This page has only limited features, please log in for full access.

Unclaimed
M. D. Laing
African Centre for Crop Improvement, School of Agricultural, Earth and Environmental Sciences, University of KwaZulu-Natal, Pietermaritzburg Private Bag X01, Scottsville 3209, South Africa

Honors and Awards

The user has no records in this section


Career Timeline

The user has no records in this section.


Short Biography

I was born and schooled in Zimbabwe, and came to the University of Natal to study biological sciences in 1977. Falling in love with Plant Pathology, and conducting of research, I have been lucky enough to make my career at this university, starting as a lecturer and ending up as the Professor and Head of Department.

Following
Followers
Co Authors
The list of users this user is following is empty.
Following: 0 users

Feed

Journal article
Published: 29 July 2021 in Sustainability
Reads 0
Downloads 0

Pearl millet (Pennisetum glaucum) is a staple food crop in Burkina Faso that is widely grown in the Sahelian and Sudano-Sahelian zones, characterised by poor soil conditions and erratic rainfall, and high temperatures. The objective of this study was to document farmers’ perceptions of the prevailing constraints affecting pearl millet production and related approaches to manage the parasitic weeds S. hermonthica. The study was conducted in the Sahel, Sudano-Sahelian zones in the North, North Central, West Central, Central Plateau, and South Central of Burkina Faso. Data were collected through a structured questionnaire and focus group discussions involving 492 participant farmers. Recurrent drought, S. hermonthica infestation, shortage of labour, lack of fertilisers, lack of cash, and the use of low-yielding varieties were the main challenges hindering pearl millet production in the study areas. The majority of the respondents (40%) ranked S. hermonthica infestation as the primary constraint affecting pearl millet production. Respondent farmers reported yield losses of up to 80% due to S. hermonthica infestation. 61.4% of the respondents in the study areas had achieved a mean pearl millet yields of <1 t/ha. Poor access and the high cost of introduced seed, and a lack of farmers preferred traits in the existing introduced pearl millet varieties were the main reasons for their low adoption, as reported by 32% of respondents. S. hermonthica management options in pearl millet production fields included moisture conservation using terraces, manual hoeing, hand weeding, use of microplots locally referred to as ‘zaï’, crop rotation and mulching. These management techniques were ineffective because they do not suppress the below ground S. hermonthica seed, and they are difficult to implement. Integrated management practices employing breeding for S. hermonthica resistant varieties with the aforementioned control measures could offer a sustainable solution for S. hermonthica management and improved pearl millet productivity in Burkina Faso.

ACS Style

Armel Rouamba; Hussein Shimelis; Inoussa Drabo; Mark Laing; Prakash Gangashetty; Isack Mathew; Emmanuel Mrema; Admire Shayanowako. Constraints to Pearl Millet (Pennisetum glaucum) Production and Farmers’ Approaches to Striga hermonthica Management in Burkina Faso. Sustainability 2021, 13, 8460 .

AMA Style

Armel Rouamba, Hussein Shimelis, Inoussa Drabo, Mark Laing, Prakash Gangashetty, Isack Mathew, Emmanuel Mrema, Admire Shayanowako. Constraints to Pearl Millet (Pennisetum glaucum) Production and Farmers’ Approaches to Striga hermonthica Management in Burkina Faso. Sustainability. 2021; 13 (15):8460.

Chicago/Turabian Style

Armel Rouamba; Hussein Shimelis; Inoussa Drabo; Mark Laing; Prakash Gangashetty; Isack Mathew; Emmanuel Mrema; Admire Shayanowako. 2021. "Constraints to Pearl Millet (Pennisetum glaucum) Production and Farmers’ Approaches to Striga hermonthica Management in Burkina Faso." Sustainability 13, no. 15: 8460.

Journal article
Published: 08 June 2021 in The European Journal of Development Research
Reads 0
Downloads 0

The significant role of agriculture in the transformation of emerging economies has been well founded in the literature. This has contributed to the implementation of a number of intervention programs aimed at improving agricultural productivity and, subsequently, household welfare. However, the magnitude of the impact of adoption of any innovation, such as improved sweetpotato varieties developed for both as human food and livestock feed and hence called dual-purpose sweetpotato (DPS) varieties, is of critical concern. This paper estimates the potential impact of DPS varieties on productivity and household welfare (proxy by consumption expenditure per capita) using an endogenous regime-switching regression that corrects both observed and hidden endogeneities. Consistent with findings in many pieces of the literature, our study shows that adoption of DPS leads to significant productivity and welfare gains, and that farmers who did not adopt would have been better-off have they adopted. In addition, DPS adoption has heterogeneous effects among the adopters’ group that varies with characteristics such as membership of farmer groups and household size. There is, therefore, a need to target specific groups among the farming households. The results of the study also indicate that development practitioners should support the production and promotion of agricultural technologies to boost productivity and improve welfare, especially among rural households.

ACS Style

Gideon Danso-Abbeam; Lloyd J. S. Baiyegunhi; Mark D. Laing; Hussein Shimelis. Productivity and Welfare Impacts of Dual-Purpose Sweetpotato Varieties’ Adoption Among Smallholder Farmers in Rwanda. The European Journal of Development Research 2021, 1 -21.

AMA Style

Gideon Danso-Abbeam, Lloyd J. S. Baiyegunhi, Mark D. Laing, Hussein Shimelis. Productivity and Welfare Impacts of Dual-Purpose Sweetpotato Varieties’ Adoption Among Smallholder Farmers in Rwanda. The European Journal of Development Research. 2021; ():1-21.

Chicago/Turabian Style

Gideon Danso-Abbeam; Lloyd J. S. Baiyegunhi; Mark D. Laing; Hussein Shimelis. 2021. "Productivity and Welfare Impacts of Dual-Purpose Sweetpotato Varieties’ Adoption Among Smallholder Farmers in Rwanda." The European Journal of Development Research , no. : 1-21.

