African Journal of Crop Science

African Journal of Crop Science ISSN 2375-1231 Vol. 6 (5), pp. 001-010, May, 2018. © International Scholars Journals

Full Length Research Paper

Variation and association among characters genetically related to yield and yield stability in Coffea canephora genotypes

E. Anim-Kwapong*, G. J. Anim-Kwapong and B. Adomako

Cocoa Research Institute of Ghana, P. O. BOX 8, New Tafo-Akim, Ghana.

Accepted 04 February, 2018

Abstract

Water deficit stress is a main factor determining yield and yield stability in Robusta coffee (Coffea canephora P.). Studies were conducted to identify agronomic traits that offer genetic sources of drought tolerance associated with yields and yield stability. In a nine-year experiment, 18 genotypes were assessed for mean value and variation in three diverse environments, for nine vegetative traits, five reproductive traits and bean yield. Drought tolerance was expressed by a visual scale of leaf scorching from 0 to 5: tolerant – susceptible on the genotypes in 2000 when there was drought, and genetic associations between leaf scorching and the traits established. Significant interaction (P ≤ 0.05), and location (P ≤ 0.05) effects were observed for leaf scorching scores and all the traits, except stem diameter and diameter of primary branches. Significant (P ≤ 0.05) genotypic effects were also observed for all the traits, except fruits per node. Canopy diameter (Span), number of primary branches per plant (NPB), fruit-set (FS) and bean yield over seven years (MY1-7) were inversely and significantly (P ≤ 0.05) correlated with leaf scorching scores. Span, NPB and FS were also significantly (P ≤ 0.05) correlated with MY1-7. Span was highly correlated with stem diameter, length and diameter of primary branches. Eight genotypes each with high mean performance for (MY1-7) and fruit set (FS), seven for Span, and five for NPB, were among the top 10 genotypes which recorded the lowest leaf scorching scores. The results indicate that, Span and its associated traits, NPB, and FS could be exploited, through indirect selection for superior Coffea canephora genotypes, for direct utilisation or for breeding for adaptation to drought-stress.

Key words: Drought tolerance, leaf scorching, agronomic traits, yield, yield stability, genetic correlations, genetic variation, indirect selection, Coffea canephora.

African Journal of Crop Science ISSN 2375-1231 Vol. 6 (5), pp. 001-011, May, 2018. © International Scholars Journals

Full Length Research Paper

Characterization of okra (Abelmoschus spp. L.) germplasm based on morphological characters in Ghana

D. Oppong-Sekyere¹, R. Akromah¹, E. Y. Nyamah², E. Brenya³ and S. Yeboah¹

¹Department of Crop and Soil Sciences, KNUST-Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.

²Department of Horticulture, KNUST-Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.

³CRIG-Cocoa Research Institute of Ghana, P. O. Box 8, New Tafo-Akim, Ghana.

Accepted 11 January, 2018

Abstract

Twenty five accessions of okra collected in Ghana were evaluated for phenotypic identity, diversity and quality based on morphological characters. Qualitative and quantitative characteristics were measured and scored as specified by the standard international crop descriptor for okra. A dendrogram was generated for morphological data based on the simple matching coefficient, and four cluster groups were observed. The distribution of the accessions into the groups, based on the morphological traits had no unique geographical relationship. The results of the matrix of similarity among the 25 accessions performed by NTsys pc programme placed two accessions in a tie, suggesting that, they were identical. Eight accessions were placed at above 80% similarity, meaning that, the accession pairs were closely related, and three accessions were 50% similar, which means they matched at half the characters measured. Six pairs of accessions measured were somewhat diverse, which can be exploited by plant breeders for further improvement. The genetic affinity between the accessions from different regions and ethnic groups could however be due to the selection and exchange of okra between farmers from different regions and ethnic groups. Distinct morphotypes exist in the Ghanaian okra germplasm, depicted by variation in petal colour, pubescence of the leaf and stem, fruit shape, anthocyanin pigmentation and number of days to 50% flowering.

Key words: Dendrogram, diversity, morphotypes, pubescence, vegetables.

African Journal of Crop Science ISSN 2375-1231 Vol. 6 (4), pp. 001-011, April, 2018. © International Scholars Journals

Full Length Research Pape

Physicochemical and functional characteristics of cassava starch in Ugandan varieties and their progenies

Ephraim Nuwamanya¹, Yona Baguma²*, Naushad Emmambux³, John Taylor³ and Rubaihayo Patrick¹

¹Department of Crop Science, Makerere University Kampala, P. O. Box 7062, Kampala, Uganda.

²National Crops Resources Research Institute (NaCRRI), P. O. Box 7084, Kampala, Uganda.

³Department of Food Science, Faculty of Agriculture, University of Pretoria, South Africa.

Accepted 09 January, 2018

Abstract

Due to poor root quality traits in improved, disease resistant cassava (Manihot esculenta Crantz.) varieties and hence low acceptability among farmers, a study was undertaken to improve these varieties by crossing them with disease susceptible, farmer preferred local landraces. Five improved varieties and four local landraces were used and hybridisations among them were made in a poly-cross nursery block. Starch isolated from the nine cassava varieties and their F ₁ progenies was analysed for physicochemical and functional properties. Significant differences were observed between varieties, progenies and within the F₁ progenies. The amylose content ranging between 19.0 - 25.0% was negatively correlated to swelling power and solubility but positively correlated to starch content. Average starch granule sizes ranged between 7.0 - 12.0 mm, though smaller granules ranged between 2 6.9 mm and large granules between 13 – 20 mm. Granules were mainly truncated in shape and similar across varieties and their progenies. Individual parents had peak viscosity, set back viscosity and viscosity at breakdown higher than the progenies suggesting inherent genetic and biochemical differences among parents used in the study. Variations were also observed in the parents and progenies for starch swelling power, solubility and starch content on dry basis. Starch associated molecules such as proteins and lipids did not vary significantly but dietary fibre significantly (P< 0.05) varied both in parents and F₁ families. Significant correlations (r > 0.45) were observed among starch properties including swelling power and breakdown viscosity. Based on these results, selections for lines with different starch quality and quantity properties can be made among the F1 families for future dietary and industrial uses.

