Narrative
Alleles at the int-c (vrs5) locus alter the size of lateral spikelets. The lemma apex of lateral kernels is rounded or weakly pointed, awnless or short-awned. Lower lateral spikelets may develop poorly in some int-c mutants, while seed development may occur in all lateral spikelets of others. Variability in lateral spikelet development among the int-c mutants is responsive, also, to environmental conditions. The Int-c.a (formally l) allele in six-rowed barley increases the size of lateral spikelets, while the int-c.b (formally i) allele in two-rowed barley prevents anther development in lateral spikelets. The int-c.5 mutant n Bonus produces fertile stamens in lateral spikelets. in the presence of the Int-c.h (formally lh) allele of Mortoni, lateral spikelets are male fertile and may occasionally set seed. Spikes of vrs5.n plants appear similar to the six-rowed spike, but lateral spikelets are smaller (less than half the size of the central spikelets) and broader. Inheritance: Monofactorial recessive. Located in chromosome 4HS, about 13.1 cM proximal from the fch9 (chlorina seedling 9) locus, and about 14.5 cM distal from the Kap (hooded lemma) locus. Previous nomenclature and gene symbolization: Intensifier for Z=W. Infertile intermedium=i. Allelic series lh, l, i. Intermedium spike-c=int-c. Six-rowed spike 5=v5. Mutational events: int-c.b in two-rowed barley; Int-c.h (lh) in Mortoni (Ciho 2210, B6-12); vrs5.n (v5) in Gamma4(38X-197, OUM338); int-c.5 in Bonus (PI 189763); int-c.7, -c.62, 0c.63 in Bonus, -c.13, -c.15, -c.16, -c.18, -c.25, -c.29 in Foma (CIho 11333), -c.33, -c.38, -c.45, -c.48, -c.49, -c.53, -c.56, -c.60 in Kristina; int-c.70, -c.76, -c.78, -c.84 in Bonus, -c.95 in Hege. Mutant used for description and seed stocks: vrs5.n in Gamma 4 (GSHO 776); int-c.b in Hordeum distichon var niginudum (GSHO 988); int-c.5 in Bonus (GSHO 1765); ..(GSHO 2003). Ref.: Forster, B.P. 1993. Coordinator's report: Chromosome 4. BGN 22:75-77.