Online first articles
Published: 26 May 2021 in African Journal of Science, Technology, Innovation and Development
Reads 0
Downloads 0

As part of the Green Revolution, plant breeding programmes such as the African Centre for Crop Improvement have trained scientists to breed crop varieties in Africa to address the challenges of low productivity. However, exposure to and adoption of these varieties is somewhat modest, and there is also a scarcity of empirical studies on the drivers of exposure and adoption. Using data from Rwanda, the counterfactual treatment effect framework was used to estimate observed and potential adoption rates, as well as the drivers of exposure and adoption of dual-purpose sweetpotato varieties bred for both food and feed, under partial exposure to information. The results show that if the entire target farming population had been aware of the varieties, the adoption rate could have been up to 70% instead of the observed rate of 42%, indicating a 28% adoption gap due to partial diffusion. The findings indicate that once these varieties have been exposed, there is scope for further expansion of their cultivation. Key drivers of variety exposure and adoption include membership of farmer groups, participation in demonstration fields, and access to extension services. Thus, conscious efforts to minimize information constraints are a prerequisite for unlocking this adoption puzzle.

ACS Style

Gideon Danso-Abbeam; Lloyd J.S. Baiyegunhi; Mark D. Laing; Hussein Shimelis. Adoption of dual-purpose sweetpotato varieties under partial population exposure in Rwanda: Insights from an African plant breeding programme. African Journal of Science, Technology, Innovation and Development 2021, 1 -10.

AMA Style

Gideon Danso-Abbeam, Lloyd J.S. Baiyegunhi, Mark D. Laing, Hussein Shimelis. Adoption of dual-purpose sweetpotato varieties under partial population exposure in Rwanda: Insights from an African plant breeding programme. African Journal of Science, Technology, Innovation and Development. 2021; ():1-10.

Chicago/Turabian Style

Gideon Danso-Abbeam; Lloyd J.S. Baiyegunhi; Mark D. Laing; Hussein Shimelis. 2021. "Adoption of dual-purpose sweetpotato varieties under partial population exposure in Rwanda: Insights from an African plant breeding programme." African Journal of Science, Technology, Innovation and Development , no. : 1-10.

Journal article
Published: 18 May 2021 in Agronomy
Reads 0
Downloads 0

Striga species cause significant yield loss in maize varying from 20 to 100%. The aim of the present study was to screen and identify maize genotypes with partial resistance to S. hermonthica (Sh) and S. asiatica (Sa) and compatible with Fusarium oxysporum f. sp. strigae (FOS), a biocontrol agent. Fifty-six maize genotypes were evaluated for resistance to Sh and Sa, and FOS compatibility. Results showed that FOS treatment significantly (p< 0.001) enhanced Striga management compared to the untreated control under both Sh and Sa infestations. The mean grain yield was reduced by 19.13% in FOS-untreated genotypes compared with a loss of 13.94% in the same genotypes treated with FOS under Sh infestation. Likewise, under Sa infestation, FOS-treated genotypes had a mean grain yield reduction of 18% while untreated genotypes had a mean loss of 21.4% compared to the control treatment. Overall, based on Striga emergence count, Striga host damage rating, grain yield and FOS compatibility, under Sh and Sa infestations, 23 maize genotypes carrying farmer preferred traits were identified. The genotypes are useful genetic materials in the development of Striga-resistant cultivars in Tanzania and related agro-ecologies.

ACS Style

John Lobulu; Hussein Shimelis; Mark Laing; Arnold Mushongi; Admire Shayanowako. Characterization of Maize Genotypes (Zea mays L.) for Resistance to Striga asiatica and S. hermonthica and Compatibility with Fusarium oxysporum f. sp. strigae (FOS) in Tanzania. Agronomy 2021, 11, 1004 .

AMA Style

John Lobulu, Hussein Shimelis, Mark Laing, Arnold Mushongi, Admire Shayanowako. Characterization of Maize Genotypes (Zea mays L.) for Resistance to Striga asiatica and S. hermonthica and Compatibility with Fusarium oxysporum f. sp. strigae (FOS) in Tanzania. Agronomy. 2021; 11 (5):1004.

Chicago/Turabian Style

John Lobulu; Hussein Shimelis; Mark Laing; Arnold Mushongi; Admire Shayanowako. 2021. "Characterization of Maize Genotypes (Zea mays L.) for Resistance to Striga asiatica and S. hermonthica and Compatibility with Fusarium oxysporum f. sp. strigae (FOS) in Tanzania." Agronomy 11, no. 5: 1004.

Journal article
Published: 22 February 2021 in Agronomy
Reads 0
Downloads 0

Rice (Oryza species) is a commercial crop worldwide. Across Africa, the potential yield and quality of rice is diminished by a lack of high performance, locally adapted varieties, and the impact of rice yellow mottle virus (RYMV). The objective of this study was to assess the performance of a diverse collection of rice germplasm for RYMV resistance and agronomic traits, and to select promising lines for breeding for Tanzanian conditions. Fifty-four rice genotypes were field evaluated in two important rice production sites (Ifakara and Mkindo) in Tanzania, which are recognized as RYMV hotspots, using a 6 × 9 alpha lattice design with two replications. There was significant (p < 0.05) genotypic variation for agronomic traits and RYMV susceptibility in the tested germplasm. Seven genotypes with moderate to high RYMV resistance were identified, including Salama M-57, SSD1, IRAT 256, Salama M-55, Mwangaza, Lunyuki, and Salama M-19, which were identified as new sources of resistance genes. Positive and significant correlations were detected between grain yield and number of panicles per plant (NPP), panicle length (PL), number of grains per panicle (NGP), percentage-filled grains (PFG), and thousand-grain weight (TGW), which are useful traits for simultaneous selection for rice yield improvement. A principal component analysis allocated five principal components, accounting for 79.88% of the total variation present in the assessed germplasm collection. Traits that contributed most to variability included NPP, number of tillers/plant (NT), PL, grain yield (GY), and days to 50% flowering (DFL). The genotypes Rangimbili, Gigante, and SARO possess complementary agronomic traits and RYMV resistance, and can be recommended for further evaluation, genetic analysis, and breeding.

