Genetic Analysis And Gene Mapping On An Barley Albino-lemma Mutant

Barley is one of the main materials for beer production, the cultivation of higher yield and better quality malting barley become more and more important. The grain yeild, grain quality and malt quality are related to the development of chloroplast in lemma. In this study, a barley albino-lemma mutant0601(AL0601) has been investigated in the phenotype, physiological characteristics, malt quality and genetic traits. Furthermore, the mutant gene was mapped preliminarily by using micro-satellite marker.1.The phenotypic characteristic of barley AL0601is observed, it is found that there are small yellow spots on the leaf of the mutant in seedling stage; After jointing, the auricle (auricale of flag leaf is voilet) and sheath base are white; During heading to maturation, the lemma assumes white, but the awn and spike-stalk are normal green2.The major agronomica traits between barley AL0601and Supi3are compared, we find that AL0601is similar with Supi3in such traits as ear number and grains per ear between wild type and mutant, but it has negative effects in plant height and heading date. AL0601’s growth duration is shortter, the accumulation of grain is inferior to Supi3, so the kernel plumpness and grain weight of AL0601are decreased, that lead to declining in yield.3.The chlorophyll content in flag leaves, second top leaves and lemma are tested and compared between the albino-lemma mutant and the wild type Supi3at the same growth stages after heading, supported by the comparing that mutant’s chlorophyll content in lemma is obviously lower than Supi3’s. Especially in fifth day after flowering, chlorophyll content in lemma of AL0601is only19.8%compared with that of Supi3. Moreover, the results show that there is no significant difference in the chlorophyll content of flag leaves and second top leaves between AL0601and Supi3at the same growth stages, and the variation trend is similar.4. Freshly harvested immature grains (5-25days after pollination; DAP) of albino-lemma mutant and wild type Supi3are used for Vanillin-HCl staining tests. Supported by the comparing that there is no difference in the synthesis of proanthocyanidins between AL0601and Supi3. The determination of proanthocyanidin content of mature grain shows that the AL0601’s proanthocyanidin content (1.15mg/g) is lower than Supi3’s (1.06mg/g), while the diffrence is not significant.5.By analysing the malt quality, it is showed that: AL0601’s malt extract is significantly lower than wild type’s, but the diastatic power, a-amino nitrogen and kolbach are significantly higher than Supi3’s.6.The albino-lemma mutant has been crossed with normal lemma plant Supi3, Yangnongpi5, Yan02173, Yan04014, DFAizhuang. Lemma of F1behaved normal, lemma F2appeared separation of lemma color (albino and green). The separation ratio of normal green lemma to albino lemma fitted the expected ratio of3:1(χ20.05=1.15<χ20.05=3.84). It is suggested that the albino-lemma trait of AL0601is controlled by one pair of recessive nuclear gene.7.The F2population of Yangnongpi5/AL0601is used as the mapping population. The genomic DNA of parent Yangnongpi5and AL0601are amplified with943pairs of microsatellite markers, which are well-distributed on7pairs of barley chromosomes. The two DNA pools of green lemma and albino lemma are amplified with the microsatellite primers with parental polymorphism, and the F2individuals are amplified with the primers that displaying polymorphism between the two pools. The MAPMAKER EXP3.0is used as linkage analysis and the part genetic linkage map of albino-lemma gene is constructed. The result shows that the albino-lemma gene is mapped on the barley chromosome3, and it is located between Bmag0508A and Bmac0871, with the genetic distance are0.2cM and0.7cM, and co-segregated with Bmac0067. The gene is temporarily named alm.