Italian common bean landraces: diversity and population structure

Phaseolus vulgaris L. is an important species that originated in Mesoamerica. A Mesoamerican and an Andean gene pool are usually distinguished in the domesticated forms. Many bean landraces are still cultivated in Italy and the Department of Applied Biology maintains an ex situ collection of 146 landraces. Although protection schemes are being developed in Italy, most landraces are extinct or at risk of extinction. To facilitate their conservation and use, geographical, morphological, biochemical and molecular (SSR) data were collected and analysed to estimate the diversity and the genetic structure of the collection. Data confirmed that both the Mesoamerican and the Andean gene pools were introduced in Italy and, although a distinction between the two gene pools exists, the Italian landrace diversity is clearly structured in three clusters that are not simply ascribable to the original gene pools. The observed structure appears also to be due to adaptation to the different environmental conditions determined by altitude. This was confirmed by assessing the presence of selective effects for some of the SSR used in this study. Finally, a certain extent of admixture in Italian landrace diversity suggests past (or recurring) hybridisation events among gene pools. The combined use of morphological, biochemical and molecular data clearly distinguished almost all the landraces. The data gathered here can assist landrace in situ protection schemes that are being developed in Italy, be used to register landraces in the European common catalogue of ‘conservation varieties’ for seed commercialisation and contribute to a better use of Italian common bean diversity in breeding for organic and conventional production systems.     

Diversity characterisation of broccoli (Brassica oleracea L. var. italica Plenck) landraces for their on-farm (in situ) safeguard and use in breeding programs

Brassica oleracea L. is an important species that originated in the eastern Mediterranean area. From there, B. oleracea L. subsp. capitata (L.) DC. convar. botrytis (L.) Alef. var. italica Plenck (broccoli) was introduced into Italy where considerable diversification took place. Several landraces of broccoli, which are highly appreciated by local people for their organoleptic traits, are presently cultivated in both large fields and home gardens. In this study, 10 landraces, 4 synthetics derived from landraces and 4 of the most used F1 hybrids were characterised for morpho-physiological and molecular traits with the principal aim of feeding information into the landrace protection schemes being developed in Italy and into breeding programs. The landraces and derived synthetics are well differentiated from each other and from the F1 hybrids for important agronomic and genetic traits. The principal component analysis based on analysis of morpho-physiological traits showed that overall the 2 main components accounted for 67.74 % of the total variation. The neighbour joining tree, based on 23 microsatellite markers, grouped accessions into 2 main clusters. One includes one synthetic variety and 2 F1 hybrids, while the other cluster includes all the other accessions. There were also several sub clusters. Most of the materials examined showed within-accession diversity. The information gathered in this study can be used to protect landraces through the schemes presently being developed in Italy and to register them in the European common catalogue of “conservation varieties”. In situ (on-farm) conservation of landrace diversity is discussed with reference to landrace use.     

Differentiation and structure of an Italian landrace of celery (Apium graveolens L.): inferences for on farm conservation

The “Sedano Nero di Trevi” (Black Celery from Trevi) is a landrace grown in Umbria (Italy) at risk of extinction. A morpho-physiological and molecular characterisation of the landrace and a detailed investigation of its cultural and cultivation context were carried out with the aim of facilitating a request for a quality mark, implement in situ (on farm) conservation schemes that are being developed in Italy and register the landrace in the European common catalogue of ‘conservation varieties’. These actions can help the landrace survive. Six farmer populations of the landrace and four élite varieties were characterised for thirteen morpho-physiological traits and nine AFLP primer combinations. The “Sedano Nero” farmer populations were better performers than élite varieties for important agronomic traits, such as yield, under the local agronomic conditions. Both morpho-physiological traits and molecular markers clearly distinguished the landrace from the élite cultivars. In addition, a structure was detected in the landrace with farmer populations being characterised by specific alleles. These results are discussed in connection with the local seed system and possible in situ conservation strategies for landraces.     

