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Rattunde H.F.W.,International Crops Research Institute for the Semi Arid Tropics | Weltzien E.,International Crops Research Institute for the Semi Arid Tropics | Diallo B.,LInstitut dEconomie Rurale | Diallo A.G.,LInstitut dEconomie Rurale | And 7 more authors.
Crop Science | Year: 2013

The first sorghum [Sorghum bicolor (L.)Moench] hybrids based on West African Guinea-racederived parents were created to enhance farmer's food security and income through increased yields. To assess their performance, eight hybrids, six experimental pure-line cultivars, one pure-line check (Lata), and a highly adapted landrace cultivar (Tieble) were evaluated in 27 farmer-managed and two on-station yield trials in Mali, West Africa, from 2009 to 2011. The hybrids were confirmed to have photoperiod sensitivity similar to the well-adapted Guinea landrace check cultivar. Genotypic differences for on-farm grain yield were highly significant and genotype × environment crossover interactions were limited. The yield superiorities of individual hybrids, relative to the landrace check, ranged from 17 to 37% over the 27 on-farm trials. The three top yielding hybrids showed 30% yield advantages across productivity levels, with absolute yield advantages averaging 380 kg ha-1 under lower (1.0-1.5 t ha-1) and 660 kg ha-1 under higher (2.0-3.5 t ha-1) productivity conditions. A mean male-parent (better parent) heterosis of 26% was observed for the four hybrids having Lata as a male parent. As the hybrids studied here were obtained with a low intensity of selection using a limited number of parents, even greater yield superiorities may be attained with development of distinct parental pools and scaled-up hybrid breeding. © Crop Science Society of America. Source

Luong K.,University of California at Riverside | Luong K.,Montana State University | Dunkel F.V.,Montana State University | Coulibaly K.,LInstitut dEconomie Rurale | Beckage N.E.,University of California at Riverside
Journal of Medical Entomology | Year: 2012

Larval management of the malaria vector, Anopheles gambiae Giles s.s., has been successful in reducing disease transmission. However, pesticides are not affordable to farmers in remote villages in Mali, and in other material resource poor countries. Insect resistance to insecticides and nontarget toxicity pose additional problems. Neem (Azadirachta indica A. Juss) is a tree with many beneficial, insect bioactive compounds, such as azadirachtin. We tested the hypothesis that neem leaf slurry is a sustainable, natural product, anopheline larvicide. A field study conducted in Sanambele (Mali) in 2010 demonstrated neem leaf slurry can work with only the available tools and resources in the village. Laboratory bioassays were conducted with third instar An. gambiae and village methods were used to prepare the leaf slurry. Experimental concentration ranges were 1,061-21,224 mg/L pulverized neem leaves in distilled water. The 50 and 90% lethal concentrations at 72 h were 8,825 mg/L and 15,212 mg/L, respectively. LC concentrations were higher than for other parts of the neem tree when compared with previous published studies because leaf slurry preparation was simplified by omitting removal of fibrous plant tissue. Using storytelling as a medium of knowledge transfer, villagers combined available resources to manage anopheline larvae. Preparation of neem leaf slurries is a sustainable approach which allows villagers to proactively reduce mosquito larval density within their community as part of an integrated management system. © 2012 Entomological Society of America. Source

Leiser W.L.,International Crops Research Institute for the Semi Arid Tropics | Leiser W.L.,University of Hohenheim | Rattunde H.F.W.,International Crops Research Institute for the Semi Arid Tropics | Piepho H.-P.,University of Hohenheim | And 5 more authors.
Crop Science | Year: 2012

Although sorghum [Sorghum bicolor (L.) Moench] in West Africa (WA) is generally cultivated with limited or no fertilization on soils of low phosphorus availability, no assessments of the genetic variation among WA sorghum varieties for adaptation to low soil P are known. We assessed grain yields of 70 diverse sorghum genotypes under -P (no P fertilization) and +P conditions at two locations in Mali over 5 yr. Genetic variation for grain yield under -P conditions and the feasibility and necessity of sorghum varietal testing for grain yield under -P conditions were evaluated. Delayed heading dates (0-9.8 d) and reductions of grain yield (2-59%) and plant height (13-107 cm) were observed in -P relative to the +P trials. High estimates of genetic variance and broad-sense heritabilities were found for grain yield across both -P (h2 = 0.93) and +P (h2 = 0.92) environments. The genetic correlation for grain yield performance between -P and +P conditions was high (rG = 0.89), suggesting that WA sorghum varieties generally possess good adaptation to low-P conditions. However, genotype × phosphorus crossover interaction was observed between some of the highest yielding genotypes from the -P and +P selected sets, with the variety IS 15401 showing specific adaptation to -P. Direct selection for grain yield in -P conditions was predicted to be 12% more efficient than indirect selection in +P conditions. Thus, selection under -P conditions should be useful for sorghum improvement in WA. © Crop Science Society of America. Source

