Enrico Noli

Utilization of SSR and AFLP markers for the assessment of distinctness in durum wheat

Molecular techniques provide new possibilities to characterize advanced genetic materials for registration purposes and for the protection of breeders’ rights. The objective of this work was to compare the simple sequence repeat (SSR) and amplified fragment length polymorphism (AFLP) markers with morphological descriptors, currently in use, for the assessment of variety distinctness in durum wheat. Fifty-six F8 or F9 lines or sublines at different levels of relatedness derived from four crosses, two BC1- and 11 BC3-derived lines, were characterized with 27 morphological traits, including 17 official Community Plant Variety Office (CPVO) descriptors, seven AFLP primer combinations, and 98 SSR primer pairs. The similarities based on all three marker classes reflected, on average, the degree of relatedness of the materials. However, molecular markers (MMs) and in particular SSRs produced classifications more closely representing the relationships among lines, allowing us to discriminate even tightly related genotypes that morphological descriptors failed to distinguish. The moderate correlations between similarities based on morphological and molecular data, and the wide range of MM differences corresponding to few or no morphological differences, imply that at present MMs should only be used as a complementary tool to assess distinctness. Based on these results, it seems that a set of 28 SSRs (one per chromosome arm) represents a useful prescreening tool to identify the entry pairs sufficiently different at MM level (≥13 polymorphisms) for which a field evaluation could be avoided, with relevant savings in resources and optimization of the field trial design.

Association Mapping Reveals Novel Stem Rust Resistance Loci in Durum Wheat at the Seedling Stage

Wheat stem rust rapidly evolves new virulence to resistance genes. Recently emerged races in East Africa, such as TTKSK (or Ug99), possess broad virulence to durum cultivars, and only a limited number of genes provide resistance. An association mapping (AM) study conducted on 183 durum wheat accessions has allowed us to identify 41 quantitative trait loci (QTLs; determination coefficient [R2] values from 1.1 to 23.1%) for seedling resistance to one or more of four highly virulent stem rust races: TRTTF, TTTTF, TTKSK (Ug99), and JRCQC, two of which (TRTTF and JRCQC) were isolated from Ethiopia. Among these loci, 24 are novel, while the remaining 17 overlapped with loci previously shown to provide field resistance in Ethiopia and/or chromosome regions known to harbor designated stem rust resistance designated loci (Sr). The identified loci were either effective against multiple races or race specific, particularly for race JRCQC. Our results highlight that stem rust resistance in durum wheat is governed in part by loci for resistance across multiple races, and in part by race‐specific ones (23 and 18, respectively). Collectively, these results provide useful information to improve the effectiveness of marker‐assisted selection towards the release of durum wheat cultivars with durable stem rust resistance.

Data on seed germination using LED versus fluorescent light under growth chamber conditions

The present investigation attempted to assess the influence of two light sources, LED versus fluorescent light, on seed germination of nine aromatic species belonging to the genus Artemisia, Atriplex, Chenopodium, Salicornia, Sanguisorba, Portulaca and Rosmarinus. Pre-germination test was carried out in petri dishes, evidencing the need to overcome seed dormancy through cold stratification in Salicornia europaea. Thereafter, seeds were germinated in small trays with peat moss substrate in two growth chambers illuminated with either LED or fluorescent light featuring similar photosynthetic photon flux density. Germination lasted 20 days, during which time five indexes of germination performance (germination percentage, speed of germination, germination energy, germination rate index, and mean daily germination) were evaluated. At the end, shoot length and seedling fresh weight were assessed as early growth traits. Data are made available to allow critical evaluation of experimental outcome.

Sugarbeet seed’s yield and quality as affected by irrigation

Irrigation to the sugar-beet seed crop is a common practice since many years in Emilia Romagna region, even though information on the most suitable ways to irrigate is very limited. The aim of this three-year long experimentation was to evaluate the influence of timing and number of irrigation treatments on seed yield and quality. Treatments at the onset, at full, and at the end of flowering, wit all their possible combinations were compared among themselves and with the non-irrigated control. During the second and third years the water content of the soil was monitored weekly, starting from just before the first treatment to harvest. These measurements indicate that the upper layers (0-20 cm), which are more subjected to evapotranspiration, are more affected by irrigations than the deeper layers (20-40). The effectiveness of irrigation treatments on seed yield was tightly dependent in the distribution of precipitations. The treatments applied in full or late flowering, both separately or together, determined significant increases in yield and in the percentage of seed balls with a diameter higher than 4.0 mm, whereas those at the beginning of flowering did not produced any improvements. No significant effects of the different treatments on 1000-seed weight and germinability were observed, except for a slightly negative influence of irrigations applied at the end of flowering.When all the traits were considered, an overall moderate correlation was detected between seed yield and quality.