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Plant breeding programmes frequently face the dilemma whether to breed for wide or specific adaptation. This is especially true for forage crop breeding, whose genetic resources may largely include landraces that are adapted to specific growing conditions. This study aimed to (1) investigate the extent and pattern of genotype × location (GL) interaction for biomass yield of recent lucerne cultivars across organically-managed sites of Northern and Central Italy and its relationship with cultivar selection environments, (2) provide an empirical assessment of yield gains derived from specific-adaptation and wide-adaptation breeding strategies, and (3) identify top-performing cultivars for different geographic regions. Cultivar adaptive responses, modelled by additive main effects and multiplicative interaction analysis, displayed wide GL interaction of cross-over type across test sites that reflected remarkably the geographic area and/or the growing conditions (particularly for extent of summer drought) of their selection environment. GL interaction patterns suggested three putative subregions to breed for specific adaptation, namely, Northern Italy north of the Po river, Northern Italy south of the Po river, and Central Italy. Growing specifically-adapted cultivars provided an estimated average advantage of 12.9% across subregions relative to the best-performing widely-adapted cultivar. Yield gains of recent top-performing material over an historical, widely-adapted cultivar indicated that selection for specific adaptation would provide 3.2-fold greater yield gain averaged across subregions, and 3.4-fold greater yield gain over the target region when weighting yield gains on the putative proportion of the target region of each subregion, compared with selection for wide adaptation. [ABSTRACT FROM AUTHOR]

Genetically heterogeneous materials of inbred crops, such as evolutionary populations (EPs) and line mixtures, could reduce the genetic erosion and increase the yield stability of crops. EPs may also be exploited for bulk-based selection of inbred lines as an alternative to single-seed descent (SSD)-derived lines. This study focused on pea to compare: (a) biparental EPs from three connected crosses and their combination, and their bulk-derived inbred lines and 6-line and 12-line static mixtures, for grain yield, yield stability, and reliability (which combines mean yield and yield stability); (b) bulk-based vs. SSD-based selection of inbred lines. Bulk-derived lines were mass-selected after four-year natural selection and underwent further multi-environment selection of elite lines and components of mixtures. EPs, selected bulk-derived lines, and static mixtures were evaluated across eight environments of Northern and Central Italy encompassing organic or conventional management and pure stand or intercropping with cereals. Bulk-based vs. SSD-based selection of inbred lines were compared across three environments. Farmers' acceptability and various adaptive traits were also recorded. We also assessed shifts for adaptive traits between EPs or derived lines for the target region and material selected for a non-target region featuring severe terminal drought. In a comparison based on best-performing material, a 6-line mixture exhibited 4–7 % greater yield or yield reliability, and EP material showed a modest penalty (actually nil in its area of initial development), compared with bulk-derived lines. Most of this material tended towards greater yield, yield stability and reliability (in a context of large genotype × environment interaction), competitive ability in intercropping and farmers' appreciation than the best-performing commercial cultivar. Bulk-derived lines displayed 24 % higher mean yield, 2.3–2.5 greater yield gain per selection cycle and greater farmers' acceptability than SSD-derived lines, and were the only lines that allowed for genetic progress over commercial cultivars. Their advantage was associated with greater tolerance to low winter temperatures and taller plant stature that favored their adaptation to intercropping or organic farming. The EPs selected in contrasting environments or their derived lines displayed rapid shifts in adaptation pattern and associated traits. Evolutionary breeding issued highly valuable populations, inbred lines and line mixtures. EPs displayed quick adaption to specific environments for a low selection cost. Our results have implications for small and large breeding programs, to increase the efficiency of phenotypic selection and favor the optimal integration of genomic selection. • Evolutionary breeding issued populations, inbred lines and line mixtures with high agronomic value. • This material tended to show high cold tolerance, yield stability and competitive ability. • Best-performing line mixtures, bulk-derived lines and evolutionary populations ranked in this order. • Evolutionary populations displayed quick adaption to specific environments for a low selection cost. • Bulk-derived, mass-selected lines allowed for much greater yield gain than single-seed descent lines. [ABSTRACT FROM AUTHOR]