Leiser W.L.,University of Hohenheim | Leiser W.L.,International Crops Research Institute for the Semi Arid Tropics | Rattunde H.F.W.,International Crops Research Institute for the Semi Arid Tropics | Weltzien E.,International Crops Research Institute for the Semi Arid Tropics | And 6 more authors.
BMC Plant Biology | Year: 2014

Background: Sorghum (Sorghum bicolor L. Moench) productivity is severely impeded by low phosphorus (P) and aluminum (Al) toxic soils in sub-Saharan Africa and especially West Africa (WA). Improving productivity of this staple crop under these harsh conditions is crucial to improve food security and farmer's incomes in WA.Results: This is the first study to examine the genetics underlying sorghum adaptation to phosphorus limitation in a wide range of WA growing conditions. A set of 187 diverse sorghum genotypes were grown in 29 -P and + P field experiments from 2006-2012 in three WA countries. Sorghum grain yield performance under -P and + P conditions was highly correlated (r = 0.85***). Significant genotype-by-phosphorus interaction was detected but with small magnitude compared to the genotype variance component. We observed high genetic diversity within our panel, with rapid linkage disequilibrium decay, confirming recent sequence based studies in sorghum. Using genome wide association mapping based on 220 934 SNPs we identified one genomic region on chromosome 3 that was highly associated to grain yield production. A major Al-tolerance gene in sorghum, SbMATE, was collocated in this region and SbMATE specific SNPs showed very high associations to grain yield production, especially under -P conditions, explaining up to 16% of the genotypic variance.Conclusion: The results suggest that SbMATE has a possible pleiotropic role in providing tolerance to two of the most serious abiotic stresses for sorghum in WA, Al toxicity and P deficiency. The identified SNPs can help accelerate breeding for increased sorghum productivity under unfavorable soil conditions and contribute to assuring food security in WA. © 2014 Leiser et al. Source

Leiser W.L.,University of Hohenheim | Rattunde H.F.W.,International Crops Research Institute for the Semi Arid Tropics | Piepho H.-P.,University of Hohenheim | Weltzien E.,International Crops Research Institute for the Semi Arid Tropics | And 3 more authors.
Crop Science | Year: 2015

Sorghum (Sorghum bicolor (L.) Moench) is widely cultivated in West Africa (WA) on soils with low phosphorus (P) availability. Large genetic variation for grain yield (GY) under low-P conditions was observed among WA sorghum genotypes, but information is lacking on the usefulness of P-tolerance ratios (relative performance in -P [no P fertilizer] vs. +P [with P fertilizer] conditions) and measures of P-acquisition and internal P-use efficiency as selection criteria for enhancing GY under low-P conditions. We evaluated 70 WA sorghum genotypes for GY performance under −P and +P conditions for 5 yr in two locations in Mali and assessed P acquisition (e.g., P content in biomass) and P-use efficiency (e.g., grain produced per unit P uptake) traits under −P and +P conditions in one site in 2010. Significant genetic variation existed for all P-tolerance ratios across multiple sites. Photoperiod- sensitive landrace genotypes showed significantly better P tolerance and less delay of heading under P-limited conditions compared with photoperiod-insensitive varieties. Genotypic correlations of P-tolerance ratios to GY under −P were moderate. Phosphorous acquisition and P-use efficiency traits independent of harvest index were of similar importance for GY under −P conditions in statistically independent trials. However grain-P and stover-P concentrations from one −P trial showed only weak correlations with GYs in statistically independent trials. Highest predicted gains for −P GY were obtained by theoretical index selection based on −P GY combined with P-use efficiency traits (e.g., low-grain P concentration). Such index selection is expected to achieve both increased sorghum productivity and P sustainability in the P-limited WA production systems. © Crop Science Society of America Source

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