Phenotypic Diversity among Faba Bean (Vicia faba L) Landraces from the Ethiopian Highlands

አህፅሮት ባቄላ በኢትዮጵያ የብዝሀነት ስርጭት ያለዉና ፈርጀ-ብዙ የአመራረት፣ የአመጋገብና የጤና ጠቀሜታ ያለው ሰብል ቢሆንም ምርታማነቱ በተለያዩ ማነቆዎች የተነሳ በሰፊው ከሚመረቱት የጥራጥሬ  ሰብሎች አንፃር እጅግ ዝቅ ያለ ነው፡፡ በመሆኑም የባቄላ ዝርያ ብዝh zRN ተለያይነት ማጥናት  እነኚህን የምርት ማነቆዎች ተቋቁመው የተሻሻሉ ምርት ሊሰጡ የሚችሉ ዝርያዎችን ለማግኘት ዕድል ይፈጠራል፡፡ የዚህ ጥናት ዓላማ ከኢትዮጵያ የባቄላ አምራች ደጋማ xካባቢዎች ከአገርአቀፍ የደጋ ጥራጥሬ ምርምር ምንጮች እንዲሁም ከአለም አቀፍ ምርምር ተቋማት የተገኙ 50 የባቄላ ብዝሃ-ዘሮችን በሆለታ ምርምር ማዕከል ውስጥ Randomized Complete Block Design ዘርቶ በመገምገም ያላቸውን የዝርያ ተለያይነት፣ ብዝሃነትና ስብጥር ምን እንደሚመስል ለማወቅ ሲሆን የዚህ ጥናት መረጃዎች በ ቫሪያንስ፣ bክሊስተር እና bፕሪንሲፓል ኮምፖንነት ትንተና ዘዴዎች ትንተና ውጤት እንdሚያመለክተዉ በባቄላ ብዝሃ-ዘሮቹ ስብስቦች መካከል ከፍተኛ የሆነ በሽታ የመቋቋም፣ የሞርፎሎጂ ባህሪያት፡ የምርታማነት እና የምርት ኮምፖነንት  ተለያይነት  እንዳላቸዉ ይጠቁማል፡፡ በተጨማሪ የክላስተር ትንተና በጥናቱ ውስጥ የተካተቱ 50 የባቄላ ብዝሃ-ዘሮችን ሶስት ቦታ ሲመድባቸው፤ በተለያየ ንዑስ ቡድን ተከፋፍለዋል፡፡ የዚህ ጥናት ውጤት በአጠቃላይ  የእነዚህ በባቄላ ብዝሃ-ዘሮቹ ስብስቦች መካከል መለያየት ዝርያ ለማሻሻያ መልካም አጋጣሚነትን  በመጠቀም በባቄላ ምርት ማሻሻያ ምርምር  ውስጥ ለመጠቀም የሚያስችል የባቄላ የብዝሃ-ዘር ተለያይነት እንዳለ በጥናቱ ይጠቁማል፡፡    AbstractKnowledge of phenotypic diversity is important for devising the breeding strategy for faba bean (Vicia faba L.) program in Ethiopia. This study was conducted to determine phenotypic diversity among 50 faba bean genotypes collected from the major faba bean growing areas of Ethiopia and International Centre for Agricultural Research in the Dry Areas (ICARDA). The genotypes were evaluated at two locations using a randomized complete block design with three replications. All agronomic data, yield and yield component, chocolate spot (Botrytis fabae) disease incidence disease severity were collected and analyzed using analysis of variance, principal component analysis and the Shanon-Weaver index, using SAS V9.3 and PAST V 3.0 software. There were significant differences (p< 0.001) among the genotypes on most of phenotypic traits, chocolate spot disease severity, yield and its component. The genotypes were categorized into three clusters and different sub-groups. Six principal components were identified explaining more than 80% of the total variation. The Shannon-Weaver diversity index, which ranged from 3.82 for pod weight to 7.15 for number of basal branches per plant, revealed high diversity among and within the genotypes. The observed high variation among the faba bean genotypes would be exploited in new faba bean varieties development program

Genetic effects and associations between grain yield potential, stress tolerance and yield stability in southern African maize (Zea mays L.) base germplasm.

Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.Maize (Zea mays L.) is the principal crop of Southern Africa but production is threatened by gray leaf spot (Cercospora zea-maydis L.) and phaeosphaeria leaf spot (Phaeosphaeria maydis L.) diseases, drought and the use of unadapted cultivars, among other constraints. There are few studies of gray leaf spot (GLS) and Phaeosphaeria leaf spot (PLS) resistance, drought tolerance, yield stability and maize cultivar preferences in Southern Africa. The objective of this study was to: a) determine farmers’ preferences for cultivars; b) investigate the gene action and heritability for resistance to GLS and PLS, and drought tolerance; and c) evaluate yield stability and its relationship with high yield potential in Southern African maize germplasm. The study was conducted in South Africa and Zimbabwe during 2003 to 2004. A participatory rural appraisal (PRA) established that farmers preferred old hybrids of the 1970s because they had better tolerance to drought stress. Farmers also preferred their local landrace because of its flintier grain and better taste than the hybrids. The major prevailing constraints that influenced farmers’ preferences were lack of appropriate cultivars that fit into the ultra short seasons, drought and low soil fertility. Thus they preferred cultivars that combine high yield potential, early maturity, and drought tolerance in all areas. However, those in relatively wet areas preferred cultivars with tolerance to low soil fertility, and weevil resistance, among other traits. A genetic analysis of 72 hybrids from a North Carolina Design II mating revealed significant differences for GLS and PLS resistance, and drought tolerance. General combining ability (GCA) effects accounted for 86% of genetic variation for GLS and 90% for PLS resistance indicating that additive effects were more important than non-additive gene action in controlling these traits. Some crosses between susceptible and resistant inbreds had high resistance to GLS suggesting the importance of dominance gene action in controlling GLS resistance. Resistance to GLS and PLS was highly heritable (62 to 73%) indicating that resistance could be improved by selection. Also large GCA effects for yield (72%), number of ears per plant (77%), and anthesis-silking interval (ASI) (77%) under drought stress indicated that predominantly additive effects controlled hybrid performance under drought conditions. Although heritability for yield declined from 60% under optimum to 19% under drought conditions, heritability for ASI ranged from 32 to 49% under moisture stress. High heritability for ASI suggested that yield could be improved through selection for short ASI, which is positively correlated with high yield potential under drought stress. The stability analyses of the hybrids over 10 environments indicated that 86% had average stability; 8% had below average stability and were adapted to favourable environments; and 6% displayed above average stability and were specifically adapted to drought stress environments. Grain yield potential and yield stability were positively correlated. In sum, the study indicated that farmers’ preferences would be greatly influenced by the major prevailing constraints. It also identified adequate genetic variation for stress tolerance, yield potential and yield stability in Southern African maize base germplasm, without negative associations among them, suggesting that cultivars combining high yield potential, high stress tolerance and yield stability would be obtainable.Submitted to the African Centre for Crop Improvement

Combining ability analysis and heterotic grouping for grain yield among maize inbred lines selected for the mid-altitude and highland zones of Rwanda

Development and identification of maize parental lines that belong to different heterotic groups is a fundamental requirement for any hybrid production programme. The objective of this study was, therefore, to determine combining ability, heterosis and heterotic patterns for grain yield among ten selected local (unknown heterotic groups) and exotic (known heterotic groups) maize inbred lines and their progenies under mid-altitude and highland conditions of Rwanda. Forty-five single crosses from a 10 x 10 half-diallel mating design plus three checkswere tested in a 6 x 8 alpha-lattice design across twelve environments. General combining ability (GCA) and specific combining ability (SCA) effects were both highly significant (P<0.001-0.01), suggesting presence of both additive and non-additive gene effects. The percentage mid-parent heterosis (MPH) for grain yield ranged from36.4to 267.7% with a mean of 164%, while high-parent heterosis (HPH) varied from 33.2% to 236% with a mean of 130.4%. Based on MPH, the seven local maize inbred lines were discriminated and assigned into four different heterotic groups (S4, S7, S4/S6 and S6/S7). The highest heterotic patterns were realized between tester S4and tester S6 (hybrid S4/S6) and between group S7 and tester S4 (hybrid S2/S4). Identified patterns would be potentially useful for maize hybrid production in Rwanda. Similarly, the resulting hybrids could be recommended in sub-Saharan African regions with similar ecosystems. Significance of both additive and non-additive geneticeffects in the current germplasm suggests that the Rwandan breeding programme could use both hybridization and recurrent selection methods