Mixed swards of white clover–grass mixtures in highly productive environments often fail to reach the minimum recommended annual clover proportion of about 0·30. This study assessed the effect on clover content and total dry matter (DM) yield of two spring N applications (0 and 45 kg N ha−1) and two distances between drilled grass-rows (0·18 and 0·36 m) over 3 years for mown swards of white clover–Italian ryegrass ( Trifolium repens–Lolium multiflorum) in binary mixtures in northern Italy. An additional aim was to determine the advantage of association of grass–clover compared with grass and clover monocultures. On average, N fertilization of mixtures resulted in almost 9% higher total yield ( P < 0·01; mean response = 18·1 kg of total DM per kg of N) but decreased the clover proportion (0·250 vs. 0·312). Wider grass-row spacing increased clover proportion (0·327 vs. 0·234; P < 0·01) with no reduction of total DM yield. N fertilization × grass-row spacing interaction occurred only for clover content ( P < 0·01). Without N fertilization, mixtures out-yielded clover and grass pure stands. With N fertilization, at double rate to pure grass, yields from mixtures were greater than from clover and comparable to Italian ryegrass. [ABSTRACT FROM AUTHOR]

Seed yield is of crucial importance for the marketing of lucerne varieties. Statistical records for farmers’ production of certified seed suggested a slightly higher seed-yielding ability of Italian landraces over improved varieties (proportionately 0·052). The aims were to: (i) assess the variation among landraces, and compare the germplasm of landrace and improved varieties, for seed-yielding ability; and (ii) investigate the relationships between seed yield, environment of origin and forage yield of the landraces. Thirteen farm landraces belonging to the seven commercial ecotypes of northern Italy and four improved varieties were evaluated for seed yield in the third cropping year and for herbage yield over twelve harvests. Landraces differed in seed yield and herbage yield ( P < 0·05). Landrace material, compared with variety germplasm, showed a non-significant trend towards higher seed yield (proportionately 0·047) and had similar herbage yield and plant density at the onset of the third cropping year. Seed yield of landraces was unrelated to forage yield and was associated with frequent mowing and earlier year of seed production on its farm of origin. [ABSTRACT FROM AUTHOR]

This study is aimed at comparing wide- versus specific-adaptation strategies for lucerne in northern Italy on the basis of actual dry matter yield gains over 12 harvests from phenotypic selection, assessing the value of specific genetic bases and selecting environments for the contrasting subregion A (no drought stress/sandy-loam soil) and subregion C (summer drought stress/silty-clay soil). A second aim is to investigate the adaptive responses of five sets of 18 half-sib progenies. The following selected populations were evaluated along with five cultivars: GW–SW, GA–SA, GA–SC, GC–SC and GC–SA (where GW, GA and GC are the genetic bases for wide adaptation, subregions A and C; SW, SA and SC are the selection environments for wide adaptation, subregions A and C). The selection and test environments were four artificial environments created by the factorial combination of two drought stress levels by two soil types. Two environments represented the subregions A and C whereas the combination of the other two environments represented the intermediate subregion B. Genotype × environment interaction ( P ≤ 0.001) due to both environmental factors and implying cross-over interaction between the contrasting subregions occurred for the populations and the five selections. Specific genetic bases (GA and GC) implied gains in their target subregions of 5.2% for subregion A and 2.9% for subregion C compared with the widely adapted one (GW). The gain of SA (‘no stress/sandy-loam soil’) over SC (‘stress/silty-clay soil’) decreased from subregion A (10.6%) through subregion C (1.7%) but exhibited an advantage per se across environments of 5.4%. The best specific selections (GA–SA for subregions A and B; GC–SA for subregion C) implied higher yields of 9.8% in subregion A and 6.5% in subregion C, and over twofold greater selection efficiency across the region, relative to GW–SW. Half-sib progeny × artificial environment interaction ( P ≤ 0.05) occurred in three sets of progenies whose parents belonged to cultivars with different or similar adaptation. [ABSTRACT FROM AUTHOR]

