Performance of an elite, hybrid family of a northern × southern highbush cross (‘Draper’ × ‘Jewel’)

Abstract

A family of the cross of the northern highbush blueberry ‘Draper’ × the southern highbush ‘Jewel’ (D × J) was propagated and phenotyped for plant size, yield, rate of flower, bud, and fruit development, leafing ability, winter hardiness, and fruit quality for 2 years in the field in Florida (FL), Georgia (GA), Michigan (MI), and Oregon (OR). In addition, a controlled greenhouse study was conducted on these progenies to estimate their chilling requirements. Significant levels of genotypic variability were observed for all the traits and the majority showed significant location and genotype × environmental interactions. Most of these traits were normally distributed across genotypes. There were many more flower buds per cane in GA than FL and OR, and many more vegetative buds broke in OR than in the southeastern states. Most of the various yield and growth traits were significantly correlated, except for flower buds per cane with plant height and width, and strength of leafing with plant width and flower buds/cane. Plants in OR developed much more slowly than those in FL and GA. There was a significant G × E effect on days to early green tip, floral bud break, and full bloom. Significant correlations were observed between all the developmental rates except between floral bud break and the days to full flowering and first blue fruit. Most individuals were severely damaged by winter cold in MI, although a few showed good tolerance. Significant location effects were observed for pH, titratable acidity (TA), soluble solids (SS), and SS/TA. Fruit in FL were a little softer and had higher SS/TA ratios than those in GA. There were significant interactions between genotype and environment for all the fruit quality traits except for fruit scar, firmness, anthocyanin content (ACY), and % juice. Fruit scar had a significant positive relationship with firmness and a significant negative relationship with flavor. Fruit color was significantly associated positively with soluble solids and ACY. Firmer fruit had significantly lower levels of ACYs. Fruit pH showed significant positive correlations with TA, TA/SS, and % juice, and significant negative relationship with SS and ACY. TA was significantly associated negatively with TA/SS and positively with ACY and % juice. TA/SS and ACY were positively correlated significantly with % juice. Two or three individuals were identified at each location that had high yields, were very early or late ripening and had excellent overall fruit quality. There were significant levels of genotypic, environmental (chilling hours) and G × E interaction among vegetative and floral buds for numbers of buds per shoot, percentage that developed and their developmental rate. The chilling requirement of highbush blueberry appears to be regulated polygenically as the D × J family segregated normally. On average, genotypes did more poorly at 250 and 350 chilling hours than the other chilling treatments.