QTL mapping and analysis of epistatic interactions for grain yield and yield-related traits in <Emphasis Type="Italic">Triticum turgidum</Emphasis> L. var. <Emphasis Type="Italic">durum</Emphasis>

A quantitative trait loci (QTL) analysis of grain yield and yield-related traits was performed on 93 durum wheat recombinant inbred lines derived from the cross UC1113 × Kofa. The mapping population and parental lines were analyzed considering 19 traits assessed in different Argentine environments, namely grain yield, heading date, flowering time, plant height, biomass per plant, and spikelet number per ear, among others. A total of 224 QTL with logarithm of odds ratio (LOD) ≥ 3 and 47 additional QTL with LOD > 2.0 were detected. These QTL were clustered in 35 regions with overlapping QTL, and 12 genomic regions were associated with only one phenotypic trait. The regions with the highest number of multi-trait and stable QTL were 3BS.1, 3BS.2, 2BS.1, 1BL.1, 3AL.1, 1AS, and 4AL.3. The effects of epistatic QTL and QTL × environment interactions were also analyzed. QTL putatively located at major gene loci (Rht, Vrn, Eps, and Ppd) as well as additional major/minor QTL involved in the complex genetic basis of yield-related traits expressed in Argentine environments were identified. Interestingly, the 3AL.1 region was found to increase yield without altering grain quality or crop phenology.     

Estimating gene action,combining ability and heterosis for grain yield and agronomic traits in extra-early maturing yellow maize single-crosses under three agro-ecologies of Ghana

Maize (Zea mays L.) is the most important cereal crop produced in Ghana. However, yield of the crop is generally low, producing just about 1.7 t/ha. The low yield is attributed to continuous use of local/unimproved varieties. Generally, hybrid varieties have proven to out-yield the local/unimproved varieties due to improved vigour. Development of hybrid varieties depend on good understanding of combining ability and inheritance of important quantitative traits such as grain yield (GY). 45 half-diallel crosses generated from 10 extra-early maturing yellow inbred lines were evaluated in 2015 under rain-fed conditions. The objectives were to determine the genetic control, breeding value and estimate heritability for GY and agronomic traits of the inbred lines under contrasting growing environments in Ghana. General combining ability (GCA) and specific combining ability (SCA) were important in the inheritance of GY and agronomic traits of the inbred lines. However, GCA was more important than SCA across environments to suggest that additive gene action was more important than non-additive gene action in the inheritance of GY and agronomic traits in the inbred lines. High broad-sense heritability, for GY and other agronomic traits indicated preponderance of additive gene action in trait expression, thus, selection based on phenotypic expression could be feasible. Inbred lines P1, P4 and P8 were good combiners for high GY. The genotype, P4 × P8, was identified as the ideal and most yielding single-cross hybrid across research environments and should be further tested on-farm before commercialization.     

Identifying and exploring significant genomic regions associated with soybean yield,seed fatty acids,protein and oil

Soybean [Glycine max (L.) Merrill] yield and seed fatty acids, protein, and oil content are important traits for which an improved understanding of significant genomic regions would be useful. To accomplish this, a soybean population consisting of 203 F5 derived recombinant inbred lines (RILs) was developed and genotyped with 11,633 polymorphic single nucleotide polymorphisms (SNPs). Each RIL was grown in a single plot at Knoxville, TN in 2010; followed by replicated, multi-location field trials in 2013 and 2014. The data from 2010, 2013, and 2014 were analyzed together in order to detect quantitative trait loci (QTL) for these traits, and 30 total QTLs were detected. Five QTLs are candidates for confirmed status and one QTL is a candidate for positional confirmation. Many of the genes with mutations in close proximity to the fatty acid QTLs are involved in biological processes for fatty acids and/or lipids and could be considered possible candidate genes. Similarly, genes with mutations in genomic regions near yield, protein, and oil QTLs were plentiful and may contribute to the variation observed in these traits. Except for yield and stearic acid, each trait displayed pleiotropic effects with other traits in this study. Notable are the pleiotropic effects for oleic and linolenic acid on chromosomes 9, 13, and 19. Overall, the findings from this research contribute new information to the genetic understanding of soybean yield and seed fatty acids, protein and oil content. This understanding will be useful in making trait improvements.     

Geospatial delineation of South Korea for adjusted barley cultivation under changing climate

Determining effective measures to alleviate the impact of climate change on crops under various regional environments is one of the most urgent issues facing agriculture. In this study, geographic regions of South Korea for future-adjusted barley cultivation were outlined and the impact of climate change on barley production in the next 100 years was evaluated under two greenhouse gas concentration trajectory scenarios: the representative concentration pathway (RCP) 4.5 and RCP 8.5. To achieve our intended study goals, a geospatial crop simulation modeling (GCSM) scheme was formulated using CERES-barley model of Decision Support System for Agricultural Technology (DSSAT) crop model package version 4.6 to simulate grid-based geospatial crop yields. Two experiments were carried out at an open field to obtain model coefficients for the nation and at temperature gradient field chambers to evaluate the performance of the CERES-barley model under elevated temperature conditions. Suitable cultivation regions for three different types of barley (naked, hooded, and malting) under changing climate were projected to expand to the northern regions under both RCP 8.5 and RCP 4.5. However, they were projected to expand more rapidly under RCP 8.5 than those under RCP 4.5. Projected yields of four barley varieties were increased with a slow phase as year progressed under RCP 4.5 scenario. However, they were rapidly increased under RCP 8.5 scenario. It appears that geospatial variation in barley yield under changing climate can be effectively outlined. Therefore, GCSM system might be useful for determining impacts of climate change on geospatial variations of crops, potentially providing means to impede food insecurity.     

