Identification of a major QTL for flag leaf glaucousness using a high-density SNP marker genetic map in hexaploid wheat

Cuticular wax plays an important role in protecting land plant against biotic and abiotic stresses. Cuticular wax production on plant surface is often visualized by a characteristic glaucous appearance. This study identified quantitative trait loci （QTLs） for wheat （Triticum aestivum L.） flag leaf glaucousness （FLG） using a high-density genetic linkage map developed from a recombinant inbred line （RIL） population derived from the cross HeynexLakin by single-seed descent. The map consisted of 2 068 single nucleotide polymorphism （SNP） markers and 157 simple sequence repeat （SSR） markers on all 21 wheat chromosomes and covered a genetic distance of 2 381.19 cM, with an average marker interval of 1.07 cM. Two additive QTLs for FLG were identified on chromosomes 3AL and 2DS with the increasing FLG allele contributed from Lakin. The major QTL on 3AL, QFIg.hwwgr-3AL, explained 17.5-37.8% of the phenotypic variation in different environments. QFIg.hwwgr-3AL was located in a 4.4-cM interval on chromosome 3AL that was flanked by two markers IWA1831 and IWA8374. Another QTL for FLG on 2DS, designated as QFIg.hwwgr-2DS which was identified only in Yangling in 2014 （YL14）, was flanked by IWA1939 and Xgwm261 and accounted for 11.3% of the phenotypic variation for FLG. QFIg.hww- gr-3AL and QFIg.hwwgr-2DS showed Additive×Environment （AE） interactions, explaining 3.5 and 4.4% of the phenotypic variance, respectively. Our results indicated that different genes/QTLs may contribute different scores of FLG in a cultivar and that the environment may play a role in FLG.

Phenotypic Variation within a Jordanian Landrace of Durum Wheat ＂Safra Ma＇an＂ （Triticum turgidum L, var, Durum）

Two hundred and eighty six lines were selected randomly from the tetraploid wheat （Tritieum turgidum L.var Durum） landrace ＂Safra Ma＇an＂. The whole population with three check cultivars （ACSAD 65, HOURANI 27 and AMRA） was evaluated at Maru Agriculture Research Station for 16 characters including grain yield per plant. The objectives were to assess the magnitude of phenotypic variations for the traits in ＂Safra Ma＇an＂ and to evaluate the potential usefulness of some of the traits identified. Results showed wide range of phenotypic variation for several traits. Monomorphism was common for juvenile growth habit, whereas, the rest of the characters exhibited polymorphism in varying degrees. Considering all characters, the average diversity （H＇） for ＂Safra Ma＇an＂ landrace was 0.65 ± 0.047. Ten lines were superior to the check （HOURANI 27） for grain yield per plant. Subsequently, the population lines were clustered into six distinct groups at a distance of about 0.55 based on their similarity for all traits, ACSAD 65 and AMRA located in separate clusters, whereas, HOURANI 27 cultivar was presented in cluster with the most lines of ＂Safra Ma＇an＂. Thirteen lines from the population showed a bluish green cast or glaucousness characters. Glaucous lines had greater kernels per spike. In contrast, this character showed no significant association with grain yield per plant despite the greater grain yield per plant obtained for the glaucous lines. The results are important for the breeding and selection in this land race.