BackgroundGenetic diversity provides the capacity for plants to meet changing environments. It is fundamentally important in crop improvement. Fifty-nine local maize lines developed at INERA and 41 exotic (temperate and tropical) inbred lines were characterized using 1057 SNP markers to (1) analyse the genetic diversity in a diverse set of maize inbred lines; (2) determine the level of genetic diversity in INERA inbred lines and patterns of relationships of these inbred lines developed from two sources; and (3) examine the genetic differences between local and exotic germplasms.ResultsRoger’s genetic distance for about 64% of the pairs of lines fell between 0.300 and 0.400. Sixty one per cent of the pairs of lines also showed relative kinship values of zero. Model-based population structure analysis and principal component analysis revealed the presence of 5 groups that agree, to some extent, with the origin of the germplasm. There was genetic diversity among INERA inbred lines, which were genetically less closely related and showed a low level of heterozygosity. These lines could be divided into 3 major distinct groups and a mixed group consistent with the source population of the lines. Pairwise comparisons between local and exotic germplasms showed that the temperate and some IITA lines were differentiated from INERA lines. There appeared to be substantial levels of genetic variation between local and exotic germplasms as revealed by missing and unique alleles.ConclusionsAllelic frequency differences observed between the germplasms, together with unique alleles identified within each germplasm, shows the potential for a mutual improvement between the sets of germplasm. The results from this study will be useful to breeders in designing inbred-hybrid breeding programs, association mapping population studies and marker assisted breeding.Electronic supplementary materialThe online version of this article (doi:10.1186/s12863-014-0127-2) contains supplementary material, which is available to authorized users.

Drought, heat stress, and unfavorable soil conditions are key abiotic factors affecting quinoa’s growth and development. The aim of this research was to examine the effect of progressive drought and N-fertilization reduction on short-cycle varieties of quinoa (c.v. Titicaca) for different sowing dates during the dry season (from October to December). A two-year experimentation (2017–2018 and 2018–2019) was carried out in Burkina Faso with four levels of irrigation (full irrigation—FI, progressive drought—PD, deficit irrigation—DI and extreme deficit irrigation—EDI) and four levels of N-fertilization (100, 50, 25, and 0 kg N ha−1). Plant phenology and development, just like crop outputs in the form of yield, biomass, and quality of the seeds were evaluated for different sowing dates having different temperature ranges and photoperiodicity. Crop water productivity (CWP) function was used for examining plant’s water use efficiency under drought stress conditions. Emerging findings have shown that CWP was highest under DI and PD (0.683 and 0.576 kg m−3, respectively), while highest yields were observed in 2017–2018 under PD and its interaction with 25 to 50 kg N ha−1 (1356 and 1110 kg ha−1, respectively). Mean temperatures close to 25 °C were suitable for optimal plant growth, while extreme temperatures at anthesis limited the production of grains. Small changes in photoperiodicity from different sowing dates were not critical for plant growth.

____________________________________________________________________________________________________________________________________________________________________________Abstract: The root length density (RLD) distribution in the soil is a key factor for water and nutrient uptake but its direct assessment is not easy. A field method is presented here to assess RLD of sorghum (Sorghum bicolor L. Moench) from the root intersection density (RID) and taking root orientations into account. The method was developed with four varieties cropped in 2006 in Bambey (Senegal) on a sandy soil, and validated on the basis of independent data obtained on two other varieties cropped in 2008 in Thiès in Senegal on a sandy loam soil. Sets of 1 × 10 -3 m 3 cubic undisturbed soil samples were collected at different positions and at three different dates for the four varieties during the first experiment. RIDs of thick and fine roots were assessed on the sides of the soil cubes and RLDs were measured in the volumes. Fine roots appeared to be isotropic when thick roots were horizontal near the surface and gradually became vertical in deeper horizons. RLD was tenfold lower for thick roots than for fine ones. This led to the development of a model to determine RLD from RID. The relationship for all roots was modeled as RLD = RID × CO, where the root orientation coefficient (CO) is equal to 1.97, indicating that the global root distribution is almost isotropic (CO = 2 for isotropic conditions). The model was validated on the basis of independent data from the second experiment. This model enables RLD mapping and description of RLD variability on sorghum from RID observations on trench profiles (with 10 × 10 cm or 5 × 5 cm surface area used for RID measurement).

Background:The low adoption of technologies, developed by research institutions, by farmers substantiates the need for client orientation in research and development. Hence, to bridge the gap between breeders and farmers and to ensure that new varieties fit farmers' preferences and suit their socioeconomic situations, Participatory Rural Appraisals (PRA) were undertaken in two agro-ecological zones (North-Sudan and South-Sudan) to determine maize varieties farmers grow, farmers' preferences in choice of the varieties and to evaluate farmers' perceptions of constraints to maize production.Results: Farmers grow both local and improved varieties to meet their multiple objectives in maize farming. Nearly 63 % of the farmers grow local maize varieties whilst about 37 % grow improved varieties. All the different varieties are grown in both northern and southern zones but, in general, early maturing maize varieties are grown in northern zones while late maturing maize varieties are planted in southern zones. This study revealed that farmers preferred varieties that carry traits like high yield potential, early maturity, tolerance to drought, Striga and low soil fertility in all districts. Maize production in the two zones is constrained by a variety of related factors, the extent of contribution of each factor varies across the districts. The main constraints to maize production are poor cash flow, inadequate farm tools, poor extension service, drought and pests. Striga is considered as the most important pest followed by termites. Conclusions:Few studies have been conducted on models on Burkina Faso agriculture and technology adoption. This study identified agro-ecological zones and others key factors in adoption decision of new maize variety. It is expected that future studies will include these factors as some of the explanatory variables in adoption models.

Path coefficient analysis showed that traits EPP, TS, PR, EASP, R-EPH were important secondary traits in the present experiment. These traits were used in a selection index to classify hybrids according to their performance under drought. The selection procedure included also a Relative Decrease in Yield (RDY) index. Some secondary traits reported as significant selection criteria for selection under drought stress were not finally established in the present study. This is because the relationship between grain and secondary traits can be affected by various factors including germplasm, environment and applied statistical analysis. Therefore, different traits and selection procedure should be applied in the selection process of drought tolerant genotypes for diverse genetic materials and growing conditions.