Horticultural Evaluation of New Citrus latipes Hybrids as Rootstocks for Citrus

In 1968, the CRA-Research Center for Citriculture and Mediterranean Crops (CRA-ACM) started a research program aimed at breeding citrus rootstocks. The monoembryonic species C. latipes (Swing.) Tan. was used as the female parent; trifoliate orange [Poncirus trifoliata (L.) Raf.], sour orange, and volkamer lemon (C. volkameriana Pasq.) were used as male parents. The behavior of some of these hybrids tested with other standard rootstocks in Sicily and Sardinia was evaluated. The cultivars under comparison included 'Washington' navel orange and 'SRA 92' clementine in Sardinia and 'Tarocco' orange in Sicily. Our results showed the dramatic influence of rootstock on plant growth and yield; only minor effects on fruit quality were observed. Among the standard rootstocks tested, Swingle citrumelo provided the highest yield. Some of the tested hybrids (F5 P12, F6 P12, and F6 P13) may improve plant yield, thus maintaining good fruit quality. Encouraging data obtained with these hybrids may justify the use of monoembryonic species of the Papeda subgenus for breeding citrus rootstocks

'Omics' and chemical approaches used to monitor iron-deficiency in citrus rootstocks

Two different 'omics' approaches were performed to a better comprehension of biological mechanisms involved in citrus iron (Fe) deficiency. Tips roots from Swingle citrumelo and Carrizo citrange (sensitive and tolerant rootstocks, respectively), growing in pots with control and chlorotic soil, were used for transcriptomic and proteomic analysis. CombiMatrix array was performed to isolate differential genes, among which glutathione peroxidase (GPX), SAUR gene and glutamate dehydrogenase (GDH) showed to be the most involved ones. They were switched on Swingle grown on calcareous conditions compared to Carrizo (in the same soil) and to the same stock in the control soil. The over-expression of GPX could be the effort of plants to neutralize the oxidative environment produced by stress. The involvement of auxin (and as consequence of SAUR gene) in the regulation of Fe deficiency responses is also well known. Both genes were considered in association to peroxidase, ferric chelate reductase activities, iron and chlorophyll content, to monitor the degree of suffering of rootstocks. Among differentially expressed proteins, identified by means of 2D-PAGE and RP-HPLC/nESI-MSMS, a strong down-regulation of cytosolic pyrophosphate-dependent phosphofructokinase β-subunit and NADPH-isocitrate dehydrogenase could produce plant inability to sustain the energetic request of cell roots

Horticultural evaluation of new <i>citrus latipes</i> hybrids as rootstocks for citrus

In 1968, the CRA-Research Center for Citriculture and Mediterranean Crops (CRA-ACM) started a research program aimed at breeding citrus rootstocks. The monoembryonic species C. latipes (Swing.) Tan. was used as the female parent; trifoliate orange [Poncirus trifoliata (L.) Raf.], sour orange, and volkamer lemon (C. volkameriana Pasq.) were used as male parents. The behavior of some of these hybrids tested with other standard rootstocks in Sicily and Sardinia was evaluated. The cultivars under comparison included 'Washington' navel orange and 'SRA 92' clementine in Sardinia and 'Tarocco' orange in Sicily. Our results showed the dramatic influence of rootstock on plant growth and yield; only minor effects on fruit quality were observed. Among the standard rootstocks tested, Swingle citrumelo provided the highest yield. Some of the tested hybrids (F5 P12, F6 P12, and F6 P13) may improve plant yield, thus maintaining good fruit quality. Encouraging data obtained with these hybrids may justify the use of monoembryonic species of the Papeda subgenus for breeding citrus rootstocks

Proteomic and genomic analysis to improve the quality and safety of agricultural productions

Food health and quality are the keywords recurring both into the VII Framework Programme of EU, both in the PNR and development plans arranged by several Italian regions. Essentially, the increase and definition of quality of agri-food products represent necessary tools to give new impulse and renovation to this sector. The late developments of European and Italian laws show a clear trend towards the need to give consumer clear indications on different qualitative aspects of agri-food products, besides their microbiological security. The capacity to increase the quantity of secondary metabolites (vitamins and antioxidants) in crops is particularly interesting for the development of products with high health value (functional food). Breeding programmes have already obtained lines improved about these characteristics. The need to develop assessment strategies giving scientifically reliable information on traceability and health of food derived from genetically modified plants. Assessment of the risk coming from genetically modified plants is mainly based on the so-called “principle of substantial equivalence” or “of comparative safety”, claiming that a transgenic genotype shouldn’t show any substantial change with respect of the corresponding non-transgenic genotype. These changes are obviously considered healthy in case of the current commercial varieties. The new “-omics” disciplines such as genomics, transcriptomics, proteomics and metabolomics, born together with and subsequent to the complete sequencing of model genomes, can give an overview of first matters and food compositions, thus allowing the making of an overall assessment of their quality and safety. These new and sophisticated tools for molecular investigation can help and strengthen the commonly used methods, meeting the new requirements of traceability and authenticity certification