Special Issue on Breeding and breeding research for resistance to Fusarium diseases in cereals
Plant Breeding, Volume 143, Issue 1, Page 1-1, February 2024.
Category Archives: Wiley: Plant Breeding
Issue Information
No abstract is available for this article.
Identification of haplotypes associated with resistance to Fusarium graminearum in spring oat (Avena sativa L.)
Abstract
Fusarium head blight (FHB) is the predominant disease in oat in Norway caused by the fungus Fusarium graminearum. It causes yield loss, reduced seed quality, reduced germination ability and accumulation of deoxynivalenol (DON). The FHB resistance is quantitative, and most genes have small effect. Markers with verified effect in the breeding program could further enhance the resistance breeding. This study aims to use a large and diverse population of 541 lines to identify quantitative trait loci (QTL) associated to FHB resistance in a genome-wide association study (GWAS) and verify their effect in independent breeding material. The material has been tested in six environments over three years and two locations in spawn inoculated and mist irrigated disease trials. The traits tested were germination ability and DON accumulation. A total of 15 significant QTL-regions were detected across 12 different linkage groups. Haplotypes for each region was constructed and the effect of the alleles in each environment was calculated, which identified the most likely resistant and susceptible alleles. Five QTL-regions were validated showing consistent effect in the GWAS population and the breeding material. Stacking of the resistant alleles of these regions from zero to five showed significant decrease in DON values and increased germination ability. The haplotype information of a set of historical and modern Nordic varieties were analysed, and the results could be used to select parents for future crossings. The validated haplotypes from this study can be used either to do marker assisted selection (MAS) or improve genomic prediction models in breeding programs.
First insights into the quantitative genetic composition of the female seed yield for an efficient hybrid seed production in wheat (Triticum aestivum L.)
Abstract
Hybrid breeding of wheat (Triticum aestivum L.) is limited by its self-pollinating nature. Past cross-pollination improvements mostly focused on optimizing male traits. We tested the hybrid seed yield of 100 diverse elite lines treated with a chemical hybridization agent (CHA) and pollinated by non-sterilized male plants in multi-environmental field trials. Plant height and phenological traits of female plants were also assessed. In parallel, control experiments without CHA sterilization were conducted to measure per se yield of the tested material. Hybrid seed yield variation is of quantitative genetic nature, and, despite the large environmental influence, this trait has a strong genotypic component and is highly heritable (h 2 = .77). The lack of correlation between hybrid seed yield and per se yield suggests a non-shared genetic control. Phenological traits and their interactions are important factors explaining together ~1/3 of hybrid seed yield variation. In contrast to plant height and flowering traits, which are influenced by major genetic factors, no significant marker–trait associations were found for the hybrid seed yield, thus suggesting a highly polygenic genetic architecture and the need of larger populations to investigate female hybrid seed yield.
Identification of SSR markers linked to new fertility restoration trait in sorghum (Sorghum bicolor (L.) Moench) for A4 (maldandi) male sterile cytoplasm
Abstract
Identification of markers associated with fertility restoration (Rf) genes is essential because they can streamline the breeding of new CMS lines and production of commercial hybrid seeds. Therefore, in the present study, F2 populations (M31-2A × DSMR 8) was utilized to identify markers linked to Rf loci on maldandi (A4) cytoplasm through bulk segregant analysis (BSA). The F2 population was analysed for seed set percentage. Chi-square (χ2) analysis showed that the fertility restoration trait followed expected digenic ratio. By BSA, simple sequence repeats (SSRs) markers, namely, Xtxp 34 and Xtxp 69 located on chromosome 3 and SB 3956 and Xtxp 312 located on chromosome 7, showed clear polymorphism between two groups of fertile and sterile bulks. The genomic region harbouring Rf locus on chromosome 3 (2.61 Mbp) predicted to encode five pentatricopeptide repeat (PPR) genes whereas, on chromosome 7, the gene SORBI_3007G047400 predicted to encode MYB (myeloblastosis) domain containing proteins. These predicted genes could be the candidate for restoring fertility on A4 cytoplasm. This finding will be fundamental in the production and rapid selection of novel restorer lines.
Selection for drought tolerance in backcross populations derived from interspecific crosses of Solanum lycopersicum × Solanum pennellii
Abstract
Drought strongly limits tomato yield, and the introgression of genes from wild tomatoes is a powerful tool to obtain drought-tolerant progenies. The aim of this study was to select drought-tolerant transgressive progeny obtained from interspecific crosses between drought-susceptible tomatoes (Solanum lycopersicum) × drought-tolerant wild species (Solanum pennellii) under in vitro and greenhouse conditions. BC1F2 populations were advanced from backcrosses between F1 × Jumbo AG-592 (cultivar for fresh consumption) and F1 × BRS Tospodoro (cultivar for industrial processing). For this, BC1F2 seeds were germinated in vitro and evaluated for tolerance to drought. Then, eight genotypes from each BC1F2 were selected and submitted to 14 days of drought (0% of water supply) or well-watered (100% of water supply) in greenhouse conditions and evaluated for growth, water balance and gas exchanges. Using in vitro assays with mannitol-induced drought proved to be effective for the initial screening of drought-tolerant BC1F2 plants, while greenhouse experiments showed that drought decreased photosynthesis in all genotypes, but almost all the BC1F2 progenies had greater photosynthetic capacity, water balance and growth than their commercial parents. As a result, we selected six progenies for fresh consumption and six progenies for industrial processing with increased drought tolerance.
