Pollen viability in natural populations of three North American diploid species of blueberry (Vaccinium, section Cyanococcus)

Number of plump seeds and fruit size are positively correlated with pollen stainability (PS) in blueberry. The objectives of this work were to (a) exa mine PS in 14 natural populations of three North American diploid blueberry species: Vaccinium elliottii, V. myrtilloides and V. tenellum; (b) determi ne the nature of the variability observed for PS; and (c) assess the relati onship between PS and the degree of genetic variability at the population l evel, as measured by segregating isozyme markers. Significant differences w ere found among species, between populations of V. tenellum, and within all the populations evaluated in two consecutive years. V. myrtilloides was th e most fertile species with higher pollen stainability than both, V. elliot tii and V. tenellum. Then was no significant variation for PS population me ans during the two years of evaluation; however, there was a significant ye ar x clones/population interaction in two V. myrtilloides populations. Comp onents of variance indicated that the variation for PS was mainly due to di fferences within populations (among individuals of the same population), an d between species. Clonal diversity was the only genetic variability parame ter (estimated by isozyme markers) that was positively correlated with PS a t the population level. Intraclass correlation estimates were high for most of the populations. This indicates that selection for PS is feasible in di ploid blueberry species. (C) 1999 Elsevier Science B.V. All rights reserved .