Novel Genes from Wild Barley Hordeum spontaneum for Barley Improvement

摘要

Narrowing the genetic basis is the bottleneck for modern plant improvement. Genetic variation in wild barley Hodeum Spontaneum is much greater than that of either the cultivated or landrace H. vulgare gene pool. It represents a valuable but under-utilized gene pool for barley improvement as no biological isolation barriers exist between H. spontaneum and cultivated barley. Novel sources of new genes were identified from H. spontaneum for yield, quality, disease resistance and abiotic tolerance. Quantitative Trait Loci (QTL) were mapped to all barley chromosomes. A QTL on chromosome 4H from wild barley consistently increased the yield by 7.7% across 6 test environments. Wild barley H. spontaneum was demonstrated as a key genetic resource for drought and salinity tolerance. Two QTLs on chromosomes 2H and 5H increased the grain yield by 12% - 22% under drought conditions. Several QTL clusters were present on chromosomes 1H, 2H, 4H, 6H, and 7H from H. spontaneum for drought and salinity tolerance. Numerous candidate genes were identified to associate with tolerance to drought or salinity and some of the candidate genes co-located with the QTLs for drought tolerance. QTLs/genes for resistance to powdery mildew, leaf rust and scald were mapped to all chromosomes. Scald resistance was found in at least 5 chromosome locations (1HS, 3H, 6HS, 7HL, and 7HS) from H. spontaneum and simple molecular markers were developed to accelerate transferring these genes into cultivated barley. Novel P-amylase allele from H. spontaneum was used to improvement barley malting quality. Advanced backcross QTL provides an efficiency approach to transfer novel genes from H. spontaneum to cultivated barley.