Yaser Hasan, William Briggs, Claudia Matschegewski, Frank Ordon, Hartmut Stützel, Holger Zetzsche, Simon Groen, Ralf Uptmoo
Theoretical and Applied Genetics, July 2016; Volume 129, Issue 7, pp 1273–1288
Abstract
Key message
QTL regions on chromosomes C06 and C09 are involved in temperature dependent time to curd induction in cauliflower.
Abstract
Temperature is the main environmental factor influencing curding time of cauliflower (Brassica oleracea var. botrytis). Temperatures above 20–22 °C inhibit development towards curding even in many summer cultivars. To identify quantitative trait loci (QTL) controlling curding time and its related traits in a wide range of different temperature regimes from 12 to 27 °C, a doubled haploid (DH) mapping population segregating for curding time was developed and days to curd initiation (DCI), leaf appearance rate (LAR), and final leaf number (FLN) were measured. The population was genotyped with 176 single nucleotide polymorphism (SNP) markers. Composite interval mapping (CIM) revealed repeatedly detected QTL for DCI on C06 and C09. The estimated additive effect increased at high temperatures. Significant QTL × environment interactions (Q × E) for FLN and DCI on C06 and C09 suggest that these hotspot regions have major influences on temperature mediated curd induction. 25 % of the DH lines did not induce curds at temperatures higher than 22 °C. Applying a binary model revealed a QTL with LOD >15 on C06. Nearly all lines carrying the allele of the reliable early maturing parental line (PL) on that locus induced curds at high temperatures while only half of the DH lines carrying the allele of the unreliable PL reached the generative phase during the experiment. Large variation in LAR was observed. QTL for LAR were detected repeatedly in several environments on C01, C04 and C06. Negative correlations between LAR and DCI and QTL co-localizations on C04 and C06 suggest that LAR has also effects on development towards curd induction.
Communicated by I. Parkin.
See: http://link.springer.com/article/10.1007/s00122-016-2702-6/fulltext.html
Fig. 2
Linkage map and QTL for days to curd initiation (DCI, filled), leaf apperence rate (diagonal stripe), and final leaf number (FLN, unfilled). Arabic numbers at QTL boxes indicate the temperature treatments between 12 and 27 °C at which the QTL was detected. QTL detected repeatedly in the same region are assumed to be the same QTL. Across environment QTL carry the abbreviation of the trait and xE if QTL × environment interactions were significant. Boxes indicate positions of LOD peaks ±2 cM, whiskers the support intervals (LOD >1)
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