The University of Florida (UF) strawberry breeding programme is employing DNA-based technology alongside traditional plant breeding to speed up the development of new and improved varieties.
By combining the methods of traditional plant breeding with of genomic-assisted breeding, Vance Whitaker and his team have been able to double the number of seedlings for first stage evaluation, enabling the team to focus on selections that express improved flavour, fruit quality and disease resistance without jeopardising early yield.
“Developing new and improved strawberry cultivars remains an ongoing challenge. With genomic-assisted breeding, the UF programme is well positioned to address the key attributes of flavour, yield and disease resistance,” explains Roy Ekland, president of soft fruit specialist Ekland Marketing.
“We must not forget, however, that we are dealing with a genetically complex living organism. Many factors influence the expression of flavour, aromatics and yield. Temperatures and plant nutrition vary from region to region and throughout the season.
“The concentration of sugars in the fruit changes according to luminosity and the time it takes for the fruit to mature. Moreover, consumer taste and what is perceived as desirable fruit colour and flavour vary from one culture and region to another.”
Indeed, achieving the perfect balance of acidity and sweetness is an elusive goal and there are many factors that need to be considered. Whitaker notes that while Brix can be a useful metric in breeding and commercial settings, consumers’ preferences actually reflect a much broader range of flavour components.
The University of Florida breeding programme has conducted its own pioneering research on the subject. Over the last six years, Whitaker and his team have determined important variables in their evaluation of flavour and aroma in their advanced selections.
It has concluded that it is important to use trained taste panels and consumer sensory panels over several harvest dates in order to validate claims about taste. The data collected from these panels has enabled the team to link specific chemical compounds to the expression of flavour and aromatic elements of the strawberry fruit.
Although the use of Brix levels to determine sweetness is still very common, the method is quite limited when comparing the sugar-acid ratios and the aromatic components of strawberry fruit across varieties. “The use of better technology and instruments will aid marketers and fruit buyers making comparisons between varieties. Plant breeding is a complicated process, and we can never presume that the challenge is resolved,” Ekland continues.
The company has licensed a great number of very skilled growers around the world who have the ability to produce top quality strawberries from its variety portfolio. It communicates the needs of growers and fruit marketers back to the breeding team who uses this information to develop cultivars that produce high quality fruit that meet the demands of the international strawberry industry.
Ultimately, the greatest challenge is to unravel the complexity of aromatics and taste that appeal to a wide consumer base while preserving the other qualities of yield, shelf-life, appearance and disease resistance, Ekland concludes.