Mapping QTLs for developmental traits in raspberry from bud break to ripe fruit

Abstract

Protected cropping systems have been adopted by the UK industry to improve fruit quality and extend the current season. Further manipulation of season, alongside consideration of climate change scenarios, requires an understanding of the processes controlling fruit ripening. Ripening stages were scored from May to July across different years and environments from a raspberry mapping population. Here the interest was in identifying QTLs for the overall ripening process as well as for the time to reach each stage, and principal coordinate analysis was used to summarise the ripening process. Linear interpolation was also used to estimate the time (in days) taken for each plot to reach each of the stages assessed. QTLs were identified across four chromosomes for ripening and the time to reach each stage. A MADS-box gene, Gene H and several raspberry ESTs were associated with the QTLs and markers associated with plant height have also been identified, paving the way for marker assisted selection in Rubus idaeus.

Characterisation of Gene H in Red Raspberry: Explaining its Role in Cane Morphology, Disease Resistance and Timing of Fruit Ripening

“…Resistance to B. cinerea and D. applanata is highest in immature tissues and Williamson and Jennings [10] have postulated that the gene increases resistance by delaying cell maturity. An unexpected effect on the timing of fruit ripening by Gene H was subsequently demonstrated, which supports this hypothesis [9].…”

“…The Hh genotype of Gene H is also associated with a slowing down of ripening across all stages from open flowers to the green/red stage compared to the hh genotype [9]. It is interesting to speculate that the DIVIA like Myb transcription factor on BAC 11G23 could be controlling both trichomes and flowering time, as WEREWOLF, a regulator of root hair pattern has also been shown to be a posttranscriptional regulator of FT, a key floral regulator.…”

“…The mapping population, as described previously [1,9,13,14] used to identify the Gene H region, consists of a full sib family generated from a cross between the European red raspberry cv. Glen Moy (genotype Hh) and the North American red raspberry cv.…”

“…To confirm BAC locations, primers were designed to putative open reading frames from BAC sequences using Primer 3 (Table 2) and the corresponding regions amplified in Glen Moy, Latham and progeny DNA as described previously [9] to determine polymorphisms. Where size polymorphisms were observed, primers were end-labelled with FAM or HEX and PCRs performed on the mapping population and analysed on the ABI3730 DNA Analyser (Applied Biosystems) as described in Graham et al [13] using Genemapper v 3 (Applied Biosystems).…”

“…than non-hairy ones [2,3] but more susceptible to cane spot (Elsinoe veneta), powdery mildew (Sphaerotheca macularis) and yellow rust (Phragmidium rubi-idaei) [4][5][6][7][8]. Gene H was shown to be the most significant marker in a QTL on Linkage Group (LG) 2 that control cane pubescence (hairs) and disease resistances [1] and also delayed ripening [9].…”