Genetic structure and diversity in Sorghum bicolor (L.) Moench landraces from marginal sorghum production lands in Senegal, based on SSR markers

Data on sorghum genetic diversity in Senegal are missing despite its importance in the food and feed in the country. In order to contribute to the sustainable in situ management of sorghum germplasm, we investigated its genetic diversity and structure in its marginal production areas. Investigations were focused on Thiès, Diourbel and Kédougou regions where sorghum landraces have been less investigated and genetic information on landraces is unknown. A total of 148 sorghum accessions representative of landraces used in production systems have been sampled and analyzed with 30 microsatellite markers. A total of 138 alleles have been recorded. The number of alleles per locus varied from 3 (7 loci) to 8 (3 loci). The observed heterozygosity varied from 0 to 0.62. The low genetic distance (0.12) was recorded between Thiès and Diourbel populations and the highest distance (0.22) between Thiès and Kédougou populations. Dendrogram obtained according to Neighbour joining classification model allowed the classification of sorghum accessions into three main groups. The Genetic structure is not function to the regions indicating that landraces are not specific to a region. The results are a first step toward the sustainable in situ management of genetic resources. Data on the whole range of existing diversity of sorghum in Senegal is an important key for its germplasm management; so, the genotyping must be extended to accessions from the whole country.

Development and Release of Two Mid-Late Maturing Maize Hybrids for the Highland Agro-Ecologies of Uganda

The maize yield in the highland areas of Uganda (1500 to 3000 masl), rarely exceeding 2 t ha-1. The use of unimproved maize genotypes, the prevalence of pests and diseases, and low levels of input use has tremendously contributed to the low grain yields. Accordingly, we obtained 100 maize inbred lines majorly from CIMMYT in the year 2013. The inbred lines were evaluated for adaptability and those selected were intercrossed to generate 80 single cross hybrids by January 2015. The 80 single cross hybrids were evaluated in preliminary yield trials in three sites namely, Kachwekano, Kalengyere and Buginyanya in 2015a season. The best combiners were crossed with the selected males to obtain 122 three-way cross hybrids. These were evaluated for adaptability in advanced yield trials in 2016a in Kachwekano, Kalengyere and Bukwo, from where the best five hybrids (BH33, BH31, BH27, BH104 and BH38) were selected for National Performance Trials (NPT) in 2016b and 2017a seasons in Bukwo, Buginyanya, Zombo, Fort portal and Kalengere. Two candidate varieties namely BH31 and BH33 exhibited good agronomic qualities such as earlier maturity, tolerance to MLN and other diseases. The selected hybrids yielded 8.2 t ha-1 and 7.2 t ha-1 for BH31 and BH33, respectively. The two varieties are appropriate for cultivation in major highland and transitional maize growing regions in Uganda and were subsequently released as NAROMAIZE 731 and NAROMAIZE 733, respectively. The newly released varieties are expected to reduce the highland maize cropping season from over six months to five months.

A Dihaploid Approach for the Selection of Forage Quality in Tall fescue (Festuca arundinacea Schreb.)

Within the Festuca-Lolium genome complex, there is a need for modern breeding approaches that can facilitate the rapid development of improved germplasm or cultivars. Traditional recurrent or mass-selection methods for population or synthetic development are labor intensive and time consuming. The recent development of annual ryegrass Lolium multiflorum Lam.) lines, when hybridized by tall fescue [(Festuca arundinacea Schreb. (syn. = Lolium arundinaceum (Schreb.) Darbysh.)], will produce F1 hybrids, that through mitotic genome loss, lose either their ryegrass or tall fescue genome and result in the recovery of ryegrass and tall fescue dihaploid (DH) lines. For breeding and selection purposes regarding forage quality, the ability to select for superior genotypes at the F1 generation, rather than at the subsequent DH generation would improve the efficiency of the technique. The study examined forage quality components of crude protein (CP), acid digestible fiber (ADF), neutral digestible fiber (NDF) and in vitro dry matter digestibility (IVDMD) expression and inheritance in the F1 and their respective recovered DH lines. Results of the study indicate that forage quality genotypes, conferred by the tall fescue gamete, are heritable and selection performed at the F1 generation will be effective in identifying DH genotypes that are not significantly different in forage quality of their respective F1 parents. Though performed only on CP, ADF, NDF and IVDMD forage quality components, the study suggests similar application toward the selection of additional quantitative forage quality or agronomic attributes for tall fescue improvement. The described selection strategy is applicable to tall fescue (L. arundinaceum) and may have application across the Lolium/Festuca genus.

