Genetic diversity in bread wheat, as revealed by coefficient of parentage and molecular markers, and its relationship to hybrid performance

Variable results have been obtained in different crop species using geneticsimilarity (GS) estimates based on molecular markers and coefficient ofparentage (COP) to predict heterosis.This study was designed: i) to assess the level of GS among 40 breadwheat (Triticum aestivum L.) cultivars selected in Central and SouthEurope; ii) to compare GS with COP; iii) to correlate the estimates ofparental diversity with the heterotic effects detected on 149 F₁hybrids obtained by crossing the 40 cultivars according to three matingdesigns.The parental cultivars and the F₁ hybrids were grown in severallocations at normal seed density. Significant heterotic effects were detectedfor grain yield and other traits including quality attributes. The parentalcultivars were assayed for DNA polymorphisms using two classes ofmarkers: 338 RFLP and 200 AFLP^® bands were scored. GS estimates werecomputed considering each molecular marker set separately (GS_RFLP,GS_AFLP) and together (GS_TOT). Ample differentiation amongthe parental cultivars was detected with the two marker sets. Although theaverage GS_TOT (0.43) was higher than COP (0.10), the twomeasurements were significantly correlated (r = 0.36, p < 0.01).Correlations between the different estimates of genetic diversity andF₁ performance or mid parent heterosis for grain yield and otherrelated traits were in general low although statistically significant.A more detailed analysis was conducted on 28 F₁ hybridsproduced in a half diallel cross of eight parental cultivars characterized byhigh heterotic effects for grain yield. The GS estimates based on RFLP,AFLP^® markers and also on RAPD were partitioned into general andspecific components. Correlations with general and specific combiningability effects for the measured traits were in several cases statisticallysignificant but too low to be predictive and therefore exploitable in practicalbreeding.     

Application of a low-cost RGB sensor to detect basil (Ocimum basilicum L.) nutritional status at pilot scale level

Precision Agriculture - In this work, basil plants were fertilized with 0, 2.5&nbsp;mM and 10&nbsp;mM nitrogen (with different NO3?/NH4+ ratios), and then monitored using a low-power...     

Soil carbon stock in olive groves agroforestry systems under different management and soil characteristics

The atmospheric concentrations of greenhouse gases have increased to unprecedented levels during last decades, raising concerns about their effect on climate change. Agriculture and land use change play an important role in atmospheric CO₂ emission and fixation, especially by affecting the soil carbon (C) storage. In this context, agroforestry systems (AFSs) could play an important role contributing to climate change mitigation. Given the importance of olive cultivation in the Mediterranean region, it is important to investigate soil C stock in olive groves, and to assess which agronomic practices could improve the soil C stock in these systems. For this reason, a study was conducted in different olive groves, including conventional and organic management, and a typical silvopastoral AFS. Furthermore, an abandoned olive grove and nearby forest were examined as a comparison. Soil samples were collected in each farm and analysed for C content and physico-chemical characteristics. This study indicates that, irrespective of the management, olive groves in the Umbria region of Italy are characterised by a high level of soil C stock if compared to those growing in other areas and to forest ecosystems, indicating that the practices adopted in the area are not negatively affecting soil C storage. A slightly lower soil C stock was measured in the silvopastoral AFS in comparison to the other farms, while high soil C stock was associated with the use of pomace, suggesting that this practice can be used to further increase soil C stock in olive orchards.