ACS Style

William Suvi; Hussein Shimelis; Mark Laing; Isack Mathew; Admire Shayanowako. Variation among Tanzania Rice Germplasm Collections Based on Agronomic Traits and Resistance to Rice Yellow Mottle Virus. Agronomy 2021, 11, 391 .

AMA Style

William Suvi, Hussein Shimelis, Mark Laing, Isack Mathew, Admire Shayanowako. Variation among Tanzania Rice Germplasm Collections Based on Agronomic Traits and Resistance to Rice Yellow Mottle Virus. Agronomy. 2021; 11 (2):391.

Chicago/Turabian Style

William Suvi; Hussein Shimelis; Mark Laing; Isack Mathew; Admire Shayanowako. 2021. "Variation among Tanzania Rice Germplasm Collections Based on Agronomic Traits and Resistance to Rice Yellow Mottle Virus." Agronomy 11, no. 2: 391.

Journal article
Published: 13 February 2021 in Crop Protection
Reads 0
Downloads 0

Cotton is a major fibre crop grown in South Africa; and is subjected to pest attacks, which reduce its yield and profitability for farmers. Field trials were conducted in 2017 and 2018 to evaluate three biopesticides, namely, Eco-Bb®, Bb endophyte, and Metarhizium rileyi in comparison with the insecticides Chlorpyrifos® 480 EC, Karate® EC, and Bandit® 350 SC. The objective was to determine their efficacy against sucking pests, leafhoppers Jacobiella facialis, aphids Aphis gossypii, thrips Thrips tabaci, whiteflies Bemisia tabaci, red spider mite Tetranychus urticae, and cotton stainers Dysdercus spp. Karate® significantly reduced the leafhopper population and outperformed all the other treatments. Eco-Bb® and Bb endophyte did not control the aphids in 2017. However, in 2018 the best aphid control resulted from the biopesticides used. In 2017 plots treated with Eco-Bb® had the lowest number of thrips, while in 2018 plots treated with Bandit® had the least thrips, followed by treatments with M. rileyi and Karate®. There were no significant differences in the populations of whiteflies, however, insecticides were more effective than the biopesticides. All the treatments, except for Bandit®, significantly reduced the number of spider mites compared in 2017. Applications of Eco-Bb® and Bb endophyte significantly reduced spider mites in 2017, while in 2018 plots treated with Karate®, followed by M. rileyi, resulted in the lowest number of spider mites. Application of Bb endophyte, Chlorpyrifos®, and Karate® resulted in the lowest number of cotton stainers. The highest mean cottonseed yields of 6395 kg ha−1, 6295 kg ha−1, and 6141 kg ha−1 were recorded in plots sprayed with Bandit®, Bb endophyte, and Eco-Bb®, respectively. Biopesticides and chemical insecticides can be combined or alternated for future IPM programmes to control cotton pests.

ACS Style

Lawrence N. Malinga; Mark D. Laing. Efficacy of three biopesticides against cotton pests under field conditions in South Africa. Crop Protection 2021, 145, 105578 .

AMA Style

Lawrence N. Malinga, Mark D. Laing. Efficacy of three biopesticides against cotton pests under field conditions in South Africa. Crop Protection. 2021; 145 ():105578.

Chicago/Turabian Style

Lawrence N. Malinga; Mark D. Laing. 2021. "Efficacy of three biopesticides against cotton pests under field conditions in South Africa." Crop Protection 145, no. : 105578.

Research article
Published: 12 February 2021 in Acta Agriculturae Scandinavica, Section B — Soil & Plant Science
Reads 0
Downloads 0

Genotype-by-environment interaction (GEI) analysis is fundamental in crop improvement programmes to guide selection and for recommendation of high performing and stable genotypes for breeding or production. The objectives of this study were to quantify the GEI effects and determine grain yield stability among diverse pigeonpea genotypes to select candidate lines for breeding in Malawi. Eighty-one pigeonpea genotypes were tested under six environments using a 9 × 9 alpha-lattice design with two replications. Data collected were subjected to additive main effects and multiplicative interaction (AMMI) analysis and genotype plus genotype-by-environment interaction (GGE) biplot analysis. Genotype, environment, and genotype × environment interaction (GEI) accounted for 16.4, 33.5, and 49.6%, respectively, of the total variation for grain yield. The test environments were delineated into three mega-environments, based on site and seasonal variability. The AMMI and GGE analyses indicated that the top-yielding and stable genotypes across the test environments were MWPLR 24, ICEAP 01155, MWPLR 14, TZA 5582, and MWPLR 4. The selected genotypes are recommended as parental lines for grain yield improvement in Malawi or similar agro-ecologies.

ACS Style

Esnart Nyirenda Yohane; Hussein Shimelis; Mark Laing; Isack Mathew; Admire Shayanowako. Genotype-by-environment interaction and stability analyses of grain yield in pigeonpea [Cajanus cajan (L.) Millspaugh]. Acta Agriculturae Scandinavica, Section B — Soil & Plant Science 2021, 1 -11.

AMA Style

Esnart Nyirenda Yohane, Hussein Shimelis, Mark Laing, Isack Mathew, Admire Shayanowako. Genotype-by-environment interaction and stability analyses of grain yield in pigeonpea [Cajanus cajan (L.) Millspaugh]. Acta Agriculturae Scandinavica, Section B — Soil & Plant Science. 2021; ():1-11.