Screening of Bread Wheat Genotypes on Physiological and Agronomical Traits in High Temperature at Different Planting

The most crucial factors that reduce developments of plants are the Abiotic stresses. Among abiotic stresses, high temperature is the imperative factor that causes a reduction in crop growth and effect yield. Nowadays, the temperature of Pakistan has raised with approximately 500C, affecting the wheat crop from anthesis stage till maturity and hence, limiting the productivity of wheat. This study focuses on examining the effects of high temperature on wheat genotypes when planted with different sowing date viz. 10th November and 20th December of the year 2017-18, using Randomize Complete Bloch Design (RCBD). Product yield from both sowing dates (early and late) were observed with significant difference in all types of genotypes; for days 75% maturity, 1000-grains yield, grain yield (kg/ha-1), biological yield (kg/ha-1) and in some physiological characters such as area (cm2) of flag leaf, relative percent of water content ( %) and chlorophyll content % at the probability level P≤0.01 and probability level P≤0.05. The early and late planting revealed significant different recorded in RWC (%) and Leaf Area. The late sowing date, the trait RWC (%) shown non-significant result. The maximum reduction recorded in HYT 10 advance line for grain yield kg/ha-1, leaf area and RWC and in HYT 09 more reduction of chlorophyll content was observed. Hence, it was due to delayed planting effect and heat stress.

Genetic analysis of Agronomic Traits of Wheat under Terminal Drought Stress

Seven wheat genotypes (Sirvan, Zarin, Pishgam, Karim, Baran, Heidary, and Rizhav) were crossed in diallel mating to develop 42 F1's hybrids. The resultant hybrids along with parents were evaluated during cropping season 2015-16 at agriculture and natural resources Pardis of Tehran University, Iran, using RCB design with 3 replications under drought stress and normal field conditions from the booting stage till physiological maturity. General combining ability (GCA) and specific combining ability (SCA) for agronomic traits were determined. The main objective of the research was the identification and proper selection of best-performing wheat parental genotypes and best F1's hybrids, based on GCA and SCA estimates. Significant differences were observed among the wheat genotypes for all the reported traits in this article. Results for combining ability analysis indicated that mean squares of GCA and SCA effects were significantly high for most of the traits. The estimates of σ2gca and σ2sca and its ratio (σ2gca/σ2sca) indicated that non-additive genetic expression was dominant for most of the traits studied, then the heterosis breading is a useful program, however selection on superior hybrids should be postponed to the next generation for these traits in recombination program. It is concluded that Zarin, and Baran are recommended as the best general combiners for a future wheat breeding program. The maximum values of SCA observed in flag leaf length in normal and peduncle length in drought condition related to crosses of Rizhav with other parents. So, it is suggested these series of crosses can be down to improve these traits at the mentioned condition

Leaf Clipping and Population Density Effects on Green Fodder and Grain Yield for Hybrid Maize (Zea mays) in Bangladesh