Genetic variability in soybean (Glycine max L.) for low soil phosphorus tolerance

Assessment of the genetic variability of soybean genotypes under low soil phosphorus (P) conditions provides an understanding of the genetic potential of the genotypes to improve the crop for low P tolerance. The study was designed objectively to estimate the extent of genetic variability of soybean genotypes for low P tolerance. Thirty six soybean genotypes that were introduced from various sources were grown in simple lattice design with three replications at three locations in Western Ethiopia characterized by P-deficient-acidic soils. It was revealed that weight of 100 seeds; plant height, root and biomass fresh weight exhibited relatively high heritability and genetic advance on low P soils. Principal component analysis also revealed that the first five principal components (PCs) accounted for more than 85% of the total variation. The first principal component that contributed for 37.7% of the total variation was influenced by root fresh weight, tap root length, root volume, fresh biomass weight, days to maturity and days to flowering in the order of importance; indicating the significance of these traits for low P tolerance screening. Cluster analysis grouped the genotypes into four clusters. Observation of large variation and relatively high heritability indicates that selection would be effective to improve soybean varieties for performance on P stressed soils and identify low P tolerant varieties that helps smallholder farmers optimize soybean productivity on P deficient soils

Farmers’ desired traits and selection criteria for maize varieties and their implications for maize breeding: A case study from KwaZulu-Natal Province, South Africa

Adoption of hybrids and improved varieties has remained low in the smallholder farming sector of South Africa, despite maize being the staple food crop for the majority of households. The objective of this study was to establish preferred maize characteristics by farmers which can be used as selection criteria by maize breeders in crop improvement. Data were collected from three villages of a selected smallholder farming area in South Africa using a survey covering 300 households and participatory rural appraisal methodology. Results indicated a limited selection of maize varieties grown by farmers in the area compared to other communities in Africa. More than 97% of the farmers grew a local landrace called Natal-8-row or IsiZulu. Hybrids and improved open pollinated varieties were planted by less than 40% of the farmers. The Natal-8-row landrace had characteristics similar to landraces from eastern and southern Africa and closely resembled Hickory King, a landrace still popular in Southern Africa. The local landrace was preferred for its taste, recycled seed, tolerance to abiotic stresses and yield stability. Preferred characteristics of maize varieties were high yield and prolificacy, disease resistance, early maturity, white grain colour, and drying and shelling qualities. Farmers were willing to grow hybrids if the cost of seed and other inputs were affordable and their preferences were considered. Our results show that breeding opportunities exist for improving the farmers’ local varieties and maize breeders can take advantage of these preferred traits and incorporate them into existing high yielding varieties

A review of genetic analysis and response to selection for resistance to Busseola fusca and Chilo partellus, stem borers in tropical maize germplasm: A Kenyan perspective

This paper provides a review on the context for the research in maize improvement for resistance to stem borers (Chilo partellus and Busseola fusca) in tropical environments. The following aspects are reviewed a) major productions constraints in East Africa, b) the stem borer problem in maize, c) genetic studies on maize resistance to stem borers. The explanations of key technical issues on progress and challenges in breeding for stem borer resistance in maize, inheritance of stem borer resistance and combining ability in maize, maize heterotic patterns, determination of heterotic orientations, application of the line x tester mating design, screening methods, selection indices, genotype x environment interactions, and response to selection for resistance to stem borers are addressed. Therefore, this paper forms a setting of reference for the study

Influence of biofortification with provitamin A on protein, selected micronutrient composition and grain quality of maize

Provitamin A-biofortified maize is currently being evaluated for use in the alleviation of vitamin A deficiency. Apart from the differences in provitamin A content, the nutritional composition of provitamin A-biofortified maize compared to white maize is hardly known. This study aimed to evaluate the protein and selected micronutrient composition of biofortified maize varieties and the quality of their grains. A total of 32 provitamin A-biofortified maize varieties was analysed for their starch, fat, protein and mineral content. The milling and storage quality of the biofortified maize grains were also assessed. When compared with the white maize variety, the biofortified varieties were higher in starch, fat and protein, but were lower in iron. The biofortified maize varieties were better sources of most of the essential amino acids relative to the white variety, but, similar to the white maize, they were deficient in histidine and lysine. Overall, the quality of the grains of the biofortified maize varieties was superior to that of the white maize grain, although, the biofortified grains were more susceptible to fungal invasion. This study indicates that, in terms of the nutrients assessed, provitamin A-biofortified maize is generally superior to white maize, except for minerals.Keywords: Biofortification, provitamin A, protein, micronutrient composition, maize.African Journal of Biotechnology Vol. 12(34), pp. 5285-529