Chicago/Turabian Style

Esnart Nyirenda Yohane; Hussein Shimelis; Mark Laing; Isack Mathew; Admire Shayanowako. 2021. "Genotype-by-environment interaction and stability analyses of grain yield in pigeonpea [Cajanus cajan (L.) Millspaugh]." Acta Agriculturae Scandinavica, Section B — Soil & Plant Science , no. : 1-11.

Journal article
Published: 23 December 2020 in Agronomy
Reads 0
Downloads 0

Selecting genetically diverse and complementary parental lines and superior crosses are pre-requisites in developing improved cultivars. The objectives of this study were to determine the combining ability effects and gene action conditioning rice yellow mottle virus disease (RYMVD) resistance and agronomic traits in rice (Oryza sativa L.). Ten parental lines and their 45 F2 progenies were field evaluated in three locations using a 5 × 11 alpha lattice design with two replications. The genotype × site interaction effects were significant (p < 0.05) for the number of tillers (NT), number of panicles per plant (NPP), number of grains per panicle (NGP), percentage of filled grains (PFG), thousand grain weight (TGW), RYMVD resistance and grain yield (GY). The analysis of general and specific combining ability (GCA and SCA) indicated involvement of both additive and non-additive gene action governing inheritance of traits. High GCA/SCA ratio estimate revealed additive genetic effect was predominant. Parental lines Mwangaza, Lunyuki, Salama M-57, Salama M-19, IRAT 256 and Salama M-55, which had negative GCA effects for RYMVD, and families such as SARO 5 × Salama M-55, IRAT 245 × Rangimbili, Rangimbili × Gigante and Rangimbili × Mwangaza, which had negative SCA effects for RYMVD, were selected for RYMV resistance breeding. The crosses Rangimbili × Gigante, Gigante × Salama M-19 and Rangimbili × Salama M-55 were selected due to their desirable SCA effects for GY. The predominance of additive gene effects for agronomic traits and RYMVD resistance in the present breeding populations suggested that rice improvement could be achieved through gene introgression using recurrent selection.

ACS Style

William Titus Suvi; Hussein Shimelis; Mark Laing; Isack Mathew; Admire I. T. Shayanowako. Determining the Combining Ability and Gene Action for Rice Yellow Mottle Virus Disease Resistance and Agronomic Traits in Rice (Oryza sativa L.). Agronomy 2020, 11, 12 .

AMA Style

William Titus Suvi, Hussein Shimelis, Mark Laing, Isack Mathew, Admire I. T. Shayanowako. Determining the Combining Ability and Gene Action for Rice Yellow Mottle Virus Disease Resistance and Agronomic Traits in Rice (Oryza sativa L.). Agronomy. 2020; 11 (1):12.

Chicago/Turabian Style

William Titus Suvi; Hussein Shimelis; Mark Laing; Isack Mathew; Admire I. T. Shayanowako. 2020. "Determining the Combining Ability and Gene Action for Rice Yellow Mottle Virus Disease Resistance and Agronomic Traits in Rice (Oryza sativa L.)." Agronomy 11, no. 1: 12.

Journal article
Published: 26 November 2020 in South African Journal of Science
Reads 0
Downloads 0

Possible endophytic colonisation of rice cultivar parts (leaves, stem and roots) by Beauveria bassiana isolates and their potential as biocontrol agents against Sesamia calamistis Hampson (African pink stem borer) were investigated. Five promising B. bassiana isolates were evaluated for their endophytic colonisation, the effectiveness of the inoculation methods and the efficacy of the isolates as biocontrol agents against S. calamistis. The plant part colonised is often dependent on the inoculation method. Colonisation of plant parts was assessed at 30 and 60 days after seed inoculation and foliar spray. For the pathogenicity activity, third instar larvae of S. calamistis were fed with rice stems that were previously inoculated with endophytic isolates of B. bassiana. Both inoculation methods led to the colonisation of the rice cultivar tissues, but were affected by the interactions of cultivars x isolates x inoculation methods. The colonisation of the cultivar plant parts varied over time (30- and 60-day intervals), and was affected by the inoculation method used. For both inoculation methods, highly significant differences were observed in the roots and the leaves over time (p=0.0001). However, with seed treatment, there was no significant difference in levels of colonisation in stems by the isolates x time (p=0.32). The B. bassiana isolates were pathogenic on the third instar larvae of S. calamistis, causing mortalities of more than 50% at 28 days after treatment. However, the virulence of the isolates varied. According to the isolates and the inoculation methods, B. bassiana formed an endophytic relationship with rice plants, and produced various mortality rates.

ACS Style

Wonroo B.A. Bancole; Mark D. Laing; Kwasi S. Yobo; Abou Togola. Establishment of Beauveria bassiana isolates as endophytes in rice cultivars and their biocontrol efficacy against rice stem borer, Sesamia calamistis. South African Journal of Science 2020, 116, 1 .

AMA Style

Wonroo B.A. Bancole, Mark D. Laing, Kwasi S. Yobo, Abou Togola. Establishment of Beauveria bassiana isolates as endophytes in rice cultivars and their biocontrol efficacy against rice stem borer, Sesamia calamistis. South African Journal of Science. 2020; 116 (11/12):1.

Chicago/Turabian Style

Wonroo B.A. Bancole; Mark D. Laing; Kwasi S. Yobo; Abou Togola. 2020. "Establishment of Beauveria bassiana isolates as endophytes in rice cultivars and their biocontrol efficacy against rice stem borer, Sesamia calamistis." South African Journal of Science 116, no. 11/12: 1.

