A diallel study to detect genetic background variation for FHB resistance in winter wheat.

Breeding for resistance to Fusarium head blight (FHB) relies strongly on a limited number of larger-effect resistance QTL that have been mapped and associated with nearby markers. Smaller-effect (background) resistance QTL may also contribute moderate levels of resistance yet are mostly poorly characterized. Overall resistance of a genotype is determined by the combined action of both types of resistance QTL. This study aimed to identify well-adapted, advanced hard red winter (HRW) wheat breeding lines with useful background resistance QTL. A diallel trial consisting of 11 parents and 55 non-reciprocal F1 hybrids was tested for Type II FHB resistance in a replicated greenhouse experiment. Significant differences were detected among entries for disease severity (DS), general combining ability (GCA) and specific combining ability (SCA) with four parents being identified as the best general combiners with lowest DS. The ratio of GCA:SCA effects suggested that additive QTL effects were of primary importance. Overall, resistance QTL showed incomplete dominance, an excess of dominant alleles, and a greater contribution of positive effect genes. F2 of the six best F1 hybrids with the lowest DS were compared in a second greenhouse FHB trial to select possible transgressive segregates for continued evaluation and line development.

The use of PI 277012-derived Fusarium head blight resistance QTL in winter wheat breeding.

Fusarium head blight (FHB) caused by Fusarium graminearum results in substantial grain yield and quality losses in common wheat (Triticum aestivum L.). Genetic resistance is partial but crucial for effective, integrated management of the disease. Host resistance is conditioned by numerous small effect quantitative trait loci (QTL) that are strongly affected by the environment and genetic background. Qfhb.rwg-5A.1 and Qfhb.rwg-5A.2 (PI 277012 is the source for both genes) are two recently discovered FHB resistance QTL that also occur in spring wheat GP80 (PI 277012 derivative). To transfer the PI 277012 resistance from GP80 to hard winter wheat (HWW), GP80 was first crossed with Novus-4. The F1 hybrid was crossed with SY Monument, following which marker-selected progeny were crossed with, and backcrossed to, ND Noreen. To potential carriers of FHB resistance QTL among the 22 F1 of the ND Noreen cross, simple sequence repeat (SSR) markers, Illumina 90 K single nucleotide polymorphism (SNP) haplotypes and greenhouse FHB Type II resistance tests were done. Likely homozygotes for Qfhb.rwg.5A.1 and Qfhb.rwg.5A.2, were selected and backcrossed to ND Noreen. In the B1F1, 131 plants were evaluated for SNP haplotypes, SSR markers and FHB resistance. Nine B1F2:3 lines were derived, and their resistance confirmed in a third greenhouse FHB trial. The results suggested that eight lines had higher resistance and were comparable to GP80 with the Qfhb.rwg-5A.2 markers occurring in all eight and the Qfhb.rwg-5A.1 markers occurring in four lines. The eight selections constitute a valuable HWW resistance breeding resource.

Documentation and on farm conservation of neglected and underutilized plant species in Lamjung district, Nepal.

Neglected and underutilized species (NUS) are proven superfoods, but still many of those species are not mainstreamed in our food system. In this regard, research was carried out to explore diversity and identify prioritized species, explore use-values, and identify the role of a socio-demographic factor in its conservation and promotion. For this, a survey was conducted at two rural municipalities' viz. Marsayndi Rural Municipality-01 (Ghanpokhara) and Kwhlosothar Rural Municipality (ward no-03, Ghalegaun & ward no-04, Bhujung) in Lamjung district of Nepal. Location wise cluster sampling was conducted for data collection and the techniques employed were direct field observation, household sampling, key informant interview, personal interviews, and field studies. 92 species were documented during the study, moreover, a significant role of socio-demographic factors was seen in characterizing, evaluating, and conserving NUS on-farm. The results indicated that the education status and primary occupation of the household head had a major role whereas ethnicity had a certain level of the role while gender had no role to play on on-farm conservation of NUS. People with basic education status and agriculture as their primary occupations showed a higher influence on conservation. The result concludes with some insight on the way forward for NUS and addresses a need to establish a research and development program including all potential participants such as with government, academics, entrepreneurs, and producers to promote NUS.