan Africa (SSA). However, research on green maize varieties is scarcely reported in the literature. Consequently there is no information on suitable genetic materials (germplasm) for green maize production. Additionally there is no data regarding quality attributes of suitable hybrids, which impacts on variety development and management. Breeding investigations were therefore conducted to investigate farmers’ preferences for hybrids and attributes of green maize hybrids in KwaZulu-Natal, in South Africa, and to determine combining ability for green maize traits of experimental inbred lines that were derived from an experimental population. The study also investigated the relationships between green maize traits and some desired agronomic traits; and also sought to identify specific inbred combinations (hybrids) with potential for green maize production. A case study was conducted at Mjindi (MJD) and Ndumo (NDO) Irrigation Schemes in KwaZulu - Natal South Africa, to determine the attributes of the “ideal” hybrid, production constraints, production trends and enterprise viability. Prior to a formal survey some focus group discussions were conducted, then 64 green maize growers were interviewed using a formal questionnaire. The study indicated that the most desired consumer traits were a combination of sweet taste, long shelf life and large ears. The required attributes of the model hybrids were high grain yield potential, high selling ability, flint grain texture, white grain color, medium ear placement, thick and long ears, short maturity period, medium plant height, long shelf life and nonpopping during roasting. This study also showed that the enterprise was viable with average gross margin of about R10,000 per ha which makes it attractive to both small and large-scale commercial farmers with implications for rural development in the second economy. Thus there is a great business potential, but lack of suitable and special hybrids appears to be the major production constraint which should be addressed by research and development. A total of 100 advanced maize inbred lines were crossed in a line x tester mating scheme to generate 200 experimental hybrids. The hybrids with sufficient seed were evaluated for green maize and agronomic traits at three sites in KwaZulu-Natal. Large genotype x environment interaction effects were observed which was reflected by the different ranking of hybrids at each site resulting in selection of different sets of top 15 hybrids with potential for production in each environment. Only a few hybrids exhibited high performance consistently in at least two mega environments. The results showed that hybrids were highly significantly different for the green maize traits such as ear yield, ear length, single ear weight and marketability indices, and also for the agronomic traits. The difference among hybrids for marketing ability indices was attributed to the testers main effects and specific combining ability (SCA) effects. Differences between the general combining ability (GCA) of the lines and testers, and SCA effects were significant for the green maize traits. These findings suggested that the traits are governed by both additive and non-additive gene effects, respectively. Additionally observation of continuous and normal distribution of hybrids for the traits indicated that quantitative minor genes were involved and therefore the base population can be improved by selection for large ears, superior marketability index, and high single ear yield. The observed top performing hybrids were recommended for further testing at many sites. Results confirmed that the current dominant variety is not adapted to summer production conditions in the Mjindi and Ndumo areas which present opportunities for breeding programmes. Future studies should therefore aim to improve both the genetics and production economics of specialty green maize hybrids to further enhance profitability of the enterprise with positive implication for the rural economy in KwaZulu-Natal

The Effect of Peeling and Boiling Process on Nutrition and Health-Promoting Compounds of Root Vegetables Harvested at Mjindi area Located in Jozini, KwaZulu Natal, South Africa

The effect of peeling and boiling process was investigated on nutrients and health-promoting compounds of amadumbe (Colocasia esculenta), carrots (Daucus carota), sweet potatoes (Ipomoea batatas) and potatoes (Solanum tuberosum). The results indicated that peeling and boiling led to significant reduction of nutrients (total soluble starch, total soluble protein, crude fibre) and health-promoting compounds (flavonols, anthocyanin and phenolic acid). Peeling effects on nutrient content did not yield similar outcome (increase and decrease). Carrots showed insignificant loss of total soluble starch after peeling and major loss was observed after boiling. Amadumbe shows substantial loss of fibre after peeling, peels yielding 42.38% and edible part yielding 8.31% compared to all of the analysed vegetables. Health-promoting compounds were reduced significantly peeling and boiling process. The nutrient and phytochemical compounds in the peels of the various vegetables depends on method of peeling. Fourier-Transform Infrared Spectroscopy (FT-IR) bands evidenced the presence of nutrients and health-promoting compounds in studied vegetables. Keywords: Boiling; Flavonols; Health promoting compounds; Nutrients; Peeling; Phenolic acid</jats:p