Original paper
Published: 09 November 2020 in Food Security
Reads 0
Downloads 0

Many empirical studies have recognized the importance of using improved crop varieties to tackle the challenges of low productivity, poverty, hunger, and food insecurity. Nevertheless, the size of the effect of any crop variety, such as dual-purpose sweetpotatoes developed for both food and animal feed, adopted by the target groups remains an empiric concern. Therefore, this study aimed to identify the determinants of adoption of dual-purpose sweetpotato varieties and, subsequently, estimate the extent to which adoption impacts household food security status. To establish causation, we used an endogenous switching probit to reduce the selection bias resulting from both observed and unobserved characteristics. The results of the adoption analysis indicate a low level of adoption (42%), and factors such as sex of the respondent, primary occupation, farm size, membership of social group, and a visit to farm demonstrations play significant roles in shaping farmers’ decision to adopt the dual-purpose sweetpotato varieties. Furthermore, the findings indicate that food insecurity continues among rural farming households, although a large proportion (63%) experiences mild food insecurity to food security. Generally, the adoption of dual-purpose sweetpotato has a positive impact on food security of the adopters, and the non-adopters would have benefited substantially from adoption if they had adopted. Thus, sweetpotato being a staple crop in Rwanda has a strong effect on the households’ food security status. Therefore, it implies the need to pursue efforts to intensify the growth of dual-purpose sweetpotato by poor rural households facing the dual problem of access and nutrition for food security and not having the means to afford food supplements.

ACS Style

Gideon Danso-Abbeam; Lloyd J. S. Baiyegunhi; Mark D. Laing; Hussein Shimelis. Food security impacts of smallholder farmers’ adoption of dual-purpose sweetpotato varieties in Rwanda. Food Security 2020, 13, 653 -668.

AMA Style

Gideon Danso-Abbeam, Lloyd J. S. Baiyegunhi, Mark D. Laing, Hussein Shimelis. Food security impacts of smallholder farmers’ adoption of dual-purpose sweetpotato varieties in Rwanda. Food Security. 2020; 13 (3):653-668.

Chicago/Turabian Style

Gideon Danso-Abbeam; Lloyd J. S. Baiyegunhi; Mark D. Laing; Hussein Shimelis. 2020. "Food security impacts of smallholder farmers’ adoption of dual-purpose sweetpotato varieties in Rwanda." Food Security 13, no. 3: 653-668.

Journal article
Published: 30 October 2020 in Agronomy
Reads 0
Downloads 0

Pigeonpea (Cajanus cajan [L,] Millspaugh) is an important source of grain protein for low-income countries such as Malawi. Knowledge of the genetic diversity in pigeonpea is essential for an effective breeding program. The study objective was to assess the genetic diversity among diverse pigeonpea accessions to select complementary and unique genotypes for breeding. Eighty-one pigeonpea accessions were evaluated in six environments in Malawi using a 9 × 9 alpha-lattice design with two replications. The cross-tabulation analysis revealed a significant genotype variation on plant growth, flower, and seed traits. The combined analysis of variance identified genotypes MWPLR 14, ICEAP 01170, ICEAP 871091, and ICEAP 01285 as early maturing varieties, while Kachangu, MWPLR 16, TZA 5582, No. 40, and MWPLR 14 were identified as high-yielding genotypes. The correlation analysis revealed a significant positive correlation between grain yield and a hundred seed weight (HSWT) (r = 0.50, p < 0.01), suggesting the usefulness of this trait for selection. The nonlinear principal component analysis identified grain yield (GDY), days to 50% flowering (DTF), days to 75% maturity (DTM), number of pods per plant (NPP), number of racemes per plant (NRP), 100 seed weight (HSWT), leaf hairiness (LH), and number of seeds per pod (NSP) as the most discriminated traits among the test genotypes. The cluster analysis using morphological traits delineated the accessions into three clusters. The selected high-yielding and early-maturing genotypes may be recommended as parental lines for breeding and grain yield improvement in Malawi or similar agro-ecologies.

ACS Style

Esnart Nyirenda Yohane; Hussein Shimelis; Mark Laing; Isack Mathew; Admire Shayanowako. Phenotypic Divergence Analysis in Pigeonpea [Cajanus cajan (L.) Millspaugh] Germplasm Accessions. Agronomy 2020, 10, 1682 .

AMA Style

Esnart Nyirenda Yohane, Hussein Shimelis, Mark Laing, Isack Mathew, Admire Shayanowako. Phenotypic Divergence Analysis in Pigeonpea [Cajanus cajan (L.) Millspaugh] Germplasm Accessions. Agronomy. 2020; 10 (11):1682.

Chicago/Turabian Style

Esnart Nyirenda Yohane; Hussein Shimelis; Mark Laing; Isack Mathew; Admire Shayanowako. 2020. "Phenotypic Divergence Analysis in Pigeonpea [Cajanus cajan (L.) Millspaugh] Germplasm Accessions." Agronomy 10, no. 11: 1682.