Collecting maize (<Emphasis Type="Italic">Zea mays</Emphasis> L. convar. <Emphasis Type="Italic">mays</Emphasis>) with potential technological ability for bread making in Portugal

The Portuguese maize bread (“broa”) manufactured from traditional maize landraces still plays an important economic and social role on Central and Northern rural communities of the country. However the traditional maize landraces agricultural systems are changing. Local maize landraces are in risk of disappearing because of the progressive adoption of hybrid varieties not suitable for bread production. These changes are contributing to a major loss of genetic diversity. An expedition took place in the Central region of Portugal (Beira Interior and Beira Litoral) with the purpose of collecting enduring maize landraces with technological ability for bread production and to access the possibility of establishing a participatory plant breeding and conservation program. A total of 51 different maize landraces and 175 other varieties of associated crops were collected. Maize landraces showed to maintain high diversity and potential for improvement. The production relayed on small farms with polycrop, quality oriented, sustainable systems. A participatory plant breeding and conservation program would be possible on this region with the proviso that local authorities would be involved. This program would allow a higher valuation of these maize populations, contributing to halt the current loss of these unique Portuguese maize landraces.     

Molecular and morphological data reveals new insights into genetic diversity and population structure of Chinese cherry (<Emphasis Type="Italic">Prunus pseudocerasus</Emphasis> Lindl.) landraces

Chinese cherry (Prunus pseudocerasus Lindl.) is an indigenous fruit crop with high nutritional and ornamental value. It is widely cultivated in China, and many landraces have accumulated in large distribution regions. Genetic diversity analysis of Chinese cherry landraces is useful for breeding programs, as it helps to select genetic material to be used for further crossing. In this study, 110 Chinese cherry accessions from nine populations were assessed using fifteen morphological traits and seventeen ISSR markers. High average coefficient of variation (CV?=?17.43%) was detected based on morphological analysis. For molecular characterization, the global gene diversity (h?=?0.2816) and Shannon information index (I?=?0.4253) suggested a moderate high level of genetic diversity. Model-based STRUCTURE and principal coordinate analysis revealed three and two major gene pools based on morphologic and molecular data, respectively. Distinct distribution patterns of genetic variation between samples from southwest China and north China indicated two potential original domestication locations. We inferred that botanical features such as predominantly selfing characteristics, long lifespan, and insects-pollinated trait lead to the survival of abundant genetic variation and special genetic structure. This study provided morphological and molecular evidences for understanding genetic diversity and new insights into genetic consequence of populations for Chinese cherry landraces. Important implications for breeding programs and resources conservation were also provided.     

Evaluation of genetic variation and grain quality of old bread wheat varieties introduced in north-western Italian environments

The increasing consumers’ request for new speciality wheat derivatives and the possible widening of marketing opportunities is giving to both landraces and old varieties, new chance of on farm survival providing a low cost way to safeguard these important genetic resources. A farmer’s consortium acting in north-western Italy, is attempting the introduction of some old bread wheat landraces in marginal environments of Piedmont and Liguria regions. The reason of this attempt is the local market demand of old bread varieties suitable for the preparation of traditional cakes and biscuits. Three Italian bread wheat landraces, a mixture of durum and bread wheat landraces and three modern varieties were evaluated. The entries were cropped in Val Borbera and Val d’Aveto (Piedmont and Liguria region, respectively) in the same growing season (2009–2010). The high variation of gliadin profile detected within the landraces indicates that all have retained the genetic heterogeneity typical of the old wheat landraces. In consequence of the health-promoting effects of whole grain consumption, eleven nutritional and technological traits of whole flours were investigated. The analysis of collected data revealed appreciable differences among the flours obtained from the landraces and the modern varieties. These differences can be mainly attributed to the intensive breeding carried out on bread wheat in the last century. The results of this study suggest that the old bread wheat landraces could have good chance of survive on farm when their characteristics fulfil the requirements of local communities.     

