5.2.1 Plant material
Forty nine genotypes of Bambara groundnut landraces were used in this study. The genotypes consisted of single plant selection from an initial collection of landraces which were characterized for their seed morphological and inter- and intra-genetic diversity. The selected genotypes represent landrace collections from seven geographical zones in the sub-Saharan Africa (Table 5.1).
5.2.2 Study site
The experiment was conducted from December, 2012-April, 2013 at the Research and Training Farm of the University of KwaZulu-Natal, Pietermaritzburg, at Ukulinga, South Africa. The site is situated on a Latitude 30o 24’S, Longitude 29o 24’E, and is 800m above sea level. The soil pH was 4-5, clay percentage 34%-38%, organic carbon 2.5%-3.2% and organic N 0.36%. Relative humidity varied between 30%- 100% throughout the season, with temperatures varying between 20-30°C, and 322 mm of rain. (Source:
University of KwaZulu-Natal weather station).
5.2.3 Experimental design, field management and data collection
The Bambara groundnut genotypes were evaluated using a partially balanced lattice design with three replications. The genotypes were randomised to the seven incomplete blocks across the three replications.
The experimental plot comprised of three rows measuring 2.2m x 3.0m, with inter and intra row spacing of 0.4 m x 1.0 m. This spacing was proposed to allow the crop to express its production potential. Sowing was done into a flat seedbed, with one seed sown to each stand. Seeds the fail to germinate were replaced
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within two weeks after sowing. All relevant agronomic practices were carried out to maintain a healthy crop.
Data on the 26 morphological traits were generated from five plants selected from the central row of each plot within the incomplete blocks over the three replicates. Both qualitative and quantitative data were recorded. The quantitative field data included number of days to 50% seedling emergence (SDE) by counting number of days from planting to 50% seedling emergence. Plant height (PHT) was measured using a measuring ruler and expressed in cm as distance from the ground level to longest terminal leaf of the plant. Canopy spread (CNS) was taken as the widest ends of the plant; terminal leaf length (TLL), terminal leaf width (TLW) were measured were measured as the distance from the leaf tip to the point the leaf by the leaf blade ends on the leaf stalk and the widest ends across the leaf blade, respectively. Petiole length (PETL) was taken between the point of attachment to the stem and the leaf blade. These records were taken from 10 weeks after planting. Qualitative data recorded included leaf colour at emergence (LCE), terminal leave shape (TLS), growth habit (GH), stem pigmentation (SPG), petiole colour (PCL), leaflet joint pigmentation (this is the pigmentation at the point of attachment of petiole to the petiole) (LJP), calyx colour (CCL), fresh pod colour (FPC), pod shape (PSP), dry pod colour (PCL), pod texture (PTX), seed shape (SSP) and seed eye pattern (SEY). The qualitative data were determined by visual observations at 8-10 weeks after planting.
Post-harvest quantitative data were taken two months after harvest by which time all the seeds in the pods were dry. They include dry biomass (BMA), pod weight (PDW), seed weight (SDW) recorded in grams (g) using an OHAUS Precision Standard Measuring Scale, while hundred (100) seed weight (HSW) was recorded also in grams using a more sensitive Mettler Scale. Seed length (SDL), seed width (SDW), and seed height (SHT) were determined using a Digital Vernier calipers (cm) on ten randomly, but well developed and uniform seeds taken from seeds used for 100 seed weight measurement for each of the accessions. Threshing of samples was done manually in preparation for the next post-harvest measurements, which include qualitative data on kernel shape (PDS), kernel colour (PDC), kernel texture (PDT), seed shape (SDS) and seed eye pattern (SEY). These measurements were recorded based on visual observations. All data were recorded according to descriptors for Bambara groundnuts (IPGRI/IITA/BAMNET, 2000) with some modifications.
5.2.4 Data analysis
All the quantitative traits over the three replications were computed for all accessions over the seven incomplete blocks and subjected to analysis of variance (ANOVA), based on the lattice procedure using Agrobase statistical software (Agrobase, 2005). Treatments’ means were separated by the least significant differences (LSD) at 5% probability. Cluster and Principal Component Analyses were conducted to
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determine similarities and dissimilarities among the genotypes using SPSS (SPSS, IBM Statistics 20). A similarity matrix was used and a dendrogram constructed to describe similarities and differences among the Bambara groundnut genotypes.
127 Table 5.1 A list of sources of Bambara groundnut accessions used in the study
S/No. Genotype Origin Seed coat colour Entry status S/No. Genotype Origin Seed coat colour Entry status
1 211-77 CAPS cream 2011 entry 26 211-75 CAPS Cream 2011 entry
2 211-87 CAPS black 2011 entry 27 211-46-3 CAPS Red 2011 entry
3 211-55 CAPS red 2011 entry 28 211-83-2 CAPS Cream 2011 entry
4 32-1-1 ZM light brown ZM 3236 29 712-4 ZM Tan ZM 5712
5 45-2 ZM tan ZM 2045 30 N211-1 KNG Cream 2011 entry
6 211-55-1 CAPS red 2011 entry 31 KB 05 ARC Cream KUBU
7 TV-79-1 IITA (Kenya)* cream TVSu 792 32 211-68 CAPS Cream 2011 entry
8 211-90 CAPS black 2011 entry 33 101-2 ZM Cream stripe ZM 5101
9 211-51 CAPS red 2011 entry 34 KB 08 ARC Cream RBF** KUBU
10 211-91 CAPS light brown 2011 entry 35 M12-1 ZIM Cream ZIM 112
11 42-2-3 ZM light brown ZM 2042 36 712-7 ZM Tan ZM 5712
12 84-2 ZM red ZM 5684 37 211-45 CAPS Red 2011 entry
13 N211K KNG cream 2011 entry 38 101-2-1 ZM Cream stripe ZM 5101
14 73-3 ZM red ZM 4673 39 42-2 ZM Light brown ZM 2042
15 211-76 CAPS cream 2011 entry 40 M01-8 ZIM Cream RBF ZIM 101
16 25-1 ZM light brown ZM 5425 41 TV-93 IITA (Kenya) Cream TVSu 793
17 B71-2 ARC cream SB 7-1 42 M02-3 ZIM Cream RBF ZIM 102
18 M09-4 ZIM cream ZIM 109 43 B71-1 ARC Cream SB 7-1
19 N212-5 KNG brown 2011 entry 44 73-2 ZM Red ZM 4273
20 TV-27 IITA (Nigeria) dark brown speckle TVSu 275 45 211-88 CAPS Black 2011 entry
21 M09-3-1 ZIM cream ZIM 109 46 N212-4 KNG Brown 2012 entry
22 011-7 PMB cream stripe 2011 entry 47 TV-39 IITA (Sudan) Dark brown speckle TVSu 390
23 N212-8 KNG brown 2012 entry 48 211-69 CAPS Cream 2011 entry
24 211-57 CAPS red 2011 entry 49 M09-3 ZIM Cream ZIM 109
25 42-1 ZM light brown ZM 2042
CAPS= CAPSTONE Seed Company, South Africa; ZM= Zambian National Program; IITA= International Institute of Tropical Agriculture in Ibadan, Nigeria; with a place origin; KNG= Kano, Nigeria; ZIM= Zimbabwean National Program; PMB= Pietermaritzburg; ARC=Agricultural Research Council of South Africa; RBF=Red butterfly eye
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