Determining the canning quality of small seeded white beans (Phaseolus vulgaris L.)

English: It is important to the producers, processors and consumers in south Africa to have dry bean cultivars with acceptable canning quality. Therefore, dry bean breeders needs sui table screening methods to evaluate the various lines at an early stage (F4) when only small amounts of seed are available. A micro-canning method to evaluate canning beans .in tomato sauce has been developed and compared to the commercial processing procedures with comparable results. External factors that influenced the canning quality like the water quality were investigated. This micro-canning method could therefore be used to investigate the effect of genotype and environment interactions that significantly influenced the canning quality. The objectives of this study were to: o Evaluate different qeriet i.c material for use as parents in the breeding program. $ To obtain a better understanding of canning quality characteristics of beans and to ensure that the most important characteristics are evaluated and the component interrelationships. • Determine the genotypic, environmental and genotype x environment interactions that influenced the canning quality. • To ascertain the patterns of interrelationships of the canning quality parameters and chemical analysis. • To investigate the patterns and relationships between standard and choice grade cultivars. e To investigate stability of locali ties between seasons as well as the clustering of different environments and seasons. Small seeded white beans, carioca and yellow haricot beans were used to determine variability in canning quality but as a result of a lower canning quality of coloured beans, only small seeded white beans were used for further investigations. As result of the investigations of different a characteristics, only the seed size, water absorption during soaking and canning, the texture and subjective visual appearance evaluations were used to determine canning quality. These characteristics were interrelated but single no parameter could explain variation' in canning quality. Canonical correlation analysis was used to determine to what extent variation of chemical components was responsible for differences in canning quality and these results indicated that mainly potassium and calcium would influence the water absorption and texture, respectively. Canonical variate analysis was used to determine the difference between unacceptable, standard and choice grade cultivars. A model was described from these analysis that could be applied to independent data sets that results in coordinates that differentiates the lines or cultivars as unacceptable, standard and choice grade. Significant interactions between genotype, environmental and seasonal effects for canning quality traits indicated that cultivar responses to variation in localities and seasons differ. Environmental effects resulted in inconsistent quality measurements since trait expression is strongly influenced by genotype x environment interactions. Results from this study suggested that the difference between cultivars could therefore be due to a complex interaction of the chemical and structural composition, which is genetically determined and influenced by the anv i ronmen t . as well as the changes that occur during processing. The Additive Main Effects and Multiplicative Interaction (AMMI) model mainly grouped KwaZulu-Natal separately as a region with poor canning quality. The rest of South Africa's localities grouped different for each season. Resulting from this investigation, several recommendations can be made: c Breeding material should be tested fo~ more than one season in order to select superior and more stable lines. o Elimination of canning quality evaluations of KwaZulu-Natal could improve the genetic progress. • Exploitation of the interactions by breeding for specific adaptation in a region of homogeneous area. Demarcating one or two areas in South Africa for the exclusive production of small white canning beans could improve the overall canning quality of the small white bean production in South Africa.