Journal article
Published: 18 September 2020 in BMC Genetics
Reads 0
Downloads 0

Background Productivity of cowpea [Vigna unguiculata(L.)Walp] in sub-Sahara Africa is curtailed by a lack of farmer-preferred and improved cultivars and modern production technologies. The objectives of the study were to determine the extent of genetic diversity present among a collection of cowpea accessions from Zambia and Malawi using phenotypic traits and single nucleotide polymorphism (SNP) markers and, to select distinct and complementary parental lines for cultivar development. One hundred cowpea genotypes were evaluated for agronomic traits in two selected sites in Zambia, using a 10 × 10 alpha lattice design with two replications. Ninety-four of the test genotypes were profiled with 14,116 SNP markers. Results Number of pods plant− 1(NPP), pod length (PDL), and number of seeds pod− 1(NSP), were significantly (p < 0.05) affected by genotype × environment interaction effects. Genotypes such as CP411, CP421, CP645, CP732, Chimponongo, and MS1–8–1-4 exhibited higher grain yield of > 1200 kg/ha with excellent performance in yield components such as NSP, PDL, HSW and GYD. Grain yield had significant (p < 0.05) associations with NPP (r = 0.50), NSP (r = 0.46) and PDL (r = 0.42) useful for simultaneous selection for yield improvement in cowpea. The SNP markers revealed gene diversity and polymorphic information content of 0.22 and 0.17, respectively, showing that the tested cowpea accessions were genetically diverse. Test genotypes were classified into four genetic groups irrespective of source of collection allowing selection and subsequent crosses to develop breeding populations for cultivar development. Conclusions Genotypes Bubebe, CP411, CP421, CP645, Chimponogo and MS1–8–1-4 were identified to be the most genetically divergent and high yielding making them ideal parental lines for breeding. This study provided a baseline information and identified promising cowpea genetic resources for effective breeding and systematic conservation.

ACS Style

Nelia Nkhoma; Hussein Shimelis; Mark D. Laing; Admire Shayanowako; Isack Mathew. Assessing the genetic diversity of cowpea [Vigna unguiculata (L.) Walp.] germplasm collections using phenotypic traits and SNP markers. BMC Genetics 2020, 21, 1 -16.

AMA Style

Nelia Nkhoma, Hussein Shimelis, Mark D. Laing, Admire Shayanowako, Isack Mathew. Assessing the genetic diversity of cowpea [Vigna unguiculata (L.) Walp.] germplasm collections using phenotypic traits and SNP markers. BMC Genetics. 2020; 21 (1):1-16.

Chicago/Turabian Style

Nelia Nkhoma; Hussein Shimelis; Mark D. Laing; Admire Shayanowako; Isack Mathew. 2020. "Assessing the genetic diversity of cowpea [Vigna unguiculata (L.) Walp.] germplasm collections using phenotypic traits and SNP markers." BMC Genetics 21, no. 1: 1-16.

Online first articles
Published: 07 August 2020 in South African Journal of Plant and Soil
Reads 0
Downloads 0

Considerable genetic diversity is present amongst the sweet potato (Ipomoea batatas (L.) Lam.) accessions that can be selected for breeding. The Agricultural Research Council of South Africa maintains 360 sweetpotato accessions that were bred locally, and introductions from various regions of the world sourced for breeding purposes. The objective of this study was to determine the phenotypic diversity of 73 accessions, using morpho-agronomical characteristics to complement data on protein content of the accessions towards breeding for improved nutritional content. A field study was conducted using a randomized complete block design. Quantitative and qualitative data were collected using 38 of the international standardized descriptors for sweetpotato. Agronomic traits including root yield and biomass, and quality traits such as dry matter, β-carotene and protein contents, and root oxidation were determined. Multivariate clustering analysis and principal component analysis grouped the 73 sweetpotato accessions into three main groups. The major traits clustering the accessions were leaf lobe type, central leaf lobe shape, vine tip pubescence, vine pigmentation colour, and flowering ability. Of the 73 accessions 16.4% produced few flowers, 21.9% had intermediate flowering and 9.5% flowered abundantly. This study provided baseline information on the phenotypic diversity of South African sweetpotato collections for effective utilization and future breeding.

ACS Style

Sonia Im Naidoo; Sunette M Laurie; Hussein Shimelis; Mark D Laing. Morpho-agronomical characterisation of local and international sweetpotato germplasm from the South African collection. South African Journal of Plant and Soil 2020, 37, 308 -320.

AMA Style

Sonia Im Naidoo, Sunette M Laurie, Hussein Shimelis, Mark D Laing. Morpho-agronomical characterisation of local and international sweetpotato germplasm from the South African collection. South African Journal of Plant and Soil. 2020; 37 (4):308-320.

Chicago/Turabian Style

Sonia Im Naidoo; Sunette M Laurie; Hussein Shimelis; Mark D Laing. 2020. "Morpho-agronomical characterisation of local and international sweetpotato germplasm from the South African collection." South African Journal of Plant and Soil 37, no. 4: 308-320.

Online first articles
Published: 26 May 2020 in South African Journal of Plant and Soil
Reads 0
Downloads 0

Systematic genetic profiling of the genetic pool is fundamental to select desirable parents for conventional and genomic-assisted breeding. The objective of this study was to assess genetic variation and population structure in a diverse population of sorghum accessions collected from various regions of Ethiopia. Using single nucleotide polymorphism (SNP) markers, potential breeding parents were then selected. In all, 342 sorghum accessions were genotyped using diversity array technology sequence-derived 5060 SNPs with > 5% minor allele frequency. Population structure, clustering, PCA, and analysis of molecular variance (AMOVA) were conducted to deduce variability within the germplasm. The AMOVA results revealed a higher percentage (58.8%) of variation among the populations followed by variation within accessions (40.4%). Polymorphic information content (PIC) values ranged from 0.184 for accessions collected from the Somali to 0.260 for the Oromia and Southern Nations, Nationalities, and Peoples (SNNP) regions. Higher genetic variation was detected among sorghum collections from Oromia followed by those of the SNNP region. The selected SNP markers were the most powerful in discriminating the tested sorghum accessions. Population structure analysis revealed the presence of two main distinct genetic clusters in which accessions were grouped based on area of collection. The present findings indicated abundant genetic variability among Ethiopian sorghum accessions, confirming that they will be useful for breeding, germplasm conservation and genomic selection.

ACS Style

Girma Mengistu; Hussein Shimelis; Mark Laing; Dagnachew Lule; Ermias Assefa; Isack Mathew. Genetic diversity assessment of sorghum (Sorghum bicolor (L.) Moench) landraces using SNP markers. South African Journal of Plant and Soil 2020, 37, 220 -226.

