The wild ancestor of cultivated barley, Hordeum vulgare subsp. spontaneum (K. Koch) A. & Gr. (H. spontaneum), is a source of wide genetic diversity, including traits that are important for malting quality. A high ␤-amylase trait was previously identified in H. spontaneum strains from Israel, and transferred into the backcross progeny of a cross with the domesticated barley cv Adorra. We have used Southern-blot analysis and ␤-amy1 gene characterization to demonstrate that the high ␤-amylase trait in the backcross line is co-inherited with the ␤-amy1 gene from the H. spontaneum parent. We have analyzed the ␤-amy1 gene organization in various domesticated and wild-type barley strains and identified three distinct ␤-amy1 alleles. Two of these ␤-amy1 alleles were present in modern barley, one of which was specifically found in good malting barley cultivars. The third allele, linked with high grain ␤-amylase activity, was found only in a H. spontaneum strain from the Judean foothills in Israel. The sequences of three isolated ␤-amy1 alleles are compared. The involvement of specific intron III sequences, in particular a 126-bp palindromic insertion, in the allele-dependent expression of ␤-amylase activity in barley grain is proposed.

The hypothesis of the association between an increase in cytokinin activity and restoration of anther fertility in mmi cytoplasm was tested. The following barley lines with Hordeum vulgare cv. Adorra nuclear gene background were studied: Adorra cytoplasm without nuclear restorer gene (fertile), Adorra cytoplasm homozygous for nuclear Rfmla gene (fertile), msml cytoplasm without restorer gene (male sterile), miml cytoplasm homozygous for nuclear Rfmia gene (fertile). Ethanolic extracts of root exudate were fractionated and bioassayed for cytokinins. Both the biological activity and the total quantity of cytokinins appeared lowest in the unrestored male sterile line. The total biological activities ofcytokinins in the three fertile lines were similar, but the quantities in the restorer gene carriers appeared lower. On the other hand, the restorer gene carriers, independent of the cytoplasm, showed 8-9 times more of a bound cytokinin. Because the bound form is evidently underestimated by the bioassay, the increase in the bound cytokinin fraction may mean even a higher total content in the Rfmla gene carriers than in Adorra without the gene. The bound cytokinin may be translocated more readily to distal organs (e.g., the anthers) compared with unbound cytokinins. Because cytokinins are associated with various ecophysiological processes, the rise in a particular form may explain the heterogeneous distribution ofthe restorer gene in wild barley populations in different regions of Israel.The msml and msm2 maternal male sterilities in barley were derived from two strains of the wild progenitor of barley originating from Israel (1, 2). The original strain carrying msml is homozygous for a dominant restorer gene designated as Rfmla (3). This msml-Rfmla system with the genetic background of a domesticated barley cultivar is considered in this article.Some genotypes of wild (4) and domesticated barley (5) are capable of partial restoration of male fertility. In partially restored msml plants, fertile anthers appear at the lowest florets ofthe spikes (5), which probably means that the agent for partial fertility is an acropetally translocated substance or substances. In previous studies (6, 7) a number of physiological features of unrestored male sterile plants could be explained as responses to decreased cytokinin level. Such features were increased chlorophyll a/b ratio, decreased carotenoid content, increased xanthophyll/,B carotene ratio, higher susceptibility to induced leaf senescence, anther protein instability, low amino nitrogen pool in the anthers, and increased rate of germinal root elongation of the seedlings. Respectively, the restored plants had features indicating normal or increased levels of cytokinins. Based on these observations, the hypothesis was proposed (i) that the carrier of the restorer gene has either a higher total cytokinin content or else greater amounts of one or more cytokinin types than has the noncarrier; (ii) because the Rfmia gene is dominant, it was probable that this gene would ...

Six enzyme activites, a-amylase, p-amylase, p-glucanase, pullulanase, proteinase and chKinase were determined in the extracts of five-day germinated samples of 175 strains of the wild barley, Hordeum vulgare ssp. spontaneum. The variations and means calculated on grain mass and soluble protein was compared with samples from cv. Bomi included in the determination sets. The activity variations of all the enzymes were found to be wide in the wild barleys, and the mean activity was usually significantly different (higher) in wild barley than in cv. Bomi. The two enzyme activities, typically quite high in wild barley, are p-amylase and p-glucanase. a-Amylase showed a wide range of activity variation starting almost from a zero activity in some strains. The corresponding enzyme inhibitor activities were not determined, but they are assumed also to vary and interfere with some of the enzyme activities. Because of the simple inheritance of the enzyme genes, recombination of a desired enzyme gene into malting barley genetic backgrounds is expected to be feasible by conventional crossing and selection.

A method is described for transfection (genetic transformation) of barley caryopsis electrophoretically with DNA. β-Glucuronidase activity was detected after the electrophoretic transfection with plasmid pBI221 DNA carrying the cauliflower mosaic virus promotor and bacterial β-glucuronidase coding sequence. Electrophoretic transfection is evidently effective with pieces of callus and seeds of many plants.

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