Turf quality is a complex character of fundamental importance in turfgrass evaluation. It takes into account aesthetic and functional aspects, and depends on several individual components which may vary with time. The use of a synthetic and simple quality score is necessary when evaluating large numbers of varieties. The quality of 110 turfgrass varieties belonging to four species ( Lolium perenne, Poa pratensis, Festuca arundinacea and F. rubra) was assessed in the second and third years of growth at three Italian locations, i.e. Lodi (Po Valley, continental climate), Perugia (central Italy, sub-Mediterranean climate) and Foggia (southern Italy, Mediterranean climate), using a visual score ranging from 9 (outstanding turf) to 1 (very poor turf). A randomized block design with three replicates was used, with varieties of the same species being blocked to facilitate the comparison within species. On average, F. rubra had the lowest turf quality score in summer, whereas the other species had the lowest quality score in winter and the highest quality score in summer and autumn. Components of variance were large for genotype (i.e. variety) main effects in all species. A variety × location interaction was found in F. arundinacea and higher-order interactions were also found for P. pratensis and F. rubra. Genotype × environment effects were small relative to genotypic effects in L. perenne. Variety × year interactions were small in all cases, whereas variety × location and variety × season interactions were greater. Stability of turf quality across sites, seasons and years was measured for each variety in terms of environmental variance, i.e. the variance of score values across sites, years and seasons. Mean scores and stability values of varieties were integrated into an index of reliability that estimated the lowest score value expected in 0·80 of cases. For each species, a small subset of highly reliable varieties could be identified. Implications of the results for the testing and breeding of varieties in Italy are discussed. [ABSTRACT FROM AUTHOR]

Eighteen common-wheat varieties grown for three seasons at 31 locations in Italy were used to study the relationships between cultivar adaptation patterns, climatic factors and morphophysiological traits of genotypes, as well as defining macro-environments for the selection and recommendation of genotypes in the region. The variances of both the genotype and genotype-season interactions were significant, the former being almost 80 % greater than the latter. Some 10.4 % of genotype-location interaction was accounted for by heterogeneity of genotype regressions on site mean, 38.0 % by the first two axes of a principal components analysis and 32.0 % by definition of four macro-environments. Occurrence of genotype-location interaction was related to the level of late frosts, winter cold, and late drought and heat stress at each location, and to heading date and tolerance of frost, Septoria blotch and lodging in each genotype. Following estimates of broad-sense heritability, breeding for specific adaptation may be envisaged for northern and central Italy on the one hand and southern Italy on the other. Morphophysiological traits contributing to better performance in each of these macro-environments were indicated. [ABSTRACT FROM AUTHOR]

Terminal drought is the main stress limiting pea ( Pisum sativum L.) grain yield in Mediterranean environments. This study aimed to investigate genotype × environment (GE) interaction patterns, define a genomic selection (GS) model for yield under severe drought based on single nucleotide polymorphism (SNP) markers from genotyping-by-sequencing, and compare GS with phenotypic selection (PS) and marker-assisted selection (MAS). Some 288 lines belonging to three connected RIL populations were evaluated in a managed-stress (MS) environment of Northern Italy, Marchouch (Morocco), and Alger (Algeria). Intra-environment, cross-environment, and cross-population predictive ability were assessed by Ridge Regression best linear unbiased prediction (rrBLUP) and Bayesian Lasso models. GE interaction was particularly large across moderate-stress and severe-stress environments. In proof-of-concept experiments performed in a MS environment, GS models constructed from MS environment and Marchouch data applied to independent material separated top-performing lines from mid- and bottom-performing ones, and produced actual yield gains similar to PS. The latter result would imply somewhat greater GS efficiency when considering same selection costs, in partial agreement with predicted efficiency results. GS, which exploited drought escape and intrinsic drought tolerance, exhibited 18% greater selection efficiency than MAS (albeit with non-significant difference between selections) and moderate to high cross-population predictive ability. GS can be cost-efficient to raise yields under severe drought.