AMA Style

Girma Mengistu, Hussein Shimelis, Mark Laing, Dagnachew Lule, Ermias Assefa, Isack Mathew. Genetic diversity assessment of sorghum (Sorghum bicolor (L.) Moench) landraces using SNP markers. South African Journal of Plant and Soil. 2020; 37 (3):220-226.

Chicago/Turabian Style

Girma Mengistu; Hussein Shimelis; Mark Laing; Dagnachew Lule; Ermias Assefa; Isack Mathew. 2020. "Genetic diversity assessment of sorghum (Sorghum bicolor (L.) Moench) landraces using SNP markers." South African Journal of Plant and Soil 37, no. 3: 220-226.

Journal article
Published: 01 March 2020 in African Entomology
Reads 0
Downloads 0

The South African citrus thrips, Scirtothrips aurantii, is a recently confirmed economic pest in South African avocado. Scarring damage by thrips results in corky tissue development, making the fruit unsuitable for export and potentially costing the country in lost export revenue. Thrips management is complicated by the multiple and protracted flowering patterns of susceptible cultivars. In addition, widespread pesticide resistance of thrips and the negative environmental effects along with minimum residue levels for export fruit limit the application of pesticides for thrips control. Monitoring an insect pest's presence and abundance is the first step in thrips management. This study aimed to investigate S. aurantii's colour preferences, establish the distribution of thrips in the orchard and population dynamics from flowering to fruit establishment. Attractiveness followed the order yellow > blue, white, clear > red, black, purple and orange. Thrips were evenly distributed throughout the orchard, with the highest populations occurring during flowering (August), declining sharply and picking up in the summer months starting December. Yellow sticky cards are recommended as a monitoring tool.

ACS Style

G.T. Bara; M.D. Laing. Attractiveness of Different Coloured Sticky Traps to the South African Citrus Thrips (Scirtothrips aurantii Faure) in Avocado, KwaZulu-Natal, South Africa. African Entomology 2020, 28, 133 -141.

AMA Style

G.T. Bara, M.D. Laing. Attractiveness of Different Coloured Sticky Traps to the South African Citrus Thrips (Scirtothrips aurantii Faure) in Avocado, KwaZulu-Natal, South Africa. African Entomology. 2020; 28 (1):133-141.

Chicago/Turabian Style

G.T. Bara; M.D. Laing. 2020. "Attractiveness of Different Coloured Sticky Traps to the South African Citrus Thrips (Scirtothrips aurantii Faure) in Avocado, KwaZulu-Natal, South Africa." African Entomology 28, no. 1: 133-141.

Journal article
Published: 01 March 2020 in African Entomology
Reads 0
Downloads 0

Avocado (Persea americana) is an important export crop for South Africa, contributing ZAR1.75 billion in export revenue to the gross domestic product. As an export-oriented industry, increasing the exportable percentage of avocado fruit is a major concern. A tussock moth, Bracharoa mixta (Snellen), is reported for the first time on avocado trees, scarring fruit and defoliating leaves. Feeding damage by the larva results in corky tissue development, making the fruit unsuitable for export. The study aimed to determine the identity of the larvae (morphologically and DNA barcoding) and ascertain levels of damage. Sequencing of the barcoding region of cytochrome oxidase subunit I (COI) gene was done. In-field fruit damage assessment of infested trees showed an 11 % scarring damage level resulting in 3.67 % downgrading of fruit. This represents a potential revenue loss of up to ZAR 1352.90/t (2.26 % revenue loss). The defoliating caterpillars also caused an 18.22 % reduction in leaf area. This study documents the potential of B. mixta to cause economic loss and sporadic, isolated outbreaks.

ACS Style

G.T. Bara; M.D. Laing. First Report of Tussock Moths (Bracharoa mixta (Lepidoptera: Erebidae)) Scarring Avocado Fruit in KwaZulu-Natal, South Africa. African Entomology 2020, 28, 115 -124.

AMA Style

G.T. Bara, M.D. Laing. First Report of Tussock Moths (Bracharoa mixta (Lepidoptera: Erebidae)) Scarring Avocado Fruit in KwaZulu-Natal, South Africa. African Entomology. 2020; 28 (1):115-124.

Chicago/Turabian Style

G.T. Bara; M.D. Laing. 2020. "First Report of Tussock Moths (Bracharoa mixta (Lepidoptera: Erebidae)) Scarring Avocado Fruit in KwaZulu-Natal, South Africa." African Entomology 28, no. 1: 115-124.

Journal article
Published: 01 August 2019 in South African Journal of Plant and Soil
Reads 0
Downloads 0
ACS Style

Sascha L Beck-Pay; Mark D Laing. The effect of conditioning Acacia mearnsii De Wild. hedge-plants under shadenetting on rooting, elemental uptake and productivity of cuttings. South African Journal of Plant and Soil 2019, 36, 347 -355.

AMA Style

Sascha L Beck-Pay, Mark D Laing. The effect of conditioning Acacia mearnsii De Wild. hedge-plants under shadenetting on rooting, elemental uptake and productivity of cuttings. South African Journal of Plant and Soil. 2019; 36 (5):347-355.

Chicago/Turabian Style

Sascha L Beck-Pay; Mark D Laing. 2019. "The effect of conditioning Acacia mearnsii De Wild. hedge-plants under shadenetting on rooting, elemental uptake and productivity of cuttings." South African Journal of Plant and Soil 36, no. 5: 347-355.

