Effectiveness of the Field Selection Parameters on Potato Yield in Atlantic Canada

Published online: 12 August 2016Cultivated potatoes (Solanum tuberosum L.) are the 4th most important crop feeding the world. Therefore, yield is a crucial trait for potato breeding and germplasm enhancement. The analysis of phenotype data of potato plants enables the extraction of crucial phenotypic characters for potato yield breeding. Using data collected from 179 advanced breeding clones that were planted in evaluation trials over three years at the Benton Ridge breeding substation in Atlantic Canada, we deciphered the dynamic properties of trait expression over the growth period based on nine parameters used in Agriculture and Agri-Food Canada’s potato breeding program. The analysis of breeding data provided valuable information to understand the factors that contribute to the phenotypic performance of potato and potato tuber yield. Linear mixed model fit by maximum likelihood and principal component analysis (PCA) were employed as complementary analysis tools to analyze these characters to try to uncover the relationship of complex agronomic traits. Our results showed that the majority of the selection parameters effectively contributed to the improvement of potato tuber yield. The first five principal components (PCs) accounted for 74.9% of the phenotypic variation observed from 2012 to 2014. The maturity, early vigor, eye depth, and top vigor are the most important phenotypic parameters affecting potato tuber yield selection. Based on the results, these selection parameters are yet highly independent variables which also displayed some degree of interrelationship

The Primate-specific Protein TBC1D3 Is Required for Optimal Macropinocytosis in a Novel ARF6-dependent Pathway

The generation of novel genes and proteins throughout evolution has been proposed to occur as a result of whole genome and gene duplications, exon shuffling, and retrotransposition events. The analysis of such genes might thus shed light into the functional complexity associated with highly evolved species. One such case is represented by TBC1D3, a primate-specific gene, harboring a TBC domain. Because TBC domains encode Rab-specific GAP activities, TBC-containing proteins are predicted to play a major role in endocytosis and intracellular traffic. Here, we show that the TBC1D3 gene originated late in evolution, likely through a duplication of the RNTRE locus, and underwent gene amplification during primate speciation. Despite possessing a TBC domain, TBC1D3 is apparently devoid of Rab-GAP activity. However, TBC1D3 regulates the optimal rate of epidermal growth factor–mediated macropinocytosis by participating in a novel pathway involving ARF6 and RAB5. In addition, TBC1D3 binds and colocalize to GGA3, an ARF6-effector, in an ARF6-dependent manner, and synergize with it in promoting macropinocytosis, suggesting that the two proteins act together in this process. Accordingly, GGA3 siRNA-mediated ablation impaired TBC1D3-induced macropinocytosis. We thus uncover a novel signaling pathway that appeared after primate speciation. Within this pathway, a TBC1D3:GGA3 complex contributes to optimal propagation of signals, ultimately facilitating the macropinocytic process