Genetic parameters of important characteristics for the development of potato cultivars designed for industrial processing
Information on genetic parameters is essential to obtain rapid progress in the development of cultivars, which is of great interest to the potato processing industry in Brazil, as the consumption of processed potatoes has increased significantly in the last 10 years. Unfortunately the lack of raw material of quality limits its growth. Thus, the objective of this study was to estimate genetic parameters of characters of importance in the development of potato cultivars aimed at this agroindustry, in a hybrid population of 20 potato families in Embrapa's Potato Breeding Program. The experiment was carried out at Embrapa, Pelotas, RS, in two growing seasons. The design was randomized blocks with four replications; each repetition was composed of five genotypes of each family, and each plot was represented by five plants of each genotype. After harvesting, the tubers of each plot were evaluated for industrial quality, yield, external physiological defects and external appearance of tubers. The estimates of the variance components and genetic parameters (Restricted Maximum Likelihood) were obtained using the Harmonic Mean of the Relative Performance of the Genetic Values. There was an estimated high broad sense heritability for film texture (TEX) and glucose (GLUC); and moderate for secondary growth (GRO), shape (SHA), dry mass (DM), general appearance (APP), percentage of commercial tubers mass (PCM), curvature (CUR), size uniformity (SIU), shape uniformity (SHU) ) and mean tuber mass (MTM). GLUC, SHA, TEX and APP showed superiority of the genotypic coefficient of variation (CVg) in relation to the residual coefficient of variation (CVe), for these characters. The highest CVg - CVe ratios were obtained for SIU, PCM, SHU, DM and GRO. In the light of this study, it is suggested that strong selection pressure can be applied to the characters GLUC, SHA, TEX and APP, and moderate selection pressure to SIU, PCM, SHU, DM, and GRO.