Utilization of landraces for the genetic enhancement of pigeonpea in eastern and southern Africa

The eastern and southern Africa (ESA) region is considered as a centre of secondary diversity for pigeonpea. Accessions (297) of pigeonpea landraces were collected from major production areas in four countries in the region and evaluated for desirable agronomic traits, particularly resistance to fusarium wilt and market-preferred traits. Selected germplasm was utilized in the regional breeding program aimed at genetic enhancement of pigeonpea. Five improved long-duration (LD) cultivars that are highly resistant to fusarium wilt and have large (100-grain weight >15.0 g) grains were developed. Similarly, six early maturing medium-duration (MD) cultivars (averaging 2.5 t/ha) for production in the high latitude areas in the region and three MD cultivars that are able to ratoon, were developed. Seed of pre-released cultivars that are preferred by the farmers was distributed widely in the region in order to facilitate adoption. Consequently, the productivity of pigeonpea and food security in the region improved significantly

Impact of a New Source of Resistance to Fusarium Wilt in Pigeonpea

Pigeonpea is an important grain legume grown by smallholder farmers in Southern Africa. Fusarium wilt, caused by the fungal pathogen Fusarium udum Butler, is the major disease limiting pigeonpea production in the region. This study was designed to evaluate the reaction to fusarium wilt as well as agronomic performance of new elite pigeonpea germplasm in three different countries during the 2001/2002 cropping season using wilt-sick plots. Per cent incidence of fusarium wilt (%FW), grain size and yield, were measured. The genotype ICEAP 00040 consistently showed a high (<20.0%) level of resistance to the disease in all three countries. In contrast, %FW score for the susceptible genotype ICEAP 00068 was 87.5, 92.0 and 90.9% in Kenya, Malawi and Tanzania, respectively. The grain size obtained for ICEAP 00040 at Ngabu (Malawi) was 25.0% larger than that at each of the remaining locations indicating environmental influence on this trait. At all the three locations, ≥1.5 ton/Ha of grain yield was obtained for ICEAP 00040 compared with <1.0 ton/Ha for ICEAP 00068. In 2003, this improved resistant genotype (ICEAP 00040) was released for commercial production and will be useful as a good source of resistance in pigeonpea genetic improvement programs in the region

Registration of pigeonpea cultivar Tumia

'Tlimia' pigeonpea [Cajanuscajan (L.) Millsp.]. (Reg. no. CV-271. PI 642783). originally designated as ICEAP 00068. was developed jointly by the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) and Ilonga Agricultural Research Institute (IARI) (Ministry of Agriculture and Food Security. Tanzania). Thmia was adopted widely in several countries in eastern and southern Africa (HSA) and released in 2003 in Tanzania jointly by ICRISAT (Nairobi. HSA) and IARI. Tumia is a medium-duration pigeonpea cul-tivar released for its earliness. ratoonability. high quality grain attributes and adaptation to diverse agro-ecologies and cropping systems in Tanzania

Registration of pigeonpea cultivar ‘ICEAP 00040'

‘ICEAP 00040’ [Cajanus cajan (L.) Millsp.] (Reg. no. CV-255, PI 639265) was developed by the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) and released in 2003 in two countries (Malawi and Tanzania) in eastern and southern Africa (ESA). In Malawi, ICEAP 00040 was released as ‘Kachangu’ jointly by three agencies, namely, ICRISAT-Nairobi (ESA), Department of Agricultural Research Services (Ministry of Agriculture, Malawi), and Legumes Fibers and Oilseeds (Ministry of Agriculture, Malawi). In Tanzania, ICEAP 00040 was released as ‘Mali’ by ICRISAT-Nairobi (ESA) and Ilonga Agricultural Research Institute (Ministry of Agriculture, Tanzania). ICEAP 00040 is a late-maturing pigeonpea cultivar released for its resistance to the fungal pathogen Fusarium udum Butler (the causal agent of Fusarium wilt), and has potential use in the cropping systems of the semiarid ESA region and as a source of germplasm for pigeonpea improvement programs

The response of pigeonpea genotypes of different duration types to variation in temperature and photoperiod under field conditions in Kenya

