Characterisation of maize and cucurbit landraces of the "Transkei" region of the Eastern Cape, Republic of South Africa

Abstract

Characterisation plays an important role in plant genetic resource conservation as it offers baseline information on collected materials with regard to basic morphological, morphological, agronomic and gastronomic properties. Thus, plant breeders use characterisation information as a guideline in prebreeding where race attributes and their heterotic patterns are established. In this study, results from the characterisation are presented in the form of a germplasm catalogue. The study follows a germplasm collection mission carried out in summer 1996 in the former Transkei, Eastern Cape. Twenty -six maize and twenty cucurbit accessions were collected in the region. Sampling was based on geographical and ethnic differences within the area. Eight districts represented the various ethnic groups and broad climatic zones within the region. The collected materials were multiplied and characterised during the summer of 1998 at the Fort Hare Research Farm. The maize accessions were self pollinated, but there was no interference with the reproduction of cucurbits. Vegetative traits were recorded during the milk stage of for the maize plants, and at flowering for the cucurbits. This thesis gives the characterisation of those accessions. Sample size for the accessions varied depending mainly on the quantity of seed stock that could be collected as well as the survival of the plants during the period of the experiment. The variation in sample size should be taken into cognisance in interpreting the data. Inevitably, the main product of a characterisation study is a germplasm catalogue for the accessions described. The idiotype of all these accessions is described in the catalogue, with intraspecific diversity for the accessions captured in the form of standard deviation or frequency of mode for all plant traits measured. Furthermore, similarity/ dissimilarity was analysed to get an understanding of the extent of diversity in the study area. Cluster analysis was used to describe this variation and expressed in the form of dendograms. From the analysis, a great potential in genetic diversity among the accessions was observed ascertaining that the former homelands are repositories of diversity in South Africa. Thus, any germplasm collection mission should focus on the conservation of materials from these areas. The diversity in th ese areas can also serve as an important genetic base in which breeders can scout for traits of particular interest. Diversity in relation to geographical areas was also evaluated. It was noticed that diversity for maize was higher in areas receiving more precipitation, whereas that of cucurbits was greater in drier areas. This was seen as having an implication on the understanding of cropping systems as they are influenced by climatic factors. The basis of morphological variation was also examined and several traits were identified as being different in accessions originating from different ecological zones. The importance of understanding indigenous knowledge is seen as a start for scientists in dealing with germplasm from traditional farmers. The endogenous information associated with the accessions was documented in the germplasm collection stage. The hypothesis that farmers intimately understand their cultivars was tested in this study was tested in this study, and was found to be true. Thus, indigenous information collected during the exploration stage was considered credible. Correlation between various morphological traits was analysed in the study, and some inferences based on “indicator” characters, like the ratio of ear:plant height were made. The idiotype of “unimproved” varieties was described, and it was apparent that approximately 23% of accessions analysed could be categorised as unimproved. This can be seen as an indicator of diversity loss, since the areas sampled were those that typically have unimproved varieties.