Characterization of temperate and tropical popcorn populations and GWAS for zeins and starch contents
Abstract
Because measuring expansion volume (EV) is simple and inexpensive, popcorn breeders have developed high-quality single crosses ignoring the contents of zeins, starch, lipids, and cellular wall components in selection. However, some methods of quantification of these quality-related traits can be applied to popcorn breeding, increasing the selection efficacy for quality. The objectives of this study were to assess methods of zeins and starch quantification that can be used in popcorn breeding, characterize a temperate and a tropical populations for zeins and starch contents and identify candidate genes for these quality-related traits. We genotyped and phenotyped 286 plants. For quantification of total zeins and zein subunits we choose the ‘lab-on-a-chip’ microfluidic electrophoresis. For quantification of starch and amylose/amylopectin, we choose the Megazyme's Amylose/Amylopectin kit assay. The temperate population has superior EV (36.0%), a higher level of the 19 kDa zein subunit (32.0%), lower levels of the 21, 22 and 27 kDa subunits (−1543.0%, −40.0% and −47.0%, respectively) and no statistical difference for the 10 kDa zein content, relative to the tropical population. Although there are statistical differences between the two populations regarding starch, amylose, and amylose/amylopectin ratio, the differences are not significant (−2.0% to 8.0%). Thirteen candidate genes were identified for the 19 and 22 kDa zeins, two for amylose and one for starch, with emphasis on the genes coding for the 19 and 22 kDa alpha-zeins, located on chromosome 4. The evaluated quantification methods can be used in popcorn breeding but for a limited number of samples, mainly because costs.
Overexpression of the TaEXPA19 gene improves low‐temperature tolerance in winter wheat (Triticum aestivum)
Abstract
Low temperature is one of the main abiotic stresses that affects plant growth, causing serious damage or even death to plants. The differential expression of the TaEXPA19 gene in the above and underground parts of winter wheat and the implications for cold resistance remain unclear. In this study, the TaEXPA19 gene was cloned and analysed for expression in winter wheat, and transgenic Arabidopsis thaliana was constructed to investigate the effect of the TaEXPA19 gene in response to low-temperature stress on plant growth. The TaEXPA19-A and TaEXPA19-D genes have different response patterns in the above and underground parts of transgenic A. thaliana. When plants were subjected to low-temperature stress, the leaves were quickly upregulated and the roots were downregulated, and then upregulated to respond to low-temperature stress to promote the growth of leaf length and leaf width petiole length. The results indicated that TaEXPA19 genes could improve low-temperature tolerance in plants. The results of this study laid a foundation for the study of the cold resistance of winter wheat.
Isolation of yellow vein mosaic virus (YVMV)‐resistant mutants of okra (Abelmoschus esculentus L.) through applied mutagenesis
Abstract
Okra, Abelmoschus esculentus (L.) Moench, being highly susceptible to yellow vein mosaic virus (YVMV) disease warrants its genetic improvement for resistance. Applied mutagenesis programme using two optimum doses of gamma radiation, namely, 350 Gy and 450 Gy radiation, was administered for the variety Pusa Sawani rated as excellent for fruit quality but highly susceptible to YVMV disease. Two selected putative mutant families, namely, 350//10///3-9////28 and 450//66///2-4////39, isolated in the M5 generation with slightly different plant morphology as compared to the parental genotype, Pusa Sawani, showed consistent resistance against YVMV disease. Upon evaluation in the M6 generation, eight morphological characteristics and five quantitative characteristics differed significantly among the mutants and Pusa Sawani. Proximate compositions and enzyme activity in leaf were significantly higher in the two YVMV-resistant mutants. Disease screening under artificial inoculation in the insect proof cages confirmed YVMV resistance in these mutants. DNA fingerprinting further validated the alterations occurred in these two isolated mutants compared to the parental genotype. These mutants deserve due attention towards the development of YVMV-resistant variety.
Identification of sources of resistance to Striga gesnerioides Willd. Vatke among cowpea (Vigna unguiculata [L.] Walp) germplasm from Togo
Abstract
Striga gesnerioides is one of the major biotic constraints to cowpea (Vigna unguiculata [L.] Walp) production throughout West Africa. The best way to control and limit the spread of this weed remains genetic control, but recent works have shown that all cowpea varieties commonly grown in Togo are susceptible to S. gesnerioides. This study aims to investigate the resistance response of cowpea germplasm from Togo to S. gesnerioides. A field test was performed under natural infestation followed by a pots test under artificial infestation. Genotyping was carried out with three molecular markers SSR1, 61RM2 and C42-2B, known for their linkage to S. gesnerioides resistance genes. The results have revealed three cowpea accessions, TG20_66, TG20_82 and TG20_108, phenotypically resistant to S. gesnerioides. All three resistant accessions have shown the RSG3-301 resistance gene presence. Potential resistance gene sources to S. gesnerioides exist among cowpea accessions from Togo.