The world's largest potato cryobank at the International Potato Center (CIP) - Status quo, protocol improvement through large-scale experiments and long-term viability monitoring

Long-term conservation of Plant Genetic Resources (PGR) is a key priority for guaranteeing food security and sustainability of agricultural systems for current and future generations. The need for the secure conservation of genetic resources collections ex situ is critical, due to rapid and extreme climatic changes which are threatening and reducing biodiversity in their natural environments. The International Potato Center (CIP) conserves one of the most complete and diverse genetic resources collections of potato, with more than 7500 accessions composed of 4900 cultivated potato and 2600 potato wild relative accessions. The clonal conservation of cultivated potato, principally landraces, through in vitro or field collections is indispensable to maintain fixed allelic states, yet it is costly and labor-intensive. Cryopreservation, the conservation of biological samples in liquid nitrogen (-196°C), is considered the most reliable and cost-efficient long-term ex-situ conservation method for clonal crops. Over the last decade, CIP has built one of the largest potato cryobanks worldwide, cyopreserving more than 4000 cultivated potato accessions which represents 84% of the total cultivated potato collection currently conserved at CIP. In approximately, four years the entire potato collection will be cryopreserved. The development of an applied, robust cryopreservation protocol for potato, serves as a model for other clonally maintained crop collections. The CIP cryobank designs experiments with a high number of genetically diverse genotypes (70-100 accessions, seven cultivated species), to obtain reliable results that can be extrapolated over the collection as genotypes can often respond variably to the same applied conditions. Unlike most published reports on cryopreservation of plants, these large-scale experiments on potato are unique as they examine the acclimatization process of in vitro plants prior to, as well as during cryopreservation on up to ten times the number of genotypes conventionally reported in the published literature. As a result, an operational cryopreservation protocol for potato has advanced that works well across diverse potato accessions, not only with reduced processing time and costs, but also with an increased average full-plant recovery rate from 58% to 73% (+LN) for routine cryopreservation. The present article describes the composition of CIP's cryobank, the cryopreservation protocol, methodology for the dynamic improvement of the operational protocol, as well as data collected on regeneration from long term cryopreserved potatoes.

Characterization of the Essential oil of the Bat-Pollinated Passiflora mucronata

The genus Passiflora is an important source of food, therapeutic substances and for the horticultural economy. In the last decades, a detailed chemical composition of the essential oil of Passiflora species has been reported, but only for few species, mainly of agricultural interest, although little attention has been paid to chiropterophilous Passifloraceae, such as P. mucronata. The present study is focused on analyzing the essential oil composition of P. mucronata, a Brazilian bat-pollinated species. From GC/FID and GC/MS analyses of the volatile fraction from fresh flowers and leaves, hydrocarbons were quantified as 47.9% and 42.8% of the total volatiles of flowers and leaves, respectively, esters for 50.8% in flowers and 6.4% in leaves, and alcohols 38.2% and 0.3% of the total volatiles from leaves and flowers, respectively. Other classes of compounds, such as monoterpenes and aldehydes, together with phytol, were detected in higher concentration in leaves compared with flowers. The higher content of methyl and ethyl esters of long chain saturated and unsaturated fatty acids, i.e. ethyl linolenate (38.3%), methyl linolenate (7.0%) and ethyl palmitate (3.6%), were the most representative suggesting that esters might play a critical role for fertilization of P. mucronata acting as bat attractors.

Morphophysiology, Phenotypic and Molecular Diversity of Auxin-induced Passiflora mucronata Lam. (Passifloraceae)

Genetic diversity allows identification of potential intraspecific genotypes in the genus Passiflora. The objective of this study was to examine the morphological and genetic diversity of auxin-induced Passiflora mucronata. The experiments were arranged in a complete randomized block design, with a 9 x 2 factorial arrangement (nine genotypes x presence and absence of auxin, indole-3-butyric acid (IBA)), with four replicates of 16 cuttings. The rooting and vegetative growth responses were variable. Genotype 5 was more responsive in the absence of IBA and genotypes 3, 8 and 9 were more responsive in the presence of IBA. Auxin increased rooting rate and percentage, reducing the average time of root protrusion in eight days. IBA also contributed to increase photosynthesis and dry root and shoot mass in 55.55 and 44.44% of the genotypes, respectively. The highest relative contribution to phenotypic diversity in the absence of auxin was rate (38.75%) and percentage (20.27%) of rooting, whereas in the presence of auxin was stomatal conductance (23.19%) and root dry mass (20.91%). Similarity was found for phenotypic and molecular divergence in the presence of IBA, in which genotypes 1 and 6; genotypes 5, 8 and 9; and genotype 3 were clustered in distinct groups.