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  • Author or Editor: Tony K. McGhie x
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We determined variance components and narrow-sense heritability estimates for total and individual anthocyanin (ACY) content and antioxidant activity (AA) in fruit from 411 genotypes in a red raspberry (Rubus idaeus L.) factorial mating design based on 42 full-sib families derived from seven female and six male parents, harvested in 2002 and 2003. Within half-sib family total ACY content ranged from ≈1-60+ mg/100 g fruit in both seasons. The four major ACYs quantified by high-performance liquid chromatography also showed wide ranges each year. Female and male parent contributions to variation in total and individual ACYs were significant (P ≤ 0.001) in combined year analysis, and together accounted for 29% to 48% of the total variation. A substantial proportion of the female contribution was attributed to the use of a pigment-deficient R. parvifolius L. × R. idaeus hybrid derivative as a female parent. Female × male interaction was nonsignificant and contributed negligibly to total variance. Year effects accounted for <2.5% of variation in ACYs and were only marginally significant. Year interactions were negligible. Within family variation (among plots and within plot) accounted for ≈50% of the variation in total ACY and 62% to 69% of the variation in individual ACYs. Combined year narrow-sense heritability estimates were high (h 2 = 0.54-0.90 for individual ACYs, 1.00 for total ACY) among all factorial genotypes, but moderate when the progeny of the R. parvifolius derivative were excluded (h 2 = 0.45-0.78 for individual ACYs, 0.74 for total ACY). The latter estimates are applicable to breeding programs in which pigment-deficient genotypes are rarely or never used in breeding. Parental main effects were significant for AA, together accounting for 19% of total variance; female × male interaction was nonsignificant. Year effects were marginally significant and year interactions nonsignificant; together these sources of variation contributed <2% of total variation in AA. The majority of AA variation was found within- and among-plots within family. The phenotypic correlation between AA and total ACY was r = 0.53, and ranged from r = 0.21-0.46 between AA and individual ACYs; genetic correlations between AA and the ACYs were similar to the phenotypic correlations, suggesting predominantly additive genetic effects accounted for the phenotypic correlations. Linear modelling for AA based on individual ACYs and their interactions explained ≈0.53 of AA variation, substantially less than that explained by total phenolic content (R 2 = 0.88). Our results show substantial variation and moderate to high narrow-sense heritability estimates for red raspberry ACYs, but ACY content and profile information are ineffective proxies and predictors for AA in red raspberry fruit.

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Dietary anthocyanins (ACYs) may give health benefits through their antioxidant activity (AA) or other physiological effects. We examined AA and ACY profiles and contents in 16 blackberry and hybridberry (Rubus L. species) cultivars harvested in 2002 and 2003 in New Zealand and Oregon. Total ACY content varied widely among cultivars harvested from a single site in a single year (e.g., from 58 to 343 mg/100 g fruit Oregon in 2003). For the 12 cultivars common to both sites and years, cultivar and year within location significantly affected total ACY content, accounting for 40% and 10% of total variation, respectively. Cultivar interactions with both location and year within location were also significant, together accounting for 39% of variation. Cyanidin 3-O-glucoside and cyanidin 3-O-rutinoside were identified in all cultivars in both locations in at least 1 year. Compared with total ACY, cultivar accounted for more variation in these two ACYs (63% and 92%, respectively), while cultivar interactions together accounted for a smaller, but statistically significant, proportion of variation (23% and 7%, respectively). Cyanidin 3-O-sophoroside and cyanidin 3-O-(2G-glucosylrutinoside) were identified in only four cultivars. Cultivar effects accounted for 64% and 76% of variation in these ACYs, respectively, while cultivar interactions together contributed 18% and 24%, respectively. For AA, cultivar effects were not significant, contributing 11% of variation; in contrast, year effect and cultivar × environment interactions were significant, contributing 22% and 55% of total variation, respectively. Based on cultivar means for all 16 genotypes, the phenotypic correlation between AA and total ACY was positive but lower than that between AA and total phenolic content (TPH) (r = 0.63 and 0.97, respectively). Combinations of individual ACYs did not provide higher correlations with AA. Thus, ACY profiles and content are not as useful as TPH as a proxy measurement for AA.

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