Haplotype analysis of molecular markers linked to stem rust resistance genes in Ethiopian improved durum wheat varieties and tetraploid wheat landraces

The recent emergence of wheat stem rust race Ug99 (TTKSK) and related strains threaten Ethiopian as well as world wheat production because they overcome widely used resistance genes that had been effective for many years. The major cause which aggravates the ineffectiveness of Ethiopian wheat varieties against stem rust is the narrow genetic base on which the breeding for resistance has been founded, however, little is known about the resistance genotypes of Ethiopian durum wheat varieties and tetraploid wheat landraces. The objective of the study was to identify stem rust resistance genes that are present in the Ethiopian tetraploid wheat landraces and improved durum wheat varieties using molecular markers and assess which genes are effective for current Ethiopian stem rust races of Puccinia graminis f. sp. tritici including Ug99. The investigated 58 tetraploid wheat accessions consisted of 32 (Triticum durum s.l. incl. Triticum aethiopicum Jakubz., Triticum polonicum) landraces and 22 registered T. durum varieties released in Ethiopia between 1966 and 2009 and four T. durum varieties from ICARDA. A total of 17 molecular markers (SSR, EST and InDel) linked or diagnostic for stem rust resistance genes Sr2, Sr13, Sr22 and Sr35 were used for genotyping. Haplotype analysis indicated that only few of the Ethiopian durum wheat varieties carried Sr13. The resistant variety ‘Sebatel’ showed a haplotype for Sr2 and Sr22 and variety ‘Boohai’ for Sr22, however further evaluation is needed for the diagnostic value of these haplotypes. This study is the first report on the presence of stem rust resistance (Sr) genes in Ethiopian durum wheat varieties and tetraploid wheat landraces based on linked or associated molecular markers. Thus it might help in the identification of varieties carrying resistant alleles that provide valuable genetic material for the development of new improved varieties in further breeding programmes.     

The European seed legislation on conservation varieties: focus, implementation, present and future impact on landrace on farm conservation

After a brief presentation of the European Directives on seed marketing of conservation varieties, data relative to their implementation status are given and discussed in relation to on farm conservation of landraces. Although generally aimed to ensure in situ conservation and the sustainable use of plant genetic resources, the Directives focus on seed production and marketing instead of genetic resource conservation per se. At present, their application has only partially favoured the registration of landraces maintained on farm or preserved in ex situ collections. They can be estimated in thousands in Europe, while only a few landrace with a verified status (51 out of a total of 184 conservation varieties) are presently included in the Common Catalogue. Reasons for this scarce registration are discussed. The European Directives on seed marketing of conservation varieties are a tool to promote on farm conservation of landraces that should be used to a greater extent than at present. Registration of landraces should be strongly and principally promoted by public bodies as a measure to give access to the genetic resources, preserve them on the long term and favour the economic profit of the farmers maintaining them.     

Genetic diversity assessment of Ethiopian tetraploid wheat landraces and improved durum wheat varieties using microsatellites and markers linked with stem rust resistance

A set of 77 markers was used to describe the genetic diversity in a group of 58 tetraploid wheat accessions. Analysis was performed using 31 neutral SSR markers, 31 SSR/STS markers linked with reported major stem rust resistance genes and 15 SSR markers linked with QTL identified for resistance to Ethiopian stem rust races of Puccinia graminis Pers. f. sp. tritici Eriks. et E. Henn. (Pgt),including Ug99. The material consisted of 32 (Triticum durum s.l. incl. T. aethiopicum Jakubz., Triticum turgidum and Triticum polonicum) landraces and 22 registered T. durum varieties from Ethiopia that were released 1966–2009 and four T. durum varieties from ICARDA. A total of 720 alleles were detected. Considering the three marker sets, the mean number of alleles was higher for major stem rust resistance gene linked markers (9.9) followed by neutral SSR markers (9.2) and markers linked with QTL for stem rust resistance (8.5). Dendrograms derived from UPGMA analysis grouped the accessions into two major clusters. The principal component analysis based on the combination of the three marker sets formed three groups. The 1st group was composed of all the improved varieties, whereas the 2nd and the 3rd group contained the landraces. All the landraces that formed the 3rd group were susceptible to Ethiopian stem rust races of Pgt including Ug99. The information on the extent of the genetic diversity of the improved varieties obtained in this investigation will be helpful for developing appropriate breeding strategies to broadening the genetic base of durum wheat varieties in further breeding programmes.     

