Division of Botany, Indian Agricultural Research Institute, Delhi-12
The inheritance of ear alignment and ear shattering was studied in a diallel cross of four parents, viz., Chevron (nodding and shattering ears), C. 138-2, N.P. 13 and Quinn (erect and non-shattering spikes). A seven parent diallel cross involving the deciduous-awned variety N.P. 13 and persistent-awned varieties, C. 138-2, C. 251, B.R. 22, Quinn, Chevron and Sandrel along with four other crosses, viz., K. 12 X N.P. 104, Putza X N.P. 104, E.B. 1341 X K. 12 and E.B. 1341 X N P. 104 were scored for awn deciduosness. F1 to F3 generations were available for study in the different crosses. The F1 showed dominance of non-shattering and awn-persistence over shattering and awn-deciduousness and partial dominance of erect spike over the nodding type.
Ear nodding and ear shattering of Chevron seem to be governed by a single pair of recessive genes, ne and se, respectively. Their allelomorphs were present in homozygous dominant condition in all the erect and non-shattering spiked parents, C. 138-2, C. 251 and Quinn.
N.P. 13 was assumed to possess two homozygous recessive factor pairs da da da2 da2 for its awn-deciduousness. The persistent-awned varieties, C. 251, C. 138-2, B.R. 22, Quinn and Sandrel carried dominant allelomorphs at these two loci in the homozygous condition. Chevron had one dominant factor for persistent awns, which was common to one of the two present in the C. 251 group. Putza and E.B. 1341 each carried a single recessive factor pair for awn deciduousness in their crosses with the persistent-awned varieties K. 12 and N.P. 104.
The genes conditioning ear alignment and ear shattering were inherited independently of each other and also did not show linkage with S s. One of the factors for awn deciduousness was found to show independent inheritance from Ne ne (ear alignment), Se se (ear shattering), S s (rachilla hairiness-7) and V v (type of ear-2).
