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Murcia, Spain

Graziani M.,DIPSA | Maccaferri M.,DIPSA | Royo C.,IRTA - Institute of Agricultural-Alimentary Research and Technology | Salvatorelli F.,DIPSA | Tuberosa R.,DIPSA
Crop and Pasture Science | Year: 2014

Dissection of the genetic basis of the adaptive response of durum wheat to unfavourable water and temperature regimes is an important prerequisite for the selection of genotypes less vulnerable to environmental constraints. An elite durum population of 249 recombinant inbred lines was tested across 16 Mediterranean environments characterised by contrasting thermo-pluviometric conditions and, consequently, a broad range of productivity (from 0.56 to 5.88t ha-1). Among the environmental variables investigated, soil moisture during grain filling showed the most consistent correlation with yield components and grain yield, whereas a weaker, albeit in some cases significant, association was noted with temperature at heading and thermal time during grain filling. Ear peduncle length appeared as a valid and easy-to-phenotype morphological proxy for the water available to the plant. In total, 76 quantitative trait loci (QTLs) were identified for yield components and for several morpho-physiological traits (peduncle length, the spectral reflectance index NDVI and leaf greenness at the milk-grain stage expressed in SPAD units) associated with the adaptive response of wheat to water and heat stresses. Although most of the QTLs were significant in only one or two environments, two major QTLs on chromosomes 2BL and 3BS showed consistent additive and epistatic effects on 1000-kernel weight, peduncle length, SPAD values and grain yield in half of the environments. In view of their strong phenotypic effects on kernel weight, these two QTLs are good candidates for positional cloning in order to gain a better understanding of the functional basis of their effect on the plasticity of grain weight and grain yield. © CSIRO 2014. Source


Alvarez E.,International Center for Tropical Agriculture | Mejia J.F.,University of Bologna | Contaldo N.,DIPSA | Paltrinieri S.,DIPSA | And 2 more authors.
Plant Disease | Year: 2014

The distribution of lethal wilt, a severe disease of oil palm, is spreading throughout South America. An incidence of about 30% was recorded in four commercial fields in Colombia. In this study, phytoplasmas were detected in symptomatic oil palm by using specific primers, based on 16S ribosomal DNA (rDNA) sequences, in nested polymerase chain reaction assays. The phytoplasmas were then identified as 'Candidatus Phytoplasma asteris', ribosomal subgroup 16SrI-B, through the use of restriction fragment length polymorphism (RFLP) analysis and sequencing. Cloning and sequencing of 16S rDNA from selected strains, together with phylogenetic analysis, confirmed the classification. Moreover, collective RFLP characterization of the groEL, amp, and rp genes, together with sequence data, distinguished the aster yellows strain detected in Colombian oil-palm samples from other aster yellows phytoplasmas used as reference strains; in particular, from an aster yellows strain infecting corn in the same country. © 2014 The American Phytopathological Society. Source


Jimenez J.F.,University of Murcia | Lopez-Romero C.,DIPSA | Rossello J.A.,University of Valencia | Sanchez-Gomez P.,University of Murcia
Plant Biosystems | Year: 2015

In this work, we analyzed inter-simple sequence repeat markers from 10 populations (298 individuals) spanning the whole distribution range of the endemic Narcissus tortifolius. We assessed genetic variation levels and distribution by estimates of genetic diversity, analysis of molecular variance (AMOVA), principal coordinates and Bayesian methods. N. tortifolius showed moderate genetic diversity at intrapopulation level and low genetic differentiation of populations. In general, Almerian populations showed slightly higher levels of genetic diversity than Murcian populations. Our results indicate that habitat fragmentation has not caused genetic depauperation in N. tortifolius but did reveal moderate genetic differentiation. Indeed, principal coordinate analysis and Mantel test revealed a slight tendency to separate populations into two groups (Murcian vs. Almerian). A recent isolation event of populations, together with the perennial nature of this species could be the main reasons for this low to moderate differentiation. Our findings could be used to establish management guidelines for the conservation of this rare species. © 2015 Societa Botanica Italiana Source

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