Genetic/phenotypic studies on spines in pejibaye (Bactris gasipaes H.B.K., palmae)

Abstract

The pejibaye, an Amazonian palm widely used for food, is starting to be genetically improved. Twenty-eight open pollinated plants were randomly sampled from a spineless stemmed sub-population from Yurimaguas, Peru, and their progeny were evaluated in a randomized block design with 4 repetitions. The character ''petiole/rachis spines'' showed high heredibilities, both narrow sense (0.36) and wide sense (0.77), while the characters ''leaflet edge spines'' showed medium (0.26 and 0.60, respectively) and ''leaflet nerve spines'' showed low (0.14 and 0.41, respectively) heredabilities. The magnitudes of the additive genetic variances were low, as were the genetic coefficients of variations and Vencovsky's ''b'' index (ratio of genetic C.V. to environmental C.V.). Statistically significant phenotypic correlations were observed between ''petiole spines'' and ''leaflet edge spines'' (r = 0.82) and between ''leaflet nerve spines'' and ''edge spines'' (r = 0.58) in the progenies, but not in the parent plants, suggesting the existence of endogenous factors that modify the expression of these characters during their development, which was confirmed for ''petiole/rachis spines'' in the field.