BGS 7, Naked caryopsis 1, nud1

Naked caryopsis = k (16).
Naked caryopsis = s (23).
Naked caryopsis = n (8, 11).
Hulless = h (12).

Monofactorial recessive (8, 16, 21).
Located in chromosome 7HL (4, 13, 14, 16, 22); near the centromere (4, 13); about 9.6 cM proximal from the lks2 (short awn 2) locus (17); about 10.5 cM proximal from the dsp1 (dense spike 1) locus (17, 18); in bin 7H-07 about 13.1 cM distal from RFLP marker MWG808 (2); co-segregating with AFLP markers KT3 and KT7 and SCAR marker sKT7 (9); about 0.06 cM distal from SCAR marker sTK3 and the same distance proximal from sTK9 (19); nud1.a is associated with SNP markers 1_1437 and 2_0685 (both at position 126.28 cM) in 7H bin 07 of the Bowman backcross-derived line BW638 (3); nud1.a is associated with SNP markers 2_0975 to 2_0485 (positions 93.97 to 121.90 cM) in 7H bins 06 to 07 of the Bowman backcross-derived line BW220 (3).

The lemma and palea do not adhere to the caryopsis and the grain will thresh free of the hull at maturity. The naked caryopsis trait is expressed in all environments (18). The naked lines fail to produce a cementing substance present in covered lines (6). The nud1.a mutant depressed the expression by 10 to 20% of other traits such as plant height, seed weight (1, 10) and altered malt quality parameters (10). The nud1.a gene is often associated with the dsp1.a (dense spike 1) gene in Japanese cultivars (18). The Bowman backcross-derived line for nud1.a, BW638, was more sensitive to environmental stress than Bowman. Plants were 15% shorter when grown at Dundee, Scotland, but almost equal to Bowman at other locations. The kernel weights of BW638 varied from 25% lower to almost equal, and grain yields ranged from 50 to 85% of those recorded for Bowman (5). Allele IV of the marker sKT7 near the nud1 locus was the only one found in naked barley cultivars (20). The geographic distribution of haplotypes with the allele IV suggests migration of naked types was toward eastern Asia (20).

In an unknown cultivar, but its origin was monophyletic probably in southwestern Iran (20), widespread in cultivated barley in Asia.

nud1.a (GSHO 115) in Himalaya (CIho 1312) (23); nud1.b (Mut 4129) in Haisa, nud1.c (Mut 3041/62) in Ackermann's Donaria (PI 161974) (15).

nud1.a (GSHO 115) in Himalaya, nud1.a from Sermo (CIho 7776) in Betzes (PI 129430)*7 (CIho 16559, GP 37), nud1.a from Sermo in Compana (CIho 5438)*7 (CIho 16185, GP 41), nud1.a from Sermo in Decap (CIho 3351)*7 (CIho 16563, GP 45) (7); nud1.a from Stamm (PI 194555) in Betzes*7 (CIho 16566, GP 48), nud1.a from Stamm in Compana*7 (CIho 16183, GP 50), nud1.a from Stamm*7 in Freja (CIho 7130)*7 (CIho 16568, GP 52) (7); nud1.a from a Chinese introduction in Bowman (PI 483237)*8 (GSHO 1847, BW638, NGB 20751); nud1.a with cur2.b (curly 2) from Choshiro-hen (UL006, GSHO 274) in Bowman*5 (GSHO 1991); nud1.a with cur2.b from Choshiro-hen in Bowman *6 (BW220, NGB 22047).

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T. Tsuchiya and T.E. Haus. 1971. Barley Genet. Newsl. 1:110.

J.D. Franckowiak and T. Konishi. 1997. Barley Genet. Newsl. 26:51-52.
J.D. Franckowiak. 2007. Barley Genet. Newsl. 37:195-196.
J.D. Franckowiak. 2014. Barley Genet. Newsl. 44:51-53.