In vitro bioproduction and enhancement of moscatilin from a threatened tropical epiphytic orchid, Dendrobium ovatum (Willd.) Kraenzl

Moscatilin, a bibenzyl derivative (stilbenoid), mostly found in one of the largest genera of Orchidaceae; Dendrobium has many therapeutic benefits. Its function as an anticancer agent has been widely demonstrated through many research investigations. However, the compound has not been produced in vitro to date. The present study highlights the development of cultures viz., seedling generation, callus induction and callus regeneration (transformation of callus into plantlets). These cultures were devised to conserve the threatened tropical epiphytic orchid species, Dendrobium ovatum and identify their potential towards moscatilin bioproduction in vitro. Among the three culture platforms, callus-derived plantlets could yield high moscatilin when treated with l-Phenylalanine as a precursor. Tissue differentiation was found to be indispensable for the high production of this polyphenol. These cultures also offer potential commercial benefits as they can serve as appropriate platforms to decode moscatilin biosynthesis and other significant bibenzyl derivatives. Elicitors, such as chitosan, salicylic acid, and methyl jasmonate, were found, causing an enhancement in moscatilin content in the cultures. The seedlings obtained can serve towards ecorestoration and preservation of the studied species. Callogenesis was useful in plantlet regeneration, as callus-derived plantlets could be utilized for the enrichment and commercial scale-up of moscatilin-like chemicals.

Genetic parameters associated with tuber yield and tuber appearance traits of potatoes in early generations of selection

The knowledge of genetic parameters of traits, in early generation selection, is important for breeding programs to define strategies and obtain success. The objective of this study was to estimate genetic parameters of yield components and tuber appearance traits in early selection generations of potatoes and their implications in the selection process. Twelve segregating potato families originated from crosses between two groups of parents of the Embrapa potato breeding program were evaluated. Group 1 was formed by foreign potato parents: Pukara, Asterix, Rioja, and Caesar; and group 2, by national parents: Eliza, C1730-07-94, and C1750-15-95. The experiment was conducted in autumn seasons of 2012 and 2013. A randomized complete block design with three replications was used. Considering all traits together, Pukara/Eliza, Asterix/Eliza, and Rioja/Eliza families had the highest means on a large number of tuber appearance and yield traits. The results of this study suggest that selection may be applied with mild to moderate intensity in the seedling generation for skin texture, tuber general appearance, tuber number, average tuber weight and total tuber yield, based on the moderate to high heritability estimated on the seedling generation. The highest selection gains were for skin texture, tuber general appearance, tuber number, average tuber weight and total tuber yield.

Expected response to early-generation selection for yield and tuber appearance traits in potatoes

The aim of this study was to evaluate the performance of potato clonal families, and to estimate genetic variance, heritability and the expected response to selection of tuber yield and appearance traits in early generations. Twelve potato families were obtained from crosses between two groups of randomly-selected genotypes, including Eliza, C1730-7-94, and C-1742-8-95 in group 1; and Shepody, Asterix, Caesar, and White Lady in group 2. The crosses were made in factorial design (3 genotypes x4 genotypes), and each family consisted of 75 genotypes. Experiments were conducted in the fall of 2010, with a seedling generation under greenhouse conditions, and in the fall of 2011, with a clonal generation under field condition. High heritability estimates suggest that mild to moderate selection can be applied in the seedling generation to eye depth, eyebrow prominence, tuber curvature, flattening and shape uniformity. The C1742-8-95/White Lady stood out as a superior cross, as did all other crosses with White Lady, regarding tuber appearance and yield traits.

Efficiency of selection in early generations of potato families with a view toward heat tolerance

The aim of this study was to evaluate the efficiency of selection of potato families in early generations for heat tolerance. Thirty families were evaluated in the seedling generation (SG), first clonal generation (FCG) in the field and greenhouse under high temperature conditions, and second clonal generation (SCG) under mild temperatures. The mean of the families was obtained in each generation. The 16 most productive families in FCG were selected, and the clones of these families were evaluated in experiments in the winter and rainy crop seasons. The results showed that family selection for tuber shape may be applied as of the SG. It was also observed that family selection in the FCG and SCG for yield and tuber specific gravity contributed to identification of clones tolerant to heat and responsive to environmental improvement.

Repeatability of family means in early generations of potato under heat stress

The selection of potato clones for yield is usually effective from the second clonal generation. It would however be ideal to select from the seedling generation (SG) or the first clonal generation (FCG). The aim of this study was to evaluate the repeatability of selection at the family level performed in the early generations with the subsequent generations, for tuber yield and specific gravity in the warm season. Thirty families were evaluated in the SG, FCG and the second, third and fourth clonal generation, without any selection. In this way, adjusted means of the 30 families were obtained for each generation. Selections were simulated independently in the different family generations, and then the repeatability of these families among generations verified, using the same selection intensity. The results showed that the family selection in the SG and FCG for specific gravity and in the FCG for tuber yield is efficient, at mild as well as warm temperatures.