From landraces to modern cultivars: field observations on taro <Emphasis Type="Italic">Colocasia esculenta</Emphasis> (L.) Schott in sub-Saharan Africa

Until recently, taro Colocasia esculenta (L.) Schott, was considered a neglected food crop due to its low palatability and inferior value compared to other root crops such as cassava, potatoes and yams. Under the impulse of new studies on plant dispersal, and in light of the severe threats posed by pests to its conservation status, this crop has finally received more attention. However, there is still insufficient knowledge on specific cultivars and their culinary and medicinal uses, especially in Africa. We studied the agrodiversity of taro cultivars in Nigeria, Cameroon, the Democratic Republic of Congo, Kenya, and Tanzania. Here, we present ethnobotanical, morphological and linguistic data of 20 taro cultivars, as well as specific notes on abandoned landraces. These traditional varieties represent valuable genetic resources and can be instrumental in protecting taro from the genetic erosion caused by preference for yautia, and diseases such as the leaf blight. With this work, we call for renewed efforts to conserve this species and its landraces.     

Enhancing conservation and use of local vegetable landraces: the Almagro eggplant (Solanum melongena L.) case study

We have used the Almagro pickling eggplant landrace as a model for the enhancement of a local vegetable landrace. The programme has included characterization, selection, and breeding activities. Considerable intra-landrace diversity has been found for morphological traits and molecular markers. Characteristic morphological traits have allowed its registration as conservation variety. Also, universal and specific simple sequence repeat markers have been found for the Almagro landrace. The chemical characterization revealed that Almagro eggplant has a high content in bioactive phenolics. Organoleptic tests revealed that pickles produced with Almagro eggplant are superior to those of the related Andalusian landrace. The selection programme has led to the development of a pure line with increased yield and reduced fruit calyx prickliness. A participatory breeding programme, in which selection is made by farmers in their own field, has been initiated to introduce the no-prickles trait from three other varieties in the genetic background of the Almagro eggplant. The results of the programmes show that plants with the Almagro eggplant ideotype and with reduced prickliness can be selected in the backcross generations. As a result of the enhancement programme the acreage and total production of Almagro eggplant has tripled in the last decade.     

On-farm conservation of 12 cereal crops among 15 ethnic groups in Yunnan (PR China)

Due to the rapid diffusion of improved crop varieties, fewer and fewer landraces are being grown by farmers. The on-farm conservation of crop landraces has been proposed as means of conserving potentially important crop germplasm as an alternative to its ex situ conservation in gene banks, but the effectiveness of this approach is unproven. Particular attention is currently focused on producers sited in remote regions. Here, we report the outcomes of a survey focusing on the conservation and utilization of landraces of corn, rice, wheat, barley, buckwheat, broomcorn sorghum, Job’s tears (coix), oats and finger, foxtail, broomcorn and barnyard millets grown by 15 ethnic groups from Yunnan province (China). Many local varieties are still in existence through their utilization on-farm. The varietal richness per village sampled was estimated to be 3.5 (maximum of 17), with rice and maize being the most heterogeneous, and glutinous sorghum and barnyard millet the least. Varietal richness was significantly and positively correlated with the number of villages surveyed, the number of families and the head of population. The choice of crops and varieties maintained varied between the ethnic groups, with the more westerly and north westerly situated villages conserving the most landraces. The number of crop species used was negatively correlated with per capita annual income, while the correlation coefficient between varietal richness and per capita annual income was less pronounced. The major factors determining the level of on-farm conservation were remoteness, fragmentation of the arable area and cultural needs. The data provide baseline information for the elaboration of optimal strategies for in situ conservation and utilization of crop germplasm in China.     

Trade-offs between on-farm varietal diversity and highly client-oriented breeding — a case study of upland rice in India