Smallholder farmers having fragmented lands need fodder and grains simultaneously for earning food security for their families. A study was conducted in Crop Physiology and Ecology Research Field and Laboratory at Hajee Mohammad Danesh Science and Technology University, Bangladesh during the period of March to July-2013 to investigate the effect of leaf clipping and population density on fodder and grain yield in maize. Three population densities (D1= 75 cm × 25 cm, D2= 60 cm × 20 cm and D3= 50 cm × 20 cm) and three clipping treatments (C1 = no clipping, C2 = removal of all leaf blades below the lowermost cob and C3 = removal of all leaf blades above the uppermost cob) at the silking stage were included as experimental treatments. The experiment was laid out in a two factors Randomized Complete Block Design (RCBD) with three replications. Results revealed that D1 required the maximum days to attain most of the phenological stages of maize. Higher population density (D3) with C3 clipping treatment gave the highest plant height, whereas D1 with non-clipping treatment gave the lowest. Highest total dry matter (TDM) was found in D2 with C1 and the lowest was found in D1 with C1 treatment. The highest yield (8.88 t ha-1) and harvest index (36.2%) were found in D3 treatment whereas the lowest yield (5.92 t ha-1) in D1 population density but harvest index (32.6 %) was lowest in D2. The highest yield (8.33 t ha-1) and harvest index (35.5 %) were obtained from C1 treatment and the lowest yield (6.55 t ha-1) and harvest index (33.5 %) were obtained from C3 treatment. The highest fodder yield (3.33 t ha-1) was obtained from D3 treatment and the lowest (2.11 t ha-1) in D1 treatment. In C2 treatment, the highest amount of fodder (4.67 t ha-1) was obtained. The interaction between population density and leaf clipping treatment showed a significant variation among the yield and yield attributes in maize. It is indicated that D3 and C1 combination showed the best performance in respect of grain yield (9.67 t ha-1) and harvest index (38.3 %) of maize. But for both grain and fodder yield, D3 with C2 showed the best performance.

Genotype X Environment Interaction and Yield Stability of Bread Wheat Genotypes in central Ethiopia

The present study was conducted to interpret Genotype main effect and GEI obtained by AMMI analysis and group the genotype having similar response pattern over all environments. Fifteen bread wheat genotypes were evaluated by RCBD using four replications at six locations in Ethiopia. The main effect differences among genotypes, environments, and the interaction effects were highly significant (P ≤ 0.001) for the total variance of grain yield. Results of AMMI analysis of mean grain yield for the six locations showed significant differences (P0.001) among the genotypes, environments and GEI. The environment had the greatest effect with the environmental sum of squares (35.28%) than the genotypes (33.46%) and GEI (31.45%) effect. The AMMI analysis for the IPCA1 captured 46.1% and the IPCA2 explained 28.6%. The two IPC cumulatively captured 74.7% of the sum of square the GEI of bread wheat genotypes, when the IPCA1 was plotted against IPCA2. The genotype ETBW8075, ETBW8070 and ETBW9470 were unstable as they are located far apart from the other genotypes in the biplot when plotted on the IPCA1 and IPCA2 scores. The ETBW8078, ETBW8459, Hidase and ETBW8311 were genotype located near to the origin of the biplot which implying that it was stable bread wheat genotypes across environments. There is closer association between Lemu and ETBW8065 which indicate similar response of the genotypes to the environment. The best genotype with respect to location Kulumsa was ETBW9470, ETBW8075 was the best genotype for Dhera, ETBW8070 was the best genotype for Holeta while ETBW9466 was the best genotype for Arsi Robe. Arsi Robe and Kulumsa is the most favorable environment for all genotypes with nearly similar yield response for grain yield.

GGE Biplot Analysis of Genotype by Environment Interaction and Grain Yield Stability of Bread Wheat Genotypes in Central Ethiopia