Assessment of popping ability of new tropical popcorn hybrids

Abstract Popcorn is an important snack food worldwide with significant nutritional benefits, including minerals and vitamins. However, adequate production of popcorn in Sub-Saharan Africa is hampered by lack of adapted varieties. This therefore calls for breeding investigations to develop new hybrids. The objectives of the study were to determine variability among hybrids for popping quality traits, gene action involved in conditioning of quality traits in popcorn hybrids and relationships among quality traits in popcorn. Random crosses were generated among inbred lines resulting in 119 experimental F 1 hybrids with adequate seed. A commercial hybrid P618 grown under the same conditions was used as a standard check. The F 1 hybrids were grown at two locations. Two popping methods were used, the microwave and the hot air popping method. The data was analysed in SAS. Significant variability was observed among hybrids for popping quality traits (p≤0.05). The study identified 15 hybrids with superior popping quality. The hybrid 11POPH13 gave the highest flake volum

Estimation of genetic diversity of germplasm used to develop insect-pest resistant maize

Genetic diversity is important in ensuring viability of germplasm for a breeding program. The objective of this study was to determine the genetic diversity of 130 S families from two populations; stemborers’ resistant and storage pests’ resistant populations, each with 65 lines; using 30 simple sequence repeats (SNP) molecular markers. The markers were found to be polymorphic with 0.46 - 0.48 polymorphism for both populations, except locus umc1367, which was monomorphic for storage pests’ resistant population. A total of 109 alleles were recorded from stemborers’ resistant population. Allele’s scores ranged from 2 to 6 alleles per locus, with a mean of 3.6, and product length ranging from 47 bp to 362 bp. The storage pests’ resistant population had a total of 103 alleles, with scores of 1 to 6 per locus, and a mean of 3.4 alleles; and product length of 47 - 320 bp. Observed gene diversity was 0.27, with expected gene diversity of 0.45 for stem borers’ resistant population and 0.48 storage pests’ resistant population. Mean polymorphism information content values ranged from 0.46 to 0.48, while unbiased expected heterozygosity ranged from 0.4 to 0.45 for both populations. Cluster analysis revealed three major clusters in each population; with cluster 1 comprising 34 - 40% of the genotypes in both populations. Cluster 2 had 55% for stem borers’ resistant genotypes, and 53% of storage pests’ resistant genotypes. The study indicates that there is ample genetic diversity in both populations which can be exploited in extracting new inbred lines for use in breeding insect resistant maize hybrids

Genetic diversity among maize inbred lines selected for the mid- altitudes and highlands of Rwanda

Understanding the genetic diversity and relationships among breeding materials is fundamentally considerable for any crop improvement program. This study was carried out to apply specific single nucleotide polymorphism (SNP) markers to determine the amount of genetic diversity prevailing among maize inbred lines selected for the mid-altitudes and highlands of Rwanda and classify the inbred lines according to their relationships for an effective hybrid breeding program. Seventy one maize inbred lines from different sources were genotyped with ninety two SNP markers. The unweighted pair group method with arithmetic mean (UPGMA) revealed that there was a random allocation of the inbred lines into different clusters and they were allocated into 2 major clusters regardless their origin. The highest (0.375) polymorphic information content (PIC) observed was exhibited by 3 markers; PZA00543_12, PZA00878_2, and PZA01735_1; while the lowest PIC value was revealed by the marker PZA01755_1 (0.1224).The PIC value (0.30) revealed in this study may confirm the potential for these SNP markers to discriminate between inbred lines from diverse origins and their usefulness for diversity analysis of maize inbred lines under this study. Genetic clustering information acquired from the current study would be suitable information not only for maize hybrid program establishment in Rwanda, but also for other collaborative tropical maize breeding programs. This might guide towards suitable heterotic patterns and groups as well as the combining ability of the inbred lines involved in this study