Key words: Progenies, starch granules, viscosity, physicochemical properties.

African Journal of Crop Science ISSN 2375-1231 Vol. 6 (4), pp. 001-011, April, 2018. © International Scholars Journals

Full Length Research Paper

Combining the yield ability and secondary traits of selected cassava genotypes in the semi-arid areas of Eastern Kenya

Joseph Kamau¹, Rob Melis², Mark Laing², John Derera², Paul Shanahan² and Eliud Ngugi³

¹Kenya Agricultural Research Institute- Katumani, Nairobi, Kenya.

²University of KwazuluNatal – Petermaritzburg, South Africa.

³University of Nairobi, Kabete Campus, Nairobi, Kenya.

Accepted 11 January, 2018

Abstract

Despite the importance of cassava for food security in semi-arid areas of Kenya, there is a lack of information regarding gene action determining yield of local varieties. Therefore the objective of this study was to estimate the combining ability for yield and associated secondary traits by crossing popular local varieties with some varieties from IITA using a NC II mating design. The F1 progenies were evaluated in a seedling trial laid out as a 7 × 7 simple lattice with two replicates. Results indicated significant variation among progenies for shoot weight, root number, root weight, root yield, biomass, harvest index, percentage dry matter, dry matter yield, cyanide content, and resistance to cassava mosaic disease and green mites. Average fresh root weight at 6 mo ranged from 1.1 kg to 1.4 kg plant^-1. To a great extent SCA effects (57 to 75%) explained variation for shoot weight, root weight, harvest index, dry matter content, root cyanide content and resistance to cassava mosaic, while GCA effects (55%) were more important for root number. Thus, our results suggested that non-additive gene action was more important than additive gene action in influencing yield and most of its associated traits in this cassava population. Overall, the results suggested that the success of cassava breeding in the semi-arid areas would depend on the ability of breeders to assemble heterotic groups of germplasm that combine well in order to achieve early vigour, disease and pest resistance, root quality and high yield potential.

Key words: Cassava, yield, secondary traits.

African Journal of Crop Science ISSN 2375-1231 Vol. 6 (3), pp. 001-012, March, 2018. © International Scholars Journals

Review

Application of advanced backcross quantitative trait locus (QTL) analysis in crop improvement

Baohua Wang and Peng W. Chee*

Molecular Cotton Breeding Laboratory, The University of Georgia-Tifton Campus, P. O. Box 748, Tifton, GA 31793 United States of America.

Accepted 02 October, 2017

Abstract

Domestication of crops is widely believed to be accompanied by a bottleneck that greatly reduces genetic diversity. This narrowing of genetic diversity restricts crop plant improvement by limiting the range of valuable traits available for use in modern plant breeding. Wild species are a broad resource to widen the germplasm and improve the traits in crop cultivars. However, genetic variation between species is often related to reproductive isolation or to adaptation to different natural environments and many introgressed genes prove difficult, if not impossible, to use in crop improvement. Advanced Backcross QTL (AB-QTL) analysis is an efficient method to utilize wild species by simultaneous discovery and transfer of valuable QTLs from unadapted germplasm into elite breeding lines. A number of its application in crop genetics and breeding are reviewed in this paper.

Key words: Advanced backcross, QTL, crop plant breeding.

African Journal of Crop Science ISSN 2375-1231 Vol. 6 (3), pp. 001-006, March, 2018. © International Scholars Journals

Full Length Research Paper

Interactive effects of P supply and drought on root growth of the mycorrhizal coriander (Coriandrum sativum L.)

Hossein Aliabadi Farahani¹, Sayed Alireza Valadabadi¹ and Mohammad Ali Khalvati²

¹Islamic Azad University of Shahr-e-Qods branch, Iran.

²Department of Plant-Microbe Interactions, German Research Centre for Environment and Health, Munich (HelmholtzZentrum München), Ingolstaedter 1, Neuherberg Germany.

Accepted 11 October, 2017

Abstract

Arbuscular mycorrhizal fungi (AMF) are among the most important plant root symbiosis fungi enhancing plant P uptake. This research was conducted in Iran during 2006. The experimental design was a split factorial on the basis of completely randomized block design with four replicates. The control and AM species, Glomus hoi were assigned to the main plots and the combination of P fertilizer including 0, 35 and 70 kg ha^-1 of triple super phosphate and the drought treatment including control (30 evaporation) and 60 mm evaporation from the evaporation pan were factorially assigned to the subplots. AM and P fertilizer significantly increased the root yield, root length, primary root dry weight and primary root length of coriander. Although the non-drought stress treatment significantly increased the root of coriander, the longest root length was achieved under the drought stress. It can be stated that AM is able to enhance the growth of coriander under drought stress through enhancing P uptake. This can have very important environmental impact through decreasing the amount of P fertilizer under control and drought stress conditions and also through enhancing the coriander resistance when subjected to the drought stress. Findings may interest farmers and agricultural researches to consider carefully on huge amount of soil phosphorus with interaction to water restriction as a challenge in environmental issues.

Key words: AM fungi, drought stress, phosphorus, root growth, coriander.