GGE biplot is an effective method based on principal component analysis to fully explore mega-environments trials data. The study conducted was to identify the best performing, high yielding stable advanced bread wheat genotype for selection environments, the identification of mega-environments and analysis of the ideal genotype and environment by GGE biplot method. Fifteen bread wheat genotypes were evaluated using RCBD with four replications at six locations in Ethiopia. The results of combined analysis of variance for grain yield of fifteen bread wheat genotypes indicated that genotype, environment and GEI were highly significant (P0.001). The factors explained showed bread wheat genotypes grain yield was affected by environment (35.28%), genotype (33.46%) and GEI (31.45%). The first two PC axes of GGE explained 88.7% of G+GEI and divided the six locations into three major groups: Group1 included Asasa, Kulumsa and Arsi Robe (moderately discriminating locations); Group2 had the highland wheat producing locations Holeta and Bekoji (most discriminating locations), while Group3 contain Dhera (least discriminating location), a moisture stress location in the rift valley. Locations within the same group were closely correlated and provided redundant information about the genotypes. Testing can be performed in any one of the locations within a group. Genotype ETBW8078 and ETBW8459 were more stable as well as low yielding. Considering simultaneously yield and stability, genotype ETBW9045 and Hiddase showed the best performances suggesting their adaptation to a wide range of environments. Lemu, ETBW8084 and ETBW8065 were considered as desirable. Genotype ETBW8075 was the least stable with low yield and had a large contribution to the GEI, having the longest distance from the average environment. ETBW9470 was specifically adapted to Group1 locations while ETBW8070 was adapted to Group2 environments. Based on yield performance advanced lines ETBW9470 and ETBW8070 are recommended to be included in variety verification trials for further release.

Combining ability analysis and gene action for yield and yield related traits in rice (Oryza sativa L.) under saline conditions

Salinity is a major abiotic constrain faced by farmers in most rice cultivating areas of the world and improving grain yield in rice is the most important breeding objective. Twenty seven hybrids were generated in a line x tester mating design and were evaluated with their parents in a Randomized Complete Block Design at the Fadama site of the Federal University of Agriculture, Abeokuta (FUNAAB) during the 2014/2015 and 2015/2016 cropping season. Analysis of variance revealed a highly significant difference (P0.01) among testers and lines for all traits except panicle length and a number of effective tillers per plant, respectively. Variances of Specific Combining Ability (SCA) were higher in magnitude than the corresponding General Combining Ability (GCA). The lines FARO 60 (P7), OG300315 (P10), NERICA L53 (P4) including a tester ITA 212 (P1) were the best general combiners for yield per plant. POKKALI (P3) was the best general combiner for reduced vegetative growth and ITA 212 (P1) and ITA 222 (P2) were the best general combiners for plant height. The best specific combiner for yield per plant was P1 x P4. P3 x P11 was the best specific combiner for reduced duration characters and P2 x P7 was the best specific combiner for plant height. Estimates of narrow sense heritability (0.00 – 0.03) for all the traits under study were low which indicated preponderance of non-additive gene action governing these traits. Therefore, inter-mating among selected segregants followed by recombination breeding in an advanced generation might be advocated for improvement of the studied traits under salinity.

Selection for Yield Improvement in Bambara Groundnut (Vigna subterranea L. Verdc.)

Selection as the most practical and economical way of improving yield in an extreme autogamous crop was carried out in a Randomized Complete Block Design (RCBD) with three replications, with thirty three accessions of Bambara groundnut {Vigna subterranea (L.) Verdc}. Qualitative characters displayed a reasonable range of variation except for eye pattern, seed shape, pod texture and growth habit. The result on the analysis of variance (ANOVA) showed significant differences (p0.05) for all traits except for plant height, number of leaves per plant and seed length that were statistically insignificant. The principal component analysis result revealed that eight components (Eigen values ≥ 1) accounted for 78.36 % of the phenotypic variance, and quantitative traits revealed more phenotypic variation among the accessions Pearson’s correlation coefficient showed that petiole length (r= 0.64), vigour index (r= 0.49), seed length (r=0.53), canopy width (r=0.38), and internode length (0.58). had a high positive correlation with seed yield. Ranking of the accessions based on significantly strong correlated traits with yield using the rank summation index (RSI) method, and the selection of the best top 5% of the entries identified accessions TVSU 1688 and 1638 with RSI scores of 31 and 43 respectively as the best high yielding Bambara groundnut lines. Correspondingly, accessions TVSU 1688 and 1638 had the highest mean seed yield per plant of 1150.5g and 720.8g respectively in the 3-year field evaluation; which further confirmed the precision of the ranking and selection result. Invariably these two accessions were inherently high yielding Bambara groundnut accessions.