Background: A thorough verification of the ability of genomic selection (GS) to predict estimated breeding values for pea (Pisum sativum L.) grain yield is pending. Prediction for different environments (inter-environment prediction) has key importance when breeding for target environments featuring high genotype × environment interaction (GEI). The interest of GS would increase if it could display acceptable prediction accuracies in different environments also for germplasm that was not used in model training (inter-population prediction)., Results: Some 306 genotypes belonging to three connected RIL populations derived from paired crosses between elite cultivars were genotyped through genotyping-by-sequencing and phenotyped for grain yield, onset of flowering, lodging susceptibility, seed weight and winter plant survival in three autumn-sown environments of northern or central Italy. The large GEI for grain yield and its pattern (implying larger variation across years than sites mainly due to year-to-year variability for low winter temperatures) encouraged the breeding for wide adaptation. Wider within-population than between-population variation was observed for nearly all traits, supporting GS application to many lines of relatively few elite RIL populations. Bayesian Lasso without structure imputation and 1% maximum genotype missing rate (including 6058 polymorphic SNP markers) was selected for GS modelling after assessing different GS models and data configurations. On average, inter-environment predictive ability using intra-population predictions reached 0.30 for yield, 0.65 for onset of flowering, 0.64 for seed weight, and 0.28 for lodging susceptibility. Using inter-population instead of intra-population predictions reduced the inter-environment predictive ability to 0.19 for grain yield, 0.40 for onset of flowering, 0.28 for seed weight, and 0.22 for lodging susceptibility. A comparison of GS vs phenotypic selection (PS) based on predicted genetic gains per unit time for same selection costs suggested greater efficiency of GS for all traits under various selection scenarios. For yield, the advantage in predicted efficiency of GS over PS was at least 80% using intra-population predictions and 20% using inter-population predictions. A genome-wide association study confirmed the highly polygenic control of most traits., Conclusions: Genome-enabled predictions can increase the efficiency of pea line selection for wide adaptation to Italian environments relative to phenotypic selection.

The intake of lupin-based foods could imply the exposure of consumers to quinolizidine alkaloids. The objectives of this study were to assess the genetic variation among and within 11 geographic regions of Lupinus albus ecotypes, verify the quinolizidine alkaloids amount of alkaloid-poor L. albus and Lupinus angustifolius varieties, and assess the effect of two climatically contrasting Italian environments on the alkaloid content. The quantitation was performed by GC-MS, and in all samples lupanine was the most abundant quinolizidine alkaloid, followed by albine and 13alpha-hydroxylupanine for L. albus and by 13alpha-hydroxylupanine and angustifoline for L. angustifolius. Some regions tended to have a high (Azores) or low (Egypt, Near East, Maghreb) total alkaloids content, but the variation among ecotypes within regions was larger than that among regions following the estimation of variance components. Alkaloid-poor varieties tended to have higher total alkaloid contents when grown in the subcontinental climate site, exceeding in some cases the limit of 0.200 mg/g.

Genotype x environment interaction effects can be exploited by breeding for specific adaptation to well-defined subregions within a target region. Previous work showed that genotype x location interaction for dry matter (DM) yield of lucerne (Medicago sativa L. subsp. sativa) cultivars in northern Italy is large and associated with soil type and level of summer drought stress of locations, suggesting the presence of two contrasting subregions. Thirteen farm landraces collected across the region and four control varieties were evaluated for DM yield in four artificial environments created at one site by the factorial combination of soil type (sandy loam or silty clay) and drought stress level (almost nil or high) for: (1) exploring the possibility to reproduce in artificial environments the adaptation patterns occurring across the region; (2) investigating the adaptation pattern of landraces and its relationship with environmental factors at collecting sites; and (3) providing a preliminary comparison of wide- versus specific-adaptation strategies based on yield gains predicted from selection of populations. Different soils filled large (24.0x1.6x0.8-m deep), bottomless containers in concrete. Water amounts were controlled by irrigation under a moving rain shelter. Cultivars varied largely for adaptation pattern across the artificial environments, mainly due to cultivar x stress interaction. Better response to stress conditions of landraces was closely associated with the level of summer drought at collecting sites (r=0.82), highlighting the importance of evolutionary adaptation. The additive main effects and multiplicative interaction-modelled responses of control cultivars successfully reproduced those observed across locations, candidating the artificial environments as a cheaper alternative to more selection locations when breeding for wide or specific adaptation. The latter implied about 40-50% greater estimated gains relative to breeding for wide adaptation.