Journal article
Published: 01 December 2018 in Cereal Research Communications
Reads 0
Downloads 0

Genetic diversity among breeding populations is key in plant breeding programs. This study aimed to determine the extent of genetic diversity among 37 diverse maize genotypes using simple sequence repeat (SSR) markers. The maize genotypes were selected based on their variable resistance to Striga asiatica. Maize genotypes were fingerprinted using 18 polymorphic SSR markers. Marker and population diversity parameters were computed. A total of 191 alleles were detected and the number of effective alleles varied from 2 to 21 per locus with a mean of 11. The polymorphic information content (PIC) of the SSR markers varied from 0.59 to 0.96, with a mean of 0.80. Significant differences were observed among populations, individuals and within individuals. Within and among individual variances accounted for 85% and 13% of the total gene diversity. The genotypes were grouped into three main genetic clusters, which were not influenced by genotype origin. Mean genetic distance (0.43) and low geneflow (0.18) were observed among the populations. High mean genetic identity (0.65) was recorded, indicating potential genetic ‘bottleneck’ among the selected germplasm. The following open pollinated varieties; Border King, Colorado, CIMMYT’s ZM OPVs, Mac Pearl, Shesha, Nel Choice, Natal 8Lines, Nel Choice QPM, Hickory King, Kep Select, Obatanpa and the Striga resistant synthetic variety DSTRYSYN15 were selected from different clusters for breeding.

ACS Style

A.I.T. Shayanowako; H. Shimelis; M.D. Laing; L. Mwadzingeni. Genetic diversity of maize genotypes with variable resistance to Striga asiatica based on SSR markers. Cereal Research Communications 2018, 46, 668 -678.

AMA Style

A.I.T. Shayanowako, H. Shimelis, M.D. Laing, L. Mwadzingeni. Genetic diversity of maize genotypes with variable resistance to Striga asiatica based on SSR markers. Cereal Research Communications. 2018; 46 (4):668-678.

Chicago/Turabian Style

A.I.T. Shayanowako; H. Shimelis; M.D. Laing; L. Mwadzingeni. 2018. "Genetic diversity of maize genotypes with variable resistance to Striga asiatica based on SSR markers." Cereal Research Communications 46, no. 4: 668-678.

Online first articles
Published: 06 July 2018 in South African Journal of Plant and Soil
Reads 0
Downloads 0

Sclerotinia sclerotiorum, the causal organism of Sclerotinia wilt, is an economically important disease affecting sunflower in South Africa. The goal of this investigation was to evaluate the potential of a strain of Trichoderma harzianum, T77, for control of S. sclerotiorum on sunflower under in vitro and greenhouse conditions. In vitro dual culture bioassays and ultrastructural studies revealed that mycoparasitism is the probable primary mode of action as initial signs of hyphae of T. harzianum coiling around hyphae of S. sclerotiorum were observed. Under greenhouse conditions, treatment of severed stems with T77 significantly reduced sclerotia formation but not the rate of disease progression. This study indicates the potential of T. harzianum in reducing sclerotia formation in sunflower and warrants further investigation.

ACS Style

James R Mathews; Benice J Sivparsad; Mark D Laing. Greenhouse evaluation of Trichoderma harzianum for the control of Sclerotinia wilt (Sclerotinia sclerotiorum) of sunflower. South African Journal of Plant and Soil 2018, 36, 69 -72.

AMA Style

James R Mathews, Benice J Sivparsad, Mark D Laing. Greenhouse evaluation of Trichoderma harzianum for the control of Sclerotinia wilt (Sclerotinia sclerotiorum) of sunflower. South African Journal of Plant and Soil. 2018; 36 (1):69-72.

Chicago/Turabian Style

James R Mathews; Benice J Sivparsad; Mark D Laing. 2018. "Greenhouse evaluation of Trichoderma harzianum for the control of Sclerotinia wilt (Sclerotinia sclerotiorum) of sunflower." South African Journal of Plant and Soil 36, no. 1: 69-72.

Original article
Published: 25 June 2018 in Plant Breeding
Reads 0
Downloads 0

This study was aimed to determine gene action for grain yield and yield‐related traits of newly developed tef populations under drought‐stressed and nonstressed conditions to improve drought tolerance. Ten crosses, along with the parents, were evaluated in the F2 generation under drought‐stressed conditions at Hastebo and Adigdad sites in 2015 and Dura site in 2016 and under nonstressed conditions at Dura site in 2016. Additive gene action predominantly controlled the inheritance of the grain yield and majority of the yield‐related traits under drought‐stressed and nonstressed conditions. Under both test conditions, the genotypes DZ‐Cr‐387 and 9415 were the best general combiners for increased grain yield and morphological traits. Conversely, genotype 222076 was the best general combiner for reduced maturity period only. The selected parents are novel genetic materials for tef breeding programmes to improve grain yield and morphological traits with reduced days to maturity for drought tolerance breeding. The family of the cross DZ‐Cr‐387 × 222076 was selected for high grain yield and early maturity in both the drought‐stressed and nonstressed environments.

ACS Style

Mizan Tesfay Abraha; Hussien Shimelis; Mark Laing; Kebebew Assefa. Gene action controlling yield and yield-related traits among tef (Eragrostis tef [Zucc.] Trotter) populations under drought-stressed and nonstressed conditions. Plant Breeding 2018, 137, 585 -597.

AMA Style

Mizan Tesfay Abraha, Hussien Shimelis, Mark Laing, Kebebew Assefa. Gene action controlling yield and yield-related traits among tef (Eragrostis tef [Zucc.] Trotter) populations under drought-stressed and nonstressed conditions. Plant Breeding. 2018; 137 (4):585-597.

Chicago/Turabian Style

Mizan Tesfay Abraha; Hussien Shimelis; Mark Laing; Kebebew Assefa. 2018. "Gene action controlling yield and yield-related traits among tef (Eragrostis tef [Zucc.] Trotter) populations under drought-stressed and nonstressed conditions." Plant Breeding 137, no. 4: 585-597.