Transformation of <Emphasis Type="Italic">Campanula</Emphasis> by wild type <Emphasis Type="Italic">Agrobacterium rhizogenes</Emphasis>

Compact growth is an important quality criterion in horticulture. Many Campanula species and cultivars exhibit elongated growth which is suppressed by chemical retardation and cultural practice during production to accommodate to the consumer’s desire. The production of compact plants via transformation with wild type Agrobacterium rhizogenes is an approach with great potential to produce plants that are non-GMO. Efficient transformation and regeneration procedures vary widely among both plant genera and species. Here we present a transformation protocol for Campanula. Hairy roots were produced on 26–90% of the petioles that were used for transformation of C. portenschlagiana (Cp), a C. takesimana × C. punctata hybrid (Chybr) and C. glomerata (Cg). Isolated hairy roots grew autonomously and vigorously without added hormones. The Cg hairy roots produced chlorophyll and generated plantlets in response to treatments with cytokinin (42 µM 2iP) and auxin (0.67 µM NAA). In contrast, regeneration attempts of transformed Cp and Chybr roots lead neither to the production of chlorophyll nor to the regeneration of shoots. Agropine A. rhizogenes strains integrate split T-DNA in T_L- and T_R-DNA fragments into the plant genome. In this study, regenerated plants of Cg did not contain T_R-DNA, indicating that a selective pressure against this T-DNA fragment may exist in Campanula.     

Molecular markers for improving control of soil-borne pathogen <Emphasis Type="Italic">Fusarium oxysporum</Emphasis> in sugar beet

Fusarium spp. cause severe damage in many agricultural crops, including sugar beet, with Fusarium oxysporum historically being considered as the most damaging of all species. Sugar beet needs to be protected from this class of soil-borne pathogens in order to ensure an optimal sugar yield in the field. Genetic control of the disease is crucial in managing these pathogens. Identification of single nucleotide polymorphism (SNP) markers linked to resistance can be a powerful tool for the introgression of valuable genes needed to develop Fusarium-resistant varieties. A candidate gene approach was carried out to identify SNP markers linked to putative Fusarium resistance sources in sugar beet. Five resistant analogue genes (RGAs) were screened by means of high resolution melting (HRM) analysis in a set of sugar beet lines, considered as resistant and susceptible to Fusarium oxysporum. HRM polymorphisms were observed in 80% of amplicons. Two HRM polymorphisms were significantly associated with Fusarium resistance (P < 0.05). The amplicons that showed association were sequenced and two SNPs were identified. The association was further validated on 96 susceptible and 96 resistant plants using competitive allele-specific PCR (KASPar) technology. The selected SNPs could be used for marker-assisted breeding of Fusarium resistance in sugar beet.     

Identification of quantitative trait locus and prediction of candidate genes for grain mineral concentration in maize across multiple environments

Trace metal elements are essential in daily diets for human health and normal growth. Maize is staple food for people in many countries. However, maize has low mineral concentration which makes it difficult to meet human requirements for micronutrients. The objective of this study was to identify quantitative trait locus (QTL) and predict candidate genes associated with mineral concentration in maize grain. Here, a recombinant inbred line population was used to test phenotype of zinc (Zn), iron (Fe), copper (Cu) and manganese (Mn) concentrations in six environments and then a QTL analysis was conducted using single environment analysis along with multiple environment trial (MET) analysis. These two strategies detected a total of 64 and 67 QTLs for target traits, respectively. Single environment analysis revealed 13 QTL bins distributed on seven chromosomes. We found that five candidate genes associated with mineral concentration were located in the same intervals identified by Comparative mapping of meta-QTLs in our previous study. The genetic and phenotypic correlation coefficients were depended on the nutrient traits and they were significant between Fe and Zn, Fe and Cu, Fe and Mn in all environments. The results of this study illustrated the genetic correlation between maize grain mineral concentrations, and identified some promising genomic regions and candidate genes for further studies on the biofortification of mineral concentration in maize grain.     

Mapping of the <Emphasis Type="Italic">ms8</Emphasis> male sterility gene in sweet pepper (<Emphasis Type="Italic">Capsicum annuum</Emphasis> L.) on the chromosome P4 using PCR-based markers useful for breeding programmes

The nuclear male sterility gene ms8 is expected to facilitate the production of sweet pepper (Capsicum annuum L.) hybrids as it provides means for hybridization without the labor-intensive hand emasculation of female inbred lines. The development of molecular markers linked to ms8 locus will help the breeding practice for the selection of hybrid parental lines. In this study, F₂ population resulting from a cross between the sweet pepper male sterile line 320 and the male fertile variety Elf was used to identify DNA markers linked to the ms8 locus. With the use of RAPD–BSA technique, seven markers linked to the ms8 locus were found. Four of them were converted into SCAR markers. In addition, two COSII/CAPS markers linked to the ms8 locus were identified. Comparative mapping with reference pepper maps indicated that the ms8 locus is located on the lower arm of the pepper chromosome P4. Identified markers are useful for molecular breeding, however, at present markers tightly linked to ms8 locus are still lacking. Identification of molecular markers linked to the ms8 locus and determination of its chromosomal localization are useful for fine mapping and also provide the perspective for ms8 gene cloning.