On-farm varietal diversity is now highest in marginal agricultural environments because, unlike the case in more favourable areas, modern varieties have not been a sufficiently attractive option for farmers to replace their landraces. However, the continued survival of landraces on farm is dependent on the continuing failure of plant breeding to provide better alternatives. Highly client-oriented breeding can produce suitable modern varieties for areas that were dominated by landraces. We examine here the case of the adoption of two upland rice varieties in three states in eastern India, Jharkhand, West Bengal and Orissa, where our surveys had confirmed low adoption of modern varieties in the upland ecosystem. The two new upland varieties were readily accepted by farmers who rapidly adopted them on large proportions of their land. On-farm diversity is maintained by the need to trade-off among varieties but once a variety with overall superiority was found this incentive was removed. The new varieties from the client-oriented breeding did not have weaknesses that farmers had to trade-off against their landraces so they were more likely to replace them. They also replaced older modern varieties. Farmers had previously maintained them along with landraces because they had to trade-off the higher yield of Kalinga III against the more stable yield of landraces or the higher yield of Vandana against the higher gain quality of the landraces. Only mean count per household could be used to test the significance of the differences between individual years. In all states, this revealed a significant reduction in landrace diversity with the adopting farmers when the addition of the two new varieties was not considered. Trends across years for mean varietal count, total count and Shannon–Wiener index showed a significant decline in Orissa, irrespective of whether the two new varieties were included in the analysis or not. In Jharkhand there was a significant decline only for mean count when the new varieties were not included. In Orissa, it was possible to test if rare landraces were as readily replaced as more common ones. Landrace replacement was unmitigated by increasing rarity yet the most rare landraces have the highest priority for genetic conservation. Some landraces were completely replaced by the farmers in the sample despite a diverse variety portfolio being a risk-reducing strategy in a region where there is a high risk of crop failure. There was little environmental heterogeneity in the marginal, drought-prone areas to slow this decline. The new varieties had an impact on the farming system because sometimes farmers brought additional upland into cultivation. They also introduced these varieties into more favourable, medium land. The strategy of releasing two new upland varieties met with some success in maintaining diversity.     

The Sierra Norte of Madrid: an agrobiodiversity refuge for common bean landraces

At the mountain area close to the city of Madrid, common beans were one of the main food crops present in everyday diet until 1960. This paper describes the morphological diversity, for forty-six phenological and morphological traits, found in forty-three traditional varieties of common beans collected in this area and seven commercial varieties used as reference. That comparison suggests that common bean breeding programs have led to later varieties with a higher production of straight pods. Quantitative traits showed also similar values when compared to the Iberian common bean collection, except for the phenological and seed size characters. The phenological differences could suggest an ecological adaptation of the studied landraces to the regional environmental conditions. The different seed size averages of both collections might correspond to the scarce presence of smaller seed-type common beans in Madrid collection. All the accessions collected in the Sierra Norte of Madrid belong to any of the groups included in the Spanish core collection. Madrilenian collection is also composed by indeterminate growth habit varieties, while the presence of bush accessions is relatively uncommon. Most of the Madrilenian landraces have a remarkable fitness for green-pod consumption (42 %) and their seeds are mainly white (30 %), ovate-shape (49 %) and medium-large (40 %). The study of seed storage protein allowed to classify the landraces according to their domesticated gene pools. Most of them (72 %), with T and C phaseolin type, seem to belong to Andean germplasm, while the remaining (28 %), with S and B phaseolin type, to Mesoamerican one. The remarkable morphological diversity of common beans found in this small area is a symptom of a broad genetic base despite genetic erosion, what indicates a widespread crop in the past. Therefore, it is advisable to design agro-environmental policies to promote the production and commercialization of common bean landraces in Sierra Norte of Madrid.     

Agro-morphological characterization of chili pepper landraces (<Emphasis Type="Italic">Capsicum annuum</Emphasis> L.) cultivated in Northern Benin

Variability study of agro-morphological characteristics is important for varietal improvement and plant breeding program. For this, 148 chili pepper landraces (Capsicum annuum L.) collected from Northern Benin were characterized using 39 (21 qualitative and 18 quantitative) morphological characters. The trial was conducted in a Fisher block design with 3 replicates at the experimental station of the Faculty of Science and Technology (FAST) of Dassa based in Central Benin. The results revealed considerable morphological variability between landraces. Twenty nine (16 quantitative and 13 qualitative) variables among the 39 examined were discriminatory and group the landraces into 4 classes when considering the qualitative variables. With quantitative variables, 9 groups were obtained. The correlations between the studied quantitative variables show that the yield parameters are correlated with the variables related to the vegetative part of the plant. This study will help breeders to better select their parents for crossing in order to produce desirable and high yielding varieties.