Field studies were conducted with pigeonpea [Cajanus cajan (L.) Millsp.] in Kenya to determine the influence of photoperiod and temperature on flowering. Variation in temperature was achieved by planting six genotypes at four locations varying in altitude where temperature decreased with increase in altitude and variation in photoperiod was achieved through artificial lighting (about 12.6 h - natural day length, 14.5 h and 16.0 h). The genotypes used in the study were carefully selected to represent different duration types (extra-short-, short-, medium- and long-duration) and major pigeonpea production regions. Equations that describe the rates of development (1/f) were used to determine rates of progress of each genotype towards flowering as influenced by temperature and photoperiod. For photoperiods below 13 h, rates of progress towards flowering were influenced by temperature in five genotypes (ICPL 90011, ICPL 87091, ICP 7035, ICP 6927 and ICEAP 00040). The optimum temperatures for rapid flowering were 24.7°C for the extra-short-duration genotype, 23.1°C for the short-duration genotype, 23.8°C and 22.2°C for medium-duration genotypes and 18.3°C for the long-duration genotypes, which indicated that the origin of the genotype had a strong influence on adaptation. The effects of photoperiod on rates of progress towards flowering were investigated only under sub-optimal temperatures. The extra-short-duration genotype (ICPL 90011) was the least responsive to variation in photoperiod, while the two long-duration genotypes (ICEAP 00040 and T-7) were most sensitive to photoperiod variation with flowering rate reduced by 0.001 d-1 per hour increase in day length

Nodulation and Growth Promotion of Chickpea by Mesorhizobium Isolates from Diverse Sources

The cultivation of chickpea (Cicer arietinum L.) in South Africa is dependent on the application of suitable Mesorhizobium inoculants. Therefore, we evaluated the symbiotic effectiveness of several Mesorhizobium strains with different chickpea genotypes under controlled conditions. The tested parameters included shoot dry weight (SDW), nodule fresh weight (NFW), plant height, relative symbiotic effectiveness (RSE) on the plant as well as indole acetic acid (IAA) production and phosphate solubilization on the rhizobia. Twenty-one Mesorhizobium strains and six desi chickpea genotypes were laid out in a completely randomized design (CRD) with three replicates in a glasshouse pot experiment. The factors, chickpea genotype and Mesorhizobium strain, had significant effects on the measured parameters (p &lt; 0.001) but lacked significant interactions based on the analysis of variance (ANOVA). The light variety desi genotype outperformed the other chickpea genotypes on all tested parameters. In general, inoculation with strains LMG15046, CC1192, XAP4, XAP10, and LMG14989 performed best for all the tested parameters. All the strains were able to produce IAA and solubilize phosphate except the South African field isolates, which could not solubilize phosphate. Taken together, inoculation with compatible Mesorhizobium promoted chickpea growth. This is the first study to report on chickpea-compatible Mesorhizobium strains isolated from uninoculated South African soils with no history of chickpea production; although, their plant growth promotion ability was poorer compared to some of the globally sourced strains. Since this study was conducted under controlled conditions, we recommend field studies to assess the performance of the five highlighted strains under environmental conditions in South Africa

A systematic review of the mental health risks and resilience among pollution-exposed adolescents

Pollution is harmful to human physical health and wellbeing. What is less well established is the relationship between adolescent mental health - a growing public health concern - and pollution. In response, we systematically reviewed studies documenting associations between pollution and mental health in adolescents. We searched Africa Wide, Medline, PsycArticles, PsycInfo, PubMed, CINAHL, ERIC, SciELO, Scopus, and Web of Science Core Collection for studies published up to 10 April 2020 that investigated exposure to any pollutant and symptoms of anxiety; depression; disruptive, impulse-control, and conduct disorders; neurodevelopmental disorders; psychosis; or substance abuse in 10-24-year-olds (i.e. adolescents as per expanded and more inclusive definition of adolescence). This identified 2291 records and we assessed 128 papers for inclusion. We used a narrative synthesis to coalesce the studies' findings. This review is registered on PROSPERO, CRD42020176664. Seventeen studies from Asia, Europe, the Middle East, and North America were included. Air and water pollution exposure was associated with elevated symptoms of depression, generalised anxiety, psychosis, and/or disruptive, impulse control and conduct disorder. Exposure to lead and solvents was associated with neurodevelopmental impairments. Most studies neglected factors that could have supported the mental health resilience of adolescents exposed to pollution. Notwithstanding the limited quality of most reviewed studies, results suggest that pollution exposure is a risk to adolescent mental health. High-quality research is urgently required, including the factors and processes that protect the mental health of pollution-exposed adolescents. Studies with adolescents living in low- and lower middle-income countries and the southern hemisphere must be prioritized.info:eu-repo/semantics/publishe